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   1119543篇
  免费   74338篇
  国内免费   1508篇
耳鼻咽喉   15602篇
儿科学   35897篇
妇产科学   29395篇
基础医学   158703篇
口腔科学   30325篇
临床医学   99509篇
内科学   213135篇
皮肤病学   25193篇
神经病学   85667篇
特种医学   44766篇
外国民族医学   202篇
外科学   170822篇
综合类   22127篇
现状与发展   1篇
一般理论   306篇
预防医学   77440篇
眼科学   25251篇
药学   88801篇
  7篇
中国医学   2850篇
肿瘤学   69390篇
  2021年   8474篇
  2019年   8718篇
  2018年   12443篇
  2017年   9746篇
  2016年   10961篇
  2015年   12302篇
  2014年   16856篇
  2013年   24263篇
  2012年   33820篇
  2011年   35742篇
  2010年   20891篇
  2009年   19471篇
  2008年   32984篇
  2007年   35272篇
  2006年   35925篇
  2005年   34141篇
  2004年   32772篇
  2003年   31376篇
  2002年   30132篇
  2001年   60367篇
  2000年   61711篇
  1999年   51286篇
  1998年   12953篇
  1997年   11416篇
  1996年   11339篇
  1995年   10634篇
  1994年   9636篇
  1993年   9105篇
  1992年   37975篇
  1991年   36450篇
  1990年   35902篇
  1989年   34432篇
  1988年   31020篇
  1987年   30121篇
  1986年   28343篇
  1985年   26579篇
  1984年   19361篇
  1983年   16285篇
  1982年   9017篇
  1979年   17111篇
  1978年   11481篇
  1977年   10298篇
  1976年   8879篇
  1975年   10100篇
  1974年   11698篇
  1973年   11301篇
  1972年   10775篇
  1971年   10107篇
  1970年   9261篇
  1969年   8947篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.

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   
4.
5.
6.
7.
As millions of people turn to social media for health information, better understanding the factors that guide health-related judgments and perceptions in this context is imperative. We report on two Web experiments (n > 400 total) examining the power of society’s widespread weight bias and related stereotypes to influence nutrition judgments in social media spaces. In Experiment 1, meals were judged as lower in nutritional quality when the person who recommended them (the source) was depicted as obese rather than of normal weight, an effect mediated by stereotypic beliefs about the source as a generally unhealthy person. Experiment 2 replicated this effect, which—notably—remained significant when controlling for objective nutritional information (calories and fat content). Results highlight spillover effects of weight bias that extend beyond person perception to color impressions of objects (here, food) that are associated with stigmatized attributes. Implications for everyday nutrition judgments and public health are considered.  相似文献   
8.
9.
10.
Past research suggests that as many as 50% of onward human immunodeficiency virus (HIV) transmissions occur during acute and recent HIV infection. It is clearly important to develop interventions which focus on this highly infectious stage of HIV infection to prevent further transmission in the risk networks of acutely and recently infected individuals. Project Protect tries to find recently and acutely infected individuals and prevents HIV transmission in their risk networks. Participants are recruited by community health outreach workers at community-based HIV testing sites and drug users' community venues, by coupon referrals and through referrals from AIDS clinics. When a network with acute/recent infection is identified, network members are interviewed about their risky behaviors, network information is collected, and blood is drawn for HIV testing. Participants are also educated and given prevention materials (condoms, syringes, educational materials); HIV-infected participants are referred to AIDS clinics and are assisted with access to care. Community alerts about elevated risk of HIV transmission are distributed within the risk networks of recently infected. Overall, 342 people were recruited to the project and screened for acute/recent HIV infection. Only six index cases of recent infection (2.3% of all people screened) were found through primary screening at voluntary counseling and testing (VCT) sites, but six cases of recent infection were found through contact tracing of these recently infected participants (7% of network members who came to the interview). Combining screening at VCT sites and contact tracing the number of recently infected people we located as compared to VCT screening alone. No adverse events were encountered. These first results provide evidence for the theory behind the intervention, i.e., in the risk networks of recently infected people there are other people with recent HIV infection and they can be successfully located without increasing stigma for project participants.  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