全文获取类型
收费全文 | 419篇 |
免费 | 19篇 |
专业分类
438篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 20篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 27篇 |
2014年 | 29篇 |
2013年 | 32篇 |
2012年 | 45篇 |
2011年 | 33篇 |
2010年 | 20篇 |
2009年 | 14篇 |
2008年 | 34篇 |
2007年 | 21篇 |
2006年 | 27篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 10篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
排序方式: 共有438条查询结果,搜索用时 15 毫秒
81.
The function of EspI, a 70 kDa protein in Mycobacterium tuberculosis, has remained unclear. Although EspI is encoded by a gene within the esx‐1 locus, in this study we clarify previous conflicting results and show that EspI is not essential for ESX‐1‐mediated secretion or virulence in M. tuberculosis. We also provide evidence that reduction of cellular ATP levels in wild‐type M. tuberculosis using the drug bedaquiline completely blocks ESX‐1‐mediated secretion. Remarkably, M. tuberculosis lacking EspI fails to exhibit this phenotype. Furthermore, mutagenesis of a highly conserved ATP‐binding motif in EspI renders M. tuberculosis incapable of shutting down ESX‐1‐mediated secretion during ATP depletion. Collectively these results show that M. tuberculosis EspI negatively regulates the ESX‐1 secretion system in response to low cellular ATP levels and this function requires the ATP‐binding motif. In light of our results the potential significance of EspI in ESX‐1 function during latent tuberculosis infection and reactivation is also discussed. 相似文献
82.
An explanation for the political processes leading to the sudden collapse of empires and states would be useful for understanding both historical and contemporary political events. We examine political disintegration across eras, cultures and geographical scale to form a simple hypothesis that can be expressed verbally yet formulated mathematically. Factions within a state make choices described by game-theory about whether to accept the political status quo, or to attempt to better their circumstances through costly rebellion. In lieu of precise data we verify our model using sensitivity analysis. We find that a small amount of dissatisfaction is typically harmless to the state, but can trigger sudden collapse when there is a sufficient buildup of political inequality. Contrary to intuition, a state is predicted to be least stable when its leadership is at the height of its political power and thus most able to exert its influence through external warfare, lavish expense or autocratic decree. 相似文献
83.
84.
85.
Arti Vasudev Talwinder Kaur Rajesh Kumari Manhas 《Archives Of Phytopathology And Plant Protection》2013,46(9-12):720-739
Proteinaceous extract obtained from Cassia occidentalis seeds with purification fold of 3.91 and 82.7% of bovine trypsin inhibitory activity was assessed at different concentrations (25, 50, 100, 200, 400 and 800 μg/ml) against Spodoptera litura. Assay of larval feeding suggested proteinaceous extract to be toxic as prepupal (80.16%) and pupal mortalities (100%) along with growth deterrent effect with only 16.71% pupation was observed at 800 μg/ml. Fifty per cent mortality (LC50) was observed at 132.91 μg/ml. Also the inhibitor affected fecundity, longevity and percentage of egg hatching. Nutritional indices were adversely affected as both efficiency of conversion of ingested and digested food decreased while approximate digestibility and metabolic cost increased. In vitro studies on proteolytic enzymes of S. litura revealed inhibition of trypsin and chymotrypsin in lumen and faecal matter at all tested concentrations. Also proteinaceous extract inhibited mycelial growth in Fusarium oxysporum, Alternaria brassicicola and Alternaria alternata at 100 μg/ml. 相似文献
86.
87.
88.
Anunay Gupta Neeraj Parakh Rajnish Juneja 《Indian pacing and electrophysiology journal》2018,18(1):39-41
Usually an electrocardiogram after right ventricular (RV) pacing should yield left bundle branch block (LBBB) pattern. However, the presence of right bundle branch block (RBBB) pattern after pacemaker implantation should alert the physician to a malposition of lead. We report a case of 18-year-old female who underwent dual chamber pacemaker implantation and had RBBB pattern post implantation. Detailed evaluation revealed an uncomplicated right ventricular outflow tract pacing. The possible causes of this abnormal pattern after an uncomplicated RV pacing are also reviewed. 相似文献
89.
90.
Satria P. Sajuthi Neeraj K. Sharma Jeff W. Chou Nicholette D. Palmer David R. McWilliams John Beal Mary E. Comeau Lijun Ma Jorge Calles-Escandon Jamehl Demons Samantha Rogers Kristina Cherry Lata Menon Ethel Kouba Donna Davis Marcie Burris Sara J. Byerly Maggie C. Y. Ng Nisa M. Maruthur Sanjay R. Patel Lawrence F. Bielak Leslie A. Lange Xiuqing Guo Michèle M. Sale Kei Hang K. Chan Keri L. Monda Gary K. Chen Kira Taylor Cameron Palmer Todd L. Edwards Kari E. North Christopher A. Haiman Donald W. Bowden Barry I. Freedman Carl D. Langefeld Swapan K. Das 《Human genetics》2016,135(8):869-880