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   2393833篇
  免费   186165篇
  国内免费   9797篇
耳鼻咽喉   30653篇
儿科学   78203篇
妇产科学   65447篇
基础医学   339532篇
口腔科学   65916篇
临床医学   225428篇
内科学   474446篇
皮肤病学   52822篇
神经病学   198626篇
特种医学   92322篇
外国民族医学   622篇
外科学   352321篇
综合类   55320篇
现状与发展   3篇
一般理论   839篇
预防医学   200673篇
眼科学   51841篇
药学   172219篇
  11篇
中国医学   4915篇
肿瘤学   127636篇
  2018年   26441篇
  2017年   20379篇
  2016年   23275篇
  2015年   26346篇
  2014年   36580篇
  2013年   55993篇
  2012年   72232篇
  2011年   77281篇
  2010年   46558篇
  2009年   44279篇
  2008年   71260篇
  2007年   75587篇
  2006年   76867篇
  2005年   74292篇
  2004年   70827篇
  2003年   68162篇
  2002年   65379篇
  2001年   109619篇
  2000年   112711篇
  1999年   94607篇
  1998年   28209篇
  1997年   25358篇
  1996年   25949篇
  1995年   25550篇
  1994年   23933篇
  1993年   22435篇
  1992年   77387篇
  1991年   75545篇
  1990年   72895篇
  1989年   69271篇
  1988年   64381篇
  1987年   63100篇
  1986年   59940篇
  1985年   57614篇
  1984年   43902篇
  1983年   37023篇
  1982年   22917篇
  1981年   20470篇
  1980年   19164篇
  1979年   39716篇
  1978年   28775篇
  1977年   23904篇
  1976年   22740篇
  1975年   23477篇
  1974年   28133篇
  1973年   27189篇
  1972年   25126篇
  1971年   23287篇
  1970年   21401篇
  1969年   19817篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
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   
6.
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   
7.

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   
8.
9.
10.
Metabolism describes the series of chemical reactions that are concerned with the provision of energy to biological systems. They may be divided into reactions involved in energy yield (catabolism: demand exceeds supply), and energy storage (anabolism: supply exceeds demand). Regulation of these pathways is critical for homeostasis, and derangements in metabolism are seen in a wide variety of pathological processes. Understanding metabolism is key to the treatment of many diseases, notably diabetes, as well as underpinning clinical nutritional support.  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