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   120206篇
  免费   8225篇
  国内免费   219篇
  2021年   1267篇
  2020年   1126篇
  2019年   1092篇
  2018年   2664篇
  2017年   2387篇
  2016年   3209篇
  2015年   4123篇
  2014年   4388篇
  2013年   5713篇
  2012年   6648篇
  2011年   5996篇
  2010年   3943篇
  2009年   3155篇
  2008年   4937篇
  2007年   4715篇
  2006年   4691篇
  2005年   3936篇
  2004年   3908篇
  2003年   3528篇
  2002年   3299篇
  2001年   4673篇
  2000年   4246篇
  1999年   3173篇
  1998年   1203篇
  1997年   956篇
  1996年   950篇
  1995年   842篇
  1992年   2155篇
  1991年   1963篇
  1990年   1877篇
  1989年   1875篇
  1988年   1627篇
  1987年   1634篇
  1986年   1443篇
  1985年   1483篇
  1984年   1141篇
  1983年   1021篇
  1979年   1250篇
  1978年   894篇
  1977年   863篇
  1975年   1024篇
  1974年   1145篇
  1973年   1103篇
  1972年   1067篇
  1971年   996篇
  1970年   1017篇
  1969年   1079篇
  1968年   947篇
  1967年   811篇
  1966年   830篇
排序方式: 共有10000条查询结果,搜索用时 448 毫秒
51.
52.
53.
54.
In male Wistar rats, the inhalation exposure to acrylonitrile (AN), 271 mg X m-3, 8 hours a day, 5 days a week, did not affect protein sulfhydryl concentration in liver and blood and decreased glutathione concentration in the liver, but not in the brain at the end of the fifth exposure. The urinary excretion of the main AN metabolites, thioethers (AN-mercapturic acids) and thiocyanate was proportional to the inhaled AN concentration (57, 125, 271 mg X m-3, respectively) in a single exposure for 12 hours, and their mutual ratio was greatly different from that after injection of AN. The results revealed that the urinary excretion of thioethers is a very sensitive and dose-related indicator of exposure to AN and extrapolation of the results indicates that the exposure to AN concentration below 10 mg X m-3 could thus be demonstrated.  相似文献   
55.
In recent years, Staphylococcus epidermidis has become a major nosocomial pathogen and the most common cause of intravascular catheter-related bacteremia, which can increase morbidity and mortality and significantly affect patient recovery. We report a draft genome sequence of Staphylococcus epidermidis AU12-03, isolated from an intravascular catheter tip.  相似文献   
56.
1. In rat kidney cortex, outer and inner medulla the development of activities of seven enzymes was investigated during postnatal ontogeny (10, 20, 30, 60 and 90 days of age). The enzymes were selected in such a manner, as to characterize most of the main metabolic pathways of energy supplying metabolism: hexokinase (glucose phosphorylation, HK), glycerol-3-phosphate dehydrogenase (glycerolphosphate metabolism or shunt, GPDH), triose phosphate dehydrogenase (glycolytic carbohydrate breakdown, TPDH), lactate dehydrogenase (lactate metabolism, LDH), citrate synthase (tricarboxylic acid cycle, aerobic metabolism, CS), malate NAD dehydrogenase (tricarboxylic acid cycle, intra-extra mitochondrial hydrogen transport, MDH) and 3-hydroxyacyl-CoA-dehydrogenase (fatty acid catabolism, HOADH). 2. The renal cortex already differs metabolically from the medullar structures on the 10th day of life. It displays a high activity of aerobic breakdown of both fatty acids and carbohydrates. Its metabolic capacity further increases up to the 30th day of life. 3. The outer medullar structure is not grossly different from the inner medulla on the 10th day of life. Further it differentiates into a highly aerobic tissue mainly able to utilize carbohydrates. It can, however, to some extent, also utilize fatty acids aerobically and produce lactate from carbohydrates anaerobically. 4. The inner medullar structure is best equipped to utilize carbohydrates by anaerobic glycolysis, forming lactate. This feature is already pronounced on the 10th day of life, its capacity increases to some extent during postnatal development, being highest between the 10th and the 60th day of life.  相似文献   
57.
58.
59.
Biomechanics and Modeling in Mechanobiology - Cell migration is a process of crucial importance for the human body. It is responsible for important processes such as wound healing and tumor...  相似文献   
60.
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