全文获取类型
收费全文 | 5355篇 |
免费 | 423篇 |
国内免费 | 4篇 |
专业分类
5782篇 |
出版年
2023年 | 30篇 |
2022年 | 71篇 |
2021年 | 141篇 |
2020年 | 81篇 |
2019年 | 91篇 |
2018年 | 160篇 |
2017年 | 123篇 |
2016年 | 173篇 |
2015年 | 264篇 |
2014年 | 291篇 |
2013年 | 351篇 |
2012年 | 453篇 |
2011年 | 466篇 |
2010年 | 254篇 |
2009年 | 238篇 |
2008年 | 317篇 |
2007年 | 336篇 |
2006年 | 315篇 |
2005年 | 255篇 |
2004年 | 219篇 |
2003年 | 231篇 |
2002年 | 203篇 |
2001年 | 40篇 |
2000年 | 31篇 |
1999年 | 33篇 |
1998年 | 34篇 |
1997年 | 30篇 |
1996年 | 24篇 |
1995年 | 26篇 |
1994年 | 28篇 |
1993年 | 23篇 |
1992年 | 27篇 |
1991年 | 22篇 |
1990年 | 20篇 |
1989年 | 21篇 |
1988年 | 10篇 |
1986年 | 14篇 |
1985年 | 20篇 |
1984年 | 24篇 |
1983年 | 23篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 16篇 |
1977年 | 16篇 |
1976年 | 16篇 |
1974年 | 12篇 |
1969年 | 10篇 |
1960年 | 10篇 |
排序方式: 共有5782条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Bharat Joshi Michele Bastiani Scott S. Strugnell Cecile Boscher Robert G. Parton Ivan R. Nabi 《The Journal of cell biology》2013,200(5):681-692
Maintenance of epithelial cell adhesion is crucial for epidermal morphogenesis and homeostasis and relies predominantly on the interaction of keratins with desmosomes. Although the importance of desmosomes to epidermal coherence and keratin organization is well established, the significance of keratins in desmosome organization has not been fully resolved. Here, we report that keratinocytes lacking all keratins show elevated, PKC-α–mediated desmoplakin phosphorylation and subsequent destabilization of desmosomes. We find that PKC-α activity is regulated by Rack1–keratin interaction. Without keratins, desmosomes assemble but are endocytosed at accelerated rates, rendering epithelial sheets highly susceptible to mechanical stress. Re-expression of the keratin pair K5/14, inhibition of PKC-α activity, or blocking of endocytosis reconstituted both desmosome localization at the plasma membrane and epithelial adhesion. Our findings identify a hitherto unknown mechanism by which keratins control intercellular adhesion, with potential implications for tumor invasion and keratinopathies, settings in which diminished cell adhesion facilitates tissue fragility and neoplastic growth. 相似文献
105.
Joshua B. Slee Ivan S. Alferiev Robert J. Levy Stanley J. Stachelek 《Journal of visualized experiments : JoVE》2014,(90)
The foreign body reaction occurs when a synthetic surface is introduced to the body. It is characterized by adsorption of blood proteins and the subsequent attachment and activation of platelets, monocyte/macrophage adhesion, and inflammatory cell signaling events, leading to post-procedural complications. The Chandler Loop Apparatus is an experimental system that allows researchers to study the molecular and cellular interactions that occur when large volumes of blood are perfused over polymeric conduits. To that end, this apparatus has been used as an ex vivo model allowing the assessment of the anti-inflammatory properties of various polymer surface modifications. Our laboratory has shown that blood conduits, covalently modified via photoactivation chemistry with recombinant CD47, can confer biocompatibility to polymeric surfaces. Appending CD47 to polymeric surfaces could be an effective means to promote the efficacy of polymeric blood conduits. Herein is the methodology detailing the photoactivation chemistry used to append recombinant CD47 to clinically relevant polymeric blood conduits and the use of the Chandler Loop as an ex vivo experimental model to examine blood interactions with the CD47 modified and control conduits. 相似文献
106.
107.
108.
109.
110.
Lihua Zhang Fenghui Yuan Junhong Bai Hongtao Duan Xueying Gu Longyu Hou Yao Huang Mingan Yang Jin‐Sheng He Zhenhua Zhang Lijun Yu Changchun Song David A. Lipson Donatella Zona Walter Oechel Ivan A. Janssens Xiaofeng Xu 《Ecology letters》2020,23(5):821-830
Grassland ecosystems account for more than 10% of the global CH4 sink in soils. A 4‐year field experiment found that addition of P alone did not affect CH4 uptake and experimental addition of N alone significantly suppressed CH4 uptake, whereas concurrent N and P additions suppressed CH4 uptake to a lesser degree. A meta‐analysis including 382 data points in global grasslands corroborated these findings. Global extrapolation with an empirical modelling approach estimated that contemporary N addition suppresses CH4 sink in global grassland by 11.4% and concurrent N and P deposition alleviates this suppression to 5.8%. The P alleviation of N‐suppressed CH4 sink is primarily attributed to substrate competition, defined as the competition between ammonium and CH4 for the methane mono‐oxygenase enzyme. The N and P impacts on CH4 uptake indicate that projected increases in N and P depositions might substantially affect CH4 uptake and alter the global CH4 cycle. 相似文献