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   722673篇
  免费   42307篇
  国内免费   1164篇
耳鼻咽喉   9650篇
儿科学   22826篇
妇产科学   18856篇
基础医学   115019篇
口腔科学   21543篇
临床医学   57795篇
内科学   140496篇
皮肤病学   18555篇
神经病学   53423篇
特种医学   23499篇
外国民族医学   92篇
外科学   101528篇
综合类   9552篇
一般理论   156篇
预防医学   61302篇
眼科学   16984篇
药学   56100篇
中国医学   1845篇
肿瘤学   36923篇
  2021年   7350篇
  2019年   7713篇
  2018年   10855篇
  2017年   7450篇
  2016年   8040篇
  2015年   8857篇
  2014年   11699篇
  2013年   17700篇
  2012年   25676篇
  2011年   27531篇
  2010年   15415篇
  2009年   13708篇
  2008年   24560篇
  2007年   26203篇
  2006年   26010篇
  2005年   25138篇
  2004年   23941篇
  2003年   22616篇
  2002年   22144篇
  2001年   29864篇
  2000年   31250篇
  1999年   25574篇
  1998年   6847篇
  1997年   5710篇
  1996年   5969篇
  1995年   5428篇
  1992年   18384篇
  1991年   18802篇
  1990年   18828篇
  1989年   17905篇
  1988年   16514篇
  1987年   16233篇
  1986年   15389篇
  1985年   14612篇
  1984年   10867篇
  1983年   9337篇
  1979年   10752篇
  1978年   7764篇
  1977年   6651篇
  1976年   6405篇
  1975年   7383篇
  1974年   8837篇
  1973年   8376篇
  1972年   8154篇
  1971年   7836篇
  1970年   7264篇
  1969年   7016篇
  1968年   6666篇
  1967年   6026篇
  1966年   5382篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy.  相似文献   
74.
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer‐legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
75.
76.
77.
78.
Formulae for the calculation of the count of microorganisms isolated from natural bacterial biocenoses of a child's body have been derived. The authors suggest a variant of simplified drip method for the computation of microorganism colonies in solid media. The described method helps cut down the nutrient media consumption at least 3-fold and is time-saving.  相似文献   
79.
80.
Perceptual asymmetry on a series of four specially constructed dichotic word tests was found to change as a function of the emotional quality of the words in the tests (P = 0.05). This was most pronounced in the case of positively valued words which produced an increase in asymmetry consistent with facilitated left-hemisphere function (P less than 0.004). Changes in asymmetry with emotion differed as a function of personality characteristics of the subjects, with repressors and high anxious subjects showing an increase with emotion while true low anxious subjects showed a decrease (P less than 0.02). Personality groups also differed in asymmetry on an emotionally neutral test (P less than 0.04) and in changes in asymmetry over time independent of emotion (P less than 0.001). These data suggest that emotion mediated activation of the left hemisphere may facilitate information processing within that hemisphere. Moreover, they indicate that dichotic listening tests may provide a non-invasive and inexpensive method for assessing emotion mediated changes in brain state that are clinically relevant.  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