全文获取类型
收费全文 | 1887275篇 |
免费 | 124758篇 |
国内免费 | 4261篇 |
专业分类
耳鼻咽喉 | 23826篇 |
儿科学 | 60406篇 |
妇产科学 | 49835篇 |
基础医学 | 264723篇 |
口腔科学 | 52713篇 |
临床医学 | 168981篇 |
内科学 | 370901篇 |
皮肤病学 | 41003篇 |
神经病学 | 148883篇 |
特种医学 | 69658篇 |
外国民族医学 | 255篇 |
外科学 | 284527篇 |
综合类 | 41930篇 |
现状与发展 | 6篇 |
一般理论 | 808篇 |
预防医学 | 141115篇 |
眼科学 | 43924篇 |
药学 | 136214篇 |
59篇 | |
中国医学 | 4775篇 |
肿瘤学 | 111752篇 |
出版年
2021年 | 15929篇 |
2019年 | 16841篇 |
2018年 | 23294篇 |
2017年 | 17926篇 |
2016年 | 19472篇 |
2015年 | 22300篇 |
2014年 | 31222篇 |
2013年 | 45322篇 |
2012年 | 63536篇 |
2011年 | 67353篇 |
2010年 | 39521篇 |
2009年 | 36858篇 |
2008年 | 62950篇 |
2007年 | 66849篇 |
2006年 | 66963篇 |
2005年 | 64571篇 |
2004年 | 62424篇 |
2003年 | 59091篇 |
2002年 | 56960篇 |
2001年 | 93380篇 |
2000年 | 94820篇 |
1999年 | 78693篇 |
1998年 | 22121篇 |
1997年 | 19334篇 |
1996年 | 19299篇 |
1995年 | 18394篇 |
1994年 | 16812篇 |
1993年 | 15471篇 |
1992年 | 58384篇 |
1991年 | 56229篇 |
1990年 | 53846篇 |
1989年 | 51557篇 |
1988年 | 47001篇 |
1987年 | 45804篇 |
1986年 | 43085篇 |
1985年 | 40925篇 |
1984年 | 30610篇 |
1983年 | 26161篇 |
1982年 | 15453篇 |
1981年 | 13782篇 |
1979年 | 26222篇 |
1978年 | 18406篇 |
1977年 | 15695篇 |
1976年 | 14602篇 |
1975年 | 15152篇 |
1974年 | 18207篇 |
1973年 | 17460篇 |
1972年 | 16054篇 |
1971年 | 14759篇 |
1970年 | 13726篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Vishnu Ambur Peter Park John P. Gaughan Scott Golarz Frank Schmieder Paul Van Bemmelen Eric Choi Ravi Dhanisetty 《Journal of vascular surgery》2019,69(2):491-496
Objective
Patient selection for open lower extremity revascularization in patients with chronic kidney disease (CKD) remains a clinical challenge. This study investigates the impact of CKD on early graft failure, postoperative complications, and mortality in patients undergoing lower extremity bypass for critical limb ischemia.Methods
The National Surgical Quality Improvement Program database was queried for all patients with critical limb ischemia from 2012 to 2015 who underwent lower extremity bypass using the targeted vascular set. The glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration Study equation. CKD categories were determined from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative staging criteria. Patients were classified into three groups: CKD stages 3 or lower (mild to moderate CKD), CKD stages 4 or 5 (severe CKD), and on hemodialysis (HD). Multiple variable analysis was used to examine graft failure, mortality, and postoperative complications.Results
The Surgical Quality Improvement Program database identified 6978 patients who underwent infrainguinal lower extremity arterial bypass during the study period. There were 6101 patients (87.4%) with mild to moderate CKD, 327 (4.7%) with severe CKD, and 550 (7.9%) on HD. Patients with severe CKD and on HD were more likely to have revascularization for tissue loss (54.9% vs 68.8% and 74.7%; P < .01). Patients with severe CKD and those on HD had higher rates of early graft failure, postoperative myocardial infarction, and rates of reoperation. Multiple variable analysis confirmed these results showing that HD was associated with postoperative myocardial infarction, readmission, and increased mortality. It also demonstrated that severe CKD was associated with graft failure (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.12-2.50; P = .01), postoperative myocardial infarction (OR, 2.16; 95% CI, 1.35-3.45; P < .01), and readmission (OR, 1.38; 95% CI, 1.06-1.80; P = .02). Other factors associated with graft failure include functional status (OR, 1.39; 95% CI, 1.08-1.80; P = .01), African American race (OR, 1.72; 95% CI, 1.39-2.13; P < .01), and distal bypass (OR, 1.33; 95% CI, 1.09-1.61; P < .01).Conclusions
CKD is a significant predictor of perioperative morbidity after lower extremity bypass. Patients with severe CKD have worse postoperative outcomes without increased mortality. Those on HD have worse survival and postoperative outcomes. 相似文献12.
