全文获取类型
收费全文 | 8070篇 |
免费 | 559篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 203篇 |
妇产科学 | 80篇 |
基础医学 | 937篇 |
口腔科学 | 336篇 |
临床医学 | 1037篇 |
内科学 | 1393篇 |
皮肤病学 | 44篇 |
神经病学 | 752篇 |
特种医学 | 279篇 |
外科学 | 867篇 |
综合类 | 499篇 |
一般理论 | 13篇 |
预防医学 | 981篇 |
眼科学 | 157篇 |
药学 | 656篇 |
中国医学 | 3篇 |
肿瘤学 | 372篇 |
出版年
2023年 | 44篇 |
2022年 | 63篇 |
2021年 | 167篇 |
2020年 | 95篇 |
2019年 | 141篇 |
2018年 | 209篇 |
2017年 | 130篇 |
2016年 | 167篇 |
2015年 | 166篇 |
2014年 | 231篇 |
2013年 | 353篇 |
2012年 | 597篇 |
2011年 | 681篇 |
2010年 | 352篇 |
2009年 | 310篇 |
2008年 | 570篇 |
2007年 | 662篇 |
2006年 | 583篇 |
2005年 | 603篇 |
2004年 | 580篇 |
2003年 | 584篇 |
2002年 | 485篇 |
2001年 | 102篇 |
2000年 | 73篇 |
1999年 | 75篇 |
1998年 | 101篇 |
1997年 | 59篇 |
1996年 | 44篇 |
1995年 | 45篇 |
1994年 | 42篇 |
1993年 | 47篇 |
1992年 | 32篇 |
1991年 | 31篇 |
1990年 | 28篇 |
1989年 | 21篇 |
1988年 | 13篇 |
1987年 | 14篇 |
1986年 | 22篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 8篇 |
1973年 | 3篇 |
排序方式: 共有8646条查询结果,搜索用时 15 毫秒
1.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献2.
Critical care nurses within acute care settings are responsible for providing healthcare to a wide variety of patients and, consequently, knowledge regarding how to care for a patient with acute necrotizing fasciitis is imperative. A case study is presented to evidence the need for a multidisciplinary approach. Necrotizing fasciitis is defined and treatment options are presented. Caring for this patient is very challenging and demands a multidisciplinary team to coordinate all aspects of care to promote better patient outcomes. 相似文献
3.
Charles Opondo Stephen Ntoburi John Wagai Jackline Wafula Aggrey Wasunna Fred Were Annah Wamae Santau Migiro Grace Irimu Mike English 《Tropical medicine & international health : TM & IH》2009,14(10):1165-1172
Objective To assess the availability of resources that support the provision of basic neonatal care in eight first‐referral level (district) hospitals in Kenya. Methods We selected two hospitals each from four of Kenya’s eight provinces with the aim of representing the diversity of this part of the health system in Kenya. We created a checklist of 53 indicator items necessary for providing essential basic care to newborns and assessed their availability at each of the eight hospitals by direct observation, and then compared our observations with the opinions of health workers providing care to newborns on recent availability for some items, using a self‐administered structured questionnaire. Results The hospitals surveyed were often unable to maintain a safe hygienic environment for patients and health care workers; staffing was insufficient and sometimes poorly organised to support the provision of care; some key equipment, laboratory tests, drugs and consumables were not available while patient management guidelines were missing in all sites. Conclusion Hospitals appear relatively poorly prepared to fill their proposed role in ensuring newborn survival. More effective interventions are needed to improve them to meet the special needs of this at‐risk group. 相似文献
4.
Popliteal artery aneurysms representing 80% of peripheral artery aneurysms rarely rupture (a reported incidence of 0.1–2.8
%) and second commonest in frequency after aorto-iliac aneurysms. They usually present with pain, swelling, occlusion or distal
embolisation and can cause diagnostic difficulties. We report a 78 year old man who was previously admitted to hospital with
a pulmonary embolus secondary to deep venous thrombosis. He was heparinized then warfarinised and was readmitted with a ruptured
popliteal aneurysm leading to a large pseudo aneurysm formation. The pulmonary embolus had been due to popliteal vein thrombosis
and propagation of the clot. A thorough review of literature identified only one previously reported case of ruptured popliteal
artery aneurysm and subsequent large pseudo aneurysm formation. We feel it is important to exclude a popliteal aneurysm in
a patient with DVT. This may be more common than the published literature suggests. 相似文献
5.
6.
7.
8.
OBJECTIVE: Pancreatic cancer is known to aggregate in some families and has been associated with a wide variety of cancer syndromes. The authors describe their experience with pancreatic cancer and the range of associated cancer syndromes. METHODS: The charts of all patients seen for concern of a hereditary cancer syndrome in the Cancer Genetics Clinic at the University of Alberta between 1995 and 2002 were reviewed. RESULTS: Forty families reported a personal or family history of pancreatic cancer in the context of a possible hereditary cancer syndrome. Three additional families reported a history of pancreatitis. Twenty-four (56%) of those families were suspected of having a hereditary breast and ovarian cancer syndrome. A further seven (16%) were suspected of having hereditary nonpolyposis colon cancer. Only three (7%) were believed to be at risk for a site-specific pancreatic cancer syndrome. Another three (7%) were suspicious for hereditary pancreatitis. The remaining family histories were suggestive of Li-Fraumeni syndrome, von Hippel-Lindau syndrome or a nonspecific cancer predisposition. CONCLUSIONS: With such a wide variety of hereditary cancer syndromes associated with pancreatic cancer, an accurate assessment of the family history is essential to determine the most appropriate cancer screening for at-risk family members and to guide any molecular testing that may be offered. 相似文献
9.
Kevin O'Brien Jean Wright Frances Conboy YeWeng Sanjie Nicky Mandall Stephen Chadwick Ivan Connolly Paul Cook David Birnie Mark Hammond Nigel Harradine David Lewis Cathy McDade Laura Mitchell Alison Murray Julian O'Neill Mike Read Stephen Robinson Dai Roberts-Harry Jonathan Sandler Ian Shaw 《American journal of orthodontics and dentofacial orthopedics》2003,124(3):234-43; quiz 339
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant. 相似文献
10.
G W Blunn A B Joshi P A Lilley E Engelbrecht L Ryd L Lidgren K Hardinge E Nieder P S Walker 《Acta orthopaedica Scandinavica》1992,63(3):247-255
106 unicondylar knee replacement tibial components were retrieved and analyzed for the amount and type of polyethylene wear. Three different designs were retrieved which had essentially the same femorotibial conformity. Each design showed a characteristic failure pattern. The polyethylene of PCA tibial components showed serious delamination after only short durations, as a result of heat pressing. St Georg sledge prostheses showed some delamination after 4 years' duration due to sub-surface cracks which were initiated by fusion defects in the polyethylene; metal backing of the components did not affect delamination of this prosthesis. The Marmor designs showed the least wear, with shiny depressions and surface pitting; no delamination was observed in the Marmor prosthesis. Molecular weight determination by gel permeation chromatography and analysis of crystallinity using Fourier transformation infra-red spectroscopy demonstrated that St George polyethylene had higher molecular weight and crystallinity than Marmor polyethylene. In some of the components investigated, crystallinity and molecular weight of the polyethylene were reduced under the wear track when compared with the unworn polyethylene. Since fusion defects may cause delamination of polyethylene we urge manufacturers to reduce the number of such defects. 相似文献