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   53759篇
  免费   2003篇
  国内免费   27篇
  2020年   558篇
  2019年   661篇
  2018年   960篇
  2017年   1047篇
  2016年   1014篇
  2015年   731篇
  2014年   887篇
  2013年   4289篇
  2012年   1530篇
  2011年   1659篇
  2010年   1072篇
  2009年   1050篇
  2008年   1473篇
  2007年   1425篇
  2006年   1305篇
  2005年   1107篇
  2004年   1042篇
  2003年   1066篇
  2002年   1043篇
  2001年   1830篇
  2000年   1811篇
  1999年   1312篇
  1998年   604篇
  1997年   499篇
  1992年   1096篇
  1991年   1042篇
  1990年   1039篇
  1989年   962篇
  1988年   934篇
  1987年   932篇
  1986年   902篇
  1985年   966篇
  1984年   781篇
  1983年   634篇
  1982年   515篇
  1981年   495篇
  1979年   804篇
  1978年   605篇
  1977年   561篇
  1976年   509篇
  1975年   733篇
  1974年   760篇
  1973年   793篇
  1972年   685篇
  1971年   584篇
  1970年   547篇
  1969年   629篇
  1968年   706篇
  1967年   630篇
  1966年   678篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
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   
53.
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   
54.
55.
56.
57.
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   
58.
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   
59.
60.
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