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   61269篇
  免费   2471篇
  国内免费   268篇
  2020年   613篇
  2019年   848篇
  2018年   1095篇
  2017年   1178篇
  2016年   1150篇
  2015年   821篇
  2014年   991篇
  2013年   4681篇
  2012年   1778篇
  2011年   1941篇
  2010年   1238篇
  2009年   1222篇
  2008年   1730篇
  2007年   1665篇
  2006年   1593篇
  2005年   1384篇
  2004年   1276篇
  2003年   1241篇
  2002年   1243篇
  2001年   2019篇
  2000年   1897篇
  1999年   1416篇
  1998年   713篇
  1997年   587篇
  1992年   1174篇
  1991年   1141篇
  1990年   1093篇
  1989年   1052篇
  1988年   1035篇
  1987年   989篇
  1986年   999篇
  1985年   1080篇
  1984年   873篇
  1983年   757篇
  1982年   616篇
  1981年   601篇
  1979年   924篇
  1978年   690篇
  1977年   608篇
  1976年   623篇
  1975年   799篇
  1974年   849篇
  1973年   925篇
  1972年   742篇
  1971年   655篇
  1970年   644篇
  1969年   683篇
  1968年   820篇
  1967年   710篇
  1966年   758篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
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   
56.
According to the Body‐Specificity Hypothesis (BSH), people implicitly associate positive ideas with the side of space on which they are able to act more fluently with their dominant hand. Though this hypothesis has been rigorously tested across a variety of populations and tasks, the studies thus far have only been conducted in linguistic and cultural communities which favor the right over the left. Here, we tested the effect of handedness on implicit space‐valence mappings in Tibetan practitioners of Bön who show a strong religious preference for the left, in comparison to an English group. Results showed that Bön right‐handers tended to implicitly associate positive valence more strongly with their dominant side of space despite strong explicit associations between the left and goodness in their religion. This pattern of results found in Bön participants was indistinguishable from that found in English speakers. The findings of the present study support the BSH, demonstrating that space‐valence mappings in people's minds are shaped by their bodily experience, which appears to be independent of space‐valence mappings enshrined in cultural conventions.  相似文献   
57.
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   
58.
59.
This study addresses the demands of alternating bimanual syncopation, a coordination mode in which the two hands move in alternation while tapping in antiphase with a metronomic tone sequence. Musically trained participants were required to engage in alternating bimanual syncopation and five other coordination modes: unimanual syncopation where taps are made (with the left or right hand) after every tone; unimanual syncopation where taps are made after every other tone; bimanual synchronization with alternating hands; unimanual synchronized tapping with every tone; and unimanual tapping with every other tone. Variability in tap timing was greatest overall for alternating bimanual syncopation, indicating that it is the most difficult. This appears to be due to instability arising from the simultaneous presence of two levels of antiphase coordination (one between the pacing sequence and the hands, the other between the two hands) rather than factors relating to movement frequency or dexterity limits of the nonpreferred hand.  相似文献   
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