全文获取类型
收费全文 | 34111篇 |
免费 | 2200篇 |
国内免费 | 975篇 |
专业分类
耳鼻咽喉 | 101篇 |
儿科学 | 953篇 |
妇产科学 | 163篇 |
基础医学 | 3399篇 |
口腔科学 | 214篇 |
临床医学 | 4211篇 |
内科学 | 8813篇 |
皮肤病学 | 214篇 |
神经病学 | 2427篇 |
特种医学 | 1393篇 |
外科学 | 1894篇 |
综合类 | 5271篇 |
预防医学 | 1915篇 |
眼科学 | 154篇 |
药学 | 4349篇 |
14篇 | |
中国医学 | 1432篇 |
肿瘤学 | 369篇 |
出版年
2024年 | 41篇 |
2023年 | 354篇 |
2022年 | 871篇 |
2021年 | 1167篇 |
2020年 | 1084篇 |
2019年 | 799篇 |
2018年 | 886篇 |
2017年 | 909篇 |
2016年 | 1009篇 |
2015年 | 1045篇 |
2014年 | 2087篇 |
2013年 | 2277篇 |
2012年 | 1836篇 |
2011年 | 2032篇 |
2010年 | 1700篇 |
2009年 | 1732篇 |
2008年 | 1784篇 |
2007年 | 1824篇 |
2006年 | 1717篇 |
2005年 | 1479篇 |
2004年 | 1191篇 |
2003年 | 1087篇 |
2002年 | 948篇 |
2001年 | 837篇 |
2000年 | 785篇 |
1999年 | 661篇 |
1998年 | 538篇 |
1997年 | 527篇 |
1996年 | 445篇 |
1995年 | 421篇 |
1994年 | 362篇 |
1993年 | 282篇 |
1992年 | 295篇 |
1991年 | 256篇 |
1990年 | 226篇 |
1989年 | 217篇 |
1988年 | 188篇 |
1987年 | 177篇 |
1986年 | 139篇 |
1985年 | 176篇 |
1984年 | 165篇 |
1983年 | 103篇 |
1982年 | 116篇 |
1981年 | 81篇 |
1980年 | 82篇 |
1979年 | 59篇 |
1978年 | 75篇 |
1977年 | 49篇 |
1976年 | 49篇 |
1975年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
《Revista portuguesa de cardiologia》2022,41(4):299-307
AimsMyocardial strain analysis enables more precise assessment of cardiac performance but is relatively load dependent. New tools have been developed with afterload adjustment. Our objective was to assess myocardial work (MW) in patients with repaired aortic coarctation (rACo).MethodsProspective study of consecutive patients with rACo who underwent a routine transthoracic echocardiogram in 2018 and 2019 at our center. Patients with significant aortic valve disease, pacemaker, or other congenital heart diseases (except for mild bicuspid aortic valve disease) were excluded. Global longitudinal strain with two dimensional speckle tracking analysis and MW were obtained (GWI:Global Work Index; GCW: Global Constructive Work; GWW: Global Wasted Work; GWE: Global Work Efficiency). Blood pressure was measured in the patient's right arm.ResultsWe included 42 patients in the analysis, mean age of 37±10 years, 38% males. In this group, 52% had hypertension and 64% had a concomitant bicuspid aortic valve. In comparison to previously published reference values, patients with rACo had significantly lower GWI (1807 vs. 1896 mmHg%) and GCW (2173 vs. 2232 mmHg%) (p<0.001), particularly in males. Systolic blood pressure is an independent predictor for GWI (β=0.432) and for GCW (β=0.534) and GLS an independent predictor of all MW parameters (β>0.594). Neither age nor gender were independent predictors.ConclusionsIn patients with rACo, there are some signs of left ventricular dysfunction with a reduction in GCW and GWI and with preserved GWE, despite normal ejection fraction and strain. 相似文献
3.
4.
Arvid Nikolai Kildahl Sissel Berge Helverschou Trine Lise Bakken Hanne Weie Oddli 《Journal of mental health research in intellectual disabilities》2020,13(3):201-230
ABSTRACT
Introduction
Individuals with autism spectrum disorder (ASD) and intellectual disability (ID) seem to be at increased risk for post-traumatic stress disorder (PTSD), but knowledge is sparse regarding its identification in this population. Previous research indicates that certain symptoms of PTSD may be more easily recognized, and that identifying reexperiencing and avoidance is particularly challenging. 相似文献5.
