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   2226758篇
  免费   166469篇
  国内免费   4442篇
耳鼻咽喉   31055篇
儿科学   76196篇
妇产科学   61501篇
基础医学   320121篇
口腔科学   61048篇
临床医学   198305篇
内科学   439617篇
皮肤病学   50258篇
神经病学   177737篇
特种医学   85884篇
外国民族医学   976篇
外科学   333992篇
综合类   47646篇
现状与发展   1篇
一般理论   785篇
预防医学   174342篇
眼科学   50009篇
药学   163121篇
  5篇
中国医学   4501篇
肿瘤学   120569篇
  2019年   17736篇
  2018年   26759篇
  2017年   19968篇
  2016年   21910篇
  2015年   24753篇
  2014年   32916篇
  2013年   50634篇
  2012年   71107篇
  2011年   74894篇
  2010年   43498篇
  2009年   40039篇
  2008年   69970篇
  2007年   74766篇
  2006年   74351篇
  2005年   72122篇
  2004年   69981篇
  2003年   67078篇
  2002年   65101篇
  2001年   101016篇
  2000年   104204篇
  1999年   88367篇
  1998年   24474篇
  1997年   21982篇
  1996年   22264篇
  1995年   21281篇
  1994年   19988篇
  1993年   18548篇
  1992年   70008篇
  1991年   68507篇
  1990年   66771篇
  1989年   63971篇
  1988年   58781篇
  1987年   58250篇
  1986年   54473篇
  1985年   52434篇
  1984年   39338篇
  1983年   33188篇
  1982年   19594篇
  1981年   17691篇
  1979年   35670篇
  1978年   25303篇
  1977年   21459篇
  1976年   20109篇
  1975年   21590篇
  1974年   25632篇
  1973年   24735篇
  1972年   22757篇
  1971年   20980篇
  1970年   19643篇
  1969年   18108篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.

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   
45.
46.

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   
47.

Background and objectives

A prompt and effective management of trauma patient is necessary. The aim of this case report is to highlight the importance of intraoperative echocardiography as a useful tool in patients suffering from refractory hemodynamic instability no otherwise explained.

Case report

A 41 year‐old woman suffered a car accident. At the emergency department, no abnormalities were found in ECG or chest X‐ray. Abdominal ultrasound revealed the presence of abdominal free liquid and the patient was submitted to urgent exploratory laparotomy. Nevertheless, she persisted suffering arterial hypotension and metabolic acidosis. Looking for the reason of her hemodynamic instability, intraoperative transthoracic echocardiography was performed, finding out the presence of pericardial effusion. Once the cardiac surgeon extracted pericardial clots, patient's situation improved clinically and analytically.

Conclusion

Every anesthesiologist should be able to use the intraoperative echocardiography as an effective tool in order to establish the appropriate measures to promote the survival of patients suffering severe trauma.  相似文献   
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