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   962124篇
  免费   104540篇
  国内免费   460篇
  2018年   8513篇
  2016年   11596篇
  2015年   15479篇
  2014年   18536篇
  2013年   25952篇
  2012年   29795篇
  2011年   30333篇
  2010年   20861篇
  2009年   19274篇
  2008年   27597篇
  2007年   28515篇
  2006年   26871篇
  2005年   25704篇
  2004年   25688篇
  2003年   24765篇
  2002年   24200篇
  2001年   40794篇
  2000年   41054篇
  1999年   32831篇
  1998年   12228篇
  1997年   12671篇
  1996年   12097篇
  1995年   11427篇
  1994年   11225篇
  1993年   11041篇
  1992年   27647篇
  1991年   27187篇
  1990年   26876篇
  1989年   26176篇
  1988年   24215篇
  1987年   23556篇
  1986年   21646篇
  1985年   21945篇
  1984年   18078篇
  1983年   15638篇
  1982年   12086篇
  1981年   10749篇
  1980年   10288篇
  1979年   17255篇
  1978年   13747篇
  1977年   12468篇
  1976年   11880篇
  1975年   13142篇
  1974年   14278篇
  1973年   14035篇
  1972年   12524篇
  1971年   11676篇
  1970年   9996篇
  1969年   9466篇
  1968年   8566篇
排序方式: 共有10000条查询结果,搜索用时 492 毫秒
861.
Journal of Evolutionary Biochemistry and Physiology - A study of the effect of a seasonal decrease in ambient temperature on the composition of free amino acids and ninhydrin-positive secondary...  相似文献   
862.
Journal of Evolutionary Biochemistry and Physiology - Due to a high occurrence of diabetes mellitus (DM) and its complications, insulin-positive cells detected in different organs are of great...  相似文献   
863.
Journal of Evolutionary Biochemistry and Physiology - Changes in bioelectrical impedance of the myocardium and liver were revealed in male Wistar rats chronically exposed to doxorubicin....  相似文献   
864.
865.
Glycine and GABA play the role of inhibitory transmitters in the lamprey spinal cord. The mechanisms of action of both amino acids to the membrane receptors producing the postsynaptic inhibition as well as role and mechanism of GABA action producing the presynaptic inhibition are considered in this paper. The data concerned with morphological substrates of both type inhibitions are discussed.  相似文献   
866.
867.
K S Gutfreund  V G Bain 《CMAJ》2000,162(6):827-833
The management of chronic viral hepatitis C is evolving rapidly. Monotherapy with interferon, the accepted standard of treatment until recently, achieves only a modest sustained virological response rate of 15%. Combination treatment with alpha-2b interferon and ribavirin has been shown to increase sustained response rates to 40% in patients who have never been treated with interferon and to 50% in those who have relapsed following monotherapy with interferon. However, side effects, which have led to the discontinuation of combination treatment in a significant proportion of patients, must be carefully monitored. Treatment with interferon alpha-2b and ribavirin has now been approved in Canada, but the selection and monitoring of patients suitable for combination treatment requires special expertise. Although improvements in current therapeutic options may be possible with more frequent, higher doses or long-acting forms of interferon together with ribavirin, low sustained response rates (i.e., below 30%) for patients with hepatitis C virus genotype 1 emphasize the need for novel antiviral medications that will target the functional sites of the HCV genome.  相似文献   
868.
Bacopa monniera Wettst. (BM, syn. Herpestis monniera L; Scrophulariaceae), is an Ayurvedic drug used as a rasayana. Its fresh juice was earlier reported to have significant antiulcerogenic activity. In continuation, methanolic extract of BM (BME) standardized to bacoside-A content (percentage-38.0 ± 0.9), when given in the dose of 10–50 mg/kg, twice daily for 5 days, showed dose-dependent anti-ulcerogenic on various gastric ulcer models induced by ethanol, aspirin, 2 h cold restraint stress and 4 h pylorus ligation. BME in the dose of 20 mg/kg, given for 10 days, twice daily showed healing effects against 50% acetic acid-induced gastric ulcers. Further work was done to investigate the possible mechanisms of its action by studying its effect on various mucosal offensive acid-pepsin secretion and defensive factors like mucin secretion, mucosal cell shedding, cell proliferation and antioxidant activity in rats. BME 20 mg/kg showed no effect on acid-pepsin secretion, increased mucin secretion, while it decreased cell shedding with no effect on cell proliferation. BME showed significant antioxidant effect per se and in stressed animals. Thus, the gastric prophylactic and curative effects of BME may be due to its predominant effect on mucosal defensive factors.  相似文献   
869.
870.
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