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41.
Feedstuffs used for poultry nutrition in Argentina were analyzed for fungal flora and natural incidence of mycotoxins. Survey of 120 samples of poultry feeds, taken from May 1998 to April 1999, showed the presence of 15 genera of filamentous fungi. The predominant genera wereFusarium spp. andPenicillium ssp., isolated in 67.5 % of the samples, followed byAspergillus spp. (57.5 %). Yeast, were significantly isolated from most of the samples. Species identification was carried down for the toxigenic genera. Fungal total counts of poultry feeds ranged from 2.0 × 103 to 3.0 × 105 CFU g-1 The fungal total counts during two months of sampling, were slightly over the limit value of 1 × 105 CFU g-1, which ensure the hygienic quality of the feed. Potentially toxicogenic species presented moderate mean colony counts. Many of the fungi isolated from poultry feeds are mycotoxin producers. Fumonisins had the highest incidence, and were found in 97 % of the analyzed samples followed by aflatoxin B1 (46 %), zearalenone (18 %) and deoxynivalenol (6 %). On the co-occurrence of both carcinogenic mycotoxins, all of the FBs contaminated feed samples were co-contaminated with AFB1. The results show the relevance of the samples screening for viable fungi propagules and the surveillance of their associated mycotoxins in poultry feeds.  相似文献   
42.
Reduced thymocyte development in sonic hedgehog knockout embryos   总被引:1,自引:0,他引:1  
The Hedgehog family of secreted intercellular signaling molecules are regulators of patterning and organogenesis during animal development. In this study we provide genetic evidence that Sonic Hedgehog (Shh) has a role in the control of murine T cell development. Analysis of Shh(-/-) mouse embryos revealed that Shh regulates fetal thymus cellularity and thymocyte differentiation. Shh is necessary for expansion of CD4(-)CD8(-) double-negative (DN) thymocytes and for efficient transition from the earliest CD44(+)CD25(-) DN population to the subsequent CD44(+)CD25(+) DN population and from DN to CD4(+)CD8(+) double-positive cells.  相似文献   
43.
We evaluated the impact of non-native rainbow trout Oncorhynchus mykiss on a population of endemic Cedarberg ghost frog Heleophryne depressa in the upper Krom River (Olifants-Doring River Catchment, Cape Fold Ecoregion). We compared H. depressa abundance (using kick-sampling and underwater video analysis) and environmental conditions between sites above and below a waterfall that marks the upper distribution limit of O. mykiss. Heleophryne depressa abundance was significantly greater above the waterfall than that below it, and, because there was no significant difference in measured environmental variables, O. mykiss presence is identified as the most likely explanation for the observed decrease in H. depressa abundance.  相似文献   
44.
Conclusion We should now be able to come to some general conclusions about the main lines of Cuvier's development as a naturalist after his departure from Normandy. We have seen that Cuvier arrived in Paris aware of the importance of physiology in classification, yet without a fully worked out idea of how such an approach could organize a whole natural order. He was freshly receptive to the ideas of the new physiology developed by Xavier Bichat.Cuvier arrived in a Paris also torn by many overlapping debates on the nature of classification, and in particular that between the natural and artificial systems. The very validity of the enterprise of classification was questioned in many quarters. Cuvier's achievement on his entry into the Parisian world of science was not simply to establish himself as a highly competent anatomist: far more important, he also began to use ideas from many different specialties to change completely the notion of what was involved in natural history.124 At the same time that he himself swung away from the guiding image of the field naturalist as the ideal of the specialty, he took ideas from the new physiology to answer questions about the order of the animal world, and from comparative anatomy to resurrect extinct creation — and to come to conclusions from that creation about the history of the forms of life and the manner of their succession. He showed himself able to alter the relationships between natural history and many other fields of study in a way that implied, rightly or wrongly, his own complete mastery over such a movement. Partly he was able to do this because the ideas he borrowed were not themselves logically articulated and thus could be easily adapted and refocused for many different specific purposes. The value of the heuristic possibilities inherent in the idea of life, for example, far outweighed its inability to generate full systems of classification. Cuvier also consistently refused to consider in science matters relating to the first causes of events. Freed from the consideration of first-order phenomena, he was able to use second-order explanations across a far wider field of applicability. Personal doubts about the validity of a theology that had used science in order to bolster its own claims were combined here with the strong influence of the Kantian critique of the limits of human reason.125 Cuvier's characteristic mode of procedure was that of intellectual appropriation and a bold capacity for altering the relationships between different fields of knowledge, rather than, with the exception of taxonomy, the technique of expanding their subject matter. His claims to originality came, first, from this reappropriation and reorientation and, second, from the sheer scope of his work, which aimed at nothing less than the cataloging and classification of all animate objects.126 They rested also on his acute use of his assertion of a certain relationship with the past of his subject. Very often he would present this history in such a way as to obscure his own intellectual genealogy, and often too he would give differing accounts of the priority of use of an idea in order to distract attention from the questionable exactitude of his own claims to originality. Cuvier came to Paris at precisely the time when society and institutions were most profitably malleable for a newcomer; it was also a time when many scientific disciplines had reached a stage advanced in terms of their factual content, yet relatively inadequate in conceptual organization. They were ripe for takeover by large-scale organizing ideas such as the animal economy and the subordination of characteristics. Paleontology is a particularly good example of a specialty in this particular form of underdevelopment in 1795.Cuvier paid a high price for his initial success. His electic applications of large-scale organizing ideas tended to mean that little of his own work had complete coherence at all levels. Ideas, as we have seen, that proved capable of providing a complete reform of the larger groups of the animal kingdom were incapable of producing its detailed working-out in the taxonomy of smaller groups, which had to be supplied from observed analogical correlations. Further, his physiological approach to classification involved the breakdown of strict correspondence between organs and functions, which left the way open for workers such as Geoffroy St. Hilaire gradually to tilt the balance away from the study of the correlations of hierarchies of functions, and toward morphology as the basis of the order of nature. Cuvier's brilliant appropriations from physiology from the beginning, therefore, contained the seeds of conflict with Geoffroy.Cuvier's eclectic approach made it very nearly impossible for him to present a clear idea of the ways in which the life sciences could be said to be lawful. In spite of his efforts to assimilate them to the position of the physical sciences in this respect, he was forced in the end to accord only an ambiguous status as laws to observational correlations. From this area of failure came much of the attempt to give his own two laws — the correlation of parts and the subordination of characteristics — predictive qualities, particularly in relation to paleontological research.It is not surprising that Cuvier's title as the legislator of natural history should represent more a claim than a reality. How, then, was he able to emerge as the leading French naturalist of his day? First of all must be adduced the sheer scale of his undertakings. Then comes his expertise as a practical anatomist, and the range of different topics toward which he turned his interest. His collaborators cannot be given credit for his output nor, as we have seen, for slavish adherence to his ideas. Cuvier was able to successfully claim to have dominated the underdeveloped specialties, such as paleontology, and turned them into a major heuristic input into both geology and comparative anatomy; but in other fields, such as physiology, he appropriated concepts and encouraged research but made little impact on the field himself. His attempts in 1812 to head off, or neutralize and absorb the growth of morphological studies landed him in a dangerously rigid position, which despite his encouragement of the new physiological research under the Restoration made further elaboration of his own conceptual underpinnings almost impossible.Cuvier's authority in the scientific world would in any case have been great because of his substantive achievement in taxonomy, but the rest of his work had enough ambiguities and dislocations for it to need the support of his political and social power. Cuvier's detractors seized on a vital fragment of the truth when they accused him of finding the political dimension all-important: it obscured the disjunctions in his theories and at the same time gave him the authority to make new claims for the status of the observational sciences - and for their relations of power with their surrounding specialties. Cuvier's science both thrived on and was halted by the power games of intellectual appropriation, manipulation of the past to confirm the present, and continual claims for hegemony.  相似文献   
45.
The Olifants River, a tributary of the Limpopo River system, is one of the most polluted rivers in South Africa. In May 2011 the concentrations of metals in fish muscle tissue from two impoundments, Loskop and Flag Boshielo dams, on the Olifants River were measured and a human health risk assessment conducted to investigate whether it was safe to consume Labeo rosae from these impoundments. Labeo rosae is one of the most common pan fish in these impoundments and is readily available to rural communities. Metals are accumulating in the muscle tissue of L. rosae even although the fish populations appear to be healthy. At Loskop Dam all L. rosae analysed exceeded the recommended hazard quotient (HQ) of 1 for antimony, and less than 50% exceeded that for lead. At Flag Boshielo Dam, the recommended HQ was exceeded for lead in less than 50% of L. rosae analysed, and more than 50% exceeded that for antimony. The weekly consumption of 150?g of L. rosae muscle tissue from these impoundments may pose an unacceptable health risk to rural communities.  相似文献   
46.

