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   4891篇
  免费   438篇
  国内免费   5篇
耳鼻咽喉   45篇
儿科学   153篇
妇产科学   57篇
基础医学   424篇
口腔科学   1782篇
临床医学   265篇
内科学   502篇
皮肤病学   73篇
神经病学   130篇
特种医学   74篇
外科学   714篇
综合类   59篇
一般理论   4篇
预防医学   180篇
眼科学   91篇
药学   431篇
  1篇
中国医学   33篇
肿瘤学   316篇
  2023年   137篇
  2022年   83篇
  2021年   144篇
  2020年   111篇
  2019年   104篇
  2018年   204篇
  2017年   185篇
  2016年   183篇
  2015年   193篇
  2014年   230篇
  2013年   276篇
  2012年   354篇
  2011年   337篇
  2010年   213篇
  2009年   243篇
  2008年   202篇
  2007年   182篇
  2006年   144篇
  2005年   106篇
  2004年   108篇
  2003年   86篇
  2002年   82篇
  2001年   97篇
  2000年   75篇
  1999年   74篇
  1998年   91篇
  1997年   59篇
  1996年   70篇
  1995年   51篇
  1994年   54篇
  1993年   49篇
  1992年   76篇
  1991年   76篇
  1990年   60篇
  1989年   74篇
  1988年   47篇
  1987年   55篇
  1986年   44篇
  1985年   37篇
  1984年   33篇
  1983年   27篇
  1982年   21篇
  1981年   24篇
  1980年   22篇
  1979年   26篇
  1978年   21篇
  1977年   19篇
  1976年   22篇
  1975年   17篇
  1974年   26篇
排序方式: 共有5334条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
We have recently shown that HPV-positive tonsillar carcinoma in young patients exhibits nonkeratinizing basaloid morphology and a characteristic immunophenotype. The purpose of this study was to review a large number of cases of oropharyngeal carcinomas, in all age groups, and to identify tumors with nonkeratinizing morphology. Using polymerase chain reaction (PCR) the prevalence and type of HPV DNA was determined in representative cases and in a control group of conventional keratinizing squamous cell carcinomas. The tumors were further characterized with a panel of immunohistochemical stains. A total of 235 carcinomas were reviewed; 141 of the tonsils and 94 in the base of tongue. Ninety (36%) of the tonsillar and 30 (32%) of the base of tongue carcinomas were nonkeratinizing (NKCa) with basal cell features; the rest were classical keratinizing squamous cell carcinomas (KSCC). HPV DNA, particularly type 16, was identified in 10 (100%) of 10 of NKCA and in only 2 (20%) of 10 of KSCC (P = .0014). NKCas were strongly reactive to p16 antibodies while KSCC showed weak and focal reactivity. Higher Ki67 and lower p53 staining scores were observed in NKCa as compared to KSCC. It is concluded that NKCa of the tonsils and base of tongue is a distinct subtype of squamous cell carcinoma of the head and neck with high prevalence of HPV DNA and a characteristic immunophenotype.  相似文献   
6.
This prospective clinic-based study evaluated the pretreatment periodontal status of the orthodontic patients seen at the University College Hospital, Ibadan, Nigeria, and assessed the relationship between dental aesthetic index (DAI) scores and periodontal status according to community periodontal index of treatment needs (CPITN) scores. One hundred forty five patients-70 (48.3%) males and 75 (51.7%) females from 6 to 45 years (mean 15.8 +/- 7.5)-were seen. World Health Organization (WHO) guidelines were followed in the examination and reporting of the periodontal status, and DAI scores were assessed based on WHO guidelines. The chi-square test was used to determine the association between the DAI and the CPITN scores. Most patients were in the 6-15 (55.9%) or 16-25 (35.9%) age groups. Based on the WHO preferred cumulative calculations of treatment need (TN), 35.2% of the patients had TN 0, 64.9% had TN 1, 24.9% had TN 2, and only 0.7% had TN 3. The relationship between DAI scores and periodontal treatment needs was not statistically significant (P >.05). Although many patients were yet to attain the WHO goal of no more than 1 sextant affected by bleeding or calculus at the age of 15, over one third had satisfactory periodontal health.  相似文献   
7.
8.
The alphavbeta6 integrin is an exclusively epithelial integrin that is highly expressed during fetal development. In adult tissue, alphavbeta6 integrin is expressed during inflammation, carcinogenesis, and in wound healing. We previously reported that alphavbeta6 integrin is highly expressed in poorly healing human wounds and its over-expression is associated with chronic wounds in a mouse model. The objective of this study was to investigate the role of alphavbeta6 integrin in compromised wound healing induced by hydrocortisone treatment or aging by using young and old mice deficient in or overexpressing the beta6 integrin subunit in the epidermis. Untreated aged beta6 integrin-deficient (beta6-/-) animals showed a significant delay in wound healing when compared to their age-matched controls or younger beta6-/- mice. The most significant delay was observed at the stages where granulation tissue deposition was occurring. Hydrocortisone treatment significantly delayed wound healing in wild-type and beta6 integrin-deficient mice in comparison with the untreated controls. However, hydrocortisone treatment in beta6 integrin overexpressing animals did not cause a significant delay in wound healing. The results of this study suggest that alphavbeta6 integrin plays an important role in wound healing in animals compromised by either age or stress mimicked by hydrocortisone.  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