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   3617749篇
  免费   255360篇
  国内免费   9469篇
耳鼻咽喉   48833篇
儿科学   119955篇
妇产科学   99379篇
基础医学   508270篇
口腔科学   102106篇
临床医学   331240篇
内科学   705180篇
皮肤病学   85351篇
神经病学   292696篇
特种医学   137171篇
外国民族医学   941篇
外科学   540149篇
综合类   77793篇
现状与发展   8篇
一般理论   1392篇
预防医学   276959篇
眼科学   83849篇
药学   264007篇
  12篇
中国医学   7988篇
肿瘤学   199299篇
  2019年   28661篇
  2018年   40853篇
  2017年   31137篇
  2016年   35432篇
  2015年   40142篇
  2014年   55555篇
  2013年   83020篇
  2012年   111905篇
  2011年   118450篇
  2010年   70933篇
  2009年   67335篇
  2008年   110299篇
  2007年   117413篇
  2006年   119037篇
  2005年   114180篇
  2004年   109866篇
  2003年   105669篇
  2002年   102062篇
  2001年   175745篇
  2000年   179881篇
  1999年   151284篇
  1998年   42991篇
  1997年   37868篇
  1996年   37993篇
  1995年   36842篇
  1994年   33680篇
  1993年   31561篇
  1992年   117089篇
  1991年   112933篇
  1990年   109311篇
  1989年   105603篇
  1988年   96565篇
  1987年   94587篇
  1986年   88802篇
  1985年   84782篇
  1984年   63205篇
  1983年   53637篇
  1982年   31459篇
  1981年   28041篇
  1979年   55911篇
  1978年   39253篇
  1977年   33404篇
  1976年   31148篇
  1975年   32958篇
  1974年   39316篇
  1973年   37578篇
  1972年   35093篇
  1971年   32572篇
  1970年   30103篇
  1969年   28767篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
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   
52.
53.
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   
54.
55.

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   
56.
57.
58.
59.
60.
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