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   60935篇
  免费   2752篇
  国内免费   18篇
  63705篇
  2020年   585篇
  2019年   773篇
  2018年   1102篇
  2017年   1139篇
  2016年   1220篇
  2015年   880篇
  2014年   986篇
  2013年   4552篇
  2012年   1832篇
  2011年   2029篇
  2010年   1244篇
  2009年   1280篇
  2008年   1758篇
  2007年   1778篇
  2006年   1614篇
  2005年   1411篇
  2004年   1302篇
  2003年   1234篇
  2002年   1339篇
  2001年   1986篇
  2000年   1962篇
  1999年   1483篇
  1998年   699篇
  1997年   620篇
  1996年   619篇
  1995年   564篇
  1992年   1250篇
  1991年   1146篇
  1990年   1138篇
  1989年   1033篇
  1988年   1019篇
  1987年   975篇
  1986年   1049篇
  1985年   1063篇
  1984年   882篇
  1983年   805篇
  1982年   568篇
  1981年   571篇
  1979年   943篇
  1978年   676篇
  1975年   767篇
  1974年   826篇
  1973年   910篇
  1972年   770篇
  1971年   724篇
  1970年   644篇
  1969年   668篇
  1968年   857篇
  1967年   776篇
  1966年   655篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
251.
Although stress and anxiety have long been assumed to play an exacerbatory role in asthma, no study has systematically documented that daily exacerbations of asthma symptoms are related to stress and/or anxiety. In this study, 24 airways obstruction patients (12 asthmatics and 12 chronic obstructive pulmonary disease patients) were instructed to monitor the severity of daily respiratory symptoms. In addition, subjects recorded their daily anxiety level and the number and perceived impact of daily stressors. The results showed that although there were differences between high- and low-stress days for both groups, there were no differences between groups on symptom severity or between high- and low-anxiety days, as measured by the State-Trait Anxiety Inventory (STAI). Thus, although the number and impact of daily stressors were found to be directly associated with the severity of asthma symptoms, anxiety does not appear to have a direct role in the exacerbation of asthma. The findings failed to support the anxiety theory of asthma but provided an explanation for the poor results obtained in previous treatment studies which employed anxiety management with asthmatics.  相似文献   
252.
Two multidimensional mood-state inventories, the Profile of Mood States (POMS) and the Eight State Questionnaire (8SQ), were administered to 289 Australian college undergraduates. Intercorrelations for the combined 14 subscales were subjected to a higher-order factor analysis in order to elucidate the central clinical states within the mood-state sphere. Results suggested four major state dimensions pertaining to Neuroticism, Hostility/Anger, Vigor, and a combined Extroversion/Arousal-Fatigue entity. Both three- and five-factor solutions were taken out for comparative purposes. Furthermore, separate higher-order factorings of the POMS on normative samples of 350 male and 650 female psychiatric outpatients were conducted, corroborating three of the four central state dimensions, at least in the case of females. The implications of these findings for behavioral assessment are discussed.This study was supported by a Research Development Grant awarded to the author by the University of Melbourne.  相似文献   
253.
A comparison study is an experiment whose primary purpose is to compare directly (regardless of experimental design) at least two different procedures for changing behavior or two or more components of such a procedure. This paper argues that, in spite of their popularity, such studies typically lead to inappropriate inferences with poor generality based on improper evidence gathered in support of the wrong question, thus wasting the limited experimental resources. The discussion considers problems concerning the functions of comparison studies, the nature of the comparisons that are attempted, the generality of their findings, and the limited role that they can play in technological research.  相似文献   
254.
255.
256.
257.
258.
259.
260.
In contrast to theoretical discussions about potential professional liability of clinical ethicists, this report gives the results of empirical data gathered in a national survey of clinical medical ethicists. The report assesses the types of activities of clinical ethicists, the extent and types of their professional liability coverage, and the influence that concerns about legal liability has on how they function as clinical ethicists. In addition demographic data on age, sex, educational background, etc. are reported. The results show that while nearly one third (28.9%) of the ethicists regularly make recommendations about patient care, only 10.8% of them regularly make entries in the medical record; only approximately half (53.0%) of them are covered by professional liability (malpractice) insurance; and the vast majority (84.3%) of them say that concerns about legal liability do not influence the way they function as clinical ethicists.  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