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71.
72.
Sucheta Sharma Abhey Bansal Surjit K. Dhillon Karaj S. Dhillon 《Plant and Soil》2010,329(1-2):339-348
High levels of selenium can cause adverse effects in plants as well as animals. In a greenhouse experiment, rapeseed (Brassica napus) was grown in an alkaline sandy loam soil treated with different levels of selenate-Se and selenite-Se ranging from 0 to 4 mg kg?1. Total dry matter yield of selenium-treated rapeseed plants decreased significantly as compared to control plants. Plants were stressed at a very early stage of vegetative growth and produced fewer rosettes and flowers. Plant height and leaf production were negatively affected by selenate-Se. Dry matter of leaves was significantly higher in selenite- than in selenate-treated plants. Selenate-treated plants accumulated 75–160 times more Se in shoots and 2–18 times more in roots as compared to selenite-treated plants at the rosette formation stage, with this difference narrowing at peak flowering stage. Rapeseed leaves were subjected to biochemical analysis at rosette and peak flowering stages. Accumulation of selenium in leaves resulted in a significant increase in lipid peroxidation, chlorophyll, vitamin C and free amino acids, and a decrease in phenols, total soluble sugars and starch concentration. 相似文献
73.
Regional activities of phosphoinositide-specific phospholipase C (PLC) were measured after lateral fluid percussion (FP) brain injury in rats. The activity of PLC on phosphatidylinositol 4,5-bisphosphate (PIP2) in the rat cortex required calcium, and at 45 M concentration it increased PLC activity by about ten-fold. The activity of PLC was significantly increased in the cytosol fraction in the injured (left) cortex (IC) at 5 min, 30 min and 120 min after brain injury. However, in the same site, increases were observed in the membrane fraction only at 5 min after brain injury. In both the contralateral (right) cortex (CC) and ipsilateral hippocampus (IH), the activity of PLC was increased in the cytosol only at 5 min after brain injury. These results suggest that increased activity of PLC may contribute to increases in levels of cellular diacylglycerol and inositol trisphosphate in the IC (the greatest site of injury), and to a smaller extent in the IH and CC, after lateral FP brain injury. It is likely that this increased PLC activity is caused by alteration in either the levels or activities of one or more of its isozymes (PLC, PLC, and PLC) after FP brain injury. 相似文献
74.
Michael E. Konkel Jeffrey E. Christensen A. Singh Dhillon Alison B. Lane Rebekah Hare-Sanford Dennis M. Schaberg Charles L. Larson 《Applied microbiology》2007,73(7):2297-2305
Campylobacter jejuni isolates possess multiple adhesive proteins termed adhesins, which promote the organism's attachment to epithelial cells. Based on the proposal that one or more adhesins are shared among C. jejuni isolates, we hypothesized that C. jejuni strains would compete for intestinal and cecal colonization in broiler chicks. To test this hypothesis, we selected two C. jejuni strains with unique SmaI pulsed-field gel electrophoresis macrorestriction profiles and generated one nalidixic acid-resistant strain (the F38011 Nalr strain) and one streptomycin-resistant strain (the 02-833L Strr strain). In vitro binding assays revealed that the C. jejuni F38011 Nalr and 02-833L Strr strains adhered to LMH chicken hepatocellular carcinoma epithelial cells and that neither strain influenced the binding potential of the other strain at low inoculation doses. However, an increase in the dose of the C. jejuni 02-833L Strr strain relative to that of the C. jejuni F38011 Nalr strain competitively inhibited the binding of the C. jejuni F38011 Nalr strain to LMH cells in a dose-dependent fashion. Similarly, the C. jejuni 02-833L Strr strain was found to significantly reduce the efficiency of intestinal and cecal colonization by the C. jejuni F38011 Nalr strain in broiler chickens. Based on the number of bacteria recovered from the ceca, the maximum number of bacteria that can colonize the digestive tracts of chickens may be limited by host constraints. Collectively, these data support the hypothesis that C. jejuni strains compete for colonization in chicks and suggest that it may be possible to design novel intervention strategies for reducing the level at which C. jejuni colonizes the cecum. 相似文献
75.
