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   469549篇
  免费   47217篇
  国内免费   405篇
  2016年   6274篇
  2015年   11094篇
  2014年   11594篇
  2013年   14107篇
  2012年   14524篇
  2011年   12118篇
  2010年   8664篇
  2009年   8210篇
  2008年   9544篇
  2007年   9976篇
  2006年   9511篇
  2005年   15005篇
  2004年   13645篇
  2003年   11580篇
  2002年   9253篇
  2001年   18975篇
  2000年   18965篇
  1999年   15936篇
  1998年   5154篇
  1997年   5297篇
  1996年   4892篇
  1995年   4715篇
  1994年   4665篇
  1993年   4630篇
  1992年   13495篇
  1991年   13172篇
  1990年   12893篇
  1989年   12508篇
  1988年   11857篇
  1987年   11279篇
  1986年   10579篇
  1985年   10736篇
  1984年   8670篇
  1983年   7409篇
  1982年   5700篇
  1981年   5309篇
  1980年   4805篇
  1979年   8468篇
  1978年   6754篇
  1977年   6143篇
  1976年   5867篇
  1975年   6700篇
  1974年   7428篇
  1973年   7415篇
  1972年   6889篇
  1971年   6277篇
  1970年   5461篇
  1969年   5439篇
  1968年   4926篇
  1967年   4271篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
[2-14C] leucine, [1-14C] alanine, [1-14C] glucose, [1-14C] lactate and [1-14C] pyruvate utilization in the protein synthesis has been studied in vivo at early stages of postnatal development of piglets. It has been established, that during the first 24 hours after birth the protein synthesis intensity, judging by [2-14C] leucine incorporation, in liver, skeletal muscle, duodenal wall and subcutaneous tissue of piglets increases 5, 7, 6.5 and 2.1 times respectively. At the age of 1-2 h the radioactive carbon incorporation from [1-14C] glucose into the brain proteins is more pronounced than into the proteins of liver and skeletal muscle. During the first days of life the intensity of the label incorporation from [1-14C] glucose into liver and skeletal muscle proteins of piglets is enhanced, whereas in brain it remains at the same level. The degree of 14C carbon incorporation from [1-14C]-alanine, [1-14C] pyruvate and [1-14C] lactate into the liver and skeletal muscle proteins of 5-days-old piglets is approximately the same, 14C substrates of protein synthesis in brain and subcutaneous adipose tissue having some peculiarities.  相似文献   
182.
183.
The authors have studied in the dog--normal or diabetic insipidus after hypothalamic lesion--submitted to oral ingestion of ethanol the effects of a few antidiuretic drug: chlorpropamid, atromid-S, carbamazepin and carisoprodol. The carisoprodol only can reduce the diuresis and the drinking provoked by ethanol.  相似文献   
184.
185.
186.
187.
188.
189.
190.
An investigational drug (2-picoline, 6-amino-4-nitro-, 1-oxide) was evaluated to characterize the anti-coccidial spectrum of the compound. Two concentrations of the drug (125 and 250 ppm) were evaluated for bioactivity; weight gain, survival, dropping, and lesion scores were the response variables utilized to ascertain activity. The activities of the picoline derivative were compared with monensin, maduramicin, and a narasin/nicarbazin (1:1) combination. The investigational drug had significant activity against Eimeria tenella and Eimeria necatrix, and the 250-ppm level was significantly more active than 125 ppm. At 250 ppm, the E. tenella activity of the picoline derivative was comparable to both monensin (120 ppm) and the 50-ppm narasin/nicarbazin combination, significantly less effective than maduramicin (6 ppm), and significantly more efficacious than 30 ppm narasin/nicarbazin. At the same level (250 ppm), the picoline derivative had significantly less E. necatrix activity than monensin (120 ppm), maduramicin (6 ppm), and narasin/nicarbazin (50 ppm), and significantly greater activity than 30 ppm narasin/nicarbazin. At best, only extremely weak Eimeria acervulina, Eimeria brunetti, and Eimeria maxima activities were noted with the investigational drug; higher concentrations of the picoline derivative may achieve greater anti-coccidial activity against these species. The efficacy of narasin/nicarbazin compared favorably with monensin and maduramicin; the 50-ppm level of the combination appeared significantly more efficacious than 30-ppm.  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