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   898篇
  免费   67篇
  国内免费   46篇
耳鼻咽喉   3篇
儿科学   42篇
妇产科学   2篇
基础医学   78篇
口腔科学   43篇
临床医学   110篇
内科学   150篇
皮肤病学   13篇
神经病学   70篇
特种医学   134篇
外科学   54篇
综合类   18篇
预防医学   33篇
眼科学   25篇
药学   190篇
中国医学   24篇
肿瘤学   22篇
  2023年   1篇
  2022年   7篇
  2021年   8篇
  2020年   6篇
  2019年   6篇
  2018年   13篇
  2017年   6篇
  2016年   5篇
  2015年   12篇
  2014年   16篇
  2013年   20篇
  2012年   32篇
  2011年   27篇
  2010年   41篇
  2009年   34篇
  2008年   30篇
  2007年   63篇
  2006年   41篇
  2005年   26篇
  2004年   29篇
  2003年   23篇
  2002年   23篇
  2001年   15篇
  2000年   28篇
  1999年   24篇
  1998年   48篇
  1997年   36篇
  1996年   44篇
  1995年   29篇
  1994年   18篇
  1993年   25篇
  1992年   18篇
  1991年   17篇
  1990年   21篇
  1989年   36篇
  1988年   37篇
  1987年   27篇
  1986年   25篇
  1985年   20篇
  1984年   10篇
  1983年   10篇
  1982年   9篇
  1981年   6篇
  1980年   7篇
  1979年   2篇
  1978年   7篇
  1977年   11篇
  1976年   5篇
  1975年   6篇
  1967年   1篇
排序方式: 共有1011条查询结果,搜索用时 31 毫秒
101.
102.
JB Epstein 《Oral diseases》1997,3(Z1):S124-S128
Kaposi's sarcoma (KS) is the most common neoplastic disease in patients with disease due to human immunodeficiency virus (HIV), and oral KS (OKS) is the commonest oral neoplasia. OKS has been managed by local excision, intralesional chemotherapy regional radiotherapy, and systemic chemotherapy. Comparison between studies is difficult as the severity of oral involvement is not well defined in most studies. This paper reviews the approach to the management of OKS and also presents a proposal for the clinical staging of OKS. Clinical staging of OKS will facilitate comparisons of outcomes of treatment of OKS and improve our understanding of the natural history of the neoplasia, which has varied presentation and rates of progression.  相似文献   
103.
Shunt surgery is considered to be the treatment of choice in patients with non-cirrhotic portal hypertension. There is little data on the effect of side-to-side lieno-renal (SSLR) shunt on oesophageal variceal size, splenic size and splenic pulp pressure (SPP) in patients with non-cirrhotic portal hypertension. We evaluated pre- and postoperatively endoscopic grading of varices, splenic size and SPP for predicting shunt patency in 86 patients with non-cirrhotic portal hypertension: 56 with extrahepatic portal venous obstruction (EHPVO) and 30 with non-cirrhotic portal fibrosis (NCPF). The EHPVO patients with patent shunts (n= 47) showed significant reduction in SPP (pre-operative 43.56±7.9 vs postoperative 29.96±7.7 cm of saline), splenic size (6.5±2.8 vs 4.00±2.6 cm below costal margin) and varices grades (2.96±0.5 vs 0.92±0.8). Patients with blocked shunt (n= 9) did not show significant reduction in SPP and varices grades. However, there was reduction in spleen size (8.6±3.0 vs 6.3±4.3). In the NCPF group, 28 had patent shunts and showed significant reduction in SPP (46.3±13.5 vs 33.8±7.6 cm of saline), splenic size (9.1±3.3 vs 6.8±4.6 cm below costal margin) and varices grades (2.8±0.7 vs 1.05±0.96). As only two patients with NCPF had blocked shunts, no statistical comparison between patients with patent and patients with blocked shunts could be done. In conclusion, following SSLR, there is a significant reduction in SPP and varices grades in patients with patent shunts. Endoscopic grading of varices can be used to predict shunt patency. However, spleen size is not a good criteria for predicting shunt patency.  相似文献   
104.
105.
小叶买麻藤中买麻藤甲素的结构研究   总被引:4,自引:0,他引:4  
从小叶买麻藤[Gnetum parvifolium(Warb.)C.Y.Cheng]茎的乙酸乙酯部分得到五个成分,经理化常数测定、光谱(UV,IR,MS,~1HNMR,~(13)CNMR和2D-NMR)分析和衍生物制备,确定买麻藤甲素为一个新的2-苯基苯并呋喃类化合物,结构为2-(3′,5′-二羟基-4′-甲氧基苯基)_-3-甲氧基5-羟基苯并呋喃。另外三个鉴定为异丹叶大黄素、白黎芦醇和β-谷甾醇.还有一个化合物正在鉴定中。  相似文献   
106.
