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   23813篇
  免费   1072篇
  国内免费   9篇
  2021年   196篇
  2020年   319篇
  2019年   329篇
  2018年   516篇
  2017年   494篇
  2016年   513篇
  2015年   386篇
  2014年   463篇
  2013年   1952篇
  2012年   889篇
  2011年   882篇
  2010年   579篇
  2009年   449篇
  2008年   747篇
  2007年   709篇
  2006年   654篇
  2005年   537篇
  2004年   481篇
  2003年   426篇
  2002年   466篇
  2001年   874篇
  2000年   857篇
  1999年   603篇
  1998年   226篇
  1997年   217篇
  1996年   212篇
  1992年   477篇
  1991年   446篇
  1990年   462篇
  1989年   390篇
  1988年   374篇
  1987年   371篇
  1986年   353篇
  1985年   360篇
  1984年   323篇
  1983年   272篇
  1982年   203篇
  1979年   326篇
  1978年   231篇
  1977年   196篇
  1975年   266篇
  1974年   327篇
  1973年   318篇
  1972年   253篇
  1971年   260篇
  1970年   219篇
  1969年   254篇
  1968年   283篇
  1967年   276篇
  1966年   209篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
This paper was not available at the time of going to press. It will be published in a future volume of the Proceedings of The Aristotelian Society.  相似文献   
12.
The three reliability and two construct validity studies presented here represent the first psychometric research on the commercially successful and popular Hartman Color Code Personality Profile. The reliability studies found high reliability after 3 and 6 weeks. The construct validity studies substantiated that the Color Code assesses some personality traits. The magnitude of the error variance suggests caution, however, in using the Color Code classifications at the individual level.  相似文献   
13.
14.
OBJECTIVE: Compare the efficacy of a multicomponent social support intervention to standard-of-care counseling on medication adherence among HIV-infected patients initiating antiretroviral therapy. DESIGN: Randomized controlled trial. Generalized estimating equations tested for differences in the percentage of participants achieving 90% adherence. MAIN OUTCOME MEASURES: Pill-taking, electronically monitored over 6 consecutive months; plasma viral load (VL), assessed at 3 and 6 months following initiation of therapy. RESULTS: Of 226 participants who were randomized and began the trial, 87 (38%) were lost to the study by 6 months. The proportion of adherent participants declined steadily over time, with no time by group interaction. Sustained adherence was associated with increased odds of achieving an undetectable VL (OR=1.78; 95% CI=1.01, 3.13). In intention-to-treat analyses, a larger proportion of the intervention group than the control group was adherent (40.15% vs. 27.59%, p=.02) and achieved an undetectable VL p=.04). However, the majority of participants who remained on study experienced some reduction in VL (>or=1-log drop or undetectable), regardless of experimental condition. CONCLUSION: The multicomponent social support intervention significantly improved medication adherence over standard-of-care counseling; evidence for improved virologic outcomes was inconsistent. Early discontinuation of care and treatment may be a greater threat to the health of HIV patients than imperfect medication-taking.  相似文献   
15.
16.
17.
陈莲笙道长生于1917年10月25日,上海市人.历任中国道教协会副会长,中国道教协会顾问,上海市道教协会会长.上海市道教协会名誉会长,上海城隍庙住持,上海道学院院长,<上海道教>杂志主编,上海市宗教学会理事,上海市政协第七届委员,上海市政协第八、九届常委等职.  相似文献   
18.
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   
19.
Book reviews     
TOATES, F. Animal Behaviour: A Systems Approach. Chichester: John Wiley and Sons. 1980. Pp. 299. Hardback £17. Paper back £6.40 ISBN 0 471 27724.

DICKINSON, A. Contemporary Animal Learning Theory. Cambridge: University Press. 1980. Pp. 177. Hardback £12.50. Paperback £3.95. ISBN 0 521 23469 7.  相似文献   
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