全文获取类型
| 收费全文 | 3520888篇 |
| 免费 | 257478篇 |
| 国内免费 | 9004篇 |
专业分类
| 耳鼻咽喉 | 48293篇 |
| 儿科学 | 116212篇 |
| 妇产科学 | 96270篇 |
| 基础医学 | 495757篇 |
| 口腔科学 | 99409篇 |
| 临床医学 | 321695篇 |
| 内科学 | 688074篇 |
| 皮肤病学 | 81617篇 |
| 神经病学 | 291577篇 |
| 特种医学 | 137111篇 |
| 外国民族医学 | 981篇 |
| 外科学 | 526102篇 |
| 综合类 | 74245篇 |
| 现状与发展 | 5篇 |
| 一般理论 | 1339篇 |
| 预防医学 | 274512篇 |
| 眼科学 | 79168篇 |
| 药学 | 258094篇 |
| 76篇 | |
| 中国医学 | 6937篇 |
| 肿瘤学 | 189896篇 |
出版年
| 2019年 | 27518篇 |
| 2018年 | 39404篇 |
| 2017年 | 30396篇 |
| 2016年 | 35295篇 |
| 2015年 | 39098篇 |
| 2014年 | 53738篇 |
| 2013年 | 81832篇 |
| 2012年 | 107822篇 |
| 2011年 | 114672篇 |
| 2010年 | 68899篇 |
| 2009年 | 65065篇 |
| 2008年 | 107374篇 |
| 2007年 | 114315篇 |
| 2006年 | 115890篇 |
| 2005年 | 111897篇 |
| 2004年 | 107704篇 |
| 2003年 | 104143篇 |
| 2002年 | 100346篇 |
| 2001年 | 167016篇 |
| 2000年 | 171914篇 |
| 1999年 | 144191篇 |
| 1998年 | 41978篇 |
| 1997年 | 37362篇 |
| 1996年 | 37549篇 |
| 1995年 | 36389篇 |
| 1994年 | 33618篇 |
| 1993年 | 31500篇 |
| 1992年 | 112674篇 |
| 1991年 | 108790篇 |
| 1990年 | 105431篇 |
| 1989年 | 101547篇 |
| 1988年 | 93173篇 |
| 1987年 | 91591篇 |
| 1986年 | 86261篇 |
| 1985年 | 82608篇 |
| 1984年 | 61951篇 |
| 1983年 | 52391篇 |
| 1982年 | 31320篇 |
| 1981年 | 28125篇 |
| 1979年 | 55349篇 |
| 1978年 | 39434篇 |
| 1977年 | 33334篇 |
| 1976年 | 30915篇 |
| 1975年 | 33100篇 |
| 1974年 | 39140篇 |
| 1973年 | 37282篇 |
| 1972年 | 34777篇 |
| 1971年 | 32305篇 |
| 1970年 | 29709篇 |
| 1969年 | 28257篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
21.