107.
ABCC transporter inhibition reduces zymosan-induced peritonitis   总被引:1,自引:0,他引:1  
Inflammatory mediators are released from injured tissues being responsible for the first steps of inflammatory processes. Multidrug efflux transporters, members of the ATP-binding cassette (ABC) family, are ubiquitously expressed. ABCC molecules transport several endogenous substances, including leukotriene C4 (LTC4) and PGE2, which are involved in zymosan-induced inflammation. The present study investigated the role played by ABCC transporters on zymosan-induced peritonitis in mice. Most of the resident peritoneal cells were macrophages, based on their morphology and membrane-activated complex 3 expression. RT-PCR demonstrated that these cells expressed ABCC, and ABCC activity was analyzed in vivo via the s.c. injection of ABCC inhibitors [probenecid (PROB) 200 mg/kg or MK571 20 mg/kg], followed by an i.v. injection of carboxyfluorescein diacetate (CFDA), an ABCC fluorescent substrate. Both inhibitors increased CFDA accumulation, suggesting ABCC impairment. Moreover, ABCC reversors decreased zymosan-induced plasma exudation by 86.6 +/- 7.4 and 97.6 +/- 2.3%, a feature related to a diminished secretion of LTC(4) (65.1+/-11 and 47.8+/-9.9%) and PGE(2) (under basal levels). Cell migration was inhibited similarly. Furthermore, PROB and MK571 inhibited IL-1ss by 83.4 +/- 13 and 71.2 +/- 13.4% and TNF-alpha content by 47 +/- 4.5 and 28.9 +/- 0.8%, respectively. NO metabolites and reactive oxygen species production were also reduced. The present results suggest that ABCC molecules have a relevant role in the acute inflammatory response produced by zymosan in mice.  相似文献   
108.
A qualitative study aiming at understanding the socio-political aspects that mediate the implantation of the Transplant Center of Piauí, identify the social topics involved in this implantation and analyze the participation of the organized civil society. Ten people directly related to the implantation of the transplant center were involved in the study, selected through the "snowball" technique. A loosely structured interview, taped, transcribed and submitted for thematic analysis was used. It was concluded that the implantation of the transplant center in Piauí was the fruit of a complex series of negotiations and interests among the State and organized civil society, as there was no political project for action in the area of transplants. This distancing from the responsibility of the public sector characterizes the importance that was given to this implantation.  相似文献   
109.
Blood transfusion is one of the principal routes of transmission of Chagas' disease, a major endemic disease in Latin America. Methods for blood screening are not accurate and may yield false results that lead to high social and economic costs. This study compares two methods of diagnosing Chagas' disease (indirect immunofluorescence and hemagglutination) and several enzyme-linked immunosorbent assays (ELISAs) with regard to specificity and sensitivity, by using human sera with known serologic and parasitologic characteristics, as well as samples with discrepant results on conventional serologic tests. An ELISA using recombinant antigens showed no cross-reactivity with sera that were positive for other diseases. All evaluated ELISAs performed well, and their use may lead to a reduction of more than 50 percent in the number of discordant sera. Further improvements are needed in view of the complexity of the serologic diagnosis of Chagas' disease.  相似文献   
110.
Vaccinia virus (VACV) has had an important role for humanity because of its use during the smallpox eradication campaign. VACV is the etiologic agent of the bovine vaccinia (BV), an emerging zoonosis that has been associated with economic, social, veterinary and public health problems, mainly in Brazil and India. Despite the current and historical VACV importance, there is little information about its circulation, prevalence, origins and maintenance in the environment, natural reservoirs and diversity. Brazilian VACV (VACV-BR) are grouped into at least two groups based on genetic and biological diversity: group 1 (G1) and group 2 (G2). In this study, we went to the field and investigated VACV clonal diversity directly from exanthemous lesions, during BV outbreaks. Our results demonstrate that the G1 VACV-BR were more frequently isolated. Furthermore, we were able to co-detect the two variants (G1 and G2) in the same sample. Molecular and biological analysis corroborated previous reports and confirmed the co-circulation of two VACV-BR lineages. The detected G2 clones presented exclusive genetic and biological markers, distinct to reference isolates, including VACV-Western Reserve. Two clones presented a mosaic profile, with both G1 and G2 features based on the molecular analysis of A56R, A26L and C23L genes. Indeed, some SNPs and INDELs in A56R nucleotide sequences were observed among clones of the same virus population, maybe as a result of an increased mutation rate in a mixed population. These results provide information about the diversity profile in VACV populations, highlighting its importance to VACV evolution and maintenance in the environment.  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