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   14798篇
  免费   884篇
  国内免费   72篇
耳鼻咽喉   390篇
儿科学   318篇
妇产科学   355篇
基础医学   1905篇
口腔科学   1031篇
临床医学   1171篇
内科学   3546篇
皮肤病学   274篇
神经病学   1185篇
特种医学   315篇
外科学   2328篇
综合类   85篇
一般理论   1篇
预防医学   1014篇
眼科学   324篇
药学   851篇
中国医学   56篇
肿瘤学   605篇
  2023年   117篇
  2022年   218篇
  2021年   581篇
  2020年   317篇
  2019年   543篇
  2018年   567篇
  2017年   362篇
  2016年   450篇
  2015年   533篇
  2014年   741篇
  2013年   797篇
  2012年   1278篇
  2011年   1356篇
  2010年   791篇
  2009年   603篇
  2008年   934篇
  2007年   960篇
  2006年   863篇
  2005年   751篇
  2004年   700篇
  2003年   540篇
  2002年   512篇
  2001年   161篇
  2000年   149篇
  1999年   137篇
  1998年   75篇
  1997年   64篇
  1996年   36篇
  1995年   40篇
  1994年   33篇
  1993年   31篇
  1992年   44篇
  1991年   61篇
  1990年   48篇
  1989年   40篇
  1988年   37篇
  1987年   31篇
  1986年   35篇
  1985年   28篇
  1984年   18篇
  1983年   17篇
  1982年   17篇
  1981年   12篇
  1980年   15篇
  1979年   15篇
  1978年   9篇
  1976年   9篇
  1975年   11篇
  1971年   7篇
  1970年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors‐encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype β was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence‐like (LAL) pattern to HEp‐2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non‐adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates.  相似文献   
5.
Enterococcus faecalis (E. faecalis) is a common cause of nosocomial infection in immunocompromised patients. The presence and dissemination of high‐risk clonal complexes, such as CC2, is an ongoing problem in hospitals. The aim of this work was to characterize 24 E. faecalis isolates from ICU patients undergoing selective decontamination of the digestive tract (SDD) by phenotypical (antimicrobial susceptibility) and genotypical (presence of virulence genes, RAPD‐PCR and MLST) methods. Our results showed high prevalence of the ST6 E. faecalis clone (91.6%), especially adapted to the hospital environment, with a multidrug resistance pattern and a multitude of putative virulence genes. In addition, ST179 (4.2%) and ST191 (4.2%) were detected. By RAPD–PCR analysis, the 22 isolates identified as ST6 showed six different DNA patterns, while the two remaining isolates, ST179 and ST191, showed two additional profiles. CC2 is a known clonal complex with high adaptability to hospital environment and worldwide distribution. The high prevalence of the ST6 clone in the studied population could be related to the presence of gentamicin in the SDD mixture since most strains were gentamicin resistant. Consequently, strict surveillance should be applied for rapid detection and control of this clone to prevent future spread outside the ICU.  相似文献   
6.
7.
IntroductionPeople with Down syndrome (DS) have high respiratory morbidity, evaluating their respiratory health with standardized, objective tests is desirable. Thus, the objective of this study was to evaluate the technical quality of Pulmonary Function Tests (PFTs) to determine which ones are most suitable for this population.MethodsParticipants included children, teenagers and adults with DS, 5 years of age or older (n = 302). The technical quality of the impulse oscillometry system (IOS), forced spirometry, lung-diffusing capacity for carbon monoxide (DLCO), and 6-min walk test (6MWT) were analyzed by age group. Capnography and pulse oximetry were included in the study. Technical quality was determined on the basis of current international PFTs standards.ResultsFifty-one percent of participants were males. A total of 184 participants (71%) who completed the IOS fulfilled the quality criteria, while 210 (70%) completed the 6MWT. Performance on forced spirometry and DLCO was poor. All pulse oximetries and 96% percent heart rates obtained had good quality, but exhaled carbon dioxide (PetCO2) and respiratory rate (RR) showed deficient repeatability.ConclusionsIOS appears to be the most reliable instrument for evaluating lung mechanics in individuals with DS.  相似文献   
8.
9.
10.
正The emerging role of gut microbiota as a key player in the development of neurodegenerative disorders:Mammals have evolved togetherwithcommensalmicrobiotatoestablishasymbioticrelationship in which they regulate reciprocally by synthesizing and responding to several common chemical substances. In this regard, gut microbiota  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