全文获取类型
收费全文 | 131篇 |
免费 | 7篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2021年 | 7篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 10篇 |
2013年 | 7篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 9篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有138条查询结果,搜索用时 16 毫秒
31.
Over 3500 patients with recent onset inflammatory polyarthritis (IP) have been recruited by the Norfolk Arthritis Register
(NOAR) since 1990. Longitudinal data from this cohort have been used to examine the prevalence and predictors of remission,
functional disability, radiological outcome, cardiovascular mortality and co-morbidity and the development of non-Hodgkin's
lymphoma. Rheumatoid factor titre, high baseline C-reactive protein and high baseline HAQ score are all predictors of a poor
outcome. There is a strong association between possession of the shared epitope and the development of erosions. Patients
who satisfy the American College of Rheumatology criteria for rheumatoid arthritis (RA) have a worse prognosis than those
who do not. However, it appears that these patients are a poorly defined subset of all those with IP rather than having an
entirely separate disease entity. New statistical techniques offer exciting possibilities for using longitudinal datasets
such as NOAR to explore the long-term effects of treatment in IP and RA. 相似文献
32.
Setiawan AN Davis LS Darby JT Lokman PM Young G Blackberry MA Cannell BL Martin GB 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2006,145(3):357-362
Penguins show varying degrees of brood reduction behavior, from obligate brood reducers to brood maximizers, and we hypothesize that this is associated with differences in prolactin secretion. To address this hypothesis, we determined the breeding season prolactin profile of the yellow-eyed penguin (Megadyptes antipodes) for comparison with those of other penguin species found in the literature. We also measured sex steroid plasma concentrations to better characterize the reproductive cycle of the species. Plasma concentrations of prolactin increased from early in the season, reaching a peak during late incubation, and remained elevated up to the guard period. This general pattern was similar to that of other penguins for which we have corresponding data. However, we found that throughout the laying period, prolactin titers in yellow-eyed penguins remained elevated while they fell to basal levels after the laying of the first egg in macaroni penguins, which corresponds to differences in incubation behavior during this time. We conclude, therefore, that differences in the brood reduction behavior in penguins, may be reflected in the pattern of PRL concentrations around the time of egg laying. 相似文献
33.
D H Rohr P M Lokman P S Davie G Young 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2001,130(4):701-714
The developmental transition from a residential, immature 'yellow' eel to a migratory, maturing adult 'silver' eel is accompanied by many morphological changes that appear to be under endocrine control. High circulating levels of the teleost, and usually male-specific, androgen 11-ketotestosterone (11-KT) are found in migrating female short-finned eels, Anguilla australis. We examined the role of this steroid in silvering by implanting immature, female short-finned eels either with blank vehicles or with vehicles containing 11-KT. Six weeks after they had received the implants, eels treated with 11-KT had developed 'chisel-shaped' snouts and black pectoral fins with tapered ends, and the size of their eyes had increased significantly. 11-KT treated eels had a thicker dermis than control eels and an epidermis with fewer or no mucous cells. Ventricular mass at the end of the experiment was two-fold larger than in control eels. 11-KT treated eels also had larger livers and gonads. Ovaries contained predominantly cortical alveolus stage III oocytes, as opposed to the smaller gonads of control eels containing previtellogenic stage II oocytes. All of these changes correspond to changes during the developmental transition from yellow to silver eels in the wild. This demonstrates that silvering in eels is under endocrine control and that the presumed male-specific steroid 11-KT is capable of inducing silvering-related changes in a female teleost. We discuss how species-specific responses to 11-KT may differ depending on tissue-specific androgen receptor abundance and how a dual demand on liver function can explain the apparently positive effects of 11-KT on liver growth. 相似文献
34.
Phylogeny of the Drosophila saltans species group based on combined analysis of nuclear and mitochondrial DNA sequences 总被引:2,自引:0,他引:2
Nucleotide sequences from two nuclear loci, alcohol dehydrogenase and
internal transcribed spacer-1 of the nuclear ribosomal DNA repeats, and two
mitochondrial genes, cytochrome oxidase I and cytochrome oxidase II, were
determined from nine species in the Drosophila saltans species group. The
partition homogeneity test and partitioned Bremer support were used to
measure incongruence between phylogenetic hypotheses generated from
individual partitions. Individual loci were generally congruent with each
other and consistent with the previously proposed morphological hypothesis,
although they differed in level of resolution. Since extreme conflict
between partitions did not exist, the data were combined and analyzed
simultaneously. The total evidence method gave a more resolved and highly
supported phylogeny, as indicated by bootstrap proportions and decay
indices, than did any of the individual analyses. The cordata and elliptica
subgroups, considered to have diverged early in the history of the D.
saltans group, were sister taxa to the remainder of the saltans group. The
sturtevanti subgroup, represented by D. milleri and D. sturtevanti,
occupies an intermediate position in this phylogeny. The saltans and
parasaltans subgroups are sister clades and occupy the most recently
derived portion of the phylogeny. As with previous morphological studies,
phylogenetic relationships within the saltans subgroup were not
satisfactorily resolved by the molecular data.
