全文获取类型
收费全文 | 3930篇 |
免费 | 318篇 |
出版年
2023年 | 33篇 |
2022年 | 78篇 |
2021年 | 160篇 |
2020年 | 82篇 |
2019年 | 104篇 |
2018年 | 119篇 |
2017年 | 103篇 |
2016年 | 143篇 |
2015年 | 251篇 |
2014年 | 271篇 |
2013年 | 280篇 |
2012年 | 454篇 |
2011年 | 367篇 |
2010年 | 213篇 |
2009年 | 187篇 |
2008年 | 262篇 |
2007年 | 243篇 |
2006年 | 170篇 |
2005年 | 163篇 |
2004年 | 117篇 |
2003年 | 113篇 |
2002年 | 94篇 |
2001年 | 24篇 |
2000年 | 14篇 |
1999年 | 28篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1980年 | 4篇 |
1979年 | 10篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1966年 | 2篇 |
1933年 | 2篇 |
排序方式: 共有4248条查询结果,搜索用时 31 毫秒
111.
Florian Pohlig Florian Guell Ulrich Lenze Florian W. Lenze Heinrich M. L. Mühlhofer Johannes Schauwecker Andreas Toepfer Philipp Mayer-Kuckuk Rüdiger von Eisenhart-Rothe Rainer Burgkart Gian M. Salzmann 《PloS one》2016,11(3)
Purpose
In patients with osteoarthritis (OA), intraarticular injection of hyaluronic acid (HA) frequently results in reduced pain and improved function for prolonged periods of time, i.e. more than 6 months. However, the mechanisms underlying these effects are not fully understood. Our underlying hypothesis is that HA modifies the enzymatic breakdown of joint tissues.Methods
To test this hypothesis, we examined osteochondral cylinders from 12 OA patients. In a bioreactor, these samples were stimulated by interleukin 1β (Il1ß) (2 ng/ml) plus mechanical load (2.0 Mpa at 0.5 Hz horizontal and 0.1 Hz vertical rotation), thus the experimental setup recapitulated both catabolic and anabolic clues of the OA joint.Results
Upon addition of HA at either 1 or 3 mg/ml, we observed a significant suppression of expression of metalloproteinase (MMP)-13. A more detailed analysis based on the Kellgren and Lawrence (K&L) OA grade, showed a much greater degree of suppression of MMP-13 expression in grade IV as compared to grade II OA. In contrast to the observed MMP-13 suppression, treatment with HA resulted in a suppression of MMP-1 expression only at 1 mg/ml HA, while MMP-2 expression was not significantly affected by either HA concentration.Conclusion
Together, these data suggest that under concurrent catabolic and anabolic stimulation, HA exhibits a pronounced suppressive effect on MMP-13. In the long-run these findings may benefit the development of treatment strategies aimed at blocking tissue degradation in OA patients. 相似文献112.
Dominique T. Monteil Xiao Shen Giulia Tontodonati Lucia Baldi David L. Hacker Florian M. Wurm 《Analytical biochemistry》2016
Disposable orbitally shaken TubeSpin bioreactor 600 tubes (TS600s) were recently developed for the bench-scale cultivation of animal cells in suspension. Here we compared batch cultures of Sf9 insect cells in TS600s, spinner flasks, and shake flasks. Superior cell growth was observed in TS600s and shake flasks as compared with spinner flasks, and more favorable oxygen-enriched cell culture conditions were observed in TS600s as compared with either spinner or shake flasks. The results demonstrated the suitability of TS600s as a disposable vessel for the cultivation of Sf9 cells in suspension. 相似文献
113.
114.
115.
116.
Different Pathways Act Downstream of the CEP Peptide Receptor CRA2 to Regulate Lateral Root and Nodule Development 总被引:1,自引:0,他引:1
117.
118.
Sarah A. Deventer Florian Uhl Thomas Bugnyar Rachael Miller W. Tecumseh Fitch Martina Schiestl Max Ringler Christine Schwab 《Ethology : formerly Zeitschrift fur Tierpsychologie》2016,122(11):881-891
While personality‐dependent dispersal is well studied, local space use has received surprisingly little attention in this context, despite the multiple consequences on survival and fitness. Regarding the coping style of individuals, recent studies on personality‐dependent space use within a habitat indicate that ‘proactive’ individuals are wider ranging than ‘reactive’ ones. However, such studies are still scarce and cover limited taxonomic diversity, and thus, more research is needed to explore whether this pattern generalises across species. We examined the link between coping style and space use in a population of crows (Corvus corone) freely inhabiting the urban zoo of Vienna, Austria. We used a binary docility rating (struggle during handling vs. no struggle) and a tonic immobility test to quantify individual coping style. Individual space use was quantified as the number of different sites at which each crow was observed, and we controlled for different number of sightings per individual by creating a space use index. Only the binary docility rating showed repeatability over time, and significantly predicted space use. In contrast to previous studies, we found that reactive crows (no struggle during handling) showed wider ranging space use within the study site than proactive individuals (who struggled during handling). The discrepancy from previous results suggests that the relationship between behavioural type and space use may vary between species, potentially reflecting differences in socioecology. 相似文献
119.
120.
Franziska Foertsch Anna Szambowska Anja Weise Alexandra Zielinski Bernhard Schlott Florian Kraft 《Cell cycle (Georgetown, Tex.)》2016,15(20):2766-2779
The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is an essential process in maintenance of chromosomal stability. A key player of HR is the strand exchange factor RAD51 whose assembly at sites of DNA damage is tightly regulated. We detected an endogenous complex of RAD51 with the calcium-binding protein S100A11, which is localized at sites of DNA repair in HaCaT cells as well as in normal human epidermal keratinocytes (NHEK) synchronized in S phase. In biochemical assays, we revealed that S100A11 enhanced the RAD51 strand exchange activity. When cells expressing a S100A11 mutant lacking the ability to bind Ca2+, a prolonged persistence of RAD51 in repair sites and nuclear γH2AX foci was observed suggesting an incomplete DNA repair. The same phenotype became apparent when S100A11 was depleted by RNA interference. Furthermore, down-regulation of S100A11 resulted in both reduced sister chromatid exchange confirming the restriction of the recombination capacity of the cells, and in an increase of chromosomal aberrations reflecting the functional requirement of S100A11 for the maintenance of genomic stability. Our data indicate that S100A11 is involved in homologous recombination by regulating the appearance of RAD51 in DSB repair sites. This function requires the calcium-binding activity of S100A11. 相似文献