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   1384003篇
  免费   100688篇
  国内免费   5956篇
耳鼻咽喉   20517篇
儿科学   40848篇
妇产科学   39225篇
基础医学   193907篇
口腔科学   40798篇
临床医学   118677篇
内科学   270376篇
皮肤病学   30927篇
神经病学   109342篇
特种医学   56043篇
外国民族医学   456篇
外科学   213565篇
综合类   37133篇
现状与发展   19篇
一般理论   441篇
预防医学   94846篇
眼科学   32569篇
药学   105288篇
  40篇
中国医学   5382篇
肿瘤学   80248篇
  2018年   13661篇
  2017年   11326篇
  2016年   12300篇
  2015年   14419篇
  2014年   19640篇
  2013年   28077篇
  2012年   37097篇
  2011年   39228篇
  2010年   23422篇
  2009年   22339篇
  2008年   36367篇
  2007年   39378篇
  2006年   39766篇
  2005年   38420篇
  2004年   36842篇
  2003年   35662篇
  2002年   34915篇
  2001年   64460篇
  2000年   66130篇
  1999年   56307篇
  1998年   15220篇
  1997年   14023篇
  1996年   13381篇
  1995年   12629篇
  1994年   11824篇
  1992年   43051篇
  1991年   41500篇
  1990年   40783篇
  1989年   39738篇
  1988年   37140篇
  1987年   36544篇
  1986年   35011篇
  1985年   33200篇
  1984年   24886篇
  1983年   21102篇
  1982年   12683篇
  1981年   11595篇
  1979年   23950篇
  1978年   17086篇
  1977年   14852篇
  1976年   13410篇
  1975年   15282篇
  1974年   18102篇
  1973年   17577篇
  1972年   16823篇
  1971年   15724篇
  1970年   14921篇
  1969年   14354篇
  1968年   13465篇
  1967年   12024篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
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   
54.
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   
55.
56.
57.
58.
59.
60.
Esophageal adenocarcinoma is the fastest rising cancer in the United States. It develops from long‐standing gastroesophageal reflux disease which affects >20% of the general population. It carries a very poor prognosis with 5‐year survival <20%. The disease is known to sequentially progress from reflux esophagitis to a metaplastic precursor, Barrett''s esophagus and then onto dysplasia and esophageal adenocarcinoma. However, only few patients with reflux develop Barrett''s esophagus and only a minority of these turn malignant. The reason for this heterogeneity in clinical progression is unknown. To improve patient management, molecular changes which facilitate disease progression must be identified. Animal models can provide a comprehensive functional and anatomic platform for such a study. Rats and mice have been the most widely studied but disease homology with humans has been questioned. No animal model naturally simulates the inflammation to adenocarcinoma progression as in humans, with all models requiring surgical bypass or destruction of existing antireflux mechanisms. Valuable properties of individual models could be utilized to holistically evaluate disease progression. In this review paper, we critically examined the current animal models of Barrett''s esophagus, their differences and homologies with human disease and how they have shaped our current understanding of Barrett''s carcinogenesis.  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