A Raf-1 mutant that dissociates MEK/extracellular signal-regulated kinase activation from malignant transformation and differentiation but not proliferation
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Dhillon AS Meikle S Peyssonnaux C Grindlay J Kaiser C Steen H Shaw PE Mischak H Eychène A Kolch W 《Molecular and cellular biology》2003,23(6):1983-1993
It is widely thought that the biological outcomes of Raf-1 activation are solely attributable to the activation of the MEK/extracellular signal-regulated kinase (ERK) pathway. However, an increasing number of reports suggest that some Raf-1 functions are independent of this pathway. In this report we show that mutation of the amino-terminal 14-3-3 binding site of Raf-1 uncouples its ability to activate the MEK/ERK pathway from the induction of cell transformation and differentiation. In NIH 3T3 fibroblasts and COS-1 cells, mutation of serine 259 resulted in Raf-1 proteins which activated the MEK/ERK pathway as efficiently as v-Raf. However, in contrast to v-Raf, RafS259 mutants failed to transform. They induced morphological alterations and slightly accelerated proliferation in NIH 3T3 fibroblasts but were not tumorigenic in mice and behaved like wild-type Raf-1 in transformation assays measuring loss of contact inhibition or anchorage-independent growth. Curiously, the RafS259 mutants inhibited focus induction by an activated MEK allele, suggesting that they can hyperactivate negative-feedback pathways. In primary cultures of postmitotic chicken neuroretina cells, RafS259A was able to sustain proliferation to a level comparable to that sustained by the membrane-targeted transforming Raf-1 protein, RafCAAX. In contrast, RafS259A was only a poor inducer of neurite formation in PC12 cells in comparison to RafCAAX. Thus, RafS259 mutants genetically separate MEK/ERK activation from the ability of Raf-1 to induce transformation and differentiation. The results further suggest that RafS259 mutants inhibit signaling pathways required to promote these biological processes. 相似文献
76.
Prasad M. Renuka Lovell Mark A Yatin Mustafa Dhillon Harbhajan Markesbery William R. 《Neurochemical research》1998,23(1):81-88
Regional levels of membrane phospholipids [phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC)] were measured in the brain of Alzheimer's disease (AD) and control subjects. The levels of PE-derived and PI-derived total fatty acids were significantly decreased in the hippocampus of AD subjects. Here significant decreases were found in PE-derived stearic, oleic and arachidonic and docosahexaenoic acids, and in PI-derived oleic and arachidonic acids. In the inferior parietal lobule of AD subjects, significant decreases were found only in PE and those decreases were contributed by stearic, oleic and arachidonic acids. In the superior and middle temporal gyri and cerebellum of AD subjects, no significant decreases were found in PC-, PE- and PI-derived fatty acids. The decrease of PE and PI, which are rich in oxidizable arachidonic and docosahexaenoic acids, but not of PC, which contains lesser amounts of these fatty acids, suggests a role for oxidative stress in the increased degradation of brain phospholipids in AD. 相似文献
77.
Nonspecific light loss and intrinsic DNA variation problems associated with feulgen DNA cytophotometry. 总被引:1,自引:0,他引:1
J P Miksche S S Dhillon G P Berlyn K J Landauer 《The journal of histochemistry and cytochemistry》1979,27(10):1377-1379
Nonspecific light loss by the cell-wall-plus-cytoplasm (CWC) can cause a 50% increase in Feulgen absorption units in peanut root-tip nuclei as determined by scanning at 450 nm, whereas this phenomenon is not evident with chicken erythrocytes. A two wavelength scanning method of subtracting nonspecific 450 nm absorption from 550 nm Feulgen absorption values eliminated the nonspecific light loss in CWC, However, the two wavelength scanning method is time consuming and somewhat impractical with a regular scanning microdensitometer such as Vickers M85. Elimination of the problem of nonspecific light loss is suggested by careful determination of background setting with the spot position close to the nucleus in CWC. The accuracy of the CWC background setting method was further tested by comparison with subtraction method. The use of plant nucleis as an internal standard in plant DNA measurements was also evaluated. Significant variation among the replicate slides due to the variation in pine nuclear DNA amounts was observed and plant nuclei generally are not reliable internal standards. Mature chicken erythrocytes are recommended as an internal standard because the cell type and metabolic state is known. 相似文献
78.
