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   2583954篇
  免费   189003篇
  国内免费   7561篇
耳鼻咽喉   34291篇
儿科学   85210篇
妇产科学   71578篇
基础医学   363638篇
口腔科学   69664篇
临床医学   234550篇
内科学   515616篇
皮肤病学   62456篇
神经病学   213478篇
特种医学   99900篇
外国民族医学   736篇
外科学   386457篇
综合类   50400篇
现状与发展   5篇
一般理论   968篇
预防医学   196252篇
眼科学   56688篇
药学   188051篇
  8篇
中国医学   5331篇
肿瘤学   145241篇
  2021年   19994篇
  2019年   20625篇
  2018年   29300篇
  2017年   22603篇
  2016年   26231篇
  2015年   29508篇
  2014年   40457篇
  2013年   60437篇
  2012年   80243篇
  2011年   84510篇
  2010年   51016篇
  2009年   49152篇
  2008年   79053篇
  2007年   83867篇
  2006年   85590篇
  2005年   81743篇
  2004年   78749篇
  2003年   76062篇
  2002年   73342篇
  2001年   128430篇
  2000年   131342篇
  1999年   110504篇
  1998年   31261篇
  1997年   27925篇
  1996年   28224篇
  1995年   27390篇
  1994年   25069篇
  1993年   23423篇
  1992年   85173篇
  1991年   81574篇
  1990年   78788篇
  1989年   76066篇
  1988年   69481篇
  1987年   68007篇
  1986年   63551篇
  1985年   60522篇
  1984年   44952篇
  1983年   37952篇
  1982年   22459篇
  1981年   19989篇
  1979年   38967篇
  1978年   27442篇
  1977年   23262篇
  1976年   21503篇
  1975年   22820篇
  1974年   26790篇
  1973年   25372篇
  1972年   23753篇
  1971年   21955篇
  1970年   20185篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
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   
43.
44.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
45.

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   
46.
47.
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