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   57231篇
  免费   1451篇
  国内免费   20篇
  2020年   418篇
  2019年   513篇
  2018年   4022篇
  2017年   3371篇
  2016年   2905篇
  2015年   743篇
  2014年   714篇
  2013年   3094篇
  2012年   1678篇
  2011年   3523篇
  2010年   3202篇
  2009年   2214篇
  2008年   2709篇
  2007年   3135篇
  2006年   1007篇
  2005年   1086篇
  2004年   990篇
  2003年   945篇
  2002年   866篇
  2001年   1333篇
  2000年   1288篇
  1999年   961篇
  1998年   478篇
  1997年   407篇
  1996年   380篇
  1995年   368篇
  1994年   372篇
  1993年   360篇
  1992年   800篇
  1991年   765篇
  1990年   729篇
  1989年   655篇
  1988年   625篇
  1987年   629篇
  1986年   599篇
  1985年   669篇
  1984年   529篇
  1983年   431篇
  1981年   360篇
  1979年   518篇
  1978年   404篇
  1977年   391篇
  1976年   360篇
  1975年   461篇
  1974年   470篇
  1973年   510篇
  1972年   404篇
  1968年   412篇
  1967年   358篇
  1966年   420篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
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   
42.
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   
43.
44.
45.
46.
47.
48.
49.
OBJECTIVE: To examine dysregulation in biological measures associated with histories of abuse in women and whether women with premenstrual dysphoric disorder (PMDD) differ in their dysregulation. DESIGN: Twenty-five women meeting prospective criteria for PMDD and 42 non-PMDD controls underwent structured interview to determine abuse histories and lifetime Axis I diagnoses, excluding those with current Axis I disorders or using medications. MAJOR OUTCOME MEASURES: Plasma cortisol and norepinephrine (NE), heart rate (HR), blood pressure (BP), and vascular resistance index (VRI) were assessed at rest and in response to mental stress. RESULTS: A greater proportion of PMDD women had prior abuse compared with non-PMDD women. Regardless of PMDD status, all abused women had lower plasma NE and higher HRs and tended to have lower plasma cortisol at rest and during stress. Abused women also reported more severe daily emotional and physical symptoms. Greater VRI and BP at rest and during stress were seen only in PMDD women with abuse. CONCLUSION: There is persistent dysregulation in stress-responsive systems in all abused women that cannot be accounted for by current psychiatric illness or medications, and PMDD women may be differentially more vulnerable to the impact of abuse on measures reflecting alpha-adrenergic receptor function.  相似文献   
50.
This article discusses the meaning of epistemological violence in the empirical social sciences. It is argued that the concept is closer to personal than to structural violence in that it has a subject, an object, and an action, even if the violence is indirect and nonphysical: the subject of violence is the researcher, the object is the Other, and the action is the interpretation of data that is presented as knowledge. Using a hypothetical example, the problem of interpretation in empirical research on the Other is discussed. Epistemological violence refers to the interpretation of social-scientific data on the Other and is produced when empirical data are interpreted as showing the inferiority of or problematizes the Other, even when data allow for equally viable alternative interpretations. Interpretations of inferiority or problematizations are understood as actions that have a negative impact on the Other. Because the interpretations of data emerge from an academic context and thus are presented as knowledge, they are defined as epistemologically violent actions. Problems, consequences, and practices surrounding this concept are discussed.  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