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   2635417篇
  免费   202710篇
  国内免费   4983篇
耳鼻咽喉   37833篇
儿科学   83968篇
妇产科学   76078篇
基础医学   371269篇
口腔科学   79565篇
临床医学   229259篇
内科学   512359篇
皮肤病学   58411篇
神经病学   212769篇
特种医学   105422篇
外国民族医学   879篇
外科学   403978篇
综合类   64343篇
现状与发展   9篇
一般理论   919篇
预防医学   195924篇
眼科学   62149篇
药学   199442篇
  7篇
中国医学   5389篇
肿瘤学   143138篇
  2018年   24094篇
  2015年   24287篇
  2014年   33704篇
  2013年   51696篇
  2012年   68715篇
  2011年   72626篇
  2010年   43132篇
  2009年   41306篇
  2008年   69765篇
  2007年   74594篇
  2006年   75578篇
  2005年   73494篇
  2004年   71977篇
  2003年   69410篇
  2002年   68199篇
  2001年   122330篇
  2000年   126093篇
  1999年   107379篇
  1998年   29282篇
  1997年   26628篇
  1996年   26115篇
  1995年   25106篇
  1994年   23603篇
  1993年   22145篇
  1992年   86585篇
  1991年   83950篇
  1990年   82187篇
  1989年   80095篇
  1988年   74573篇
  1987年   73415篇
  1986年   70090篇
  1985年   67243篇
  1984年   50374篇
  1983年   43249篇
  1982年   25674篇
  1981年   23213篇
  1980年   21756篇
  1979年   48282篇
  1978年   34043篇
  1977年   29072篇
  1976年   26830篇
  1975年   29314篇
  1974年   35478篇
  1973年   34220篇
  1972年   32040篇
  1971年   30130篇
  1970年   28135篇
  1969年   26725篇
  1968年   24853篇
  1967年   22382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