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   980165篇
  免费   71170篇
  国内免费   1388篇
耳鼻咽喉   13625篇
儿科学   26130篇
妇产科学   24711篇
基础医学   139657篇
口腔科学   30307篇
临床医学   85792篇
内科学   192551篇
皮肤病学   19945篇
神经病学   76827篇
特种医学   38434篇
外国民族医学   79篇
外科学   158713篇
综合类   18297篇
现状与发展   1篇
一般理论   254篇
预防医学   66208篇
眼科学   22110篇
药学   76089篇
  3篇
中国医学   2231篇
肿瘤学   60759篇
  2018年   10320篇
  2017年   8289篇
  2016年   9028篇
  2015年   9973篇
  2014年   13225篇
  2013年   19850篇
  2012年   26994篇
  2011年   28118篇
  2010年   16369篇
  2009年   15538篇
  2008年   27168篇
  2007年   28433篇
  2006年   29073篇
  2005年   27910篇
  2004年   26745篇
  2003年   25708篇
  2002年   25162篇
  2001年   56058篇
  2000年   57917篇
  1999年   48011篇
  1998年   11157篇
  1997年   9835篇
  1996年   9908篇
  1995年   9286篇
  1994年   8599篇
  1993年   7866篇
  1992年   36179篇
  1991年   34584篇
  1990年   33412篇
  1989年   32531篇
  1988年   29661篇
  1987年   28886篇
  1986年   26839篇
  1985年   25719篇
  1984年   18373篇
  1983年   15564篇
  1982年   8089篇
  1981年   7015篇
  1979年   16153篇
  1978年   10882篇
  1977年   9282篇
  1976年   8072篇
  1975年   8864篇
  1974年   10719篇
  1973年   10078篇
  1972年   9558篇
  1971年   9045篇
  1970年   8614篇
  1969年   8072篇
  1968年   7365篇
排序方式: 共有10000条查询结果,搜索用时 624 毫秒
11.
12.
13.
14.
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   
15.
Aims: In neuropsychological evaluations, it is often difficult to ascertain whether poor performance on measures of validity is due to poor effort or malingering, or whether there is genuine cognitive impairment. Dunham and Denney created an algorithm to assess this question using the Medical Symptom Validity Test (MSVT). We assessed the ability of their algorithm to detect poor validity versus probable impairment, and concordance of failure on the MSVT with other freestanding tests of performance validity.

Methods: Two previously published datasets (n?=?153 and n?=?641, respectively) from outpatient neuropsychological evaluations were used to test Dunham and Denney’s algorithm, and to assess concordance of failure rates with the Test of Memory Malingering and the forced choice measure of the California Verbal Learning Test, two commonly used performance validity tests.

Results: In both datasets, none of the four cutoff scores for failure on the MSVT (70%, 75%, 80%, or 85%) identified a poor validity group with proportionally aligned failure rates on other freestanding measures of performance validity. Additionally, the protocols with probable impairment did not differ from those with poor validity on cognitive measures.

Conclusions: Despite what appeared to be a promising approach to evaluating failure on the easy MSVT subtests when clinical data are unavailable (as recommended in the advanced interpretation program, or advanced interpretation [AI], of the MSVT), the current findings indicate the AI remains the gold standard for doing so. Future research should build on this effort to address shortcomings in measures of effort in neuropsychological evaluations.  相似文献   

16.
17.

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   
18.
19.
20.
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