全文获取类型
收费全文 | 1978篇 |
免费 | 272篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 50篇 |
妇产科学 | 33篇 |
基础医学 | 268篇 |
口腔科学 | 113篇 |
临床医学 | 196篇 |
内科学 | 393篇 |
皮肤病学 | 7篇 |
神经病学 | 127篇 |
特种医学 | 116篇 |
外科学 | 260篇 |
综合类 | 103篇 |
一般理论 | 1篇 |
预防医学 | 206篇 |
眼科学 | 25篇 |
药学 | 238篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 107篇 |
出版年
2021年 | 29篇 |
2020年 | 15篇 |
2019年 | 20篇 |
2018年 | 42篇 |
2017年 | 32篇 |
2016年 | 28篇 |
2015年 | 22篇 |
2014年 | 53篇 |
2013年 | 89篇 |
2012年 | 82篇 |
2011年 | 109篇 |
2010年 | 35篇 |
2009年 | 38篇 |
2008年 | 82篇 |
2007年 | 91篇 |
2006年 | 97篇 |
2005年 | 89篇 |
2004年 | 91篇 |
2003年 | 77篇 |
2002年 | 67篇 |
2001年 | 73篇 |
2000年 | 50篇 |
1999年 | 54篇 |
1998年 | 23篇 |
1997年 | 15篇 |
1996年 | 22篇 |
1995年 | 27篇 |
1994年 | 22篇 |
1993年 | 25篇 |
1992年 | 40篇 |
1991年 | 45篇 |
1990年 | 65篇 |
1989年 | 57篇 |
1988年 | 39篇 |
1987年 | 49篇 |
1986年 | 55篇 |
1985年 | 48篇 |
1984年 | 31篇 |
1983年 | 30篇 |
1982年 | 13篇 |
1981年 | 28篇 |
1980年 | 12篇 |
1979年 | 38篇 |
1978年 | 20篇 |
1977年 | 26篇 |
1976年 | 13篇 |
1975年 | 16篇 |
1972年 | 12篇 |
1969年 | 12篇 |
1968年 | 14篇 |
排序方式: 共有2255条查询结果,搜索用时 31 毫秒
41.
Screening for subclinical subclavian artery stenosis before coronary artery bypass grafting: Should we do it? 下载免费PDF全文
Ali Abdul Jabbar MD Justin Houston MD Mark Burket MD Zachary J. Il'Giovine MD Bal K. Srivastava MD Ajay Agarwal MD 《Echocardiography (Mount Kisco, N.Y.)》2017,34(6):928-933
Atherosclerotic subclavian artery disease is detected in about 5% of patients referred for coronary artery bypass (CABG) surgery. The internal mammary artery, a branch of the subclavian artery, is the most frequently utilized graft to restore coronary circulation because of its longevity. Stenosis or occlusion of the subclavian artery can cause retrograde blood flow in the ipsilateral internal mammary artery, known as “steal,” compromising coronary circulation supplied by the graft. Steal may be asymptomatic or may result in symptoms of myocardial ischemia. Symptomatic subclavian artery stenosis post bypass is referred to as coronary subclavian steal syndrome post‐CABG. The incidence is not well defined, and the benefits of screening patients referred for CABG are not known. Despite the various modalities available to detect subclavian artery stenosis, current guidelines fail to provide guidance about screening high‐risk patients for this entity. Detection of subclavian artery disease prior to CABG can reduce complications posed by post‐mammary artery graft cardiac ischemia. This review discusses the utility of preoperative subclavian artery screening prior to CABG. 相似文献
42.
Carol M. Baldwin Frank P. Houston Michelle N. Podgornik R. Scott Young Carol A. Barnes Mark L. Witten 《Archives of environmental & occupational health》2013,68(3):216-226
To determine whether JP-8 jet fuel affects parameters of the Functional Observational Battery (FOB), visual discrimination, or spatial learning and memory, the authors exposed groups of male Fischer Brown Norway hybrid rats for 28 d to aerosol/vapor-delivered JP-8, or to JP-8 followed by 15 min of aerosolized substance P analogue, or to sham-confined fresh room air. Behavioral testing was accomplished with the U.S. Environmental Protection Agency's Functional Observational Battery. The authors used the Morris swim task to test visual and spatial learning and memory testing. The spatial test included examination of memory for the original target location following 15 d of JP-8 exposure, as well as a 3-d new target location learning paradigm implemented the day that followed the final day of exposure. Only JP-8 exposed animals had significant weight loss by the 2nd week of exposure compared with JP-8 with substance P and control rats; this finding compares with those of prior studies of JP-8 jet fuel. Rats exposed to JP-8 with or without substance P exhibited significantly greater rearing and less grooming behavior over time than did controls during Functional Observational Battery open-field testing. Exposed rats also swam significantly faster than controls during the new target location training and testing, thus supporting the increased activity noted during Functional Observational Battery testing. There were no significant differences between the exposed and control groups' performances during acquisition, retention, or learning of the new platform location in either the visual discrimination or spatial version of the Morris swim task. The data suggest that although visual discrimination and spatial learning and memory were not disrupted by JP-8 exposure, arousal indices and activity measures were distinctly different in these animals. 相似文献
43.
