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   2389篇
  免费   6篇
  2021年   19篇
  2019年   18篇
  2018年   25篇
  2017年   36篇
  2016年   29篇
  2015年   18篇
  2014年   29篇
  2013年   34篇
  2012年   35篇
  2011年   77篇
  2010年   27篇
  2009年   29篇
  2008年   56篇
  2007年   56篇
  2006年   56篇
  2005年   52篇
  2004年   65篇
  2003年   66篇
  2002年   64篇
  2001年   64篇
  2000年   57篇
  1999年   43篇
  1992年   69篇
  1991年   82篇
  1990年   102篇
  1989年   110篇
  1988年   71篇
  1987年   81篇
  1986年   57篇
  1985年   73篇
  1984年   53篇
  1983年   44篇
  1981年   25篇
  1980年   14篇
  1979年   43篇
  1978年   34篇
  1977年   27篇
  1976年   33篇
  1975年   43篇
  1974年   52篇
  1973年   50篇
  1972年   45篇
  1971年   35篇
  1970年   39篇
  1969年   35篇
  1968年   37篇
  1967年   30篇
  1966年   24篇
  1965年   22篇
  1959年   14篇
排序方式: 共有2395条查询结果,搜索用时 31 毫秒
191.
192.
Influence of endogenic and exogenic heparin in vivo on the basic forms of serum lipids content: cholesterol ethers, triacylglycerols, free fatty acids; as well as that glycosaminoglycan effect in vivo and in vitro on total lipoproteine lipase (LPL) activity and lecithin-cholesterol acyltransferase (LCAT) activity of human blood serum were investigated on food lipidemia model. The decrease of intercell reserve heparin content and increase of the background and post-heparin levels of blood serum LPL activity were indicated after two hours food load. The role of two factors, endogenic heparin being one of them, in the increase of postprandial LPL activity of blood serum were discussed. At the same time, some inhibition of blood serum LCAT activity two hours after food reception (evidently, as a result of endogenic heparin action) and to a considerable extent inhibition of cholesterol etherification under the action of exogenic heparin in vivo were ascertain. Heparin in vitro (50 U/ml of blood serum) did not influence LCAT and total LPL activities. It was summarised that endogenic heparin is a factor, taking part in lipolysis processes regulation.  相似文献   
193.
A significant heterogeneity between bacteria Rhizobium galegae bv. officinalis and R. galegae bv. orientalis forming the nitrogen-fixing symbiosis with Galega officinalis and G. orientalis, respectively, and not forming any single cross-inoculation group, was found by means of RAPD and RFEL methods. The high level of sequence similiraty between lectins of these plants indicates at their close relationship. However the sequences of lectin sugar binding peptides (SBP) of G. orientalis (TYCNPGWDPRDR) and G. officinalis (TFYNEEWDLVIKDEH) were highly diverged. Amino acids of SBP which are involved in linkage of Ca2+ and Mn2+ ions responsible for stabilization of spatial structure of carbohydrate-binding "pocket", keep their position in peptide. It suggests that lectins participate in Rhizobium-legume symbiosis and that carbohydrate-binding site plays a key role in this process.  相似文献   
194.
Nucleotide sequence of Bacillus stearothermophilus SE-589 DNA fragment which includes an operone for site-specific NM-system with a gene for BstSEI nickase has been determined. Analysis of the regions adjacent to nickase gene has revealed two genes encoding DNA methyltransferases, which belong to different classes. Three genes which form system operone are separated with short open reading frames (ORFs). Analysis of these ORFs has shown that they encode polypeptides which are homologous to different parts of BstSEI nickase, NatB protein and arginase. A difference in GC-content of the beginning and ending regions of the cloned DNA fragment as well as presence of short ORFs similar to genes for known proteins may indicate that NM.BstSEI system operone has evolved by horizonthal DNA transfer.  相似文献   
195.
196.
197.
198.
199.
200.
Eĭdus LKh 《Biofizika》2005,50(4):693-703
A conception of the molecular mechanism of the universal nonspecific cell response (NCR) to the action of all damaging factors of physical and chemical nature is described. The mechanism is shown to be closely related to the general principles of the structural-functional organization of cells and to the properties of biological macromolecules. Among them are the phenomenon of nonspecific regulation of the enzyme activity by low-molecular substances and the compartmentation of the latter within the cell, which is provided by the system of intracellular membranes. Special attention is paid to the role of disturbance of the barrier function, of membranes in the development of the nonspecific cell response, and the activation of repair of cell injuries. Based on the theory of nonspecific cell response, the stimulating effect of weak action of agents that damage the cells at high doses (the phenomenon named as hormesis) is explained.  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