首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1620篇
  免费   119篇
  2023年   6篇
  2022年   27篇
  2021年   50篇
  2020年   27篇
  2019年   38篇
  2018年   55篇
  2017年   38篇
  2016年   55篇
  2015年   87篇
  2014年   91篇
  2013年   99篇
  2012年   133篇
  2011年   131篇
  2010年   82篇
  2009年   74篇
  2008年   91篇
  2007年   96篇
  2006年   89篇
  2005年   68篇
  2004年   58篇
  2003年   48篇
  2002年   46篇
  2001年   17篇
  2000年   14篇
  1999年   19篇
  1998年   10篇
  1997年   14篇
  1996年   8篇
  1995年   5篇
  1994年   6篇
  1993年   4篇
  1991年   7篇
  1990年   7篇
  1989年   7篇
  1988年   9篇
  1987年   10篇
  1986年   10篇
  1985年   12篇
  1984年   9篇
  1983年   5篇
  1982年   10篇
  1981年   10篇
  1980年   5篇
  1979年   7篇
  1977年   4篇
  1976年   3篇
  1975年   4篇
  1974年   3篇
  1973年   7篇
  1972年   3篇
排序方式: 共有1739条查询结果,搜索用时 31 毫秒
131.
Several simple scoring methods were examined for 2 series of beta-secretase (BACE-1) inhibitors to identify a docking/scoring protocol which could be used to design BACE-1 inhibitors in a drug discovery program. Both the PLP1 score and MMFFs interaction energy (E(inter)) performed as well or better than more computationally intensive methods for a set of substrate-based inhibitors, while the latter performed well for both sets of inhibitors.  相似文献   
132.
Genetically modified mouse strains derived from embryonic stem (ES) cells are powerful tools for gene function analysis. ES cells from the C57BL/6 mouse strain are not widely used to generate mouse models despite the advantage of a defined genetic background. We assessed genetic variation in six such ES cell lines with 275 SSLP markers. Compared to C57BL/6, Bruce4 differed at 34 SSLP markers and had significant heterozygosity on three chromosomes. BL/6#3 and Dale1 ES cell lines differed at only 3 SSLP makers. The C2 and WB6d ES cell lines differed at 6 SSLP markers. It is important to compare the efficiency of producing mouse models with available C57BL/6 ES cells relative to standard 129 mouse strain ES cells. We assessed genetic stability (the tendency of cells to become aneuploid) in 110 gene-targeted ES cell clones from the most widely used C57BL/6 ES cell line, Bruce4, and 710 targeted 129 ES cell clones. Bruce4 clones were more likely to be aneuploid and unsuitable for ES cell-mouse chimera production. Despite their tendency to aneuploidy and consequent inefficiency, use of Bruce4 ES cells can be valuable for models requiring behavioral studies and other mouse models that benefit from a defined C57BL/6 background. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
133.
134.
135.
136.
Next generation NNRTIs are sought which possess both broad spectrum antiviral activity against key mutant strains and a high genetic barrier to the selection of new mutant viral strains. Pyridones were evaluated as an acyclic conformational constraint to replace the aryl ether core of MK-4965 (1) and the more rigid indazole constraint of MK-6186 (2). The resulting pyridone compounds are potent inhibitors of HIV RT and have antiviral activity in cell culture that is superior to other next generation NNRTI’s.  相似文献   
137.
A novel series of amide T-type calcium channel antagonists were prepared and evaluated using in vitro and in vivo assays. Optimization of the screening hit 3 led to identification of the potent and selective T-type antagonist 37 that displayed in vivo efficacy in rodent models of epilepsy and sleep.  相似文献   
138.
139.
Advances in technologies associated with mass spectrometry-based proteomic techniques have added a new dimension to the field of biomedical research. Most of the existing research on human gestation has focused on the application of these high-throughput methodologies in the study of amniotic fluid. In cases of fetal aneuploidies, the use of proteomic platforms has contributed to the identification of relevant protein biomarkers that could potentially change early diagnosis and treatment. The current article focuses on studies of normal amniotic fluid using proteomic technologies and describes alterations noted in the amniotic fluid proteome in the presence of fetal aneuploidies.  相似文献   
140.
Adult pancreatic β cells can replicate during growth and after injury to maintain glucose homeostasis. Here, we report that β cells deficient in Dnmt1, an enzyme that propagates DNA methylation patterns during cell division, were converted to α cells. We identified the lineage determination gene aristaless-related homeobox (Arx), as methylated and repressed in β cells, and hypomethylated and expressed in α cells and Dnmt1-deficient β cells. We show that the methylated region of the Arx locus in β cells was bound by methyl-binding protein MeCP2, which recruited PRMT6, an enzyme that methylates histone H3R2 resulting in repression of Arx. This suggests that propagation of DNA methylation during cell division also ensures recruitment of enzymatic machinery capable of modifying and transmitting histone marks. Our results reveal that propagation of DNA methylation during cell division is essential for repression of α cell lineage determination genes to maintain pancreatic β cell identity.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号