Philip S. Vendittelli Bassent Botros Howard S. Rosman Viren Govindaraju Anwar Zaitoun Tariq S. Marroush 《The American journal of the medical sciences》2019,357(4):333-337
Coronary embolism (CE) is an uncommon and unique cause of acute myocardial infarction. In this report, we review 216 cases of CE including 2 new cases from our institution. The mean patient age was 52.5 years and 62% of the patients were males. Chest pain was the most common presenting symptom followed by dyspnea, and the most commonly affected vessel was the left anterior descending artery. Leading etiologies of the embolus were atrial fibrillation, septic emboli, and iatrogenic causes. Treatment approaches varied with thrombus aspiration being used in 30% of cases. In-hospital mortality rate was 36% and 13% of the cases were complicated by cerebrovascular accident. CE is a unique pathology that leads to acute myocardial infarction. It portends a high mortality rate and requires a high level of suspicion as symptoms may be misleading. Further research is needed in order to improve recognition and management and to lower associated mortality. 相似文献
6.
孤独症谱系障碍(ASD)是影响儿童健康的严重公共问题之一,以社交沟通障碍、兴趣或活动范围狭窄以及重复刻板行为为特征。近年来越来越多的研究显示,ASD患儿维生素D(VitD)水平明显低于同龄健康儿童,VitD缺乏可能与ASD的发病机制相关。本文就VitD与ASD的相关研究进行综述。 相似文献
7.
《Clinical gastroenterology and hepatology》2022,20(5):1112-1121.e4
- Download : Download high-res image (419KB)
- Download : Download full-size image
8.
Alexandra Katsimardou Konstantinos Imprialos Konstantinos Stavropoulos Alexandros Sachinidis Michalis Doumas 《Expert opinion on pharmacotherapy》2020,21(10):1241-1252
ABSTRACT
Introduction
Type 1 diabetes mellitus (T1DM) is a chronic, autoimmune disease that is characterized by total absence of insulin production. Hypertension is a common comorbidity in T1DM with complex pathophysiology, while it is also a well-recognized risk factor for the development of cardiovascular disease (CVD), as well as other microvascular diabetic complications. 相似文献9.
Context: Baicalin has many pharmacological activities, including protective function against myocardial ischemia by antioxidant effects and free radical scavenging activity. However, its rapid elimination half-life in plasma and poor water solubility limits its clinical efficacy.Objective: Novel baicalin-loaded PEGylated nanostructured lipid carriers (BN-PEG-NLC) were developed to improve bioavailability of BN, to prolong retention time in vivo and to enhance its protective effect.Methods: In this study, BN-PEG-NLC were prepared by the emulsion-evaporation and low temperature-solidification method using a mixture of glycerol monostearate and polyethylene glycol monostearate as solid lipids, and oleic acid as the liquid lipid. The physicochemical properties of NLC were characterized. The pharmacokinetic and pharmacodynamic behaviors of BN-PEG-NLC or BN-NLC were evaluated in acute MI rats.Results and discussion: The particle size, zeta potential, and entrapment efficiency for BN-PEG-NLC were observed as 83.9?nm, ?32.1?mV, and 83.5%, respectively. The release profiles of BN from both BN-PEG-NLC and BN-NLC were fitted to the Ritger–Peppas modal, which presented burst release initially and prolonged release afterwards. Pharmacokinetics results indicated that BN-PEG-NLC exhibited a 7.2-fold increase in AUC in comparison to BN solution, while a 3-fold increase in comparison to BN-NLC. Biodistribution results revealed that BN-PEG-NLC exhibited higher heart drug concentration compared with BN-NLC as well as BN solution. In the present study, BN-PEG-NLC significantly ameliorated infarct size.Conclusion: The results of the present study imply that PEG-NLC could be the biocompatible carriers for heart-targeted drug delivery to improve myocardial ischemia. 相似文献
10.
冠状病毒(coronavirus,CoVs)感染主要累及肺部,但对心血管系统损伤作用也不容忽视。CoVs感染引起的心脏损伤并非罕见,其发生与病情的严重程度密切相关。本文首先从CoVs引起心血管损伤的证据入手,进一步探讨了CoVs对心肌的直接损伤,以及肾素血管紧张素(RAS)系统激活和细胞因子风暴与炎症反应对心血管损伤的可能作用机制。相关心血管损伤的可能机制包括,(1)病毒直接作用:CoVs在心肌细胞复制,损伤心肌;(2)RAS系统激活:感染CoVs后,心脏血管紧张素转化酶2(angiotensin-converting enzyme 2,ACE2)的表达下调,激活RAS系统,使得血管紧张素Ⅱ(AngiotensinⅡ,AngⅡ)收缩血管功能增强,Ang1-7保护心脏效应减弱;(3)诱发细胞因子风暴:循环细胞因子和全身炎症反应引起心脏损伤;(4)其他:包括低氧血症和儿茶酚胺心脏毒性。本文就相关内容作一综述,为后续的详尽机制和治疗策略研究提供思路。 相似文献