全文获取类型
收费全文 | 72073篇 |
免费 | 4788篇 |
国内免费 | 288篇 |
专业分类
耳鼻咽喉 | 961篇 |
儿科学 | 1745篇 |
妇产科学 | 1203篇 |
基础医学 | 8636篇 |
口腔科学 | 1552篇 |
临床医学 | 7755篇 |
内科学 | 14804篇 |
皮肤病学 | 1268篇 |
神经病学 | 7015篇 |
特种医学 | 2269篇 |
外科学 | 11873篇 |
综合类 | 913篇 |
一般理论 | 77篇 |
预防医学 | 5554篇 |
眼科学 | 1420篇 |
药学 | 4600篇 |
3篇 | |
中国医学 | 98篇 |
肿瘤学 | 5403篇 |
出版年
2023年 | 385篇 |
2022年 | 623篇 |
2021年 | 1563篇 |
2020年 | 908篇 |
2019年 | 1520篇 |
2018年 | 1789篇 |
2017年 | 1337篇 |
2016年 | 1483篇 |
2015年 | 1710篇 |
2014年 | 2351篇 |
2013年 | 3316篇 |
2012年 | 5033篇 |
2011年 | 5549篇 |
2010年 | 2975篇 |
2009年 | 2701篇 |
2008年 | 4708篇 |
2007年 | 4882篇 |
2006年 | 4815篇 |
2005年 | 4742篇 |
2004年 | 4487篇 |
2003年 | 4261篇 |
2002年 | 3946篇 |
2001年 | 699篇 |
2000年 | 626篇 |
1999年 | 745篇 |
1998年 | 824篇 |
1997年 | 667篇 |
1996年 | 620篇 |
1995年 | 602篇 |
1994年 | 486篇 |
1993年 | 429篇 |
1992年 | 451篇 |
1991年 | 395篇 |
1990年 | 389篇 |
1989年 | 328篇 |
1988年 | 372篇 |
1987年 | 335篇 |
1986年 | 328篇 |
1985年 | 333篇 |
1984年 | 337篇 |
1983年 | 332篇 |
1982年 | 395篇 |
1981年 | 334篇 |
1980年 | 268篇 |
1979年 | 186篇 |
1978年 | 195篇 |
1977年 | 157篇 |
1976年 | 110篇 |
1974年 | 131篇 |
1973年 | 135篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献14.
15.
Jennifer C. Sasaki Ashley Allemang Steven M. Bryce Laura Custer Kerry L. Dearfield Yasmin Dietz Azeddine Elhajouji Patricia A. Escobar Albert J. Fornace Jr Roland Froetschl Sheila Galloway Ulrike Hemmann Giel Hendriks Heng-Hong Li Mirjam Luijten Gladys Ouedraogo Lauren Peel Stefan Pfuhler Daniel J. Roberts Véronique Thybaud Jan van Benthem Carole L. Yauk Maik Schuler 《Environmental and molecular mutagenesis》2020,61(1):114-134
In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114–134, 2020. © 2019 Wiley Periodicals, Inc. 相似文献
16.
Although hepatitis E virus (HEV) is the primary cause of enterically transmitted acute hepatitis and jaundice in developing countries, locally acquired HEV infections are increasing in nonendemic countries. As such, HEV is emerging as an underdiagnosed cause of infection. This report describes three clinically variable cases of HEV infection with unusual clinical presentations. These cases highlight the fact that HEV should be considered in the differential diagnosis of patients with unexplained hepatitis (acute or chronic) with or without extrahepatic manifestations. HEV should also be considered in patients with persistently elevated liver enzymes who have not travelled to known HEV-endemic regions. Lack of knowledge among physicians and an absence of standardized diagnostic tests may result in increased morbidity and mortality from HEV infection. 相似文献
17.
We report a case of dichorionic, diamniotic twins who developed similar erythematous, annular, erosive plaques in the inguinal folds in the first few weeks of life that were refractory to topical antifungals and oral antibiotics. The twins were found to have high transaminase levels, antinuclear antibody positivity, and anti‐SSS/Ro) and anti‐SSB/La autoantibodies. The rash resolved without scarring by 7 months of age with the use of low‐potency topical corticosteroids. We suggest that physicians consider neonatal lupus erythematosus in neonates with atypical eruptions occurring in sun‐protected skin. 相似文献
18.
19.