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   1124篇
  免费   35篇
  1159篇
  2021年   17篇
  2020年   10篇
  2019年   14篇
  2018年   22篇
  2017年   25篇
  2016年   32篇
  2015年   22篇
  2014年   29篇
  2013年   48篇
  2012年   56篇
  2011年   57篇
  2010年   35篇
  2009年   26篇
  2008年   59篇
  2007年   48篇
  2006年   39篇
  2005年   43篇
  2004年   37篇
  2003年   34篇
  2002年   37篇
  2001年   30篇
  2000年   26篇
  1999年   19篇
  1998年   11篇
  1997年   10篇
  1996年   9篇
  1995年   9篇
  1992年   22篇
  1991年   25篇
  1990年   22篇
  1989年   17篇
  1988年   15篇
  1987年   14篇
  1986年   24篇
  1985年   23篇
  1984年   12篇
  1983年   20篇
  1982年   6篇
  1981年   8篇
  1980年   7篇
  1979年   7篇
  1978年   11篇
  1977年   17篇
  1976年   12篇
  1975年   10篇
  1973年   6篇
  1972年   12篇
  1971年   11篇
  1970年   6篇
  1969年   9篇
排序方式: 共有1159条查询结果,搜索用时 0 毫秒
141.
The problem of correlation of the parameters of the immune system in the normal subjects and in patients with immunological diseases has been considered. The most informative relations have been determined and an attempt has been made to reveal common and specific signs of various immunological diseases.  相似文献   
142.
It is shown, that rats, bred in conditions of intraspecies isolation are able to competition for water in the kin group, having usual experience of intraspecies intercourse. At the same level of drinking motivation in conditions of competition for water the intraspecies activity is significantly higher in rats, bred in isolation in comparison with grouped animals. Rats-isolants significantly more often than the grouped animals use extraordinary tactics of intraspecies behaviour, which increase their competitive ability in conditions of limited access to water.  相似文献   
143.
144.
Nucleoids obtained from E. coli cells by extraction with 1 M NaCl and detergents containing solution were further extracted with 2 M NaCl. From these samples, that contain only tightly bound proteins, fractions of protein core and peripheral nucleoprotein were obtained. It is shown that DNA synthesis proceeds mainly in the core structures. We have found that DNA polymerase I, which is bound with DNA nucleoid loops and with the above mentioned core structures, is not dissociating in 2M NaCl solution.  相似文献   
145.
By means of ethograms record and analysis, connection has been studied between the properties of rats behaviour organization in the open field, determining the level of behaviour entropy in this test, and the speed of conditioned reflexes formation in the Skinner chamber. According to behaviour entropy level the rats are significantly divided into four groups; the lowest speed of conditioned reflexes formation in the Skinner's chamber is observed in the animals of the first (low entropy) group, the highest--in the fourth (high entropy) group. The obtained data are discussed according to Pavlov's concepts on the characteristics of the basic nervous processes, determining individual-typological characteristics of the higher nervous activity of the animal. Conclusion is made that division according to the level of behaviour entropy in the open field test may serve as a safe method of express-estimation of the animals abilities to conditioned habits formation.  相似文献   
146.
The signal recognition particle (SRP) directs ribosome-nascent chain complexes (RNCs) displaying signal sequences to protein translocation channels in the plasma membrane of prokaryotes and endoplasmic reticulum of eukaryotes. It was initially proposed that SRP binds the signal sequence when it emerges from an RNC and that successful binding becomes impaired as translation extends the nascent chain, moving the signal sequence away from SRP on the ribosomal surface. Later studies drew this simple model into question, proposing that SRP binding is unaffected by nascent chain length. Here, we reinvestigate this issue using two novel and independent fluorescence resonance energy transfer assays. We show that the arrival and dissociation rates of SRP binding to RNCs vary according to nascent chain length, resulting in the highest affinity shortly after a functional signal sequence emerges from the ribosome. Moreover, we show that SRP binds RNCs in multiple and interconverting conformations, and that conversely, RNCs exist in two conformations distinguished by SRP interaction kinetics.  相似文献   
147.
148.
Accumulation and renewal of thiamine in tissues of the uneven-aged rats have been investigated. The activity of thiamine-metabolizing and thiamine-retaining systems is shown to decrease in tissues of the digestive system with aging; the same refers to the intensity of enterohepatic recirculation of that vitamin. These phenomena underlie the revealed retardation of the thiamine renewal in organs of the digestive system.  相似文献   
149.
150.
Interaction of membrane Na+, K+-ATPase preparation from brain gray matter with spin-labelled ATP analogue, in which free iminoxyl radical is joined as a result of 2'(3')-OH ribose groups acylation, is studied. The rotatory mobility of spin-labelled ATP analogue in Na+,K+-ATPase preparation is found to change in non-linear manner during temperature variation (the break-point on the curve being at 20-23degrees C). It correlates with temperature dependence of Na+,K+-ATPase and temperature dependence of lipid viscosity in the membranes, determined by means of hydrophobic spin probes. Substitution of Mg2+ ions with paramagnetic Mn2+ ions resulted in an intense magnetic dipole-dipole interaction between a spin label and Mn2+ ion, which indicated the formation of triple complex enzyme--spin-labelled ATP--Mn2+.  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