Correction to: EMBO Reports (2019) 20: e47074. DOI 10.15252/embr.201847074 | Published online 6 May 2019The authors noticed that the control and disease labels had been inverted in their data analysis resulting in publication of incorrect data in Figure 1C. The corrected figure is displayed below. This change affects the conclusions as detailed below. The authors apologize for this error and any confusion it may have caused.In the legend of 1C, change from, “Differential gene expression analysis of pediatric ileal CD patient samples (n = 180) shows increased (> 4‐fold) IMP1 expression as compared to non‐inflammatory bowel disease (IBD) pediatric samples (n = 43)”.Open in a separate windowFigure 1CCorrected Open in a separate windowFigure 1COriginal To, "Differential gene expression analysis of pediatric ileal CD patient samples (n = 180) shows decreased (> 4‐fold) IMP1 expression as compared to non‐inflammatory bowel disease (IBD) pediatric samples (n = 43)”.In abstract, change from, “Here, we report increased IMP1 expression in patients with Crohn''s disease and ulcerative colitis”.To, “Here, we report increased IMP1 expression in adult patients with Crohn''s disease and ulcerative colitis”.In results, change from, “Consistent with these findings, analysis of published the Pediatric RISK Stratification Study (RISK) cohort of RNA‐sequencing data 38 from pediatric patients with Crohn''s disease (CD) patients revealed that IMP1 is upregulated significantly compared to control patients and that this effect is specific to IMP1 (i.e., other distinct isoforms, IMP2 and IMP3, are not changed; Fig 1C)”.To, “Contrary to our findings in colon tissue from adults, analysis of published RNA‐sequencing data from the Pediatric RISK Stratification Study (RISK) cohort of ileal tissue from children with Crohn’s disease (CD) 38 revealed that IMP1 is downregulated significantly compared to control patients in the RISK cohort and that this effect is specific to IMP1 (i.e., other distinct isoforms, IMP2 and IMP3, are not changed; Fig 1C)”.In discussion, change from, “Indeed, we report that IMP1 is upregulated in patients with Crohn''s disease and ulcerative colitis and that mice with Imp1 loss exhibit enhanced repair following DSS‐mediated damage”.To “Indeed, we report that IMP1 is upregulated in adult patients with Crohn''s disease and ulcerative colitis and that mice with Imp1 loss exhibit enhanced repair following DSS‐mediated damage”.  相似文献   
47.