相似文献
35.
Alaa Fehaid Mohammad S. Al-Ghamdi Khalid J. Alzahrani Abdulrahman Theyab Osama M. Al-Amer Saad S. Al-Shehri Mohammad Algahtani Atif Abdulwahab A. Oyouni Mrim M. Alnfiai Mohamed H. Aly Khalaf F. Alsharif Ashraf Albrakati Rami B. Kassab Hussam A. Althagafi Fahad Alharthi Ahmed E. Abdel Moneim Maha S. Lokman 《Journal of biochemical and molecular toxicology》2023,37(3):e23275
Exposure to lead (Pb) is associated with serious health problems including hepatorenal toxicity. Apigenin is a natural-sourced flavonoid with promising antioxidant and anti-inflammatory effects. In this research, we investigated the potential protective role of apigenin against lead acetate (PbAc)-induced hepatorenal damage. Thus, this experiment studied the exposure of male Wistar Albino rats to apigenin and/or PbAc and their effects in comparison to the control rats. Apigenin administration decreased the levels of Pb and prevented the histopathological deformations in liver and kidney tissues following PbAc exposure. This was confirmed by the normalized levels of liver and kidney function markers. Additionally, apigenin inhibited significantly oxidative reactions through upregulating Nrf2 and HO-1, and activating their downstreamed antioxidants accompanied by a marked depletion of pro-oxidants. Moreover, apigenin decreased the elevated pro-inflammatory cytokines and inhibited cell loss in liver and kidney tissues in response to PbAc intoxication in both tissues. The obtained results demonstrated that apigenin could be used to attenuate the molecular, biochemical, and histological alterations associated with Pb exposure due to its potent antioxidant, anti-inflammatory, and antiapoptotic effects. 相似文献
36.
Clunes MT Lindsay SL Roussa E Quinton PM Bovell DL 《Journal of molecular histology》2004,35(4):339-345
The localisation of the vacuolar proton pump (V-H+ -ATPase) and the enzyme carbonic anhydrase II (CAII) was investigated in the human eccrine sweat gland employing standard immunohistochemical techniques after antigen retrieval using microwave heat treatment and high pressure. The high-pressure antigen retrieval unmasked the presence of V-H+ -ATPase in the clear cells of the secretory coil, with a distribution similar to that previously observed for CAII. However, the dark cells were unreactive to both antibodies. In addition, heat and high-pressure antigen retrieval demonstrated the presence of CAII in the apical zone of luminal cells of the reabsorptive duct, a location not previously reported. The localisation of V-H+ -ATPase and CAII in the secretory coil clear cells suggests that the formation of HCO3- and H+ by carbonic anhydrase II and the transport of H+ by V-H+ -ATPase may play an role in sweat fluid secretion. Their presence at the apex of the duct cells indicates involvement in ductal ion reabsorption. 相似文献
37.
38.
39.
Angelique C. W. Franken Ernst R. Werner Hubertus Haas B. Christien Lokman Cees A. M. J. J. van den Hondel Arthur F. J. Ram Sandra de Weert Peter J. Punt 《Applied microbiology and biotechnology》2013,97(22):9773-9785
Heme is a suggested limiting factor in peroxidase production by Aspergillus spp., which are well-known suitable hosts for heterologous protein production. In this study, the role of genes coding for coproporphyrinogen III oxidase (hemF) and ferrochelatase (hemH) was analyzed by means of deletion and overexpression to obtain more insight in fungal heme biosynthesis and regulation. These enzymes represent steps in the heme biosynthetic pathway downstream of the siroheme branch and are suggested to play a role in regulation of the pathway. Based on genome mining, both enzymes deviate in cellular localization and protein domain structure from their Saccharomyces cerevisiae counterparts. The lethal phenotype of deletion of hemF or hemH could be remediated by heme supplementation confirming that Aspergillus niger is capable of hemin uptake. Nevertheless, both gene deletion mutants showed an extremely impaired growth even with hemin supplementation which could be slightly improved by media modifications and the use of hemoglobin as heme source. The hyphae of the mutant strains displayed pinkish coloration and red autofluorescence under UV indicative of cellular porphyrin accumulation. HPLC analysis confirmed accumulation of specific porphyrins, thereby confirming the function of the two proteins in heme biosynthesis. Overexpression of hemH, but not hemF or the aminolevulinic acid synthase encoding hemA, modestly increased the cellular heme content, which was apparently insufficient to increase activity of endogenous peroxidase and cytochrome P450 enzyme activities. Overexpression of all three genes increased the cellular accumulation of porphyrin intermediates suggesting regulatory mechanisms operating in the final steps of the fungal heme biosynthesis pathway. 相似文献
40.