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   38661篇
  免费   739篇
  国内免费   4篇
  2019年   274篇
  2018年   3750篇
  2017年   3075篇
  2016年   2527篇
  2015年   415篇
  2014年   419篇
  2013年   1629篇
  2012年   1102篇
  2011年   2978篇
  2010年   2826篇
  2009年   1862篇
  2008年   2217篇
  2007年   2718篇
  2006年   565篇
  2005年   641篇
  2004年   615篇
  2003年   507篇
  2002年   478篇
  2001年   525篇
  2000年   596篇
  1999年   383篇
  1998年   253篇
  1997年   211篇
  1996年   202篇
  1995年   186篇
  1994年   173篇
  1992年   308篇
  1991年   299篇
  1990年   325篇
  1989年   298篇
  1988年   281篇
  1987年   246篇
  1986年   269篇
  1985年   279篇
  1984年   202篇
  1983年   227篇
  1982年   174篇
  1980年   169篇
  1979年   258篇
  1978年   228篇
  1975年   230篇
  1974年   258篇
  1973年   284篇
  1972年   233篇
  1971年   220篇
  1970年   171篇
  1969年   202篇
  1968年   256篇
  1967年   245篇
  1966年   211篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Our aim was to explore the role of parents in the transmission of stereotypical body size attitudes and awareness of weight loss strategies to preschool children. Participants were 279 3‐year‐old children and their parents, who provided data at baseline and 1 year later. Parents completed self‐report body size attitude and dieting measures. Child weight bias and awareness of weight loss strategies were assessed through interview. Over time, negative associations with large bodies and awareness of weight loss strategies increased. Fathers’ attitudes prospectively predicted boys’ weight bias and awareness of weight loss strategies. Among girls, parental attitudes were less predictive. Findings confirm the importance of fathers in the development of boys’ body attitudes and inform prevention programmes.  相似文献   
13.
14.
15.
Most studies of suicide in younger patients have demonstrated significant alterations in the serotonin system. Although a high percentage of completed suicides occur in late-life, to date very few studies of the biology of suicide have focused on this age group. This chapter describes age-related changes in the central nervous system pertinent to the biology of suicide, then reviews post-mortem biological studies of the brains of suicides and suicide attempters. As suicide attempts in the elderly are characterized by the use of violent means, biologic studies of impulsive violence are discussed. Finally we describe data on the effect of degenerative diseases on the serotonin system and the possible link to increased suicidal behavior in affected patients. This review underscores the need for further study of the biology of suicide in the geriatric age group.  相似文献   
16.
ABSTRACT In this essay the argument set forth by Michael Levin regarding the abnormality of homosexual behaviour is reviewed and criticized. Against his argument which holds that homosexual behaviour is abnormal because it constitutes an evolutionary aberration, I argue that Levin's and all similarly constructed arguments fail to show that evolutionary origins of sexual behaviour have any significant normative force. I contend that his notion of homosexuality is confused and that he fails to consider alternative methods of how homosexuality might have indeed served evolutionary adaptive purposes or been the result of surplus adaptations. I argue, too, that Levin's linking of unhappiness with homosexual behaviour is spurious and ill-supported. Consequently, I reject Levin's claims that public policy ought to do what it can to minimize the incidence of such behaviour. I argue by contrast that if happiness is the end of public policy decisions, then society ought to take what measures it can to protect persons in respect of their homosexual behaviour and identities.  相似文献   
17.
Convergent and divergent stereo mechanisms were compared in their ability to recover structure from motion. Contrary to a recent result reported by Richards and Lieberman, no difference in their performance was found; both mechanisms appeared equally capable of supporting the perception of good structure from motion. Possible reasons for the disparate results are discussed.  相似文献   
18.
19.
20.
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