Background

Protein kinase C (PKC) serves as the receptor for tumor-promoting phorbol esters, which are potent activators of conventional (c) and novel (n) PKCs. We recently showed that these activators induced selective upregulation of PKCη in breast cancer cells. The objective of this study is to understand unique regulation of PKCη and its importance in breast cancer.

Methods

The levels of PKC isozymes were monitored in breast cancer cells following treatment with inhibitors of kinases, proteasome and proteases by Western blotting. PKCε was introduced by adenoviral delivery. PKCη and PDK1 were depleted by siRNA silencing. Cell growth was determined by the MTT or clonal assay.

Results

The general PKC inhibitors Gö 6983 and bisindolylmaleimide but not cPKC inhibitor Gö 6976 led to substantial PKCη downregulation, which was partly rescued by the introduction of nPKCε. Inhibition of phosphoinositide-dependent kinase-1 (PDK1) by Ly294002 or knockdown of PDK1 also led to downregulation of basal PKCη but had no effect on PKC activator-induced upregulation of PKCη. Proteasome inhibitors blocked PKCη downregulation triggered by PDK1 inhibition/depletion but not by Gö 6983. PKCη level increased in malignant but not in non-tumorigenic or pre-malignant cells in the progressive MCF-10A series associated with activated PDK1, and knockdown of PKCη inhibited breast cancer cell growth and clonogenic survival.

Conclusion

Upregulation of PKCη contributes to breast cancer cell growth and targeting either PKCε or PDK1 triggers PKCη downregulation but involves two distinct mechanisms.

