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   2297篇
  免费   142篇
  国内免费   77篇
耳鼻咽喉   2篇
儿科学   174篇
妇产科学   27篇
基础医学   256篇
口腔科学   58篇
临床医学   265篇
内科学   587篇
皮肤病学   74篇
神经病学   60篇
特种医学   397篇
外科学   101篇
综合类   48篇
预防医学   97篇
眼科学   22篇
药学   106篇
  2篇
肿瘤学   240篇
  2023年   7篇
  2022年   7篇
  2021年   11篇
  2020年   16篇
  2019年   18篇
  2018年   36篇
  2017年   25篇
  2016年   26篇
  2015年   43篇
  2014年   53篇
  2013年   65篇
  2012年   49篇
  2011年   57篇
  2010年   93篇
  2009年   87篇
  2008年   59篇
  2007年   100篇
  2006年   63篇
  2005年   69篇
  2004年   37篇
  2003年   32篇
  2002年   36篇
  2001年   58篇
  2000年   41篇
  1999年   36篇
  1998年   131篇
  1997年   156篇
  1996年   133篇
  1995年   109篇
  1994年   115篇
  1993年   98篇
  1992年   39篇
  1991年   46篇
  1990年   41篇
  1989年   57篇
  1988年   51篇
  1987年   46篇
  1986年   51篇
  1985年   49篇
  1984年   26篇
  1983年   20篇
  1982年   28篇
  1981年   36篇
  1980年   29篇
  1979年   17篇
  1978年   15篇
  1977年   24篇
  1976年   27篇
  1975年   19篇
  1974年   8篇
排序方式: 共有2516条查询结果,搜索用时 31 毫秒
991.
992.
993.
994.
995.
996.
OBJECTIVES: The main aim of this study was to reach consensus between students, faculty and general practice teachers on the educational objectives and requirements of the clerkship in general practice. METHOD: The consensus procedure consisted of four steps and all active general practice teachers (n = 116) were asked to participate in the study. RESULTS: We identified 189 educational objectives: 127 complaints (problems, symptoms, syndromes), 29 clinical skills and 37 objectives concerning the theoretical dimensions of general practice. Educational requirements crystallized to 16 essential preconditions of a teaching practice and 35 didactic activities to be performed by the general practice teachers. CONCLUSIONS: These consensus results will be used to structure the medical curriculum and as guidelines for the educational process during the clerkship.   相似文献   
997.
998.
999.
The effect of HLA-B27 polymorphism on antigen presentation was analysed by comparing the binding of three Epstein-Barr virus-derived peptide epitopes to HLA-B27 subtypes with their immunogenicity and antigenicity in the context of these subtypes. The effect of altering the major anchor residue Arg2 on binding or on recognition by peptide-specific cytotoxic T lymphocytes (CTL) was also examined. The three peptides bound significantly to all the B*2701-B*2706 subtypes. This did not correlate with the peptides being immunogenic or recognized by specific CTL in the context of only particular subtypes. In addition, of the three viral epitopes tested, those that were immunogenic in B*2702- or B*2705-restricted responses bound to these subtypes less efficiently than one peptide that was immunogenic only in the B*2704 context. Thus, among several potentially immunogenic peptides from the same virus, the antiviral response is not necessarily directed against the one that binds best to the restricting subtype. These results indicate that HLA- B27 polymorphism influences antigen presentation in ways other than simply peptide affinity. Synthetic analogues lacking the canonical Arg2 motif of HLA-B27-bound peptides, even when binding much worse to the restricting subtype, were recognized equally by CTL specific for the parental peptide. This indicates that Arg2 is not required to maintain the structure of the epitope. The implications of these results for pathogenetic models of HLA-B27-associated disease are discussed.   相似文献   
1000.
BACKGROUND: Incomplete resection of a basal cell carcinoma does not necessarily imply tumour recurrence. OBJECTIVE: The purpose of our study was to determine the clinical features most often associated with positive surgical margins and to establish whether positive margins effectively imply tumour recurrence. METHODS: We did a retrospective evaluation of 273 basal cell carcinomas in a total of 248 subjects. For each case, data regarding tumour location, sex, histological type and the presence or absence of affected surgical margins were collected. Follow-up was available in 151 cases. RESULTS: Positive margins were most often observed in facial lesions, particularly in the nasal and perioral areas, and for morphoeic histological types. Tumours with margin involvement exhibited a higher recurrence rate (26%) than those with free margins (14%) over a 5-year follow-up period. CONCLUSIONS: Individualized management, with special considerations depending on tumour location and histological type, is needed to treat basal cell carcinomas and cases with affected margins. Re-excision, preferably with Mohs' surgery, is advised in the latter as recurrences are much more complicated to treat. Furthermore, all cases need adequate follow-up, even in cases with unaffected surgical margins.  相似文献   
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