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   140528篇
  免费   8768篇
  国内免费   914篇
耳鼻咽喉   1559篇
儿科学   4103篇
妇产科学   3217篇
基础医学   19469篇
口腔科学   2647篇
临床医学   11943篇
内科学   32022篇
皮肤病学   2905篇
神经病学   12865篇
特种医学   5132篇
外国民族医学   54篇
外科学   19502篇
综合类   2032篇
一般理论   54篇
预防医学   8731篇
眼科学   2215篇
药学   10761篇
  4篇
中国医学   631篇
肿瘤学   10364篇
  2023年   615篇
  2022年   1061篇
  2021年   2569篇
  2020年   1611篇
  2019年   2488篇
  2018年   3413篇
  2017年   2522篇
  2016年   2553篇
  2015年   3040篇
  2014年   3797篇
  2013年   5577篇
  2012年   8084篇
  2011年   8246篇
  2010年   4896篇
  2009年   4165篇
  2008年   7232篇
  2007年   7538篇
  2006年   7114篇
  2005年   7023篇
  2004年   7261篇
  2003年   6887篇
  2002年   6882篇
  2001年   4883篇
  2000年   4859篇
  1999年   3930篇
  1998年   1405篇
  1997年   1056篇
  1996年   1002篇
  1995年   952篇
  1994年   823篇
  1993年   791篇
  1992年   2310篇
  1991年   2235篇
  1990年   1955篇
  1989年   1876篇
  1988年   1710篇
  1987年   1564篇
  1986年   1529篇
  1985年   1367篇
  1984年   1011篇
  1983年   885篇
  1982年   556篇
  1979年   734篇
  1978年   516篇
  1975年   516篇
  1974年   612篇
  1973年   577篇
  1972年   541篇
  1971年   513篇
  1969年   492篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
European Radiology - The strongest adverse prognostic factor in myxoid/round cell liposarcomas (MRC-LPS) is the presence of a round cell component above 5% within the tumor bulk. Its identification...  相似文献   
2.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  相似文献   

3.
4.
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   
5.
Chondrocytes are the main cells in the extracellular matrix (ECM) of articular cartilage and possess a highly differentiated phenotype that is the hallmark of the unique physiological functions of this specialised load-bearing connective tissue. The plasma membrane of articular chondrocytes contains a rich and diverse complement of membrane proteins, known as the membranome, which defines the cell surface phenotype of the cells. The membranome is a key target of pharmacological agents and is important for chondrocyte function. It includes channels, transporters, enzymes, receptors, and anchors for intracellular, cytoskeletal and ECM proteins and other macromolecular complexes. The chondrocyte channelome is a sub-compartment of the membranome and includes a complete set of ion channels and porins expressed in these cells. Many of these are multi-functional proteins with “moonlighting” roles, serving as channels, receptors and signalling components of larger molecular assemblies. The aim of this review is to summarise our current knowledge of the fundamental aspects of the chondrocyte channelome, discuss its relevance to cartilage biology and highlight its possible role in the pathogenesis of osteoarthritis (OA). Excessive and inappropriate mechanical loads, an inflammatory micro-environment, alternative splicing of channel components or accumulation of basic calcium phosphate crystals can result in an altered chondrocyte channelome impairing its function. Alterations in Ca2+ signalling may lead to defective synthesis of ECM macromolecules and aggravated catabolic responses in chondrocytes, which is an important and relatively unexplored aspect of the complex and poorly understood mechanism of OA development.  相似文献   
6.
7.
8.
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