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   2589347篇
  免费   184578篇
  国内免费   7596篇
耳鼻咽喉   34303篇
儿科学   85251篇
妇产科学   71659篇
基础医学   363799篇
口腔科学   69682篇
临床医学   234631篇
内科学   515848篇
皮肤病学   62458篇
神经病学   213566篇
特种医学   99939篇
外国民族医学   736篇
外科学   386612篇
综合类   50397篇
现状与发展   5篇
一般理论   969篇
预防医学   196225篇
眼科学   56695篇
药学   188077篇
  8篇
中国医学   5334篇
肿瘤学   145327篇
  2021年   20023篇
  2019年   20664篇
  2018年   29313篇
  2017年   22625篇
  2016年   26259篇
  2015年   29537篇
  2014年   40473篇
  2013年   60471篇
  2012年   80304篇
  2011年   84572篇
  2010年   51059篇
  2009年   49192篇
  2008年   79115篇
  2007年   83911篇
  2006年   85649篇
  2005年   81799篇
  2004年   78800篇
  2003年   76110篇
  2002年   73395篇
  2001年   128431篇
  2000年   131363篇
  1999年   110529篇
  1998年   31271篇
  1997年   27937篇
  1996年   28228篇
  1995年   27388篇
  1994年   25074篇
  1993年   23420篇
  1992年   85175篇
  1991年   81582篇
  1990年   78807篇
  1989年   76078篇
  1988年   69481篇
  1987年   68008篇
  1986年   63556篇
  1985年   60525篇
  1984年   44948篇
  1983年   37954篇
  1982年   22459篇
  1981年   19986篇
  1979年   38971篇
  1978年   27442篇
  1977年   23253篇
  1976年   21504篇
  1975年   22815篇
  1974年   26792篇
  1973年   25377篇
  1972年   23752篇
  1971年   21961篇
  1970年   20186篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
BackgroundThe aim of this study was to estimate the prevalence of dental prosthetic treatment and to investigate the demographic, social, economic and medical factors associated with the use of fixed and removable dentures in a representative sample of adults living in France.MethodsThe data were obtained from the 2002–2003 Decennial Health Survey, a cross-sectional study of a representative sample of the population living in France, which included 29,679 adults. Information was collected by interview. The variables collected were fixed denture, removable denture, age, gender, number of children, area of residence, nationality, educational attainment, family social status, employment status, annual household income per capita, supplementary insurance, chronic disease, eyesight problems/glasses, hearing problems/hearing aids. Multinomial logistic regression models were used to study the relationship between prosthetic treatment and demographic, socioeconomic and medical characteristics unadjusted, adjusted for age and adjusted for all the characteristics.ResultsThe prevalence of prosthetic treatment was 34.6% (95% confidence interval (CI): [34.1; 35.2]) for fixed prosthetic dentures and 13.8% (95% CI: [13.4; 14.2]) for removable prosthetic dentures. We showed a gradient between educational attainment and removable dentures; the odds ratio adjusted for all the variables (aOR) associated with no or primary education compared to post-secondary education was 2.56; 95% CI: [2.09; 3.13]. When annual household income per capita was low, subjects were less likely to report fixed dentures (aOR = 0.68; 95% CI: [0.62; 0.75]) than those with high annual household income per capita. Individuals without insurance less often reported fixed dentures than those with private insurance. Those reporting chronic disease were less likely to report fixed dentures (aOR = 0.87; 95% CI: [0.79; 0.95]) but more likely to report removable dentures (aOR = 1.29; 95% CI: [1.17; 1.43]) than those without chronic disease.ConclusionThis study reveals social, economic and medical inequalities in fixed and removable prosthetic treatment among adults in France.  相似文献   
3.
4.
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   
5.
6.

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   
7.
8.
9.
10.
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