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   33911篇
  免费   1353篇
  国内免费   20篇
  2020年   378篇
  2019年   517篇
  2018年   680篇
  2017年   757篇
  2016年   721篇
  2015年   519篇
  2014年   579篇
  2013年   2715篇
  2012年   987篇
  2011年   1085篇
  2010年   722篇
  2009年   693篇
  2008年   980篇
  2007年   928篇
  2006年   868篇
  2005年   713篇
  2004年   657篇
  2003年   691篇
  2002年   622篇
  2001年   1223篇
  2000年   1185篇
  1999年   861篇
  1998年   374篇
  1997年   310篇
  1995年   308篇
  1994年   314篇
  1992年   730篇
  1991年   699篇
  1990年   669篇
  1989年   615篇
  1988年   587篇
  1987年   584篇
  1986年   554篇
  1985年   612篇
  1984年   476篇
  1983年   373篇
  1979年   466篇
  1978年   344篇
  1977年   331篇
  1976年   309篇
  1975年   415篇
  1974年   417篇
  1973年   476篇
  1972年   384篇
  1971年   320篇
  1970年   309篇
  1969年   327篇
  1968年   378篇
  1967年   334篇
  1966年   385篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Suicides among older adults in the United States and Canada in the last decade have accounted for an increasing share of all suicides. In both countries the use of firearms among older adults has steadily increased. Despite these trends, little is known about the extent to which crisis centers are prepared to prevent elder suicide. A survey of AAS-listed crisis prevention centers examined the training, knowledge, and current practices relevant to elder suicide among personnel in 321 crisis prevention centers in both countries. Results revealed insufficient training, a lack of familiarity with recent suicide trends, and limited outreach to older adults.  相似文献   
42.
Cancellation tests are commonly used in the clinical assessment of visuospatial function, but there has been little study of task characteristics influencing performance. This study was designed to assess factors which affect cancellation performance. Sixteen healthy subjects sequentially performed four random-array letter cancellation tasks. The forms contained 50 and 100 stimuli and target:distractor (T/D) ratios of 1:4 and 1:9 with target letter “A” and randomly selected letter distractors. The primary performance measure was calculated as the number of correctly cancelled targets divided by the time to complete the task, corrected for accuracy. This measure revealed a strong effect of T/D ratio (p< .0001), with performance adversely affected by higher proportion of distractors. There was no effect of stimulus number. This suggests that T/D ratio should be considered in cancellation test design and interpretation.  相似文献   
43.
44.
45.
46.
The token economy has been the primary model for the behavioral management of inpatient populations. However, this basically operant approach seldom emphasizes the development of cognitive-coping skills to help patients more effectively manage stressors that result in hospitalization. The Therapeutic Contract Program (TCP) is described as an inpatient-treatment strategy that is designed to help foster such cognitive-coping and self-control skills. While external structure is provided by components of this program, subprograms of the TCP have as their goal the development of internally-attributed coping skills and self-perceptions of competence. This preliminary report describes the structure of the TCP, as well as planned and in-progress measures of program participation and treatment outcome.  相似文献   
47.
48.
49.
50.
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