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   37958篇
  免费   1557篇
  国内免费   29篇
  39544篇
  2020年   410篇
  2019年   505篇
  2018年   717篇
  2017年   692篇
  2016年   798篇
  2015年   537篇
  2014年   637篇
  2013年   3108篇
  2012年   1231篇
  2011年   1238篇
  2010年   749篇
  2009年   857篇
  2008年   1092篇
  2007年   1142篇
  2006年   1007篇
  2005年   890篇
  2004年   866篇
  2003年   858篇
  2002年   859篇
  2001年   1150篇
  2000年   1144篇
  1999年   891篇
  1998年   417篇
  1997年   405篇
  1996年   386篇
  1995年   420篇
  1993年   392篇
  1992年   716篇
  1991年   667篇
  1990年   634篇
  1989年   616篇
  1988年   613篇
  1987年   564篇
  1986年   553篇
  1985年   611篇
  1984年   534篇
  1983年   508篇
  1982年   405篇
  1979年   571篇
  1978年   429篇
  1977年   395篇
  1976年   419篇
  1975年   438篇
  1974年   517篇
  1973年   531篇
  1972年   451篇
  1971年   381篇
  1968年   455篇
  1967年   402篇
  1966年   375篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
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   
22.
23.
24.
This study examines the relationship of life stress, daily hassles, and perceived self-efficacy to adjustment in a community sample of 32 men and 32 women between ages 65 and 75. In a structured interview, negative life change events, daily hassles, self-efficacy, depression, psychosomatic symptoms, and negative well being were assessed. Both negative life events and daily hassles were related to psychological distress and physical symptoms for men, and hassles were associated with psychological distress and physical symptoms for women. An inverse relationship between self-efficacy and maladjustment was also found. Hassles showed the most powerful relationship to distress.  相似文献   
25.
A growing literature has observed a significant reduction in pain sensitivity among hypertensive animals and humans. It is uncertain whether a reduced sensitivity to pain can be observed in nonnotensive individuals who go on to develop high blood pressure. Blood pressure (BP) was reassessed in one hundred fifteen 19-year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Hierarchical regression analyses indicated that information regarding pain tolerance improved prediction of changes in systolic and diastolic blood pressure beyond that afforded by differences in BP at age 14, parental history of hypertension, and body mass index. These analyses suggest that pain sensitivity may be associated with physiological processes involved in the development of sustained high blood pressure.  相似文献   
26.
27.
28.
29.
30.
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   
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