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   5264篇
  免费   313篇
  国内免费   30篇
耳鼻咽喉   49篇
儿科学   110篇
妇产科学   137篇
基础医学   728篇
口腔科学   90篇
临床医学   417篇
内科学   1146篇
皮肤病学   119篇
神经病学   603篇
特种医学   97篇
外科学   466篇
综合类   9篇
一般理论   1篇
预防医学   406篇
眼科学   62篇
药学   451篇
中国医学   17篇
肿瘤学   699篇
  2024年   6篇
  2023年   39篇
  2022年   107篇
  2021年   176篇
  2020年   117篇
  2019年   137篇
  2018年   151篇
  2017年   130篇
  2016年   136篇
  2015年   170篇
  2014年   206篇
  2013年   261篇
  2012年   461篇
  2011年   377篇
  2010年   215篇
  2009年   186篇
  2008年   332篇
  2007年   343篇
  2006年   360篇
  2005年   362篇
  2004年   328篇
  2003年   298篇
  2002年   253篇
  2001年   35篇
  2000年   22篇
  1999年   31篇
  1998年   48篇
  1997年   32篇
  1996年   38篇
  1995年   39篇
  1994年   26篇
  1993年   27篇
  1992年   15篇
  1991年   17篇
  1990年   5篇
  1989年   8篇
  1988年   15篇
  1987年   8篇
  1986年   9篇
  1985年   5篇
  1984年   10篇
  1983年   9篇
  1982年   4篇
  1981年   5篇
  1979年   7篇
  1978年   9篇
  1976年   5篇
  1975年   4篇
  1974年   5篇
  1968年   3篇
排序方式: 共有5607条查询结果,搜索用时 46 毫秒
91.
92.
93.
94.
Streptococcus bovis is one of the nonenterococcal species included among the streptococci group D. It is part of the normal bowel flora in humans and animals, but it is also responsible for infectious diseases (10-15% of all cases of bacterial endocarditis). Many cases of bacteremia and metastatic abscesses (spleen, liver, soft tissues, bone, meninges, endocardium) caused by S. bovis were reported as associated with digestive tract diseases, mainly colonic disease, and, in particular colonic neoplasms, or chronic liver diseases. A role in carcinogenesis has been suggested for this microorganism. The authors report two cases of S. bovis sepsis, one associated with colonic neoplasm and the other with liver cirrhosis and gastric carcinoma. Discussion is focused on probable mechanisms that favor gastric colonization and systemic diffusion of S. bovis from the gut in patients with gastrointestinal neoplasms or chronic liver disease and provides clinical recommendations for patients with S. bovis infections.  相似文献   
95.
96.

Background

The interpretation of “indeterminate” results of the recombinant immunoblot assay (RIBA) is a particularly sensitive issue for Transfusion Services, and donors with such a serological condition require long-term follow-up.

Materials and methods

In the Immunohaematology and Transfusion Medicine Division of Umberto I University Hospital (Rome, Italy), 102,979 donor blood units were screened for hepatitis C virus (HCV) antibodies by enzyme-linked immunosorbent assay (ELISA) over a 5-year period (01.01.2000 – 31.12.2004). Since 24.10.2001, HCV -RNA testing was added. All samples repeatedly reactive by ELISA were then submitted to a HCV confirmatory assay (RIBA).

Results

Among the 102,979 donors we found 271 positive to HCV ELISA testing. The results of the RIBA assay for these donors were negative in 178 (65.7%) cases, positive in 28 (10.3%) and indeterminate in 65 (24.0 %).Of the 65 subjects with an indeterminate pattern, 24 completed a sufficient follow-up (median 25 months; range, 6 – 52), during which some (n=8; 33%) converted to a negative status, some (n=16; 67%) maintained their reactivity pattern, but none became seropositive for HCV.

Conclusions

The HCV-RIBA indeterminate status may indicate either a non-specific reaction (false positive) or a real pre-existing or initial infection and does not, therefore, enable a prediction of outcome. The use of HCV genomic assays (nucleic acid amplification testing), which are more specific than antibody-based assays (ELISA, RIBA), therefore improves HCV blood donor testing by allowing an accurate interpretation of such primary assays.  相似文献   
97.
98.
99.
Introduction: Inhaled corticosteroids are the only drugs that effectively suppress the airway inflammation, but they can induce considerable systemic and adverse effects when they are administered chronically at high doses. Consequently, the pharmaceutical industry is still searching for newer entities with an improved therapeutic index.

Areas covered: Herein, the authors review the research in the glucocorticoid field to identify ligands of the glucocorticoid receptor (GR). These ligands preferentially induce transrepression with little or no transactivating activity, in order to have a potent anti-inflammatory action and a low side-effects profile.

Expert opinion: Several agents have been synthesized, but few have been tested in experimental models of asthma. Furthermore, only three (BI-54903, GW870086X and AZD5423) have entered clinical development, although the development of at least one of them (BI-54903) was discontinued. The reason for the limited success so far obtained is that the model of transactivation versus transrepression is a too simplistic representation of GR activity. It is difficult to uncouple the therapeutic and harmful effects mediated by GR, but some useful information that might change the current perspective is appearing in the literature. The generation of gene expression ‘fingerprints’ produced by different GR agonists in target and off-target human tissues could be useful in identifying drug candidates with an improved therapeutic ratio.  相似文献   

100.
BackgroundCardiovascular diseases constitute an important group of causes of death in the country. Ischemic heart diseases that are the main causes of cardiopulmonary arrest, leading to an impact on the mortality of the cardiovascular diseases in the health system.ObjectiveAssess the number of home deaths by cardiopulmonary arrest notified by the Mobile Emergency Medical Service (SAMU) in March 2018, 2019 and 2020.MethodsObservational study carried out from the analysis of cardiopulmonary arrest mortality data of citizens assisted by SAMU in Belo Horizonte, Minas Gerais, Brazil. Social and clinical characteristics and occurrence information of the patients were analyzed. The mortality rate due to cardiopulmonary arrest in relation to the total number of attendances was assessed. A significance level of 95% was considered.ResultsThere was increase of home deaths due to cardiopulmonary arrest in March 2020 compared to March 2018 (p<0.001) and March 2019 (p=0.050). Of the deaths reported in 2020, 63.8% of the patients were aged 60 years or older, 63.7% of the occurrences were performed in the afternoon and approximately 87% of the cardiopulmonary arrest notified had associated clinical comorbidities, with systemic arterial hypertension and heart failure represented by 22.87% and 13.03% of the reported cases, respectively. The majority of the evaluated sample of this study did not have any medical care follow-up (88.7%).ConclusionConsidering the increase in the number of the deaths, we suggest reflections and readjustments regarding the monitoring of chronic non-transmissible diseases during a pandemic, as well as improvements in death surveillance. (Arq Bras Cardiol. 2021; 116(2):266-271)  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