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   38480篇
  免费   1486篇
  国内免费   21篇
  2019年   486篇
  2018年   674篇
  2017年   720篇
  2016年   705篇
  2015年   532篇
  2014年   636篇
  2013年   3259篇
  2012年   1032篇
  2011年   1168篇
  2010年   772篇
  2009年   803篇
  2008年   1037篇
  2007年   1003篇
  2006年   924篇
  2005年   800篇
  2004年   762篇
  2003年   811篇
  2002年   768篇
  2001年   1299篇
  2000年   1247篇
  1999年   927篇
  1998年   477篇
  1997年   422篇
  1996年   395篇
  1994年   395篇
  1993年   411篇
  1992年   827篇
  1991年   778篇
  1990年   737篇
  1989年   698篇
  1988年   664篇
  1987年   667篇
  1986年   621篇
  1985年   681篇
  1984年   568篇
  1983年   464篇
  1982年   410篇
  1981年   400篇
  1979年   560篇
  1978年   456篇
  1977年   426篇
  1976年   400篇
  1975年   529篇
  1974年   524篇
  1973年   546篇
  1972年   453篇
  1971年   394篇
  1968年   430篇
  1967年   387篇
  1966年   440篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
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   
43.
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   
44.
45.
46.
47.
48.
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   
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