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   2351926篇
  免费   171348篇
  国内免费   3332篇
耳鼻咽喉   32053篇
儿科学   75987篇
妇产科学   62704篇
基础医学   348477篇
口腔科学   63693篇
临床医学   211473篇
内科学   457750篇
皮肤病学   51736篇
神经病学   185355篇
特种医学   88046篇
外国民族医学   489篇
外科学   354163篇
综合类   47509篇
现状与发展   12篇
一般理论   848篇
预防医学   182758篇
眼科学   54356篇
药学   175212篇
  11篇
中国医学   4588篇
肿瘤学   129386篇
  2021年   19015篇
  2019年   19559篇
  2018年   27085篇
  2017年   20381篇
  2016年   22767篇
  2015年   25681篇
  2014年   36124篇
  2013年   53999篇
  2012年   74771篇
  2011年   79504篇
  2010年   47101篇
  2009年   44618篇
  2008年   74694篇
  2007年   79555篇
  2006年   80378篇
  2005年   77858篇
  2004年   74439篇
  2003年   71746篇
  2002年   69429篇
  2001年   108794篇
  2000年   111514篇
  1999年   93536篇
  1998年   27012篇
  1997年   23670篇
  1996年   24071篇
  1995年   22734篇
  1994年   20910篇
  1993年   19728篇
  1992年   72050篇
  1991年   70118篇
  1990年   68421篇
  1989年   65688篇
  1988年   60330篇
  1987年   59160篇
  1986年   55246篇
  1985年   53028篇
  1984年   39323篇
  1983年   33408篇
  1982年   19863篇
  1979年   35887篇
  1978年   25658篇
  1977年   21235篇
  1976年   20339篇
  1975年   21821篇
  1974年   26158篇
  1973年   24812篇
  1972年   23203篇
  1971年   22046篇
  1970年   20255篇
  1969年   19328篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
3.
4.
5.
Graefe's Archive for Clinical and Experimental Ophthalmology - The published online version contains mistake as the author's first name and last name have been interchanged as "Hild...  相似文献   
6.
7.
8.
The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (Leq) measurements were collected during flight operations (Leq (flt ops)), non-flight operations (Leq (non-flt ops)), and over 24-hr periods (Leq (24-hr)). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Value (TLV®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The Leq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between Leq (flt ops), Leq (non-flt ops), and Leq (24-hr) and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) Leq (24-hr): 70.8–105.4 dBA; (2) Leq (flt ops): 70–101.2 dBA; and (3) Leq (non-flt ops): 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean Leqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The Leqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.  相似文献   
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