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   2658187篇
  免费   187494篇
  国内免费   3706篇
耳鼻咽喉   36203篇
儿科学   86222篇
妇产科学   71017篇
基础医学   397608篇
口腔科学   71533篇
临床医学   239378篇
内科学   511906篇
皮肤病学   58937篇
神经病学   206535篇
特种医学   99535篇
外国民族医学   532篇
外科学   398698篇
综合类   52934篇
现状与发展   12篇
一般理论   922篇
预防医学   206700篇
眼科学   62411篇
药学   198517篇
  11篇
中国医学   5267篇
肿瘤学   144509篇
  2021年   21241篇
  2019年   21663篇
  2018年   30183篇
  2017年   22589篇
  2016年   25385篇
  2015年   28565篇
  2014年   40154篇
  2013年   60330篇
  2012年   83866篇
  2011年   89468篇
  2010年   52923篇
  2009年   49784篇
  2008年   83729篇
  2007年   89488篇
  2006年   90059篇
  2005年   87081篇
  2004年   83482篇
  2003年   80570篇
  2002年   77887篇
  2001年   120299篇
  2000年   123235篇
  1999年   103455篇
  1998年   29962篇
  1997年   26211篇
  1996年   26553篇
  1995年   25046篇
  1994年   23031篇
  1993年   21743篇
  1992年   79674篇
  1991年   78452篇
  1990年   76739篇
  1989年   74002篇
  1988年   68014篇
  1987年   66957篇
  1986年   62526篇
  1985年   60192篇
  1984年   44745篇
  1983年   38042篇
  1982年   22343篇
  1979年   41342篇
  1978年   29630篇
  1977年   24433篇
  1976年   23702篇
  1975年   25950篇
  1974年   30751篇
  1973年   29326篇
  1972年   27482篇
  1971年   26093篇
  1970年   24020篇
  1969年   22961篇
排序方式: 共有10000条查询结果,搜索用时 0 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