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   2262篇
  免费   142篇
  国内免费   6篇
耳鼻咽喉   40篇
儿科学   72篇
妇产科学   52篇
基础医学   429篇
口腔科学   16篇
临床医学   246篇
内科学   484篇
皮肤病学   54篇
神经病学   203篇
特种医学   86篇
外科学   234篇
综合类   8篇
一般理论   2篇
预防医学   158篇
眼科学   22篇
药学   129篇
中国医学   8篇
肿瘤学   167篇
  2023年   10篇
  2022年   28篇
  2021年   30篇
  2020年   27篇
  2019年   50篇
  2018年   65篇
  2017年   33篇
  2016年   42篇
  2015年   37篇
  2014年   67篇
  2013年   82篇
  2012年   149篇
  2011年   186篇
  2010年   92篇
  2009年   98篇
  2008年   177篇
  2007年   148篇
  2006年   145篇
  2005年   150篇
  2004年   132篇
  2003年   126篇
  2002年   149篇
  2001年   46篇
  2000年   49篇
  1999年   45篇
  1998年   29篇
  1997年   19篇
  1996年   15篇
  1995年   15篇
  1994年   12篇
  1993年   14篇
  1992年   15篇
  1991年   24篇
  1989年   12篇
  1988年   9篇
  1987年   6篇
  1986年   6篇
  1985年   7篇
  1984年   3篇
  1983年   4篇
  1982年   5篇
  1980年   3篇
  1979年   9篇
  1978年   4篇
  1974年   7篇
  1973年   3篇
  1972年   3篇
  1971年   3篇
  1969年   4篇
  1968年   5篇
排序方式: 共有2410条查询结果,搜索用时 0 毫秒
21.
Coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 is associated with a wide spectrum of disease, ranging from asymptomatic infection to acute respiratory distress syndrome. Some biomarkers may predict disease severity. Among them, the anti-SARS-CoV-2 antibody response has been related to severe disease. The aim of this study was to assess the correlation between the anti-SARS-CoV-2 serological response and COVID-19 outcome. Demographic, clinical, and biological data from nasopharyngeal-PCR confirmed COVID-19 hospitalized patients were prospectively collected between April and August 2020 at our institution. All patients had serial weekly serology testing for a maximum of three blood samples or until discharge. Two different serological assays were used: a chemiluminescent assay and an in-house developed Luminex immunoassay. Kinetics of the serological response and correlation between the antibody titers and outcome were assessed. Among the 70 patients enrolled in the study, 22 required invasive ventilation, 29 required non-invasive ventilation or oxygen supplementation, and 19 did not require any oxygen supplementation. Median duration of symptoms upon admission for the three groups were 13, 8, and 9 days, respectively. Antibody titers gradually increased for up to 3 weeks since the onset of symptoms for patients requiring oxygen supplementation with significantly higher antibody titers for patients requiring invasive ventilation. Antibody titers on admission were also significantly higher in severely ill patients and serology performed well in predicting the necessity of invasive ventilation (AUC: 0.79, 95% CI: 0.67–0.9). Serology testing at admission may be a good indicator to identify severe COVID-19 patients who will require invasive mechanical ventilation.  相似文献   
22.
The brown alga Cystoseira baccata harvested along the Atlantic coasts of Morocco yielded seven new meroditerpenoids (1-4) and derivatives (5-7), whose chemical structures were elucidated mainly by 2D NMR and mass spectrometry. Surprisingly, for all these compounds, which possess a bicyclo[4.3.0]nonane ring system, a trans fusion of the bicyclic system was deduced by stereochemical studies even though such compounds isolated from Cystoseira species are known to have a typical cis orientation for the bridgehead methyls. The antifouling and antibacterial activities of compounds 1-5 and 7 were evaluated, as well as their toxicity toward nontarget species. Compounds 4, 5, and 7 showed antifouling activities against growth of microalgae, macroalgal settlement, and mussel phenoloxidase activity, while being nontoxic to larvae of sea urchins and oysters.  相似文献   
23.
