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   58613篇
  免费   1552篇
  国内免费   15篇
  2020年   466篇
  2019年   602篇
  2018年   4052篇
  2017年   3452篇
  2016年   2963篇
  2015年   792篇
  2014年   841篇
  2013年   3242篇
  2012年   1865篇
  2011年   3606篇
  2010年   3220篇
  2009年   2239篇
  2008年   2823篇
  2007年   3291篇
  2006年   1144篇
  2005年   1171篇
  2004年   1069篇
  2003年   952篇
  2002年   945篇
  2001年   1223篇
  2000年   1193篇
  1999年   900篇
  1998年   420篇
  1997年   428篇
  1996年   375篇
  1995年   367篇
  1994年   358篇
  1993年   360篇
  1992年   755篇
  1991年   659篇
  1990年   721篇
  1989年   621篇
  1988年   648篇
  1987年   600篇
  1986年   618篇
  1985年   559篇
  1984年   510篇
  1983年   492篇
  1982年   357篇
  1979年   571篇
  1978年   406篇
  1975年   460篇
  1974年   501篇
  1973年   541篇
  1972年   396篇
  1971年   395篇
  1970年   356篇
  1969年   403篇
  1968年   477篇
  1967年   433篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
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   
45.
46.
Previous work on children's intuitive knowledge about the natural world has documented their difficulty in acquiring an overarching concept of biological life that includes plants as well as humans and non‐human animals. It has also suggested that the acquisition of fundamental biological concepts like alive and die may be influenced by the language used to describe them, as evidenced by differences between English‐ and Indonesian‐speaking children's performance in tasks involving these concepts. Here, we examine one particularly important source of linguistic information available to children during this acquisition process: everyday conversations with their parents. We take a cross‐linguistic approach in analysing the evidence available to English‐ and Indonesian‐speaking children as they acquire meanings for words corresponding to the concepts alive and die . Our analysis illustrates that young children acquiring English and Indonesian are faced with distinct problems, but that parental input in both languages does little to support the acquisition of broad, inclusive biological concepts.  相似文献   
47.
The current study was designed to gain a better understanding of the nature of the relationship between substance use and sexual risk taking within a community sample of women (N = 1,004). Using confirmatory factor analysis, the authors examined the factor structure of sexual risk behaviors and substance use to determine whether they are best conceptualized as domains underlying a single, higher order, risk-taking propensity. A 2 higher order factor model (sexual risk behavior and substance use) provided the best fit to the data, suggesting that these 2 general risk domains are correlated but independent factors. Sensation seeking had large general direct effects on the 2 risk domains and large indirect effects on the 4 first-order factors and the individual indicators. Negative affect had smaller, yet still significant, effects. Impulsivity and anxiety were unrelated to sexual health risk domains.  相似文献   
48.
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