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   2999191篇
  免费   217562篇
  国内免费   5121篇
耳鼻咽喉   41202篇
儿科学   98980篇
妇产科学   81674篇
基础医学   439234篇
口腔科学   83673篇
临床医学   272052篇
内科学   576972篇
皮肤病学   66657篇
神经病学   237421篇
特种医学   113122篇
外国民族医学   768篇
外科学   449565篇
综合类   64899篇
现状与发展   12篇
一般理论   1162篇
预防医学   236310篇
眼科学   70065篇
药学   221683篇
  13篇
中国医学   5875篇
肿瘤学   160535篇
  2019年   24041篇
  2018年   33360篇
  2017年   25305篇
  2016年   28474篇
  2015年   32034篇
  2014年   45132篇
  2013年   68221篇
  2012年   92953篇
  2011年   98927篇
  2010年   59007篇
  2009年   55653篇
  2008年   92888篇
  2007年   98863篇
  2006年   99838篇
  2005年   96773篇
  2004年   93010篇
  2003年   89520篇
  2002年   86685篇
  2001年   135709篇
  2000年   139284篇
  1999年   117225篇
  1998年   34121篇
  1997年   30142篇
  1996年   30361篇
  1995年   28871篇
  1994年   26646篇
  1993年   25102篇
  1992年   91661篇
  1991年   89600篇
  1990年   87617篇
  1989年   84402篇
  1988年   77465篇
  1987年   76473篇
  1986年   71608篇
  1985年   68865篇
  1984年   51457篇
  1983年   43702篇
  1982年   26146篇
  1979年   47464篇
  1978年   34054篇
  1977年   28447篇
  1976年   27248篇
  1975年   29050篇
  1974年   35045篇
  1973年   33391篇
  1972年   31194篇
  1971年   29521篇
  1970年   27202篇
  1969年   25847篇
  1968年   23771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.
9.
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   
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