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   560609篇
  免费   30768篇
  国内免费   903篇
耳鼻咽喉   7018篇
儿科学   17852篇
妇产科学   13106篇
基础医学   97120篇
口腔科学   12819篇
临床医学   51418篇
内科学   101917篇
皮肤病学   12566篇
神经病学   36389篇
特种医学   20977篇
外国民族医学   69篇
外科学   81944篇
综合类   8880篇
现状与发展   3篇
一般理论   109篇
预防医学   40929篇
眼科学   12567篇
药学   43831篇
  7篇
中国医学   1741篇
肿瘤学   31018篇
  2021年   4902篇
  2019年   4665篇
  2018年   6683篇
  2017年   4816篇
  2016年   5564篇
  2015年   6228篇
  2014年   8204篇
  2013年   11913篇
  2012年   17617篇
  2011年   19432篇
  2010年   11212篇
  2009年   9855篇
  2008年   17195篇
  2007年   18970篇
  2006年   18412篇
  2005年   17632篇
  2004年   17103篇
  2003年   16437篇
  2002年   15900篇
  2001年   23404篇
  2000年   23927篇
  1999年   19772篇
  1998年   5556篇
  1997年   4649篇
  1996年   4634篇
  1995年   4319篇
  1992年   14888篇
  1991年   16286篇
  1990年   16378篇
  1989年   16023篇
  1988年   14732篇
  1987年   14552篇
  1986年   13520篇
  1985年   13032篇
  1984年   9629篇
  1983年   8179篇
  1982年   4289篇
  1979年   9138篇
  1978年   6487篇
  1977年   5268篇
  1976年   5610篇
  1975年   6707篇
  1974年   7544篇
  1973年   7256篇
  1972年   6719篇
  1971年   6387篇
  1970年   5978篇
  1969年   5562篇
  1968年   5245篇
  1967年   4700篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
101.
Sagging eyelid is considered as an outward of skin ageing and may cause medical issues. However, little is known about the factors involved in sagging eyelid. The study, which aims at determining genetic risk factors for eyelid sagging, was conducted in a cohort of 502 unrelated Caucasian women living in the Paris region. All included participants were aged between 44 and 70 years old (mean age, 57.6 years old). The severity of sagging eyelid was graded in 6 categories by a dermatologist using standardized photographs of the face. A genome wide association study adjusted on potential risk factors (including age and smoking habits) was conducted to identify genetic associations. Two single nucleotide polymorphisms in total linkage disequilibrium on chromosome 10, rs16927253 (P = 7.07 × 10‐10) and rs4746957 (P = 1.06 × 10‐8), were significantly associated with eyelid sagging severity. The rs16927253‐T and rs4746957‐A alleles showed a dominant protective effect towards eyelid sagging. These polymorphisms are located in intronic parts of the H2AFY2 gene which encodes a member of the H2A histone family and very close to the AIFM2 gene that induces apoptosis. Additionally, single nucleotide polymorphisms with a false discovery rate below 0.25 were located nearby the type XIII collagen COL13A1 gene on chromosome 10 and in the ADAMTS18 gene on chromosome 16. Several relevant genes were identified by the genome wide association study for their potential role in the sagging eyelid severity.  相似文献   
102.
103.
104.
105.
106.
Among the numerous signaling pathways involved in tumorigenesis, PI3K‐AKT‐mTOR is a key one that regulates diverse cellular functions. However, its prognostic value in esophageal carcinoma remains unclear. In our study, we examined the immunohistochemical expression of phosphorylated (p‐) AKT, mTOR, p70S6K and 4E‐BP1 along with the mutational status of PIK3CA and AKT1 genes by High Resolution Melting Analysis and Pyrosequencing in 44 esophageal carcinomas. The results were correlated with the clinicopathological characteristics of the patients in an effort to define their possible prognostic significance. Total p‐mTOR cytoplasmic expression, assessed in 10 random areas, was positively correlated with tumor stage (Kruskal–Wallis ANOVA, I/II vs III/IV, p = 0.0500). Μoreover, maximum p‐mTOR cytoplasmic immunoexpression, estimated in hot spot areas, was positively associated with tumor grade (Mann–Whitney U test, I/II vs III, p = 0.0565). Interestingly, p‐4E‐BP1 immunoreactivity was negatively correlated with tumor histological grade (Mann–Whitney U test, I/II vs III, p = 0.0427). No mutation was observed in exons 9 and 20 of PIK3CA gene and in exon 4 of AKT1 gene. In conclusion, our findings depict the presence of activated PI3K/AKT/mTOR pathway in esophageal cancer bringing forward p‐mTOR and p‐4E‐BP1 for their potential role in esophageal carcinogenesis. Additional studies are warranted to validate our findings.  相似文献   
107.
108.
109.
Taurodontism is a rare embryologic anomaly of teeth, defined by an apical displacement of the furcation of roots and enlarged pulp chambers. Taurodontism has been classified as hypo‐, meso‐ or hypertaurodontism according to the severity of the anomaly. The aim of this case report was to illustrate a clinical case with multiple bilateral taurodonts and to describe the endodontic management of the hypertaurodontic mandibular left second molar with a C‐shaped canal and extensive dental pulp calcifications. A healthy 20‐year‐old male patient was referred for the endodontic treatment of his lower left second molar. Cone beam computed tomography revealed a C‐shaped root canal configuration and several dental pulp calcifications in this tooth. The endodontic treatment was performed in two appointments under an operating dental microscope. A panoramic radiograph, made during the 18 months follow‐up appointment, revealed nine other taurodontic molars, most of them associated with dental pulp calcifications.  相似文献   
110.
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