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   17389篇
  免费   1243篇
  国内免费   54篇
耳鼻咽喉   180篇
儿科学   757篇
妇产科学   401篇
基础医学   2753篇
口腔科学   274篇
临床医学   1615篇
内科学   3900篇
皮肤病学   202篇
神经病学   1706篇
特种医学   715篇
外科学   2827篇
综合类   171篇
一般理论   9篇
预防医学   1052篇
眼科学   302篇
药学   882篇
中国医学   17篇
肿瘤学   923篇
  2022年   141篇
  2021年   279篇
  2020年   151篇
  2019年   240篇
  2018年   323篇
  2017年   246篇
  2016年   248篇
  2015年   324篇
  2014年   453篇
  2013年   659篇
  2012年   880篇
  2011年   923篇
  2010年   516篇
  2009年   498篇
  2008年   836篇
  2007年   806篇
  2006年   785篇
  2005年   856篇
  2004年   786篇
  2003年   650篇
  2002年   687篇
  2001年   419篇
  2000年   379篇
  1999年   348篇
  1998年   168篇
  1997年   161篇
  1996年   150篇
  1995年   151篇
  1992年   311篇
  1991年   283篇
  1990年   297篇
  1989年   320篇
  1988年   286篇
  1987年   290篇
  1986年   271篇
  1985年   266篇
  1984年   185篇
  1983年   208篇
  1982年   149篇
  1981年   148篇
  1980年   129篇
  1979年   237篇
  1978年   211篇
  1977年   158篇
  1976年   172篇
  1975年   145篇
  1974年   153篇
  1973年   151篇
  1972年   164篇
  1969年   119篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
This report discusses the following issues related to typing of group A streptococci (GAS): The development and use of the 5' emm variable region sequencing (emm typing) in relation to the existing serologic typing system; the designation of emm types in relation to M types; a system for validation of new emm types; criteria for validation of provisional M types to new M-types; a list of reference type cultures for each of the M-type or emm-type strains of GAS; the results of the first culture exchange program for a quality control testing system among the national and World Health Organization collaborating centers for streptococci; and dissemination of new approaches to typing of GAS to the international streptococcal community.  相似文献   
102.
The World Health Organization and the Pugwash Conferences on Science and World Affairs (Nobel Peace Prize 1995) have been involved in questions concerning chemical and biological arms since the early 1950s. This memoir reviews a number of milestones in the efforts of these organizations to achieve the elimination of these weapons through international treaties effectively monitored and enforced for adherence to their provisions. It also highlights a number of outstanding personalities who were involved in the efforts to establish and implement the two major treaties now in effect, the Biological Weapons Convention of 1972 and the Chemical Weapons Convention of 1993.  相似文献   
103.
Location, location, location   总被引:1,自引:0,他引:1  
  相似文献   
104.
105.
Until 1970, primary sclerosing cholangitis (PSC) was considered to be a medical curiosity. With the development of endoscopic cholangiography, PSC is now recognized more frequently and is a common indication for liver transplantation. PSC is usually progressive, leading to cirrhosis, portal hypertension, and liver failure. The manifestations of disease may be clinically similar to those of other causes of bile duct obstruction and must be distinguished from gallstone disease, bile duct carcinoma, primary biliary cirrhosis, and secondary biliary cirrhosis due to bile duct stricture. Medical management of PSC must take into account the likelihood that destroyed bile ducts do not regenerate as hepatocytes do. Hence, PSC should be treated early in its course. The goal of therapy is to prevent further damage and destruction of bile ducts. In this article, we will present relevant data concerning the medical management of primary sclerosing cholangitis. Received for publication on March 8, 1999; accepted on April 5, 1999  相似文献   
106.
Krauss GL  Krumholz A  Carter RC  Li G  Kaplan P 《Neurology》1999,52(7):1324-1329
OBJECTIVE: We identified clinical risk factors for seizure-related motor vehicle crashes in patients with epilepsy. BACKGROUND: Current US laws permit epilepsy patients with controlled seizures to drive. These laws attempt to balance the important economic and social value of driving with the risk to public safety from seizure-related crashes. Various clinical factors are considered in these laws, particularly the seizure-free interval. Driving restrictions range from 3 to 18 months, however, and studies have not established how these various seizure-free intervals and other clinical factors influence the risk for seizure-related motor vehicle crashes. METHODS: We performed a retrospective case-control study to determine the influence of clinical risk factors associated with seizure-related motor vehicle crashes. Both "case" and "control" patients had epilepsy, drove, and were from the same clinic, but the cases differed in having had seizure-related crashes. RESULTS: Fifty patients with epilepsy who crashed during seizures and 50 matched control patients were compared. Factors that significantly decreased the odds of patients with epilepsy having motor vehicle crashes due to seizures were: long seizure-free intervals, reliable auras, few prior nonseizure-related accidents, and having had their antiepileptic drugs (AEDs) reduced or switched. For example, patients who had seizure-free intervals > or = 12 months had a 93% reduced odds for crashing compared to patients with shorter intervals. Other findings were: 25% of patients had more than one seizure-related crash and 20% had missed an AED dose just prior to their crash. The majority (54%) of patients who crashed were driving illegally, with seizure-free intervals shorter than legally permitted. CONCLUSION: Seizure-free intervals, the presence of reliable auras, AED therapy modifications, and a history of nonseizure-induced crashes should be considered when counseling patients with epilepsy on driving and when formulating driving regulatory policy. Case control studies of crashes due to seizures can help in assessing and monitoring such risks.  相似文献   
107.
108.
This article documents the ways in which a school-based developmental evaluation can be an effective and powerful alternative to the traditional clinic-based evaluation. The child is not taken to a strange new place but observed and evaluated in his or her naturalistic environment. The families have increased access to care, and the foundation is laid for cohesive, trusting working relationships with families and teachers. Children are evaluated in one of two models or a combination of both naturalistic observation and individual direct assessment. Tensions between the clinical and educational system exist, but the early childhood evaluator who educates himself or herself about the cultures and forces at work can build from the strengths of each system to effect positive growth for young children at risk for developmental delays or psychiatric disorders.  相似文献   
109.
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