Arne de Niet Michel M.P.J. Reijnen Clark J. Zeebregts 《Journal of vascular surgery》2019,69(2):348-356
Objective
The objective of this study was to investigate the feasibility of a specific custom-made fenestrated aortic cuff in the treatment of complex abdominal aortic aneurysms (AAAs).Methods
Between 2013 and 2016, a total of 57 custom-made Fenestrated Anaconda (Vascutek, Inchinnan, Scotland, UK) aortic cuffs were placed in 38 centers worldwide. All centers were invited to participate in this retrospective analysis. Postoperative and follow-up data included the presence of adverse events, necessity for reintervention, and renal function.Results
Fifteen clinics participated, leading to 29 cases. Median age at operation was 74 years (interquartile range [IQR], 71-78 years); five patients were female. Two patients were treated for a para-anastomotic AAA after open AAA repair, 19 patients were treated because of a complicated course after primary endovascular AAA repair, and 8 cases were primary procedures for AAA. A total of 76 fenestrations (mean, 2.6 per case) were used. Four patients needed seven adjunctive procedures. Two patients underwent conversion, one because of a dissection of the superior mesenteric artery and one because of perforation of a renal artery. Median operation time was 225 minutes (IQR, 150-260 minutes); median blood loss, 200 mL (IQR, 100-500 mL); and median contrast volume, 150 mL (IQR, 92-260 mL). Primary technical success was achieved in 86% and secondary technical success in 93%. The 30-day morbidity was 7 of 29 with a mortality rate of 4 of 29. Estimated glomerular filtration rate remained unchanged before and after surgery (76 to 77 mL/min/m2). Between preoperative and median follow-up of 11 months, estimated glomerular filtration rate was reduced statistically significantly (76 to 63 mL/min/m2). During follow-up, 9 cases had an increase in aneurysm sac diameter (5 cases >5 mm); 14 cases had a stable or decreased aneurysm sac diameter; and in 2 cases, no aneurysm size was reported. No type I endoleak was reported, and two cases with a type III endoleak were treated by endovascular means during follow-up. Survival, reintervention-free survival, and target vessel patency at 1 year were 81% ± 8%, 75% ± 9%, and 99% ± 1%, respectively. After 2 years, these numbers were 81% ± 8%, 67% ± 11%, and 88% ± 6%, respectively. During follow-up, the two patients with a type III endoleak needed endograft-related reinterventions.Conclusions
Treatment with this specific custom-made fenestrated aortic cuff is feasible after complicated previous (endovascular) aortic repair or in complex AAAs. The complexity of certain AAA cases is underlined in this study, and the Fenestrated Anaconda aortic cuff is a valid option in selected cases in which few treatment options are left. 相似文献22.
Paul Macadam Kim D. Simperingham John B. Cronin 《Journal of Science and Medicine in Sport》2019,22(3):348-352
Objectives
Arm swing is a distinctive characteristic of sprint-running with the arms working in a contralateral manner with the legs to propel the body in a horizontal direction. The purpose of this study was to determine the acute changes in kinematics and kinetics when wearable resistance (WR) of 1 kg (equivalent to ～1% body mass) was attached to each forearm during over ground short distance (20 m) maximal sprint-running.Design
Cross-sectional study.Methods
Twenty-two male amateur rugby athletes (19.4 ± 0.5 years; 97.0 ± 4.8 kg; 180.4 ± 7.2 cm) volunteered to participate in the study. Radar and Optojump were used to examine kinematic and kinetics between WR and unloaded sprint-running conditions.Results
No significant (p < 0.05) differences were found at 2 m or 5 m between conditions, however, the WR condition resulted in a significant increase in 10 m, 20 m and 10–20 m split time (all, ～2%, small effect size) compared to the unloaded condition. Significant decreases were also found in theoretical maximum velocity (V0) (?1.4%, small effect size) and relative peak horizontal power production (Pmax) (?5.5%, small effect size). Step length (2.1%, small effect size) and contact time (6.5%, medium effect size) were significantly increased, while step frequency (?4.1%, small effect size) and flight time (?5.3%, medium effect size) were significantly decreased.Conclusions
WR forearm loading provides a movement specific overload of the arms which significantly alters step kinematics and sprint times ≥10 m. 相似文献23.
Javed Butler Mei Yang Massimiliano Alfonzo Manzi Gregory P. Hess Mahesh J. Patel Thomas Rhodes Michael M. Givertz 《Journal of the American College of Cardiology》2019,73(8):935-944
Background
Epidemiology of patients with worsening heart failure and reduced ejection fraction (HFrEF) in the real-world setting is not well described.Objectives
The purpose of this study was to describe incidence, clinical characteristics, treatment, and outcomes of patients with HFrEF who develop worsening heart failure (HF) in the real-world setting.Methods
Data on patients with incident HFrEF from the National Cardiovascular Data Registry PINNACLE were linked to pharmacy, private practitioner, and hospital claims databases. Incidence, clinical characteristics, treatment (angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist) and outcomes of patients with worsening HF, defined as ≥90 days of stable HF with subsequent worsening requiring intravenous diuretic agents, were assessed.Results
Of 11,064 HFrEF patients, 1,851 (17%) developed worsening HF on average 1.5 years following initial HF diagnosis. Patients who developed worsening HF were more likely to be African American, be octogenarians, and have higher comorbidity burden (p < 0.001). At the onset of worsening HF, 42.4% of patients were on monotherapy, 43.4% were on dual therapy, and 14.1% were on triple therapy. A total of 48%, 61%, and 98% of patients were on >50% target dose for angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist, respectively. The 2-year mortality rate was 22.5%, and 56% of patients were rehospitalized within 30 days of the worsening HF event.Conclusions
In the real-world setting, 1 in 6 patients with HFrEF develop worsening HF within 18 months of HF diagnosis. These patients have a high risk for 2-year mortality and recurrent HF hospitalizations. The use of standard-of-care therapies both before and after the onset of worsening HF is low. With high unmet medical need, patients with worsening HF require novel treatment strategies as well as greater optimization of existing guideline-directed therapy. 相似文献24.
