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   925篇
  免费   69篇
  994篇
  2023年   3篇
  2022年   6篇
  2021年   8篇
  2020年   14篇
  2019年   14篇
  2018年   25篇
  2017年   16篇
  2016年   23篇
  2015年   42篇
  2014年   39篇
  2013年   62篇
  2012年   87篇
  2011年   61篇
  2010年   41篇
  2009年   43篇
  2008年   50篇
  2007年   45篇
  2006年   35篇
  2005年   33篇
  2004年   31篇
  2003年   38篇
  2002年   40篇
  2001年   15篇
  2000年   22篇
  1999年   21篇
  1998年   13篇
  1997年   9篇
  1996年   10篇
  1995年   9篇
  1994年   4篇
  1992年   17篇
  1991年   9篇
  1990年   11篇
  1989年   11篇
  1988年   15篇
  1985年   8篇
  1984年   5篇
  1983年   5篇
  1982年   6篇
  1980年   7篇
  1979年   6篇
  1976年   2篇
  1975年   2篇
  1974年   3篇
  1973年   4篇
  1971年   2篇
  1970年   3篇
  1969年   3篇
  1966年   2篇
  1965年   2篇
排序方式: 共有994条查询结果,搜索用时 0 毫秒
991.
Variations in the spontaneous contractile activity during 6 hours following isolation of uterine horns from proestrus, metestrus and spayed rats, were explored. In estrus and metestrus preparations the contractions declined during 60 min and between 180--200 min a progressive spontaneous recovery (abolished by indomethacin) was observed up to 360 min. Uteri from proestrus and spayed animals exhibited a continuous depression without recovery during the whole experimental period. At 60 min, uterine horns from estrus animals (which showed a marked contractile decrement) released to the suspending medium significantly less prostaglandin E-like material than at 360 min, i.e. when contractions had almost completely recovered. No modification in the amount of prostaglandin F-like material was detected accompanying these spontaneous contractile variations. In the spayed group at 60 min of functioning (i.e. when the contractile impairment was significantly smaller than at a later time) the release of PGE was greater than at 360 min. These findings suggest a possible control of rat uterine contractions by PGE, rather than by PGF.  相似文献   
992.
Sixty male Wistar rats were used for this experiment and assigned at random to the control group or to the stimulation method. Control rats show cerebral asymmetry with right bias at the frontal and occipital lobes. In the case of stimulated rats the differences from the occipital zone increase while those from the frontal lobe disappear.  相似文献   
993.
The uptake of 14C-arachidonic acid (14C-AA) and 14C-dihomogamma-linolenic acid (14C-DGLA) into phospholipids (PLs) and neutral lipids (NLs) in uterine tissue obtained from ovariectomized controls (C) and from ovariectomized-diabetic rats (D) was studied. Uterine strips from D rats incorporate significantly less (P less than 0.05) 14C-AA into PLs than C rats. On the other hand the uptake of 14C-AA into NLs is significantly smaller (P less than 0.05) in uterine tissue from C than from D animals. The estrogenization of the C animals did not modify the incorporation of 14C-AA into PLs or NLs. On the contrary, uterine tissue obtained from D rats treated with 17-beta-estradiol incorporated significantly more labelled AA (P less than 0.05) into PLs and significantly less 14C-AA (P less than 0.05) into NLs than untreated D animals. The incorporation of 14C-DGLA into PLs shows similar pattern in uterine tissue obtained from C and D animals. Estrogenization increased significantly (P less than 0.01) in both cases, the incorporation into PLs. Regarding the incorporation of 14C-DGLA, it was clearly shown that DGLA is taken up significantly more (P less than 0.01) by NLs than by PLs, both in C and D rats. The estrogenization of C and D rats induces a significant decrease in the incorporation of 14C-DGLA into NLs in both experimental groups. The distribution of 14C-AA into the different subfractions of PLs is not uniform.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
994.
The effect of nuclease on transformation efficiency in Serratia marcescens   总被引:1,自引:0,他引:1  
No differences in the efficiency of transformation were observed from both plasmid and chromosomal DNA in Serratia marcescens 2170 and an extracellular nuclease defective isogenic strain. The efficiency of transformation was the same for Escherichia coli 5K and E. coli containing a recombinant plasmid conferring the ability to synthesize a S. marcescens nuclease. From these results we conclude that the extracellular nuclease of S. marcescens 2170 is not the main cause of the low efficiency of transformation observed in this bacterium.  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