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   2356933篇
  免费   174784篇
  国内免费   5655篇
耳鼻咽喉   30839篇
儿科学   76609篇
妇产科学   65485篇
基础医学   348485篇
口腔科学   65594篇
临床医学   227345篇
内科学   452766篇
皮肤病学   48676篇
神经病学   193648篇
特种医学   85842篇
外国民族医学   604篇
外科学   329146篇
综合类   51053篇
现状与发展   4篇
一般理论   1004篇
预防医学   201121篇
眼科学   52558篇
药学   173752篇
  12篇
中国医学   4830篇
肿瘤学   127999篇
  2019年   19636篇
  2018年   26830篇
  2017年   20409篇
  2016年   22213篇
  2015年   25434篇
  2014年   35294篇
  2013年   54523篇
  2012年   74406篇
  2011年   79196篇
  2010年   46003篇
  2009年   43195篇
  2008年   73284篇
  2007年   78038篇
  2006年   77722篇
  2005年   75608篇
  2004年   72419篇
  2003年   69089篇
  2002年   66932篇
  2001年   102653篇
  2000年   105314篇
  1999年   88771篇
  1998年   25649篇
  1997年   23266篇
  1996年   23251篇
  1995年   22109篇
  1994年   20650篇
  1993年   19330篇
  1992年   70893篇
  1991年   69789篇
  1990年   67677篇
  1989年   64756篇
  1988年   60018篇
  1987年   58854篇
  1986年   56146篇
  1985年   53569篇
  1984年   40501篇
  1983年   35109篇
  1982年   21115篇
  1979年   37880篇
  1978年   27479篇
  1977年   22677篇
  1976年   21783篇
  1975年   22764篇
  1974年   27833篇
  1973年   27393篇
  1972年   25577篇
  1971年   23895篇
  1970年   22363篇
  1969年   20749篇
  1968年   19575篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
Background: Lay belief systems about the malleability of human attributes have been shown to impact behavior change in multiple domains. Addiction mindset—i.e., beliefs about the permanence (vs. malleability) of addiction — may affect cigarette smokers’ ability to quit, but this has never been examined. Objectives: The aims of the present research were to develop a measure of addiction mindset (study 1) and examine its associations with various psychological aspects of quitting smoking (study 2). Methods: In Study 1, using factor analysis of current smokers’ and nonsmokers’ (n?=?600) responses to 22 items designed to measure addiction mindset, we developed a reliable six-item Addiction Mindset Scale (AMS). In Study 2, adult smokers (n?=?200) completed the AMS, and measures of a number of psychological processes related to smoking. Results: Higher scores on the AMS, indicative of the belief that addiction is malleable (referred to as a growth mindset), were positively and significantly associated with greater motivation to quit, greater commitment to quitting, greater self-efficacy to abstain, less attribution of failure to lack of ability to change addiction, and fewer self-reported barriers to cessation (all p’s < .05). Conclusions: The results of this study show a relationship between the beliefs about the permanence of addiction and psychological processes relevant to quitting smoking. The findings underscore the potential of future research exploring how addiction mindsets relate to successful smoking cessation as well as other types of addictive behavior and how they can be applied to change people’s behavior.  相似文献   
43.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
44.
Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...  相似文献   
45.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
46.
47.
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