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   177191篇
  免费   7808篇
  国内免费   163篇
  185162篇
  2021年   1515篇
  2020年   2798篇
  2019年   3462篇
  2018年   3635篇
  2017年   4057篇
  2016年   4724篇
  2015年   3938篇
  2014年   4832篇
  2013年   23609篇
  2012年   4842篇
  2011年   3931篇
  2010年   4024篇
  2009年   4844篇
  2008年   4131篇
  2007年   3728篇
  2006年   4270篇
  2005年   4164篇
  2004年   3668篇
  2003年   3279篇
  2002年   3108篇
  2001年   3392篇
  2000年   3227篇
  1999年   3235篇
  1998年   2839篇
  1997年   2678篇
  1996年   2582篇
  1995年   2444篇
  1994年   2399篇
  1993年   2346篇
  1992年   2695篇
  1991年   2484篇
  1990年   2386篇
  1989年   2261篇
  1988年   2260篇
  1987年   2260篇
  1986年   2228篇
  1985年   2415篇
  1984年   2543篇
  1983年   2336篇
  1982年   2373篇
  1981年   2350篇
  1980年   2193篇
  1979年   2255篇
  1978年   2208篇
  1977年   2158篇
  1976年   1974篇
  1975年   2042篇
  1974年   2092篇
  1973年   1988篇
  1972年   1536篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
143.
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   
144.
145.
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   
146.
147.
148.
149.
陈莲笙道长生于1917年10月25日,上海市人.历任中国道教协会副会长,中国道教协会顾问,上海市道教协会会长.上海市道教协会名誉会长,上海城隍庙住持,上海道学院院长,<上海道教>杂志主编,上海市宗教学会理事,上海市政协第七届委员,上海市政协第八、九届常委等职.  相似文献   
150.
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   
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