全文获取类型
收费全文 | 12236篇 |
免费 | 1019篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 105篇 |
儿科学 | 371篇 |
妇产科学 | 225篇 |
基础医学 | 1885篇 |
口腔科学 | 186篇 |
临床医学 | 1733篇 |
内科学 | 2420篇 |
皮肤病学 | 386篇 |
神经病学 | 991篇 |
特种医学 | 402篇 |
外国民族医学 | 2篇 |
外科学 | 1154篇 |
综合类 | 126篇 |
一般理论 | 21篇 |
预防医学 | 1327篇 |
眼科学 | 278篇 |
药学 | 893篇 |
中国医学 | 20篇 |
肿瘤学 | 751篇 |
出版年
2023年 | 52篇 |
2022年 | 86篇 |
2021年 | 241篇 |
2020年 | 165篇 |
2019年 | 224篇 |
2018年 | 286篇 |
2017年 | 195篇 |
2016年 | 226篇 |
2015年 | 246篇 |
2014年 | 319篇 |
2013年 | 513篇 |
2012年 | 695篇 |
2011年 | 745篇 |
2010年 | 394篇 |
2009年 | 350篇 |
2008年 | 661篇 |
2007年 | 683篇 |
2006年 | 654篇 |
2005年 | 677篇 |
2004年 | 652篇 |
2003年 | 593篇 |
2002年 | 590篇 |
2001年 | 305篇 |
2000年 | 312篇 |
1999年 | 258篇 |
1998年 | 167篇 |
1997年 | 127篇 |
1996年 | 124篇 |
1995年 | 95篇 |
1994年 | 86篇 |
1993年 | 75篇 |
1992年 | 198篇 |
1991年 | 177篇 |
1990年 | 183篇 |
1989年 | 186篇 |
1988年 | 154篇 |
1987年 | 150篇 |
1986年 | 138篇 |
1985年 | 120篇 |
1984年 | 112篇 |
1983年 | 87篇 |
1982年 | 84篇 |
1981年 | 61篇 |
1980年 | 59篇 |
1979年 | 82篇 |
1978年 | 65篇 |
1977年 | 71篇 |
1975年 | 56篇 |
1974年 | 54篇 |
1973年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Anela Stanic Denis Rybin Francis Cannata Carole Hohl Jennifer Brody Jessie Gaeta 《AIDS care》2021,33(1):1-9
ABSTRACT The lack of stable housing can impair access and continuity of care for patients living with human immunodeficiency virus (HIV). This study investigated the relationship between housing status assessed at multiple time points and several core HIV-related outcomes within the same group of HIV patients experiencing homelessness. Patients with consistently stable housing (CSH) during the year were compared to patients who lacked CSH (non-CSH group). The study outcomes included HIV viral load (VL), CD4 counts, and health care utilization. Multivariable and propensity weighted analyses were used to assess outcomes adjusting for potential group differences. Of 208 patients, 88 (42%) had CSH and 120 (58%) were non-CSH. Patients with CSH had significantly higher proportion of VL suppression and higher mean CD4 counts. The frequency of nurse visits in the CSH group was less than a half of that in the non-CSH group. Patients with CSH were less likely to be admitted to the medical respite facility, and if admitted, their length of stay was about a half of that for the non-CSH group. Our study findings show that patients with CSH had significantly better HIV virologic control and immune status as well as improved health care utilization. 相似文献
2.
3.
Paul J. Devlin Brian W. McCrindle James K. Kirklin Eugene H. Blackstone William M. DeCampli Christopher A. Caldarone Ali Dodge-Khatami Pirooz Eghtesady James M. Meza Peter J. Gruber Kristine J. Guleserian Bahaaladin Alsoufi Linda M. Lambert James E. OBrien Erle H. Austin Jeffrey P. Jacobs Tara Karamlou 《The Journal of thoracic and cardiovascular surgery》2019,157(2):684-695.e8
Objective
Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.Methods
From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.Results
Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).Conclusions
Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes. 相似文献4.
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
5.
6.
7.
The MMPI was administered during the patient-perceived best time of the menstrual cycle and during the patient-perceived worst time of the cycle in order to examine the stability of MMPI profile configurations. Subjects were 214 women who were referred to two metropolitan outpatient premenstrual syndrome (PMS) clinics for moderate to severe premenstrual complaints. This sample was selected from 1,849 intake files after screening by strict selection criteria for PMS. The results indicate that there are wide fluctuations in profile patterns between the best and worst times of the menstrual cycle for a large number of patients. Caution in using the MMPI is strongly advised. 相似文献
8.
9.
The present study reports the differential effects of pertussis toxin on muscarinic regulation of intracellular Ca2+ and inositol phosphate generation and alpha 2-adrenoceptor-mediated inhibition of cAMP formation in SH-SY5Y human neuroblastoma cells. Carbachol caused a biphasic increase in intracellular Ca2+ (release of internal stores and Ca2+ entry) and a dose-dependent increase in inositol phosphate formation. Pertussis toxin pretreatment did not affect either of these components of the signal transduction pathway but did completely reverse the alpha 2-adrenoceptor-mediated inhibition of forskolin-stimulated cAMP formation. These data indicate that muscarinic regulation of inositol phosphate generation occurs via a pertussis toxin-insensitive G-protein and that Ca2+ entry in these cells may not occur via a G-protein. 相似文献
10.
The action of papain and bromelain, prepared over a pH range from 4.6 to 8.6, was evaluated for the ability to render red cells agglutinable by five incomplete antibodies of differing blood group specificities using a two-stage technique. The optimal pH for treatment of red cells by activated papain or bromelain was between 5.4 and 5.8. Above this pH range, a fall in serological sensitivity was apparent which was much more pronounced with papain than with bromelain. The optimal pH for enzyme treatment of red cells can be achieved in two-stage techniques, but not in one-stage techniques due to the buffering effect of serum proteins. 相似文献