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   511篇
  免费   23篇
  国内免费   3篇
耳鼻咽喉   8篇
儿科学   15篇
妇产科学   37篇
基础医学   73篇
口腔科学   1篇
临床医学   28篇
内科学   131篇
皮肤病学   9篇
神经病学   43篇
特种医学   10篇
外科学   70篇
预防医学   41篇
眼科学   13篇
药学   27篇
中国医学   1篇
肿瘤学   30篇
  2022年   5篇
  2021年   12篇
  2020年   6篇
  2019年   11篇
  2018年   13篇
  2017年   9篇
  2016年   9篇
  2015年   11篇
  2014年   14篇
  2013年   22篇
  2012年   26篇
  2011年   24篇
  2010年   12篇
  2009年   11篇
  2008年   22篇
  2007年   29篇
  2006年   26篇
  2005年   23篇
  2004年   23篇
  2003年   33篇
  2002年   17篇
  2001年   16篇
  2000年   17篇
  1999年   15篇
  1998年   6篇
  1997年   4篇
  1996年   4篇
  1995年   6篇
  1994年   3篇
  1993年   2篇
  1992年   15篇
  1991年   11篇
  1990年   7篇
  1989年   7篇
  1988年   8篇
  1987年   5篇
  1986年   12篇
  1985年   3篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1979年   3篇
  1974年   3篇
  1973年   3篇
  1972年   2篇
  1969年   2篇
  1968年   4篇
  1967年   2篇
  1965年   2篇
排序方式: 共有537条查询结果,搜索用时 15 毫秒
51.
52.
Choroidal tubercles with tuberculous meningitis   总被引:1,自引:0,他引:1  
We found choroidal tubercles in two children with meningitis. This finding supposed an important clue in establishing a tuberculous etiology. Following, we discuss the evolution and fluorescein angiographie findings of choroidal tubercles. As many authors have remarked, a thorough fundus examination is of great value in cases of fever of undetermined origin and meningitis. Choroidal tubercles can also be the first sign of a common pulmonary or extrapulmonary tuberculosis.  相似文献   
53.
Endothelins (ET-1, ET-2, ET-3) are a family of regulatory peptides with diverse biological functions, including modulation of smooth muscle tone. To evaluate the possible role of endothelins in the control of the detrusor smooth muscle of urinary bladder, we have investigated the responses of isolated strips of bladder dome and base to endothelins, in organ chambers, and characterized the receptors for these isopeptides in bladder membranes. ET-1, ET-2 and to a lesser extent ET-3 caused sustained concentration-dependent contraction of bladder dome and base. The contraction to endothelins, unlike the short-lived contraction produced by cholinergic agents, was long lasting and difficult to wash out. Equilibrium binding studies demonstrated that endothelin isoforms bound to bladder membrane receptors specifically, with high affinity (KD of 0.4-0.6 nM) and limited capacity (60-420 fmol/mg protein). Competition analysis showed two populations of receptors: one with high affinity for ET-1 and ET-2 and low affinity for ET-3 and another with high affinity for ET-1, ET-2 and ET-3. Chemical affinity labeling of endothelins to bladder membranes demonstrated that ET-1 and ET-2 were cross-linked to three proteins (75, 52 and 34 kDa, respectively), whereas ET-3 was cross-linked mainly to a 34 kDa protein. The data obtained from equilibrium binding studies, competition analysis and cross-linking experiments suggest that at least two endothelin receptor subtypes exist in bladder tissue. These observations further suggest that bladder smooth muscle tone may be modulated by endothelin or an endothelin-like substance via interaction with specific receptor sites.  相似文献   
54.
During the past decade several corticosteroid-dependent, low mol wt proteins with phospholipase-A2 (PLA2) inhibitory activity have been described. This family of proteins is collectively known as lipocortins. Blastokinin or uteroglobin (utg), a progesterone-induced protein, first discovered in the pregnant rabbit uterus, is also a potent PLA2 inhibitor, but genetically distinct from lipocortins. Although utg has been found in rabbits, its presence in humans has not been well established. Here, we present biochemical, immunological, and immunohistological evidence for the detection of a utg-like protein in the human uterus. Since inhibition of PLA2 may modulate tissue eicosanoid levels and since rabbit utg has been reported to be a potent PLA2 inhibitor, we also studied the temporal relationship between utg and tissue prostaglandin E2 and F2 alpha levels in estrogen- and progesterone-dominated endometrial tissue. We found an inverse temporal relationship between utg-like protein and eicosanoid levels in this organ. Since some eicosanoids (e.g. prostaglandins, leukotrienes, etc.) are known to be involved in smooth muscle contractility and inflammatory processes, our findings may help to understand the pathogenesis of some human disorders in which abnormal eicosanoid production occurs.  相似文献   
55.
56.
57.
58.
The solid fibrous solitary tumour of the oral cavity is an extremely rare entity. It is also of complicated diagnosis because of its extensive morphologic diversity (especially when there is a small amount of biopsied tissue) and because of its similarity to many mesenchymal injuries, mostly with hemangiopericytoma. The prognosis is reserved because of the few cases reported, mainly depending on tumour location and size.  相似文献   
59.
60.
Risk factors for hepatocellular carcinoma in patients with liver cirrhosis.   总被引:1,自引:0,他引:1  
OBJECTIVE: Although cirrhosis is known to predispose toward hepatocellular carcinoma (HCC), there is no agreement on the factors that can influence the risk for HCC in patients with cirrhosis. This study was designed to identify differences in cirrhosis-related risk factors for developing HCC in relation to epidemiological characteristics, stage of the disease and etiology. METHODS: 512 patients from southwestern Spain with Child-Pugh stage A or B cirrhosis were examined periodically by ultrasonography, and alpha-fetoprotein (AFP) concentration was measured. RESULTS: The average length of follow-up was 37 months. A total of 52 cases of HCC were detected, which represented a risk of 17% after 5 years of follow-up. The Cox model showed that the risk of HCC increased by 8% per year of increasing age. Male sex (relative risk: 3.4), hepatitis C virus infection (relative risk: 4.6), hepatitis B virus infection (relative risk: 2.9) and AFP levels higher than 15 ng/ml (relative risk: 2.5) were also shown to be risk factors. Among alcoholic patients, only age (risk increased by 15% per year), and hepatitis C virus infection (relative risk: 5.4) were risk factors for HCC. However, in patients infected by hepatitis C virus, the main risk factors were age (relative risk increased by 8% per year), male sex (relative risk: 3.9), co-infection with hepatitis B virus (relative risk: 4.9), and increased AFP (relative risk: 2.8). Of the patients with HCC, 71% were infected with hepatitis C virus. Alcoholism, Child-Pugh stage and duration of cirrhosis did not increase the risk of the appearance of HCC. CONCLUSIONS: The risk of HCC increased to 17% after 5 years of follow-up in patients with Child-Pugh stage A or B cirrhosis. Hepatitis C virus infection was the main risk factor in patients with cirrhosis. Other risk factors were age, male sex, hepatitis B virus infection and altered AFP level.  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