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   39493篇
  免费   1477篇
  国内免费   13篇
  40983篇
  2019年   437篇
  2018年   639篇
  2017年   580篇
  2016年   674篇
  2015年   490篇
  2014年   589篇
  2013年   3786篇
  2012年   973篇
  2011年   1034篇
  2010年   667篇
  2009年   647篇
  2008年   986篇
  2007年   881篇
  2006年   826篇
  2005年   695篇
  2004年   670篇
  2003年   708篇
  2002年   686篇
  2001年   1244篇
  2000年   1205篇
  1999年   918篇
  1998年   412篇
  1996年   523篇
  1995年   503篇
  1994年   497篇
  1993年   460篇
  1992年   939篇
  1991年   842篇
  1990年   839篇
  1989年   746篇
  1988年   740篇
  1987年   727篇
  1986年   739篇
  1985年   706篇
  1984年   636篇
  1983年   531篇
  1982年   433篇
  1981年   437篇
  1979年   599篇
  1978年   452篇
  1975年   559篇
  1974年   548篇
  1973年   605篇
  1972年   582篇
  1971年   519篇
  1970年   471篇
  1969年   440篇
  1968年   565篇
  1967年   492篇
  1966年   470篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
23.
The ability to make egocentric distance estimates of a single point source of light, seen in darkness and without the cues of changing size and luminance, was investigated in sixteen observers. The attenuation required to maintain constant luminance, when the target was viewed from different distances, was shown to follow the inverse square law providing the angle subtended by the light was less than 20 s arc. Distance changes were also simulated by means of a split mirror which produced vergence cues, or by test lenses to provide accommodation cues. Over the range 0.5 to 9.2 m distance estimates were surprisingly accurate, although there was some overestimation of near and underestimation of far distances. Most observers made good judgements when only convergence cues were varied, whereas no observers made consistently good judgements when only accommodation cues were varied. The difficulties are discussed in terms of the accommodation-convergence link. When distance was simulated by changing convergence and accommodation cues, estimates were not as good as when real distance was changed. Since good estimates were made with brief target exposures, these judgements were not based on subsequent convergence or accommodation changes. It is suggested that the metric or reference against which the apparently absolute judgements were made was the efferent demand signal associated with a 'resting' position of convergence in darkness.  相似文献   
24.
25.
26.
Previous research suggests that children gradually understand the mitigating effects of apology on damage to a transgressor's reputation. However, little is known about young children's insights into the central emotional implications of apology. In two studies, children ages 4–9 heard stories about moral transgressions in which the wrongdoers either did or did not apologize. In Study 1, children in the no‐apology condition showed the classic pattern of ‘happy victimizer’ attributions by expecting the wrongdoer to feel good about gains won via transgression. By contrast, in the apology condition, children attributed negative feelings to the transgressor and improved feelings to the victim. In Study 2, these effects were found even when the explicit emotion marker ‘sorry’ was removed from the apology exchange. Thus, young children understand some important emotional functions of apology.  相似文献   
27.
28.
29.
A meta-analysis of published studies with adult human participants was conducted to evaluate whether physical fitness attenuates cardiovascular reactivity and improves recovery from acute psychological stressors. Thirty-three studies met selection criteria; 18 were included in recovery analyses. Effect sizes and moderator influences were calculated by using meta-analysis software. A fixed effects model was fit initially; however, between-studies heterogeneity could not be explained even after inclusion of moderators. Therefore, to account for residual heterogeneity, a random effects model was estimated. Under this model, fit individuals showed significantly attenuated heart rate and systolic blood pressure reactivity and a trend toward attenuated diastolic blood pressure reactivity. Fit individuals also showed faster heart rate recovery, but there were no significant differences in systolic blood pressure or diastolic blood pressure recovery. No significant moderators emerged. Results have important implications for elucidating mechanisms underlying effects of fitness on cardiovascular disease and suggest that fitness may be an important confound in studies of stress reactivity.  相似文献   
30.
Book reviews     
  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