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   289篇
  免费   0篇
  2021年   1篇
  2020年   1篇
  2014年   1篇
  2012年   5篇
  2011年   8篇
  2010年   1篇
  2008年   4篇
  2007年   9篇
  2006年   9篇
  2005年   6篇
  2004年   8篇
  2003年   12篇
  2002年   9篇
  2001年   12篇
  2000年   9篇
  1999年   15篇
  1992年   8篇
  1991年   5篇
  1990年   7篇
  1989年   7篇
  1988年   6篇
  1987年   8篇
  1986年   6篇
  1985年   6篇
  1984年   6篇
  1983年   6篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1979年   7篇
  1978年   6篇
  1977年   4篇
  1976年   6篇
  1975年   9篇
  1974年   11篇
  1973年   10篇
  1972年   10篇
  1971年   9篇
  1970年   7篇
  1969年   9篇
  1968年   7篇
  1967年   3篇
  1966年   8篇
  1965年   4篇
排序方式: 共有289条查询结果,搜索用时 24 毫秒
81.
82.
Opiate addiction is accompanied by long-term structural and functional changes in brain regions persisting during abstinence, this status being an experimental model of the aberrant neuroplasticity. Nitric oxide is known to be involved in mechanisms of psychopathological events during opiate abstinence. In this study, indices of a nitregic system (nitric synthase activity--NOS, nitrites and nitrates concentration--NOx-) were measured in the rat brain region during morphine abstinence. Prior to this, the rats were tested for anxiety in an elevated plus maze. NOS activity increased in hippocampus 3 days after morphine withdrawal, while NOx--6 days after withdrawal. No changes of the nitrergic system could be revealed in other brain regions under study. Six days (but not 3 days) after morphine withdrawal, rats visited the open arms of the plus maze more frequently and spent more time in these arms as compared with respective controls. The data suggest that nitrergic system changes in the hippocampus may be involved in molecular mechanisms of behavioural alteration during morphine abstinence in rats.  相似文献   
83.
Visualization of molecular structures aids in the understanding of structural and functional roles of biological macromolecules. Macromolecular transport between the cell nucleus and cytoplasm is facilitated by the nuclear pore complex (NPC). The ring structure of the NPC is large and contains several distinct proteins (nucleoporins) which function as a selective gate for the passage of certain molecules into and out of the nucleus. In this note we demonstrate the utility of a python code that allows direct mapping of the physiochemical properties of the constituent nucleoporins on the scaffold of the yeast NPC׳s cytoplasmic view. We expect this tool to be useful for researchers to visualize the NPC based on their physiochemical properties and how it alters when specific mutations are introduced in one or more of the nucleoporins. The code developed using Python is available freely from the authors.  相似文献   
84.
In present work we studied DNA damage in human and bovine lymphocytes and spermatozoa by means of single cell gel electrophoresis followed by silver staining. The spontaneous frequency of DNA damage estimated manually in spermatozoa from healthy donors did not exceed 9% (on average -- 4.8 +/- 1.2%). The frequency of DNA damages in bull sperm after short (less than a year) and long period (more than 20 years) of cryopreservation was assessed as 3.1 +/- 0.9 and 4.3 +/- 0.5%, correspondingly. The comparative estimation of DNA damages in lymphocytes followed by silver staining is a valuable tool to estimate DNA damage in populations of somatic and reproductive cells.  相似文献   
85.
Changes in the contents of adenine nucleotides, creatine phosphate, inorganic phosphate, creatine, glucose-6-phosphate and glycogen and the activity of adenylate cyclase, creatine kinase, glycogen phosphorylase 31:51-AMP-phosphodiesterase and glycogen synthetase in muscles and of blood catecholamines were studied in adult rats before loading, immediately after the cessation of the muscular activity, and at rest. Adenine nucleotides are established to play a regulatory role in catabolic and anabolic processes nucleotides are established to play a regulatory role in catabolic and anabolic processes related to the muscular activity. It is established that compensation and supercompensation of the working losses of muscular creatine phosphate and glycogen are due to activation of anabolic processes under conditions of higher phosphorylation of the adenylic system.  相似文献   
86.
87.
This work deals with the previously described process of cellular autophagocytosis in regenerating rat liver. The experimental data obtained indicate that the early appearance of acid phosphatase positive cytoplasmic vacuoles (with diameter more than 2 mu) occur only in a certain portion of the parenchymal cell population (nearly 30% of the total number of hepatocytes) and mainly in the central area of the hepatic lobule. It may be concluded that the observed reaction of the cell vacuolar apparatus concerns hepatocytes that undergo the entry into the mitotic cycle much later than does the main part (ca 60%) of cell population.  相似文献   
88.
Acclimation of rats to cooling (10 and 3 degrees C) for 2 weeks is accompanied by changes in the content of cholesterol, various forms of phospholipids and the degree of saturation of their fatty acids. No changes in the lipid composition of tissues were noted which might indicate pathological condition in animals.  相似文献   
89.
90.
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