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   2351751篇
  免费   176021篇
  国内免费   3329篇
医药卫生   2531101篇
  2021年   19272篇
  2019年   19864篇
  2018年   27442篇
  2017年   20651篇
  2016年   23018篇
  2015年   25932篇
  2014年   36533篇
  2013年   54567篇
  2012年   75525篇
  2011年   80302篇
  2010年   47546篇
  2009年   44990篇
  2008年   75333篇
  2007年   80213篇
  2006年   81034篇
  2005年   78524篇
  2004年   74922篇
  2003年   72175篇
  2002年   69824篇
  2001年   108806篇
  2000年   111520篇
  1999年   93553篇
  1998年   27062篇
  1997年   23713篇
  1996年   24095篇
  1995年   22755篇
  1994年   20932篇
  1993年   19744篇
  1992年   72023篇
  1991年   70085篇
  1990年   68411篇
  1989年   65685篇
  1988年   60316篇
  1987年   59141篇
  1986年   55227篇
  1985年   53016篇
  1984年   39323篇
  1983年   33401篇
  1982年   19851篇
  1979年   35791篇
  1978年   25586篇
  1977年   21133篇
  1976年   20259篇
  1975年   21760篇
  1974年   26092篇
  1973年   24767篇
  1972年   23186篇
  1971年   22021篇
  1970年   20224篇
  1969年   19291篇
排序方式: 共有10000条查询结果,搜索用时 512 毫秒
31.
MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer‐enriched miRNA is required for prostate tumorigenesis. We identify miR‐205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR‐205 is not required for normal prostate development and homeostasis, genetic deletion of miR‐205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR‐205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR‐205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR‐205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR‐205 in the progression of Pten null‐induced prostate cancer.  相似文献   
32.
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   
33.
34.
35.
36.
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   
37.
38.
39.
40.
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