首页 | 官方网站   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   3912122篇
  免费   298467篇
  国内免费   6684篇
医药卫生   4217273篇
  2018年   42178篇
  2017年   31993篇
  2016年   35701篇
  2015年   40330篇
  2014年   57668篇
  2013年   87741篇
  2012年   119291篇
  2011年   126827篇
  2010年   75443篇
  2009年   71408篇
  2008年   119392篇
  2007年   127204篇
  2006年   128401篇
  2005年   124809篇
  2004年   120067篇
  2003年   115530篇
  2002年   113166篇
  2001年   175022篇
  2000年   180536篇
  1999年   152772篇
  1998年   45584篇
  1997年   40431篇
  1996年   39871篇
  1995年   38052篇
  1994年   35510篇
  1993年   33329篇
  1992年   121363篇
  1991年   118560篇
  1990年   115192篇
  1989年   110963篇
  1988年   102812篇
  1987年   100982篇
  1986年   95347篇
  1985年   91627篇
  1984年   69104篇
  1983年   58896篇
  1982年   35617篇
  1981年   31849篇
  1979年   64803篇
  1978年   45938篇
  1977年   38475篇
  1976年   36724篇
  1975年   38963篇
  1974年   47550篇
  1973年   45295篇
  1972年   42831篇
  1971年   40078篇
  1970年   37300篇
  1969年   35099篇
  1968年   32246篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
51.
52.
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   
53.
54.
55.
56.
57.
58.
Dietary assessment in infants is challenging but necessary to understand the relationship between nutrition and growth and development. Currently no simple, validated methods exist to assess nutrient intake in New Zealand (NZ) infants. Therefore, this study aimed to assess the relative validity and reproducibility of a Complementary Food Frequency Questionnaire (CFFQ) to determine nutrient intakes of NZ infants. Ninety‐five parent–infant pairs (infant age 10 ± 1 months) completed the CFFQ twice (CFFQ‐1 and CFFQ‐2), 4 weeks apart (to assess reproducibility). A 4‐day weighed food record (4dWFR) was collected between CFFQ administrations (to assess validity). Validity and reproducibility were assessed for intakes of energy and 18 nutrients using Bland–Altman analysis, Pearson's correlation coefficients, cross‐classification, and weighted Kappa (κ). The CFFQ showed acceptable validity: Nutrients from the CFFQ were comparable with the 4dWFR (bias, 9–28%), correlation between methods ranged from r = .18 (saturated fat) to r = .81 (iron; mean r = .52), 54% (mean) of participants were correctly classified (range 39% to 67%), and 7.1% (mean) misclassified into opposite tertiles (range 2.1% to 14.7%). There was acceptable agreement between the CFFQ and 4dWFR (κ = 0.20–0.60). The CFFQ showed good reproducibility: Correlations ranged from r = .34 (folate) to r = .80 (zinc); for 16 nutrients, >50% of participants were correctly classified, and for all nutrients, <10% of participants were grossly misclassified. All nutrients showed acceptable to good agreement (κ > 0.20). The CFFQ has acceptable relative validity and good reproducibility for assessing nutrient intake in NZ infants aged 9–12 months, making it a useful tool for use in future research.  相似文献   
59.
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   
60.
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-23

京公网安备 11010802026262号