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   77827篇
  免费   3051篇
  国内免费   40篇
  2020年   839篇
  2019年   1059篇
  2018年   1486篇
  2017年   1557篇
  2016年   1593篇
  2015年   1091篇
  2014年   1326篇
  2013年   6582篇
  2012年   2330篇
  2011年   2591篇
  2010年   1582篇
  2009年   1587篇
  2008年   2358篇
  2007年   2282篇
  2006年   2025篇
  2005年   1807篇
  2004年   1720篇
  2003年   1659篇
  2002年   1656篇
  2001年   2600篇
  2000年   2517篇
  1999年   1868篇
  1998年   961篇
  1997年   820篇
  1996年   742篇
  1995年   755篇
  1994年   757篇
  1993年   751篇
  1992年   1562篇
  1991年   1496篇
  1990年   1435篇
  1989年   1326篇
  1988年   1262篇
  1987年   1266篇
  1986年   1227篇
  1985年   1349篇
  1984年   1056篇
  1983年   876篇
  1979年   1051篇
  1978年   787篇
  1976年   709篇
  1975年   928篇
  1974年   974篇
  1973年   1007篇
  1972年   867篇
  1971年   745篇
  1969年   717篇
  1968年   866篇
  1967年   818篇
  1966年   803篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
291.
292.
Assessment of methods for measuring social support   总被引:2,自引:0,他引:2  
A rapidly expanding literature documents the effects of social support on physical and psychological well-being. Although definitions vary, most include both tangible components (e.g., financial assistance and physical aid) and intangible components (e.g., encouragement and guidance). Social support has been implicated in the mediation of stressful life events, recovery from illness, and increased program adherence. There are many inconsistent findings in the literature, however, and it is difficult to resolve discrepancies because measures of social support vary widely from study to study. To guide in the selection of measurement methods for research and applied work, 23 techniques for assessing social support are reviewed and evaluated. Criteria for favorable evaluation included reliability coefficients greater than .8 and documentation of validity. Correlations between various social support and criterion measures are simulated in order to demonstrate the consequences of choosing a measure with low reliability. Scale developers reported reliability data for 19 of the reviewed measures. Internal consistency coefficients ranged from .31 to .98. Test-retest coefficients ranged from .22 to .96. At least some validity documentation was available for 13 of the scales. Discriminant validity evidence, however, is almost universally absent. Despite psychometric weaknesses and variability among the scales, researchers have several instruments available to them.  相似文献   
293.
The cynomolgus macaque provides a suitable primate model for studying how psychosocial factors contribute to coronary artery atherogenesis. Important interactions with diet, sex, and behaviorally elicited cardiovascular reactivity are described.  相似文献   
294.
Despite widespread popular belief in the activation of recurrent lesions in genital herpes simplex virus (HSV) by psychosocial stress, little empirical evidence supports that contention. This study retrospectively examined the role of stress in activation of HSV lesions as mediated by social support. Participants were 59 volunteers who had self-reported culture-positive genital HSV for at least 10 months. Measures of stress proneness (State-Trait Anxiety Inventory; STAI-Trait), recent stressful events (Schedule of Recent Events; SRE), and subjective appraisal of stress (global self-rating) were administered along with measures of general social support and herpes-specific social support. When retrospective reports of HSV symptoms were examined using a multiple-regression approach, duration of disease and amount of herpes-specific social support were found to be significant moderators of the relation between stress and number of HSV recurrences in the preceding 12 months. When duration of disease was short (less than 4 years), stress (SRE) and number of recurrences were positively associated; when disease duration was longer, there was no relationship. Similarly, at low levels of herpes-specific social support, a positive relation between stress (SRE) and number of recurrences was found. However, at higher levels of herpes-specific social support, no association was found. No relation was found between stress proneness (STAI-Trait) and HSV symptoms. However, subjective appraisal (global rating) of stress in the preceding 12 months was positively and significantly correlated with reported number of recurrences. Results are discussed in terms of their clinical implications.  相似文献   
295.
This study examined the independent and joint effects of cigarette smoking and caffeine consumption on blood pressure (BP) and heart rate (HR) reactions to stress in male and female college students. Following an initial physiological baseline, participants received one of four experimental treatments (paced smoking, caffeine, smoking plus caffeine, or neither) and had BP and HR measured before, during, and after two stressful tasks. The results revealed that, compared with the control condition, caffeine ingestion enhanced the magnitude of stress-induced systolic BP and HR reactions. Smoking combined additively with stress, and the joint effect of smoking and caffeine was no greater than either taken alone. Males and females were generally similar in their BP and HR responses to smoking, caffeine, and stress. Inconsistencies with previous research and possible physiological mechanisms underlying the observed effects are discussed.  相似文献   
296.
We explored what kind of information is acquired when amnesic patients are able to exhibit significant retention on tests of cued recall and recognition memory. Amnesic patients and control subjects attempted to learn sets of sentences. Memory for the last word in each sentence was tested after 1 hr in the case of the amnesic patients, or after 1 to 2 weeks in the case of (delayed) control subjects. Amnesic patients and (delayed) control subjects performed at similar levels on tests of cued recall and recognition memory. Amnesic patients were just as confident of their correct answers as were control subjects. However, amnesic patients were no more disadvantaged than control subjects when they were cued indirectly by presenting paraphrases of the original sentences. These findings demonstrate that the residual knowledge retained by amnesic patients can be as flexible, as accessible to indirect cues, and as available to awareness as the knowledge retained by (delayed) control subjects.  相似文献   
297.
298.
Correlates of responses to two potential hazards   总被引:2,自引:0,他引:2  
  相似文献   
299.
300.
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