Tarlochan S Dhillon Alice P.W Poon Dorothy Chan Alvin J Clark 《FEMS microbiology letters》1998,161(1):129-133
A smooth colony strain, resistant to phages λ and P22, was isolated from sewage and identified as Escherichia coli (strain H). Four temperate phages plaquing on strain H were isolated from sewage. The archetype, HK620, does not plaque on strains C and K12 of E. coli nor on the LT2 strain of Salmonella enterica. Bacterial mutants resistant to a clear plaque mutant of HK620 produce rough colonies. Some are also galactose-negative, a few are histidine auxotrophs, and most show sensitivity to λ. HK620 can transduce a wide variety of auxotrophic mutants of E. coli H to prototrophy. It can recombine with λ but its virions resemble those of P22. 相似文献
79.
Murine IL-10 gene transfer inhibits established collagen-induced arthritis and reduces adenovirus-mediated inflammatory responses in mouse liver 总被引:2,自引:0,他引:2
Quattrocchi E Dallman MJ Dhillon AP Quaglia A Bagnato G Feldmann M 《Journal of immunology (Baltimore, Md. : 1950)》2001,166(10):5970-5978
The effects of homologous IL-10 administration during an established autoimmune disease are controversial, given its reported immunostimulatory and immunosuppressive properties. Studies of collagen-induced arthritis have shown efficacy with repeated administrations of IL-10; however, when the EBV IL-10 homologue was administered via adenovirus gene transfer technology the results were equivocal. Therefore, the present study was undertaken to elucidate the effects of prolonged homologous IL-10 administration via adenovirus-mediated gene delivery on the progression of established arthritis. Collagen type II (CII)-immunized mice received i.v. injections of 10(7) or 10(8) PFU of an E1-deleted adenoviral vector containing the murine IL-10 gene (AdIL-10), after arthritis onset. Mice were monitored for 3 wk for disease progression, and gene transduction was assessed by quantification of serum mIL-10. CII-specific cell-mediated and humoral immune responses were analyzed by lymph node cell proliferation, cytokine production, and anti-CII Ab responses. Furthermore, because adenoviral vectors have been reported to induce organ dysfunction due to cell-mediated immune responses to the viral Ags, we have also evaluated delayed-type hypersensitivity responses and reactive hepatitis to the systemically delivered adenovirus and whether the IL-10 produced could influence those responses. Sustained suppression of autoimmune arthritis and elevated serum levels of IL-10 were achieved in our study. AdIL-10 treatment reduced cell-mediated immune reactivity, but did not affect humoral responses. Furthermore, IL-10 was able to reduce, but not totally abrogate, adenovirus-induced hepatic inflammation. These findings provide further insights into the diverse interplay of immune processes involved in autoimmune inflammation and the mechanism of cytokine immunotherapy. 相似文献
80.
cAMP-dependent protein kinase and lipolysis in rat adipocytes. I. Cell preparation, manipulation, and predictability in behavior 总被引:16,自引:0,他引:16
With the use of -cAMP/+cAMP activity ratios of cAMP-dependent protein kinase (A-kinase) in fat cell extracts as an index of cellular cAMP concentrations, it is apparent from both the current literature and from data presented in this paper that classical cell isolation procedures yield cells whose behavior is unpredictable from day to day. Herein, procedures are described for isolating adipocytes, preparing cytosolic extracts, and assaying A-kinase that result in kinase activity ratios in isolated cells equal to those in the fat pad from which cells are derived, approximately 0.05. An important modification in the procedure is the inclusion of 200 nM exogenous Ado in all cell manipulation media, and the data indicate that variable removal of contaminating endogenous Ado accounts for unpredictable results with standard cell isolation techniques. A further benefit of Ado inclusion is greatly reduced cell lysis. Acute removal of Ado with adenosine deaminase results in rapid elevation of A-kinase activity ratios and lipolysis which, in fasted animals, equals that achieved with lipolytic hormones. Cells from fed animals exhibit poor predictability in behavior. Moreover, A-kinase activity ratios exhibit seasonal tendencies in response to Ado removal, with cells isolated in spring being more activated than cells isolated later in the year. The information and procedures in this paper form the basis for succeeding papers on the regulation of adipocyte metabolism by hormones. 相似文献