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   32410篇
  免费   1721篇
  国内免费   11篇
  34142篇
  2023年   144篇
  2022年   342篇
  2021年   654篇
  2020年   414篇
  2019年   539篇
  2018年   782篇
  2017年   647篇
  2016年   1039篇
  2015年   1396篇
  2014年   1599篇
  2013年   2022篇
  2012年   2284篇
  2011年   2242篇
  2010年   1395篇
  2009年   1204篇
  2008年   1626篇
  2007年   1563篇
  2006年   1449篇
  2005年   1332篇
  2004年   1183篇
  2003年   1183篇
  2002年   985篇
  2001年   394篇
  2000年   323篇
  1999年   310篇
  1998年   207篇
  1992年   280篇
  1991年   274篇
  1990年   239篇
  1989年   255篇
  1988年   280篇
  1987年   273篇
  1986年   254篇
  1985年   288篇
  1984年   231篇
  1983年   204篇
  1979年   263篇
  1978年   183篇
  1977年   159篇
  1976年   161篇
  1975年   186篇
  1974年   278篇
  1973年   275篇
  1972年   265篇
  1971年   249篇
  1970年   269篇
  1969年   250篇
  1968年   189篇
  1967年   198篇
  1966年   174篇
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
31.
In chronic renal failure AMP-deaminase operates in the erythrocytes at a much higher velocity than in healthy subjects, with a simultaneous shift from the AMP-adenine-inosine-hypoxanthine pathway (55% and 19%, respectively) to the pathway initiated by AMP-deaminase (45% and 81%, respectively).  相似文献   
32.
33.
34.
35.
The development of tolerance to ethanol-induced hypothermia and hypnosis, and cross-tolerance with morphine was studied in mice and rats. Ethanol significantly decreased the body temperature in rats (3.0 and 3.2 g/kg) and in mice (3.5 and 4.0 g/kg). Chronic administration of ethanol resulted in the tolerance not only to ethanol hypothermia but also to hypothermic effects of morphine in examined animals. Implantation of morphine pellets caused the development of cross tolerance to ethanol-induced hypothermia in rats but not in mice. The hypnotic effect of ethanol was significantly shorter in chronic alcoholized rats but not in morphine-implanted rats. Neither chronic ethanol administration nor implantation of morphine pellets changed the duration of ethanol-induced hypnosis in mice. These results seem to support the hypothesis on the opiate-like mechanism of ethanol action.  相似文献   
36.
37.
The fluorometric method is described for determination of the final product of dopamine metabolism homovanillic acid in urine, amniotic fluid and tissue extracts. The metabolite was isolated using three chromatographic columns (1-Amberlit CG-50, 2-Dowex AG 1 x 2, 8-Aluminium oxide). Oxidation of eluates to emitter was done with potassium ferricyanide in alkalic medium. The use of internal standards made high recovery of compound and a good specificity and sensitivity of detection.  相似文献   
38.
39.
The flux through branched-chain alpha-ketoacid dehydrogenase and the activity of the branched-chain alpha-ketoacid dehydrogenase complex were measured in hepatocytes isolated from fed, starved and alloxan diabetic rats. The highest rate of branched-chain alpha-ketoacid oxidation was found in hepatocytes isolated from starved rats, slightly lower in those from fed rats, and significantly lower in diabetic hepatocytes. The amount of the active form of branched-chain alpha-ketoacid dehydrogenase was only slightly diminished in diabetic hepatocytes, whereas the flux through the dehydrogenase was inversely correlated with the rate of endogenous ketogenesis. The same was observed in hepatocytes isolated from starved rats when branched-chain alpha-ketoacid oxidation was measured in the presence of added oleate. In both cases the diminished flux through the dehydrogenase, restored by a short preincubation of hepatocytes with insulin, was paralleled by a decrease of fatty acid-derived ketogenesis. The significance of these findings is discussed in relation to the role of insulin in branched-chain alpha-ketoacid oxidation in liver of diabetic rats.  相似文献   
40.
The capacity to phagocytosis in monocytic macrophages was investigated in 24 patients with plasmocytoma. The investigation of this capacity was made by using short-term cultures with sheep erythrocytes loaded with antibodies and complement. In comparison to the control group the percentage of phagocyting macrophages was lowered in 16 from 24 patients. This impairment of the function of monocytic macrophages seems to be bound neither to the type of plasmocytoma nor to the stage of disease. Among other things, the nature of cell defect is discussed. The necessity of further investigations is emphasized.  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