全文获取类型
收费全文 | 2368477篇 |
免费 | 198227篇 |
国内免费 | 4203篇 |
学科分类
医药卫生 | 2570907篇 |
出版年
2018年 | 24206篇 |
2016年 | 20583篇 |
2015年 | 23293篇 |
2014年 | 33555篇 |
2013年 | 50852篇 |
2012年 | 68770篇 |
2011年 | 72317篇 |
2010年 | 42487篇 |
2009年 | 40879篇 |
2008年 | 68803篇 |
2007年 | 73142篇 |
2006年 | 74037篇 |
2005年 | 72082篇 |
2004年 | 69365篇 |
2003年 | 67048篇 |
2002年 | 66288篇 |
2001年 | 112466篇 |
2000年 | 116539篇 |
1999年 | 98352篇 |
1998年 | 27863篇 |
1997年 | 25532篇 |
1996年 | 25451篇 |
1995年 | 24612篇 |
1994年 | 23162篇 |
1993年 | 21556篇 |
1992年 | 79399篇 |
1991年 | 76413篇 |
1990年 | 73589篇 |
1989年 | 70854篇 |
1988年 | 65856篇 |
1987年 | 64809篇 |
1986年 | 61335篇 |
1985年 | 58410篇 |
1984年 | 44228篇 |
1983年 | 37666篇 |
1982年 | 22802篇 |
1981年 | 20240篇 |
1980年 | 18935篇 |
1979年 | 41227篇 |
1978年 | 28914篇 |
1977年 | 24251篇 |
1976年 | 22753篇 |
1975年 | 23908篇 |
1974年 | 29590篇 |
1973年 | 28013篇 |
1972年 | 26209篇 |
1971年 | 24146篇 |
1970年 | 22730篇 |
1969年 | 21070篇 |
1968年 | 19118篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Adjuvant irradiation is the standard treatment after breast conservative surgery. Normofractionated regimen with an overall treatment time of 5 to 6 weeks is often considered as a limiting factor for irradiation compliance. In order to answer this issue, moderate and more recently extreme hypofractionated protocols appeared. We report here oncological outcomes and toxicity of hypofractionated breast irradiation. After defining the frame of moderate and extreme hypofractionated breast irradiations based on overall treatment time, patient selection criteria were listed. According to their levels of proof, the results of moderate and extreme hypofractionated breast irradiation were analysed. Overall treatment time for moderate hypofractionated breast irradiation ranged from 3 to 4 weeks, while for extreme hypofractionated breast irradiation, it was less than 1 week. For moderate hypofractionated breast irradiation, whole breast irradiation was currently performed with or without lymph node irradiation. Moderate hypofractionated breast irradiation has proven to be as safe and as efficient as normofractionated breast irradiation with level IA evidence. For extreme hypofractionated breast irradiation, phase III randomized trials confirmed that accelerated partial breast irradiation was non-inferior in terms of local control compared to normofractionated whole breast irradiation (with external beam radiation therapy and multicatheter brachytherapy), with similar acute and late toxicity. While the use of intraoperative breast irradiation remains under debate, new very accelerated partial breast irradiation (overall treatment time not exceeding 2 days) protocols emerged with encouraging results. Accelerated partial breast irradiation is warranted for extreme hypofractionated breast irradiation and is indicated for low-risk breast cancers. Moderate and extreme hypofractionated breast irradiation regimens are validated and can be routinely proposed according to patient selection criteria. 相似文献
22.
23.
Tonya J.H. White 《Journal of the American Academy of Child and Adolescent Psychiatry》2019,58(11):1042-1050
24.
Jeffrey J. Silbiger 《Echocardiography (Mount Kisco, N.Y.)》2019,36(5):954-957
Secondary tricuspid regurgitation (TR) caused by right ventricular enlargement in the setting of left heart disease/pulmonary hypertension has been well described. In contrast, that associated with right atrial enlargement—atrial functional TR (AF‐TR)—remains largely underappreciated. AF‐TR most often occurs in the setting of lone atrial fibrillation, although it is also seen in its absence (idiopathic AF‐TR). Several recent studies have found that the prevalence, hemodynamic significance, and prognosis of AF‐TR are not inconsequential, suggesting increased physician awareness of this novel clinical entity is warranted. This article discusses the pathogenesis, echocardiographic findings, and treatment of this underappreciated cause of secondary TR. 相似文献
25.
26.
27.
28.
29.
Robert C. Lynall J. Troy Blackburn Kevin M. Guskiewicz Stephen W. Marshall Prudence Plummer Jason P. Mihalik 《Journal of Science and Medicine in Sport》2019,22(5):503-508
Objectives
Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls.Design
Cross-sectional, laboratory study.Methods
Fifteen participants with a concussion history (age: 19.7 ± 0.9 years; 9 females; median time since concussion 126 days, range 28–432 days), and 15 matched controls (19.7 ± 1.6 years; 9 females) with no recent concussion history participated. We measured center-of-pressure (COP) outcomes (velocity, path length, speed, dual-task cost) under 4 tandem gait conditions: (1) tandem gait, (2) tandem gait, eyes closed, (3) tandem gait, eyes open, cognitive distraction, and (4) tandem gait, eyes closed, cognitive distraction.Results
The concussion history group demonstrated slower tandem gait velocity compared to the control group (4.0 cm/s difference), thus velocity was used as a covariate when analyzing COP path length and speed. The concussion history group (23.5%) demonstrated greater COP speed dual-task cost than the control group (16.3%) during the eyes closed dual-task condition. No other comparisons were statistically significant.Conclusions
There may be subtle dynamic balance differences during tandem gait that are detectable after return-to-activity following concussion, but the clinical significance of these findings is unclear. Longitudinal investigations should identify acute movement deficits in varying visual and cognitive scenarios after concussion in comparison with recovery on traditional concussion assessment tools while also recording musculoskeletal injury outcomes. 相似文献30.
Alexander E. J. Trevatt David R. Thomson Robert Miller Matthew Colquhoun Akinyemi I. Idowu Shakeel Rahman 《Journal of plastic surgery and hand surgery》2019,53(2):97-104
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia. 相似文献