Andrea Garatti Andrea Daprati Marzia Cottini Claudio F. Russo Margherita Dalla Tomba Giovanni Troise Antonio Salsano Francesco Santini Roberto Scrofani Francesca Nicolò Elisa Mikus Alberto Albertini Luca Di Marco Davide Pacini Marco Picichè Loris Salvador Guglielmo M. Actis Dato Paolo Centofanti Lorenzo Menicanti 《The Annals of thoracic surgery》2021,111(4):1242-1251
- Download : Download high-res image (165KB)
- Download : Download full-size image
25.
26.
27.
Rebecca Robillard Karianne Dion Marie‐Helene Pennestri Elizaveta Solomonova Elliott Lee Mysa Saad Anthony Murkar Roger Godbout Jodi D. Edwards Lena Quilty Alexander R. Daros Raj Bhatla Tetyana Kendzerska 《Journal of sleep research》2021,30(1):e13231
This study aimed to evaluate changes in sleep during the COVID‐19 outbreak, and used data‐driven approaches to identify distinct profiles of changes in sleep‐related behaviours. Demographic, behavioural and psychological factors associated with sleep changes were also investigated. An online population survey assessing sleep and mental health was distributed between 3 April and 24 June 2020. Retrospective questions were used to estimate temporal changes from before to during the outbreak. In 5,525 Canadian respondents (67.1% females, 16–95 years old: Mean ± SD = 55.6 ± 16.3 years), wake‐up times were significantly delayed relative to pre‐outbreak estimates (p < .001, = 0.04). Occurrences of clinically meaningful sleep difficulties significantly increased from 36.0% before the outbreak to 50.5% during the outbreak (all p < .001, g ≥ 0.27). Three subgroups with distinct profiles of changes in sleep behaviours were identified: “Reduced Time in Bed”, “Delayed Sleep” and “Extended Time in Bed”. The “Reduced Time in Bed” and “Delayed Sleep” subgroups had more adverse sleep outcomes and psychological changes during the outbreak. The emergence of new sleep difficulties was independently associated with female sex, chronic illnesses, being employed, family responsibilities, earlier wake‐up times, higher stress levels, as well as heavier alcohol use and television exposure. The heterogeneity of sleep changes in response to the pandemic highlights the need for tailored interventions to address sleep problems. 相似文献
28.
29.
Though cerebrovascular complications of pregnancy remain relatively rare, they represent a potentially devastating event that necessitates prompt identification and treatment. Eighteen percent of strokes occurring in young women are linked to pregnancy. They occur mostly in the third trimester or during the post-partum period. Their biggest risk factors are hypertension, preeclampsia/eclampsia and migraine. Cerebrovascular events occurring during this period may involve specific pathophysiological processes that include embolic phenomena or endothelial dysfunction, but can also have common etiologies that are simply favored by the context of pregnancy. Thus, posterior encephalopathy and vasoconstriction cerebral syndrome are relatively frequently involved in cerebrovascular complications of pregnancy. Other very specific causes like amniotic fluid embolism or postpartum cardiomyopathy can also be responsible for such events. The management of stroke during pregnancy must be multidisciplinary and include a neurovascular expertise. Some conditions can lead to a long-life follow-up and modify the management of a future pregnancy. 相似文献
30.