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   2633870篇
  免费   202592篇
  国内免费   4980篇
耳鼻咽喉   37789篇
儿科学   83927篇
妇产科学   76063篇
基础医学   371032篇
口腔科学   79556篇
临床医学   229086篇
内科学   512039篇
皮肤病学   58373篇
神经病学   212630篇
特种医学   105321篇
外国民族医学   879篇
外科学   403760篇
综合类   64338篇
现状与发展   9篇
一般理论   918篇
预防医学   195803篇
眼科学   62131篇
药学   199346篇
  7篇
中国医学   5389篇
肿瘤学   143046篇
  2018年   24052篇
  2015年   24248篇
  2014年   33669篇
  2013年   51631篇
  2012年   68640篇
  2011年   72544篇
  2010年   43089篇
  2009年   41256篇
  2008年   69672篇
  2007年   74531篇
  2006年   75504篇
  2005年   73432篇
  2004年   71915篇
  2003年   69344篇
  2002年   68142篇
  2001年   122299篇
  2000年   126048篇
  1999年   107353篇
  1998年   29264篇
  1997年   26615篇
  1996年   26102篇
  1995年   25089篇
  1994年   23587篇
  1993年   22130篇
  1992年   86558篇
  1991年   83931篇
  1990年   82173篇
  1989年   80077篇
  1988年   74556篇
  1987年   73398篇
  1986年   70077篇
  1985年   67224篇
  1984年   50358篇
  1983年   43236篇
  1982年   25668篇
  1981年   23211篇
  1980年   21752篇
  1979年   48272篇
  1978年   34033篇
  1977年   29066篇
  1976年   26822篇
  1975年   29305篇
  1974年   35464篇
  1973年   34209篇
  1972年   32026篇
  1971年   30116篇
  1970年   28130篇
  1969年   26724篇
  1968年   24848篇
  1967年   22376篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects arou  相似文献   
94.
95.
96.
97.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
98.
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.  相似文献   
99.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  相似文献   
100.
Reactive lymphoid infiltrates of the skin composed predominantly of gamma‐delta (γδ) T cells are not well described in the literature. Herein we report a case of an otherwise healthy 4‐year‐old male who presented with a waxing and waning papular rash characterized by small, discrete crusted papules spread across his trunk, face and extremities. Clinical evaluation revealed no evidence of systemic disease. Microscopic examination revealed a dermal, perivascular infiltrate of highly atypical lymphocytes with a γδ T cell phenotype, worrisome for primary cutaneous γδ T cell lymphoma. The clinical course, however, was that of a reactive condition and prompted consideration of a diagnosis of pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP). In many ways, this case defies current classification schemes and seems to expand the spectrum of reactive γδ T cell infiltrates of the skin.  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