24.
Lobar congenital emphysema is a rare pulmonary malformation corresponding to progressive overinflation of a pulmonary lobe secondary to partial bronchial obstruction. Prenatal diagnosis is mainly based on lung hyperechoic area. Sonographic features are not specific highlighting the interest of fetal MRI or postnatal tomodensitometry. This case report describes prenatal detection including pitfalls and postnatal management.  相似文献   
25.
Algo is a clinical decision algorithm developed to support nonoccupational therapists in establishing assistive technology recommendations to enable physically disabled adults to perform their hygiene at home. This study aimed to explore the in-depth clinical reasoning of nonoccupational therapists using Algo to pinpoint the items leading to disagreements regarding recommendations. A multiple-case study was conducted with eight nonoccupational therapists trained to use Algo and filmed while using it with six standardized clients. Explicitation interviews were conducted for the conflicting recommendations. Identifying the key reasoning skills to develop in Algo users has led to three recommendations to enhance standardization with seniors.  相似文献   
26.
27.
28.
29.
Incidence of dementia increases sharply with age and, because of the increase in life expectancy, the number of dementia cases is expected to rise dramatically over time. Some studies suggest that controlling some modifiable risk factors for dementia like diabetes or hypertension could lower its incidence. However, as treating these vascular factors would also reduce mortality risk, the actual impact of such public-health intervention on dementia prevalence is not known. Accounting for the impact of dementia and risk factors on mortality, the aim of this work was (1) to compute projections of age- and-sex specific prevalence of dementia in France from 2010 to 2030, (2) to evaluate how public-health interventions targeting risk factors for dementia could change these projections. Age-and-sex specific incidence of dementia and mortality of demented subjects were estimated from the Paquid population-based cohort using a semi-parametric illness-death model. Future global mortality rates and population sizes were obtained from national demographic projections. Under the assumption that life expectancy will increase by 3.5 years for men and 2.8 years for women by 2030, the number of subjects with dementia was estimated to increase by about 75 % from 2010 to 2030 with a 200 % increase after 90 years of age. Therapeutic intervention on the whole population reducing high blood pressure prevalence would lead to a decrease in both dementia incidence rates and mortality and would have a modest impact on the number of dementia cases. On the other hand, a preventive dementia treatment targeting ApoE4 carriers would probably not improve survival and hence would decrease dementia prevalence by 15–25 %.  相似文献   
30.
OBJECTIVE: To investigate the value of serum antitissue transglutaminase IgA antibodies (IgA-TTG) and IgA antiendomysial antibodies (IgA-EMA) in the diagnosis of coeliac disease in cohorts from different geographical areas in Europe. The setting allowed a further comparison between the antibody results and the conventional small-intestinal histology. METHODS: A total of 144 cases with coeliac disease [median age 19.5 years (range 0.9-81.4)], and 127 disease controls [median age 29.2 years (range 0.5-79.0)], were recruited, on the basis of biopsy, from 13 centres in nine countries. All biopsy specimens were re-evaluated and classified blindly a second time by two investigators. IgA-TTG were determined by ELISA with human recombinant antigen and IgA-EMA by an immunofluorescence test with human umbilical cord as antigen. RESULTS: The quality of the biopsy specimens was not acceptable in 29 (10.7%) of 271 cases and a reliable judgement could not be made, mainly due to poor orientation of the samples. The primary clinical diagnosis and the second classification of the biopsy specimens were divergent in nine cases, and one patient was initially enrolled in the wrong group. Thus, 126 coeliac patients and 106 controls, verified by biopsy, remained for final analysis. The sensitivity of IgA-TTG was 94% and IgA-EMA 89%, the specificity was 99% and 98%, respectively. CONCLUSIONS: Serum IgA-TTG measurement is effective and at least as good as IgA-EMA in the identification of coeliac disease. Due to a high percentage of poor histological specimens, the diagnosis of coeliac disease should not depend only on biopsy, but in addition the clinical picture and serology should be considered.  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