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   52149篇
  免费   2155篇
  国内免费   37篇
  54341篇
  2020年   552篇
  2019年   693篇
  2018年   972篇
  2017年   981篇
  2016年   1113篇
  2015年   759篇
  2014年   909篇
  2013年   4202篇
  2012年   1649篇
  2011年   1669篇
  2010年   1015篇
  2009年   1048篇
  2008年   1371篇
  2007年   1439篇
  2006年   1250篇
  2005年   1129篇
  2004年   1080篇
  2003年   1024篇
  2002年   1053篇
  2001年   1703篇
  2000年   1652篇
  1999年   1255篇
  1998年   533篇
  1996年   515篇
  1995年   498篇
  1992年   1020篇
  1991年   964篇
  1990年   950篇
  1989年   884篇
  1988年   897篇
  1987年   815篇
  1986年   832篇
  1985年   871篇
  1984年   717篇
  1983年   632篇
  1982年   500篇
  1979年   789篇
  1978年   566篇
  1977年   496篇
  1976年   494篇
  1975年   617篇
  1974年   754篇
  1973年   792篇
  1972年   665篇
  1971年   603篇
  1970年   579篇
  1969年   567篇
  1968年   720篇
  1967年   629篇
  1966年   593篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
OBJECTIVE: To examine dysregulation in biological measures associated with histories of abuse in women and whether women with premenstrual dysphoric disorder (PMDD) differ in their dysregulation. DESIGN: Twenty-five women meeting prospective criteria for PMDD and 42 non-PMDD controls underwent structured interview to determine abuse histories and lifetime Axis I diagnoses, excluding those with current Axis I disorders or using medications. MAJOR OUTCOME MEASURES: Plasma cortisol and norepinephrine (NE), heart rate (HR), blood pressure (BP), and vascular resistance index (VRI) were assessed at rest and in response to mental stress. RESULTS: A greater proportion of PMDD women had prior abuse compared with non-PMDD women. Regardless of PMDD status, all abused women had lower plasma NE and higher HRs and tended to have lower plasma cortisol at rest and during stress. Abused women also reported more severe daily emotional and physical symptoms. Greater VRI and BP at rest and during stress were seen only in PMDD women with abuse. CONCLUSION: There is persistent dysregulation in stress-responsive systems in all abused women that cannot be accounted for by current psychiatric illness or medications, and PMDD women may be differentially more vulnerable to the impact of abuse on measures reflecting alpha-adrenergic receptor function.  相似文献   
32.
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   
33.
34.
35.
36.
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   
37.
38.
39.
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   
40.
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