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   93663篇
  免费   313篇
  国内免费   886篇
  94862篇
  2021年   6篇
  2019年   8篇
  2018年   11843篇
  2017年   10674篇
  2016年   7457篇
  2015年   596篇
  2014年   292篇
  2013年   308篇
  2012年   4217篇
  2011年   12823篇
  2010年   12008篇
  2009年   8229篇
  2008年   9809篇
  2007年   11381篇
  2006年   280篇
  2005年   533篇
  2004年   998篇
  2003年   1056篇
  2002年   808篇
  2001年   288篇
  2000年   184篇
  1999年   51篇
  1998年   17篇
  1997年   31篇
  1996年   20篇
  1995年   8篇
  1994年   10篇
  1993年   35篇
  1992年   38篇
  1991年   46篇
  1990年   12篇
  1989年   14篇
  1988年   23篇
  1987年   21篇
  1986年   7篇
  1984年   11篇
  1983年   23篇
  1982年   6篇
  1979年   7篇
  1978年   14篇
  1975年   8篇
  1972年   252篇
  1971年   276篇
  1970年   16篇
  1969年   10篇
  1968年   11篇
  1965年   13篇
  1962年   24篇
  1944年   12篇
  1940年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Five strains of bovine diarrhea virus were isolated from Japanese cattle using bovine tissue cultures. These are the first isolations of this virus from Japanese cattle to be reported. Of importance is the finding that the new isolates, which are non-cytopathogenic, induce an exaltation of Newcastle disease virus in bovine testicular cell culture. This finding has provided a laboratory tool whereby the assay of the virus and its neutralizing antibody can readily be performed.  相似文献   
64.
65.
66.
The kinetics of haemolysis of rabbit erythrocytes byCroton tiglium lectin was studied as a function of concentration of the lectin and erythrocytes. The length of the prelytic period decreased with increasing lectin concentrations, indicating that the secondary events at the membrane which follow the binding of the lectin to cell surface carbohydrate receptors are accelerated at higher surface concentrations of the lectin. The rate or extent of haemolysis was not affected by the inclusion of ions like K+, Ca2+ and Mg2+ in the medium or by the substitution of ionic medium by a non-ionic medium. The inhibition of haemagglutination and haemolysis of rabbit red cells byCroton tiglium lectin by antilectin rabbit serum was observed. A possible mechanism of haemolysis by the lectin is discussed.  相似文献   
67.
N-Acetyl-D-galactosamine in β-linkage being ubiquitous in cell surface glycoproteins, their interaction with lectins specific for this sugar moiety may be a significant event in cell adhesion phenomena. This article discusses the common β-N-acetyl galactosamine-specific lectins, with particular stress on the lectin from winged beans (Psophocarpus tetragonolobus).  相似文献   
68.
A PROCESS called “excitation-contraction coupling” has been generally accepted to take place only in the direction of excitation to contraction. Through this mechanism a propagated action potential initiates an active state in skeletal or cardiac muscle and the muscle contracts. We propose that, in the mammalian ventricular myocardium at least, the process is not unidirectional and an important reverse coupling between the contractile system and the excitable plasma membrane has been overlooked. Through this feedback interaction the mode of contraction (that is, isotonic or isometric) not only determines the instantaneous electrical state of the plasma membrane, but also influences the mechanical events of the subsequent beats. Thus when Kaufmann et al.1 recorded intracellular action potentials from cat papillary muscle, the time course of the repolarization was altered depending on the mode of contraction. Some kind of contraction-excitation feedback has also been suggested by Stauch2 and Lab3,4. They showed a difference in the shape of the monophasic action potential, as recorded by a suction electrode, when comparing isotonic and isovolumic contraction of the intact ventricle. But their experimental conditions did not allow satisfactory analysis of the phenomenon.  相似文献   
69.
The galactose binding protein is the part of the galactose chemoreceptor which recognizes the attractants galactose, glucose and a number of structurally related chemicals.  相似文献   
70.
Ribosomes,G-factor and Siomycin   总被引:13,自引:0,他引:13  
G-factor interacts with the 50S ribo-somal subunit at a site which is distinct from the peptidyl transferase centre and which is inactivated by siomycin.  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