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   2585963篇
  免费   189500篇
  国内免费   7559篇
耳鼻咽喉   34323篇
儿科学   85316篇
妇产科学   71731篇
基础医学   364222篇
口腔科学   69923篇
临床医学   234697篇
内科学   515613篇
皮肤病学   62621篇
神经病学   213745篇
特种医学   100080篇
外国民族医学   736篇
外科学   386987篇
综合类   50396篇
现状与发展   5篇
一般理论   970篇
预防医学   196143篇
眼科学   56639篇
药学   188185篇
  8篇
中国医学   5339篇
肿瘤学   145343篇
  2021年   20045篇
  2019年   20666篇
  2018年   29348篇
  2017年   22643篇
  2016年   26284篇
  2015年   29576篇
  2014年   40542篇
  2013年   60560篇
  2012年   80439篇
  2011年   84705篇
  2010年   51133篇
  2009年   49285篇
  2008年   79227篇
  2007年   84060篇
  2006年   85769篇
  2005年   81942篇
  2004年   78909篇
  2003年   76214篇
  2002年   73529篇
  2001年   128531篇
  2000年   131454篇
  1999年   110598篇
  1998年   31299篇
  1997年   27964篇
  1996年   28260篇
  1995年   27416篇
  1994年   25098篇
  1993年   23456篇
  1992年   85226篇
  1991年   81619篇
  1990年   78845篇
  1989年   76125篇
  1988年   69526篇
  1987年   68066篇
  1986年   63604篇
  1985年   60561篇
  1984年   44986篇
  1983年   37996篇
  1982年   22495篇
  1981年   20015篇
  1979年   38982篇
  1978年   27470篇
  1977年   23286篇
  1976年   21541篇
  1975年   22844篇
  1974年   26818篇
  1973年   25408篇
  1972年   23770篇
  1971年   21989篇
  1970年   20216篇
排序方式: 共有10000条查询结果,搜索用时 656 毫秒
61.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
62.
63.

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   
64.
65.
66.

Introduction

Several studies demonstrated that simulator-acquired skill transfer to the operating room is incomplete. Our objective was to identify trainee characteristics that predict the transfer of simulator-acquired skill to the operating room.

Methods

Trainees completed baseline assessments including intracorporeal suturing (IS) performance, attentional selectivity, self-reported use of mental skills, and self-reported prior clinical and simulated laparoscopic experience and confidence. Residents then followed proficiency-based laparoscopic skills training, and their skill transfer was assessed on a live-anesthetized porcine model. Predictive characteristics for transfer test performance were assessed using multiple linear regression.

Results

Thirty-eight residents completed the study. Automaticity, attentional selectivity, resident perceived ability with laparoscopy and simulators, and post-training IS performance were predictive of IS performance during the transfer test.

Conclusions

Promoting automaticity, self-efficacy, and attention selectivity may help improve the transfer of simulator-acquired skill. Mental skills training and training to automaticity may therefore be valuable interventions to achieve this goal.  相似文献   
67.
68.
69.
70.
Henna, derived from a combination of natural leaves and coloring additives, is a common decorative dye traditionally used in many Islamic religious celebrations. Para‐phenylenediamine (PPD), a major component of black henna tattoo, is a strong sensitizer and common allergen. We report a case of severe connubial allergic contact dermatitis after black henna heterotransfer in a girl.  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