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   80525篇
  免费   3308篇
  国内免费   37篇
  83870篇
  2020年   902篇
  2019年   1102篇
  2018年   1565篇
  2017年   1633篇
  2016年   1651篇
  2015年   1203篇
  2014年   1413篇
  2013年   6804篇
  2012年   2601篇
  2011年   2694篇
  2010年   1669篇
  2009年   1682篇
  2008年   2367篇
  2007年   2274篇
  2006年   2108篇
  2005年   1772篇
  2004年   1752篇
  2003年   1726篇
  2002年   1621篇
  2001年   2735篇
  2000年   2609篇
  1999年   1931篇
  1998年   921篇
  1997年   767篇
  1996年   843篇
  1995年   762篇
  1994年   764篇
  1993年   743篇
  1992年   1616篇
  1991年   1507篇
  1990年   1482篇
  1989年   1399篇
  1988年   1374篇
  1987年   1299篇
  1986年   1261篇
  1985年   1361篇
  1984年   1094篇
  1983年   919篇
  1979年   1119篇
  1978年   838篇
  1977年   732篇
  1975年   938篇
  1974年   1026篇
  1973年   1096篇
  1972年   912篇
  1971年   816篇
  1969年   740篇
  1968年   929篇
  1967年   798篇
  1966年   831篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
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   
62.
Despite this virtue's history as an instrument of women's oppression, modesty, at its most basic, means voluntary restraint of one's power, undertaken for the sake of others. It is a mechanism that modifies unequal power relationships and encourages greater compassion and fairness. I use a Christian perspective with influences from Jewish and Muslim sources to examine modesty. The modest person, I argue, must be in relationship with others, must be honestly aware of her impacts on others, must be sensitive to those impacts, compassionate toward others, and willing to hold back for others' sakes. Moreover, modesty is not only a virtue that pertains to sexuality and clothing, but it also can promote virtuous environmental behavior, particularly as it leads to awareness of, and sensitivity to, the effects of everyday behaviors on vulnerable others.  相似文献   
63.
64.
65.
66.
67.
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   
68.
This study examined information communication technologies and workplace friendship dynamics. Employees reported factors that influenced their initiation of friendship with a coworker and reported patterns and perceptions of communication with their workplace friend via different communication methods. Results indicated that personality, shared tasks, and perceived similarity are the most important factors to coworker friendship initiation, and the importance of physical proximity to workplace friendship is diminishing in the electronically connected workplace. Results confirm the primacy of face‐to‐face interaction for workplace friendship initiation and maintenance. E‐mail, phone, and texting were also central to communication among workplace friends. The amount of time spent telecommuting affected workplace friendship initiation and communication. Finally, generational differences were identified with respect to Internet‐based communication methods.  相似文献   
69.
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   
70.
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