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   59735篇
  免费   2420篇
  国内免费   18篇
  2020年   559篇
  2019年   747篇
  2018年   998篇
  2017年   1029篇
  2016年   1108篇
  2015年   799篇
  2014年   948篇
  2013年   4387篇
  2012年   1772篇
  2011年   1944篇
  2010年   1188篇
  2009年   1185篇
  2008年   1714篇
  2007年   1712篇
  2006年   1573篇
  2005年   1369篇
  2004年   1270篇
  2003年   1195篇
  2002年   1303篇
  2001年   1968篇
  2000年   1949篇
  1999年   1469篇
  1998年   688篇
  1997年   613篇
  1996年   613篇
  1993年   551篇
  1992年   1242篇
  1991年   1143篇
  1990年   1128篇
  1989年   1028篇
  1988年   1008篇
  1987年   966篇
  1986年   1052篇
  1985年   1051篇
  1984年   881篇
  1983年   805篇
  1982年   563篇
  1981年   563篇
  1979年   934篇
  1978年   667篇
  1975年   763篇
  1974年   820篇
  1973年   913篇
  1972年   767篇
  1971年   726篇
  1970年   642篇
  1969年   670篇
  1968年   858篇
  1967年   778篇
  1966年   654篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
To evaluate expectations derived from ego-identity theory and symbolic-interaction theories about the association between self-concept and peer-group affiliations in adolescence, we examined the self-esteem of 221 7th through 12th graders associated by peers with one of five major school crowds and 106 students relatively unknown by classmates and not associated with any school crowd. Among crowd members, self-esteem was directly related to the position of one's crowd in the peer-group status hierarchy (based on both peer-rated and self-perceived crowd affiliation). Outsiders' self-esteem differed in relation to the accuracy of their reflected appraisal of and the salience they attached to crowd affiliation. Crowd members as a whole exhibited higher self-esteem than outsiders as a whole. Differences, however, were mediated by crowd status, salience of crowd affiliation, and the accuracy of reflected appraisals. An adequate interpretation of the findings required an integration of Festinger's (1954, 1957) social comparisons and cognitive-dissonance theories, Cooley's (1902) notions of reflected appraisal, and Newman and Newman's (1976) extrapolations from ego-identity theory.  相似文献   
942.
943.
944.
945.
The results of an evaluation of the perfusion scintigraphy findings of 350 hospitalised neurological patients and 55 more strictly selected neurosurgical patients with cerebrovascular complaints, revealed an accuraty of 83%, a sensitivity of 89%, and a specificity of 83%. The selection of the patients had no influence on the results as a whole. Compared with contrast-medium angiography, incorrect diagnosis must be expected in 17% of the cases. This includes erroneous negative findings in 10% of the cases. Grounds for misinterpretations are suggested, and the biological and methodological limitations of the method are set forth.  相似文献   
946.
The paper investigates 54 myelograms and their influence on diagnostic thinking efficacy, on patient management efficacy, and on ultimate outcome efficacy, using statistical methods. Conventional myelography contributes to diagnostic thinking efficacy having a LLR- value of approximately 0.9. With an accuracy value of 0.95 it can be regarded as a reliable method of diagnosis. It alters diagnostic thinking efficacy in no less than 83% (94%) of the cases and patients management efficacy in 89%. Thus, by definition, myelography may be said to affect the state of health of the myelographed patients in 94.4%.  相似文献   
947.
This article attempts to apply a theory of aggression as motivation to overcome obstacles to the understanding of phobic states and their formation. The role of aggression in the genesis of phobic conditions is discussed, and the traditional analytic view of aggression as instinctual drive is contrasted with a motivational approach. The motivational view offers the advantage of a clearer understanding of the stimulus contexts, representational connections, and both real and imaginary object connections that are lacking in the more traditional understanding of aggression as a biological drive.  相似文献   
948.
Four of our own cases that presented a clinical picture of dementia are discussed. A study of the relative literature has failed to reveal any "swing" in the pattern of the clinical condition: Just as it did ninety years age, paralytic dementia accounts today for well over 60% of all cases, those clinical pictures erroneously regarded as "typical" "classic", accounting for a mere 10%-15% of cases. The need for routine lues serology is pointed out.  相似文献   
949.
950.
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