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   2627篇
  免费   136篇
  国内免费   27篇
耳鼻咽喉   40篇
儿科学   78篇
妇产科学   49篇
基础医学   378篇
口腔科学   160篇
临床医学   239篇
内科学   509篇
皮肤病学   34篇
神经病学   283篇
特种医学   108篇
外科学   185篇
综合类   13篇
一般理论   1篇
预防医学   339篇
眼科学   48篇
药学   237篇
中国医学   27篇
肿瘤学   62篇
  2023年   15篇
  2022年   29篇
  2021年   58篇
  2020年   46篇
  2019年   67篇
  2018年   70篇
  2017年   48篇
  2016年   54篇
  2015年   56篇
  2014年   87篇
  2013年   120篇
  2012年   171篇
  2011年   188篇
  2010年   120篇
  2009年   103篇
  2008年   144篇
  2007年   161篇
  2006年   119篇
  2005年   117篇
  2004年   98篇
  2003年   98篇
  2002年   77篇
  2001年   59篇
  2000年   58篇
  1999年   41篇
  1998年   25篇
  1997年   21篇
  1996年   15篇
  1995年   16篇
  1994年   17篇
  1992年   30篇
  1991年   22篇
  1990年   34篇
  1989年   26篇
  1988年   29篇
  1987年   22篇
  1986年   28篇
  1985年   24篇
  1984年   19篇
  1983年   15篇
  1982年   17篇
  1980年   12篇
  1979年   23篇
  1978年   16篇
  1977年   17篇
  1976年   14篇
  1974年   12篇
  1972年   13篇
  1969年   18篇
  1968年   17篇
排序方式: 共有2790条查询结果,搜索用时 15 毫秒
1.
Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.  相似文献   
2.
3.
4.
The laryngeal mask in failed intubation   总被引:1,自引:0,他引:1  
  相似文献   
5.
6.
Truncus Arteriosus With Patent Ductus Arteriosus and Normal Aortic Arch   总被引:1,自引:0,他引:1  
In hearts with a common arterial trunk (truncus arteriosus), there is almost always an inverse development of the aortic arch and the ductus arteriosus. Truncus with a normal aortic arch and a patent ductus is a rare echocardiographic and surgical finding. In this report, we describe 2 neonates in whom truncus arteriosus with a normal aortic arch and a medium or large patent ductus was diagnosed by preoperative echocardiography (without catheterization) and confirmed intraoperatively.  相似文献   
7.
8.
BACKGROUND: Elevated liver enzymes are infrequent in patients with hepatitis C virus (HCV) infection undergoing chronic hemodialysis (HD), suggesting that the alanine aminotransferase (ALT) is a poor predictor of hepatocellular damage in this population. OBJECTIVE: To establish a more appropriate cut-off value of ALT to identify biochemical activity due to HCV infection in HD patients. STUDY DESIGN: A total of 217 patients, with an average age of 51.2 years, were evaluated between January and October 2002; 130 were males (60%). Serum ALT was measured by a kinetic method in five consecutive monthly blood samples, from which an average was obtained and divided by the upper limit of normal (ULN). HCV antibodies were determined using an enzyme immunoassay, the serum HCV-RNA by nested-PCR and HCV genotype by hybridization of the amplified sequence from the 5'-non-coding region. The cut-off value of ALT was obtained from a ROC curve. RESULTS: Within the 217 patients, 18 (8.3%) were anti-HCV-positive, 17 (7.8%) of whom were also HCV-RNA-positive. Genotype distribution was: 1a=47%; 1b=18%; 3a=35%. Mean ALT/ULN (0.77+/-0.57) of the 18 anti-HCV-positive cases was higher (p<0.001) than the negative group (0.38+/-0.23). The mean ALT/ULN (0.81+/-0.57) of the 17 HCV-RNA-positive cases was also higher (p<0.0001) than the negative cases (0.37+/-0.23). The cut-off value of ALT to distinguish the anti-HCV-positive from negative patients was 0.50% or 50% of the ULN (sensitivity=67%; specificity=83%). According to the HCV-RNA, the cut-off value of ALT was 0.45% or 45% of the ULN (sensitivity=71%; specificity=80%). CONCLUSION: Reducing the cut-off of ALT by half, enables a better identification of biochemical activity in patients with HCV infection on chronic HD.  相似文献   
9.
10.
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