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   54265篇
  免费   2160篇
  国内免费   28篇
  2020年   591篇
  2019年   737篇
  2018年   1096篇
  2017年   1150篇
  2016年   1127篇
  2015年   832篇
  2014年   919篇
  2013年   4465篇
  2012年   1670篇
  2011年   1817篇
  2010年   1151篇
  2009年   1036篇
  2008年   1568篇
  2007年   1489篇
  2006年   1359篇
  2005年   1149篇
  2004年   1050篇
  2003年   1068篇
  2002年   1038篇
  2001年   1822篇
  2000年   1784篇
  1999年   1291篇
  1998年   575篇
  1997年   486篇
  1996年   497篇
  1992年   1089篇
  1991年   1049篇
  1990年   1012篇
  1989年   944篇
  1988年   934篇
  1987年   900篇
  1986年   873篇
  1985年   944篇
  1984年   745篇
  1983年   615篇
  1981年   481篇
  1979年   772篇
  1978年   566篇
  1977年   511篇
  1976年   489篇
  1975年   655篇
  1974年   743篇
  1973年   795篇
  1972年   640篇
  1971年   587篇
  1970年   553篇
  1969年   551篇
  1968年   701篇
  1967年   618篇
  1966年   645篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
41.
Although perceived health risk plays a prominent role in theories of health behavior, its empirical role in risk taking is less clear. In Study 1 (N = 129), 2 measures of drivers' risk-taking behavior were found to be unrelated to self-estimates of accident concern but to be related to self-ratings of driving skill and the perceived thrill of driving. In Study 2 (N = 405), out of a wide range of potential influences, accident concern had the weakest relationship with risk taking. The authors concluded that although health risk is a key feature in many theories of health behavior and a central focus for researchers and policy makers, it may not be such a prominent factor for those actually taking the risk.  相似文献   
42.
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.  相似文献   
43.
44.
45.
46.
47.
OBJECTIVE: This report reviews the evidence that informs the role of health and mental health care providers in addressing youth smoking cessation. DESIGN: Qualitative literature review. RESULTS: Physicians do not consistently screen adolescents for tobacco use and fail to provide recommended cessation advice. Challenges to addressing smoking cessation include the need for procedures to ensure confidentiality and the existence of competing demands to provide other services. Few published studies have specifically addressed the effectiveness of clinical interventions. Interventions that require return visits or follow-up phone contacts are technically difficult to implement in this population. Successful interventions may require resources not available in nonresearch settings. Most studies have used brief clinical intervention as a control condition, making it impossible to evaluate its effectiveness. CONCLUSION: There is little evidence that supports current clinical smoking cessation guidelines for adolescents. More research is needed to develop inexpensive, efficient clinical interventions that can provide youths access to smoking cessation help. Future challenges include reorganizing clinical systems to offer greater counseling by support staff or in electronic formats and to provide effective booster messages and follow-up care in a population that is difficult to track.  相似文献   
48.
An electronic apparatus using infrared beams for monitoring the movements of individual bees under dark conditions is described. The searching behavior of workers in an arena was monitored over 2-h periods. Mean ambulatory velocity for one bee over a distance of 100 mm was 45.6±1.51 mm/sec (n=45). Thigmokinesis and temporal activity patterns are illustrated.  相似文献   
49.
50.
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