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   2599091篇
  免费   185316篇
  国内免费   7589篇
耳鼻咽喉   34355篇
儿科学   85587篇
妇产科学   71802篇
基础医学   365238篇
口腔科学   69854篇
临床医学   235695篇
内科学   518112篇
皮肤病学   62608篇
神经病学   214622篇
特种医学   100215篇
外国民族医学   738篇
外科学   387780篇
综合类   50512篇
现状与发展   5篇
一般理论   975篇
预防医学   196920篇
眼科学   57056篇
药学   188527篇
  8篇
中国医学   5343篇
肿瘤学   146044篇
  2021年   20117篇
  2019年   20803篇
  2018年   29455篇
  2017年   22726篇
  2016年   26389篇
  2015年   29683篇
  2014年   40665篇
  2013年   60767篇
  2012年   80720篇
  2011年   85041篇
  2010年   51337篇
  2009年   49449篇
  2008年   79477篇
  2007年   84372篇
  2006年   86080篇
  2005年   82208篇
  2004年   79241篇
  2003年   76488篇
  2002年   73804篇
  2001年   128712篇
  2000年   131616篇
  1999年   110730篇
  1998年   31376篇
  1997年   28033篇
  1996年   28300篇
  1995年   27488篇
  1994年   25144篇
  1993年   23495篇
  1992年   85391篇
  1991年   81787篇
  1990年   79014篇
  1989年   76252篇
  1988年   69654篇
  1987年   68187篇
  1986年   63731篇
  1985年   60678篇
  1984年   45099篇
  1983年   38093篇
  1982年   22562篇
  1981年   20092篇
  1979年   39095篇
  1978年   27565篇
  1977年   23342篇
  1976年   21577篇
  1975年   22908篇
  1974年   26915篇
  1973年   25480篇
  1972年   23840篇
  1971年   22046篇
  1970年   20263篇
排序方式: 共有10000条查询结果,搜索用时 12 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.
5.
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   
6.
7.

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   
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