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   1404612篇
  免费   99403篇
  国内免费   2299篇
耳鼻咽喉   20607篇
儿科学   46642篇
妇产科学   41131篇
基础医学   205483篇
口腔科学   38926篇
临床医学   118015篇
内科学   274347篇
皮肤病学   29817篇
神经病学   111600篇
特种医学   56784篇
外国民族医学   390篇
外科学   219412篇
综合类   27417篇
现状与发展   1篇
一般理论   335篇
预防医学   98665篇
眼科学   32615篇
药学   106657篇
  1篇
中国医学   2780篇
肿瘤学   74689篇
  2018年   14033篇
  2016年   12700篇
  2015年   14586篇
  2014年   19138篇
  2013年   28670篇
  2012年   40137篇
  2011年   42167篇
  2010年   24978篇
  2009年   23159篇
  2008年   41243篇
  2007年   44790篇
  2006年   45361篇
  2005年   44749篇
  2004年   42864篇
  2003年   41866篇
  2002年   41173篇
  2001年   62278篇
  2000年   63764篇
  1999年   54263篇
  1998年   15340篇
  1997年   13724篇
  1996年   13759篇
  1995年   12912篇
  1994年   12283篇
  1993年   11360篇
  1992年   42591篇
  1991年   41946篇
  1990年   41456篇
  1989年   40147篇
  1988年   37324篇
  1987年   36572篇
  1986年   34870篇
  1985年   33272篇
  1984年   24805篇
  1983年   21500篇
  1982年   12859篇
  1981年   11362篇
  1979年   23578篇
  1978年   16568篇
  1977年   14335篇
  1976年   13495篇
  1975年   14972篇
  1974年   17484篇
  1973年   16801篇
  1972年   16056篇
  1971年   14921篇
  1970年   13828篇
  1969年   13313篇
  1968年   12554篇
  1967年   11005篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
993.
Background  Nonmelanoma skin cancer (NMSC) has been linked to cutaneous human papillomaviruses of the genus beta (betaPV).
Objectives  We sought to assess the presence of betaPV in NMSC biopsies from a group of Scottish skin cancer patients, both immunocompetent (IC) patients and immunosuppressed (IS) organ transplant recipients.
Methods  One hundred and twenty-one paraffin-embedded skin tumours (27 actinic keratosis, 41 intraepidermal carcinoma, 53 squamous cell carcinoma) and 11 normal skin samples were analysed for the presence of betaPV by a polymerase chain reaction–reverse hybridization assay designed to detect the presence of the 25 known betaPV genotypes.
Results  In IC patients, betaPV was detected in 30 of 59 (51%) tumours and two of 11 (18%) normal skin samples ( P  =   0·046). In IS patients, betaPV was found in 27 of 62 (44%) tumours; no normal skin samples were available for comparison. The most frequently found genotypes were HPV-24, HPV-15 and HPV-38. Of those tumours infected with betaPV, 28 of 57 (49%) were infected with more than one genotype (range 2–8). Tumours from IS patients were from a younger age group (mean age 57·4 years) than IC patients (mean age 73·8 years). Multiple infections were more common in tumours from IC patients (21 of 30; 70%) compared with those from IS patients (seven of 27; 26%) ( P  <   0·001). In the IC group, age did not appear to influence the distribution of single and multiple infections whereas in IS patients the proportion of multiple infections to single infections increased with age. There were no multiple infections in normal skin.
Conclusions  A wide spectrum of betaPV types was detected in our samples. Further characterization of betaPV in vivo is needed in order to determine the mechanisms by which the virus contributes to cutaneous carcinogenesis.  相似文献   
994.

Background  

Advances in intensive care medicine have increased survival rates of patients with critical neurological conditions. The focus of prognostication for such patients is therefore shifting from predicting chances of survival to meaningful neurological recovery. This study assessed the variability in long-term outcome predictions among physicians and aimed to identify factors that may account for this variability.  相似文献   
995.
FDA’S Perspectives on Cardiovascular Devices   总被引:1,自引:0,他引:1  
The Food and Drug Administration (FDA) decision process for approving or clearing medical devices is often determined by a review of robust clinical data and extensive preclinical testing of the device. The mission statement for the Center for Devices and Radiological Health (CDRH) is to review the information provided by manufacturers so that it can promote and protect the health of the public by ensuring the safety and effectiveness of medical devices deemed appropriate for human use (Food, Drug & Cosmetic Act, §903(b)(1, 2(C)), December 31, 2004; accessed December 17, 2008 ). For high-risk devices, such as ventricular assist devices (VADs), mechanical heart valves, stents, cardiac resynchronization therapy (CRT) devices, pacemakers, and defibrillators, the determination is based on FDA’s review of extensive preclinical bench and animal testing followed by use of the device in a clinical trial in humans. These clinical trials allow the manufacturer to evaluate a device in the intended use population. FDA reviews the data from the clinical trial to determine if the device performed as predicted and the clinical benefits outweigh the risks. This article reviews the regulatory framework for different marketing applications related to cardiovascular devices and describes the process of obtaining approval to study a cardiovascular device in a U.S. clinical trial.  相似文献   
996.
997.
Abstract:  In Sweet's syndrome, the essential features are the characteristic morphology of the lesions, their histologic appearance, the dramatic response to corticosteroids and the absence of scarring. We report an 8-month-old infant in whom Sweet's syndrome was diagnosed and who developed acquired cutis laxa in the skin lesions.  相似文献   
998.
999.
1000.

Introduction  

Ethanol has a suppressive effect on inflammation and the immune system, but the effect of ethanol on tendon healing in vivo has not been studied. The purpose of this study was to investigate the histological and biomechanical effects of ethanol intake on tendon healing in a rat tendon injury model.  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