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   529146篇
  免费   28231篇
  国内免费   495篇
耳鼻咽喉   6680篇
儿科学   16918篇
妇产科学   12536篇
基础医学   92590篇
口腔科学   12341篇
临床医学   48456篇
内科学   95302篇
皮肤病学   11866篇
神经病学   33996篇
特种医学   19800篇
外国民族医学   53篇
外科学   78060篇
综合类   7610篇
现状与发展   2篇
一般理论   107篇
预防医学   38487篇
眼科学   11917篇
药学   41400篇
  1篇
中国医学   1126篇
肿瘤学   28624篇
  2021年   3896篇
  2018年   5736篇
  2017年   4127篇
  2016年   4872篇
  2015年   5361篇
  2014年   7121篇
  2013年   10500篇
  2012年   15577篇
  2011年   17391篇
  2010年   9958篇
  2009年   8825篇
  2008年   15714篇
  2007年   17449篇
  2006年   16947篇
  2005年   16265篇
  2004年   15884篇
  2003年   15266篇
  2002年   14785篇
  2001年   22432篇
  2000年   22980篇
  1999年   18931篇
  1998年   5234篇
  1997年   4364篇
  1996年   4397篇
  1995年   4125篇
  1992年   14414篇
  1991年   15818篇
  1990年   15949篇
  1989年   15625篇
  1988年   14310篇
  1987年   14200篇
  1986年   13171篇
  1985年   12688篇
  1984年   9395篇
  1983年   8002篇
  1982年   4177篇
  1979年   8937篇
  1978年   6382篇
  1977年   5150篇
  1976年   5504篇
  1975年   6613篇
  1974年   7419篇
  1973年   7158篇
  1972年   6597篇
  1971年   6309篇
  1970年   5888篇
  1969年   5467篇
  1968年   5161篇
  1967年   4621篇
  1966年   3964篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
Transitional progressive multiple sclerosis: MRI and MTI findings   总被引:1,自引:0,他引:1  
Transitional progressive multiple sclerosis (MS) is quite an unusual form of presentation and course of the disease. A case with this progressive form is presented and brain MRI and MTI findings are discussed in relation to the possible insight they may provide for understanding the mechanisms that determine progressive disability in MS.  相似文献   
973.
The aim of this study was to prospectively evaluate endoscopic ultrasonography and microscopic examination of duodenal bile in the diagnosis of cholecystolithiasis not detected by conventional ultrasonography. Forty five consecutive patients (26 females, 19 males, mean age: 50 years) with suspected cholecystolithiasis and at least two normal transcutaneous ultrasonography examinations were included. Endoscopic ultrasonographic criteria for the diagnosis of cholecystolithiasis were the presence of stones with or without acoustic shadowing or sludge. Criteria of microscopic examination of bile were cholesterol or bilirubinate crystals or spheroliths. Thirty three patients underwent cholecystectomy and lithiasis was found in gall bladder bile in 24. Twelve patients who were not operated on and were followed up (median: 17 months), had no evidence of cholecystolithiasis. Endoscopic ultrasonography and duodenal bile examination were 96% and 67% sensitive, respectively (p < 0.03). The specificity was not different (86 and 91%, respectively). None of the 16 patients with negative results in both procedures had evidence of cholecystolithiasis. It was found that for the diagnosis of cholecystolithiasis in patients with normal conventional ultrasonography, the sensitivity of endoscopic ultrasonography is higher than that of microscopic examination of duodenal bile. If endoscopic ultrasonography and microscopic examination of duodenal bile are negative, the risk of underdiagnosing cholecystolithiasis is negligible.  相似文献   
974.
975.
976.
977.
978.
979.
Evaluating HMO/IPA contracts for family physicians: one group's experiences   总被引:1,自引:0,他引:1  
This article reports the experience of a 15-person primary care group with two health maintenance organization/independent practice association (HMO/IPA) contracts. In 1986 the group received over $1.5 million in capitated payments from the plan to cover medical care of approximately 4,000 patients. The expenses exceeded the income for one plan. Analysis of primary care, specialty care, and ancillary services provides insight into factors that must be considered in evaluating HMO/IPA contracts. Eleven questions that should be asked before signing contracts and guidelines for utilization review and quality assurance are reviewed.  相似文献   
980.
A mu-capture enzyme-linked immunosorbent assay (ELISA) for detecting chlamydia-specific IgM was developed by use of the heat stable, lipopolysaccharide group-specific antigen and an alkaline phosphatase-labelled anti-chlamydia group-specific monoclonal antibody conjugate. The test was used to study the serological response in chlamydial respiratory tract infection among patients with acute respiratory tract symptoms in Cambridgeshire during the past 7 years. Results were compared with those of the complement fixation test (CFT) in routine use as well as those of a whole inclusion indirect immunofluorescence (WIF) test for IgM. Correlation between results of the mu-capture ELISA and those of the WIF test was 87.5%. The percentage of patients in whom specific IgM was found fell with increasing age. This may be due to lack of recall of IgM as a response to reinfection. Chlamydia-specific IgM was more likely to be detected when the CFT titre was greater than or equal to 64 and was rarely detected more than 6 months after the onset of symptoms. However, several patients less than 20 years of age were found to have specific IgM with CF antibody titres less than 64. We have found the mu-capture ELISA a useful test for the diagnosis of respiratory tract chlamydial infections, particularly in younger patients.  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