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   22782篇
  免费   2239篇
  国内免费   50篇
耳鼻咽喉   372篇
儿科学   700篇
妇产科学   368篇
基础医学   3265篇
口腔科学   611篇
临床医学   2281篇
内科学   4160篇
皮肤病学   301篇
神经病学   1715篇
特种医学   823篇
外科学   3352篇
综合类   568篇
一般理论   26篇
预防医学   2448篇
眼科学   685篇
药学   1423篇
中国医学   16篇
肿瘤学   1957篇
  2021年   298篇
  2020年   176篇
  2019年   263篇
  2018年   357篇
  2017年   266篇
  2016年   317篇
  2015年   347篇
  2014年   491篇
  2013年   737篇
  2012年   1032篇
  2011年   1012篇
  2010年   585篇
  2009年   531篇
  2008年   896篇
  2007年   1017篇
  2006年   963篇
  2005年   990篇
  2004年   878篇
  2003年   886篇
  2002年   797篇
  2001年   761篇
  2000年   768篇
  1999年   673篇
  1998年   298篇
  1997年   284篇
  1996年   280篇
  1995年   247篇
  1994年   245篇
  1993年   228篇
  1992年   585篇
  1991年   520篇
  1990年   488篇
  1989年   521篇
  1988年   451篇
  1987年   433篇
  1986年   411篇
  1985年   399篇
  1984年   326篇
  1983年   269篇
  1982年   203篇
  1981年   223篇
  1979年   296篇
  1978年   264篇
  1977年   184篇
  1976年   172篇
  1975年   189篇
  1974年   253篇
  1973年   195篇
  1972年   203篇
  1971年   169篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Summary Ultrastructural studies of cells and tissues in the acquired immunodeficiency syndrome (AIDS) have revealed two distinct cytomembranous inclusions referred to as tubuloreticular inclusions (TRI) and confronting cylindrical cisterns (CCC). TRI are found most often in leukocytes and endothelial cells in conditions with elevated levels of alpha-interferon, such as viral infections, autoimmune diseases and certain neoplasms. On the other hand, CCC are detected almost exclusively in mononuclear inflammatory cells and are limited to a few conditions, of which AIDS is the most common. CCC have been proposed as an ultrastructural marker for human immunodeficiency virus (HIV) infection. We describe CCC in mononuclear inflammatory cells in the brain of a patient with AIDS. Finding CCC in brain tissue with no other specific feature such as multinucleated giant cells, nevertheless, should alert the neuropathologist to the possibility that the patient might have AIDS.  相似文献   
103.
Superficial skin cancer is the most common malignancy in man, and radiotherapy has played an important curative role since the early part of the 20th century. We present an overview of the changing pattern of care for patients with superficial skin cancer at the Queensland Radium Institute (QRI), Brisbane--the skin cancer "capital" of the world. Although some 90,000 clinically-diagnosed skin cancers have been treated by radiotherapy at the QRI during the period 1944-1985, we document a dramatic decline in radiotherapy usage for superficial skin cancers over the past 10-15 years. We identify and discuss the major reasons for this changing pattern of care: (a) policy changes initiated by radiation oncologists because of unsightly radiation scars caused by the Queensland climate, (b) improvements in the availability and technical aspects of surgery and dermatology, and (c) surgical preference.  相似文献   
104.
105.
106.
Abstract This study illustrates how the Total Life Concept (TLC) program originated by AT&T was successfully transplanted to another work site, Sandia National Laboratories. Demographics of the participants at A T&T and Sandia differ and make comparisons difficult, but it is possible to assess program impact in terms of participation rates for each program. The original AT&T TLC pilot study had three major components: orientation, testing, and risk interpretation; lifestyle-improvement courses; and activities to promote health. Sandia kept the three major components of the AT&T TLC concept and made some modifications to meet Sandia's needs. Sandia's experience of adopting a model program and tailoring it to local needs worked well, demonstrating that an existing model can be successfully altered to meet the needs of different companies in varied settings.  相似文献   
107.
Mosaic ring 12p and total anomalous pulmonary venous return   总被引:1,自引:0,他引:1  
An infant born with total anomalous pulmonary venous return (TAPVR) was found to have an extra chromosome present as a small ring. Spectral karyotyping and FISH analysis identified the material as a duplication involving the short arm of chromosome 12. Previous cases describing a variety of cytogenetic abnormalities that have been associated with TAPVR are reviewed along with prior cases of duplication 12p with their associated findings. We believe ours is the first case to report the occurrence of mosaic ring 12p and its association with TAPVR.  相似文献   
108.
A 4-month-old girl presented with myoclonic seizures and an electroencephalogram showing hypsarrhythmia. Hyperglycinuria and a cerebrospinal fluid to plasma glycine ratio of 0.2 suggested the diagnosis of non-ketotic hyperglycinaemia. Propionic acid and methyl citric acid were present in the urine, and propionyl coenzyme A carboxylase was deficient in leucocytes and fibroblasts. The ketotic and non-ketotic hyperglycinaemias cannot be differentiated by CSF: plasma glycine ratios.  相似文献   
109.
Variation has been observed in the structural polypeptides of swine vesicular disease viruses isolated from the United Kingdom and Hong Kong. Despite the limited number of isolates examined, several distinct polypeptide patterns were obtained when the virus structural proteins were examined by polyacrylamide gel electrophoresis. Isolates from outbreaks in the United Kingdom which were known to be connected gave the same polypeptide pattern, whereas viruses with different polypeptide patterns could not be traced to a common source. The different polypeptide patterns were obtained consistently and were not altered by passage of the virus in tissue culture. In general, isolates with identical polypeptide patterns could not be distinguished by neutralization or antibody blocking tests or by competition radioimmunoassays. However, isolates with different polypeptide patterns could be differentiated by antibody blocking tests or radioimmunoassay. The correlation between the serological tests and the polyacrylamide gel electrophoresis analyses illustrates the value of analyzing structural polypeptides in the epidemiological study of swine vesicular disease.  相似文献   
110.
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