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13.
Spyridon G. Deftereos Dimitrios A. Vrachatis Christos Angelidis Agathi-Rosa Vrettou Eleni K. Sarri Sotiria G. Giotaki Efthymia Varytimiadi Charalampos Kossyvakis Eleana Kotsia Gerasimos S. Deftereos Konstantinos Doudoumis Georgios Giannopoulos 《Clinical therapeutics》2019,41(1):21-29
Purpose
The goal of this review was to summarize, analyze, and compare trials studying the efficacy of colchicine in the prevention of atrial fibrillation (AF) post-operatively (POAF) and post–catheter ablation. Ongoing studies and current guidelines are also presented and reviewed.Methods
Published studies on the field were identified through a literature search of the PubMed and clinicaltrials.gov databases.Findings
Four original studies regarding POAF, two original studies regarding post–catheter ablation AF, and six meta-analyses were identified. In addition, the 3 most recent guidelines/expert consensus documents were scrutinized.Implications
AF occurs frequently after cardiac surgery (POAF) and catheter pulmonary vein isolation (postablation AF) and is associated with increased cardiovascular morbidity. A number of trials over the last few years have investigated the role of colchicine in the prevention of POAF and postablation AF targeting the local and systemic inflammatory process that leads to initiation and maintenance of AF. Available data imply that colchicine may have a preventive role in POAF and/or postablation AF. However, certain limitations of these studies underline the need for further investigation. 相似文献14.
15.
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
16.
17.
T. Maishman H. Sheikh P. Boger J. Kelly K. Cozens A. Bateman S. Davies M. Fay D. Sharland A. Jackson 《Clinical oncology (Royal College of Radiologists (Great Britain))》2021,33(5):e225-e231
AimsSelf-expanding metal stents provide rapid improvement of dysphagia in oesophageal cancer but are associated with complications. The aim of the present study was to test the effectiveness of an alternative treatment of combining biodegradable stents with radiotherapy.Materials and methodsA Simon two-stage single-arm prospective phase II trial design was used to determine the efficacy of biodegradable stents plus radiotherapy in patients with dysphagia caused by oesophagus cancer who were unsuitable for radical treatment. Fourteen patients were recruited and data from 12 were included in the final analyses.ResultsFive of 12 patients met the primary end point: one stent-related patient death; four further interventions for dysphagia within 16 weeks of stenting (41.7%, 95% confidence interval 15.2–72.3%). The median time to a 10-point deterioration of quality of life was 2.7 weeks. Nine patients died within 52 weeks of registration. The median time to death from any cause was 15.0 weeks (95% confidence interval 9.6–not reached).ConclusionThe high re-intervention observed, which met the pre-defined early stopping criteria, meant that the suggested alternative treatment was not sufficiently effective to be considered for a larger scale trial design. Further work is needed to define the place of biodegradable stents in the management of malignant oesophageal strictures. 相似文献
18.
19.
Daniel J. Snyder Thomas R. Kroshus Aakash Keswani Evan B. Garden Karl M. Koenig Kevin J. Bozic David S. Jevsevar Jashvant Poeran Calin S. Moucha 《The Journal of arthroplasty》2019,34(4):613-618