General significance

The status of PKCη may serve as a potential biomarker for breast cancer malignancy.  相似文献   
48.
Diabetes mellitus is a heterogeneous metabolic disorder characterized by hyperglycaemia resulting in defective insulin secretion, resistance to insulin action or both. The use of biguanides, sulphonylurea and other drugs are valuable in the treatment of diabetes mellitus; their use, however, is restricted by their limited action, pharmaco-kinetic properties, secondary failure rates and side effects. Trigonella foenum-graecum, commonly known as fenugreek, is a plant that has been extensively used as a source of antidiabetic compounds from its seeds and leaf extracts. Preliminary human trials and animal experiments suggest possible hypoglycaemic and anti-hyperlipedemic properties of fenugreek seed powder taken orally. Our results show that the action of fenugreek in lowering blood glucose levels is almost comparable to the effect of insulin. Combination with trace metal showed that vanadium had additive effects and manganese had additive effects with insulin on in vitro system in control and diabetic animals of young and old ages using adipose tissue. The Trigonella and vanadium effects were studied in a number of tissues including liver, kidney, brain peripheral nerve, heart, red blood cells and skeletal muscle. Addition of Trigonella to vanadium significantly removed the toxicity of vanadium when used to reduce blood glucose levels. Administration of the various combinations of the antidiabetic compounds to diabetic animals was found to reverse most of the diabetic effects studied at physiological, biochemical, histochemical and molecular levels. Results of the key enzymes of metabolic pathways have been summarized together with glucose transporter, Glut-4 and insulin levels. Our findings illustrate and elucidate the antidiabetic/insulin mimetic effects of Trigonella, manganese and vanadium.  相似文献   
49.
Early acquisition of Pseudomonas aeruginosa is associated with a poorer prognosis in patients with cystic fibrosis. We investigated whether polymorphisms in CD14, the lipopolysaccharide receptor, increase the risk of early infection. Forty-five children with cystic fibrosis were investigated with annual bronchoalveolar lavage (BAL) and plasma sCD14 levels. Plasma sCD14 levels were significantly lower in children from whom P.aeruginosa was subsequently isolated (492.75 μg/ml vs. 1339.43 μg/ml, p = 0.018). Those with the CD14 -159CC genotype had a significantly increased risk of early infection with P.aeruginosa suggesting that CD14 C-159T plays a role in determining the risk of early infection with P.aeruginosa.  相似文献   
50.
The current study was conducted to investigate the effects of dietary zinc oxide (ZnO) on the antioxidant capacity, small intestine development, and jejunal gene expression in weaned piglets. Ninety-six 21-day-old piglets were randomly assigned to three dietary treatments. Each treatment had eight replicates with four piglets per replicate. The piglets were fed either control diet (control) or control diet supplemented with in-feed antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) or pharmacological doses of ZnO (3000 mg/kg). The experiment lasted 4 weeks. Blood samples were collected at days 14 and 28, while intestinal samples were harvested at day 28 of the experiment. Dietary high doses of ZnO supplementation significantly increased the body weight (BW) at day 14 and average daily gain (ADG) of days 1 to 14 in weaned piglets, when compared to control group (P < 0.05). The incidence of diarrhea of piglets fed ZnO-supplemented diets, at either days 1 to 14, days 14 to 28, or the overall experimental period, was significantly decreased in comparison with those in other groups (P < 0.05). Supplementation with ZnO increased the villus height of the duodenum and ileum in weaned piglets and decreased the crypt depth of the duodenum, when compared to the other groups (P < 0.05). Dietary ZnO supplementation decreased the malondialdehyde (MDA) concentration at either day 14 or day 28, but increased total superoxide dismutase (T-SOD) at day 14, when compared to that in the control (P < 0.05). ZnO supplementation upregulated the messenger RNA (mRNA) expression of zonula occludens-1 (ZO-1) and occludin in the jejunum mucosa of weaned piglets, compared to those in the control (P < 0.05). The pro-inflammatory cytokine interleukin-lβ (IL-1β) mRNA expression in the jejunum mucosa was downregulated in the ZnO-supplemented group, compared with the control (P < 0.05). Both in-feed antibiotics and ZnO supplementation decreased the mRNA expression of interferon-γ (IFN-γ), but increased the mRNA expression of transforming growth factor-β (TGF-β), in the jejunum mucosa of piglets, when compared to those in the control (P < 0.05). In summary, supplemental ZnO was effective on the prevention of post-weaning diarrhea (PWD) in weaned piglets and showed comparative growth-promoting effect on in-feed antibiotics, probably by the mechanism of improvement of the antioxidant capacity, restoration of intestinal barrier function and development, and modulation of immune functions.  相似文献   
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