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   8463篇
  免费   571篇
  国内免费   17篇
耳鼻咽喉   87篇
儿科学   433篇
妇产科学   113篇
基础医学   1070篇
口腔科学   386篇
临床医学   538篇
内科学   1829篇
皮肤病学   116篇
神经病学   573篇
特种医学   246篇
外科学   1092篇
综合类   223篇
一般理论   2篇
预防医学   487篇
眼科学   369篇
药学   750篇
中国医学   74篇
肿瘤学   663篇
  2023年   39篇
  2022年   138篇
  2021年   339篇
  2020年   132篇
  2019年   188篇
  2018年   257篇
  2017年   185篇
  2016年   250篇
  2015年   243篇
  2014年   355篇
  2013年   440篇
  2012年   701篇
  2011年   591篇
  2010年   389篇
  2009年   301篇
  2008年   435篇
  2007年   440篇
  2006年   400篇
  2005年   363篇
  2004年   324篇
  2003年   306篇
  2002年   274篇
  2001年   173篇
  2000年   178篇
  1999年   171篇
  1998年   86篇
  1997年   68篇
  1996年   49篇
  1995年   55篇
  1994年   37篇
  1993年   37篇
  1992年   110篇
  1991年   93篇
  1990年   95篇
  1989年   92篇
  1988年   80篇
  1987年   70篇
  1986年   57篇
  1985年   59篇
  1984年   56篇
  1983年   48篇
  1982年   27篇
  1981年   20篇
  1979年   41篇
  1978年   28篇
  1977年   19篇
  1976年   17篇
  1974年   23篇
  1973年   23篇
  1970年   23篇
排序方式: 共有9051条查询结果,搜索用时 15 毫秒
1.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
2.
3.
4.
5.
6.
7.
8.
9.
P N Nair  H E Schroeder 《Immunology》1986,57(2):171-180
Minor salivary glands (MSG) play a substantial role in the secretory immunoglobulin A (sIgA)-mediated immunity of the oral cavity. There are two possibilities for the induction of this immunity: (i) an explicitly local antigenic stimulus, or (ii) a remote stimulus as part of the so-called 'common mucosal immune system'. This communication is an attempt to consolidate available evidence in support of both possibilities and to address the former in detail. Although there is strong circumstantial evidence supporting the feasibility of MSG functioning as a part of the common mucosal immune system, direct experimental evidence is yet to emerge. On the other hand, there is increasing structural and physiological evidence in support of MSG serving as a local immunological organ. The purely local response is attributed to the presence of MSG duct-associated lymphoid tissue (DALT), which is comparable to gut- or bronchial-associated lymphoid tissue (GALT or BALT) in origin, tissue organization and function. DALT is accessible to oral antigens by retrograde passage through MSG ducts. Repeated topical antigenic challenging via the oral mucosa may result in the appearance of interacinar plasma cells carrying specific homologous antibodies in MSG. Gut or enteric priming of the same antigen, by passing the oral mucosa by gastric intubation, need not evoke a remote immune response in MSG. Since DALT is more likely to occur in healthy, young growing individuals, who are less likely to undergo bioptic examination of MSG, it has not yet been documented in humans. The physiologically induced DALT is apt to be confused with focal accumulations of lymphoid tissue in pathologically altered MSG, as a consequence of local and some systemic autoimmune diseases. An attempt is made to demarcaate healthy and pathological MSG on the basis of currently available clinical, serological, immunological and genetic evidence.  相似文献   
10.
BACKGROUND: Diabetes mellitus is considered as a risk factor for the initiation and progression of periodontal disease. The diabetic patients often exhibit decreased immune response and increased susceptibility to infection. In the present study, a quantitative estimation of the gingival tissue immunoglobulin concentrations in diabetic and non diabetic subjects with periodontitis was assessed and compared with that of clinically healthy gingiva. METHOD: 40 gingival tissue samples obtained from 20 diabetic (Type 2) and 20 non-diabetic subjects were subjected to quantitative estimation of immunoglobulins G, A, and M. The data thus obtained were compared to the level of immunoglobulin found in clinically healthy gingiva. RESULTS: The IgG and IgA level in the tissues of both diabetic and non-diabetic subjects with periodontitis were found to be significantly higher than that of healthy subjects. The diabetic group also showed a significantly higher IgG and IgA levels compared to the non-diabetic group with periodontitis. CONCLUSION: These findings support the concept that the humoral immune response plays an important role in the pathogenesis of periodontal disease in diabetics. The significantly higher levels of immunoglobulin in the gingival tissues might be a protective mechanism against the increased bacterial challenge in diabetic subjects.  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