Clinically defined psychosis is recognizable and distinguishable from nonclinical or subclinical psychosis by virtue of its clinical relevance (ie, its associated distress and its need for care and/or treatment). According to the continuum hypothesis, subclinical psychosis is merely quantitatively different from more extreme phenotypic expressions and as such should also be indicative of distress and help-seeking behavior but to a lesser extent. Using data from the Adult Psychiatric Morbidity Survey, the current study focused on self-reported psychosis and help-seeking experiences in a general population sample free from clinically defined psychosis (N = 7266). After statistically controlling for the effects of a series of potential help-seeking correlates the findings showed that subclinical psychosis symptom experience was significantly associated with various forms of help-seeking behavior. Individuals who reported subclinical experiences of thought control, paranoia, and strange experiences were on average 2 times more likely to attend their general practitioner for emotional problems compared with those individuals who reported no psychosis. Individuals who reported subclinical experiences of paranoia were 3 times more likely to be in receipt of counseling/therapy compared with those with no experience of paranoia. Multiple subclinical psychotic experiences also predicted elevated help-seeking behavior. These findings may have a positive impact on the detection of individuals who are at increased risk of psychological distress and aid in the design and implementation of more effective treatments at both clinical and subclinical levels. 相似文献
44.
45.
Fletcher B Berra K Ades P Braun LT Burke LE Durstine JL Fair JM Fletcher GF Goff D Hayman LL Hiatt WR Miller NH Krauss R Kris-Etherton P Stone N Wilterdink J Winston M;Council on Cardiovascular Nursing;Council on Arteriosclerosis Thrombosis Vascular Biology;Council on Basic Cardiovascular Sciences;Council on Cardiovascular Disease in the Young;Council on Clinical Cardiology;Council on Epidemiology Prevention;Council on Nutrition Physical Activity 《Circulation》2005,112(20):3184-3209
Current data and guidelines recommend treating abnormal blood lipids (ABL) to goal. This is a complex process and requires involvement from various healthcare professionals with a wide range of expertise. The model of a multidisciplinary case management approach for patients with ABL is well documented and described. This collaborative approach encompasses primary and secondary prevention across the lifespan, incorporates nutritional and exercise management as a significant component, defines the importance and indications for pharmacological therapy, and emphasizes the importance of adherence. Use of this collaborative approach for the treatment of ABL ultimately will improve cardiovascular and cerebrovascular morbidity and mortality. 相似文献
46.
A patient’s history of bleeding, whether spontaneous or in response to challenges, provides important information about both the likelihood of that patient having a biochemically-defined hemostatic defect, and that patient’s risk of future bleeding. Other variables including age, comorbidities and medications influence these probabilities. Scoring systems have been devised in an effort to make the estimates quantitative in specific populations. An example of a bleeding score is the MCMDM1-VWD questionnaire, which was developed to predict the likelihood of a patient having von Willebrand disease. It sums standardized details of the bleeding history, weighted by severity. The HAS-BLED score typifies bleeding prediction tools, developed to predict bleeding during anticoagulant therapy. Although prior bleeding is one item in this score, other comorbidities like hypertension or a history of stroke count for more. A third and related concept is that of bleeding case definitions, which are critical to standardize the reporting of outcomes in trials of antithrombotic agents, and which have entrenched the recognition of different severities of bleeding. We advocate that future efforts should blend some of these features. Information about comorbidities and medication use could refine the interpretation of bleeding events in a bleeding score. So could the introduction of a denominator reflecting the number and duration of challenges to which the patient has been exposed when bleeding might have been expected. More detailed information about the type, frequency and severity of prior bleeding could improve the prognostic power of bleeding prediction tools. More detailed history-based scores might ultimately supersede biochemical testing in many cases. 相似文献
47.
Amanda C. Blok Daniel J. Amante Timothy P. Hogan Rajani S. Sadasivam Stephanie L. Shimada Susan Woods Kim M. Nazi Thomas K. Houston 《Journal of general internal medicine》2021,36(3):592
BackgroundIn an effort to foster patient engagement, some healthcare systems provide their patients with open notes, enabling them to access their clinical notes online. In January 2013, the Veterans Health Administration (VA) implemented online access to clinical notes (“VA Notes”) through the Blue Button feature of its patient portal.ObjectiveTo measure the association of online patient access to clinical notes with changes in healthcare utilization and clinician documentation behaviors.DesignA retrospective cohort study.PatientsPatients accessing My HealtheVet (MHV), the VA’s online patient portal, between July 2011 and January 2015.Main MeasuresUse of healthcare services (primary care clinic visits and online electronic secure messaging), and characteristics of physician clinical documentation (readability of notes).Key ResultsAmong 882,575 unique portal users, those who accessed clinical notes (16.2%; N = 122,972) were younger, more racially homogenous (white), and less likely to be financially vulnerable. Compared with non-users, Notes users more frequently used the secure messaging feature on the portal (mean of 2.6 messages (SD 7.0) v. 0.87 messages (SD 3.3) in January–July 2013), but their higher use of secure messaging began prior to VA Notes implementation, and thus was not temporally related to the implementation. When comparing clinic visit rates pre- and post-implementation, Notes users had a small but significant increase in rate of 0.36 primary care clinic visits (2012 v. 2013) compared to portal users who did not view their Notes (p = 0.01). At baseline, the mean reading ease of primary care clinical notes was 53.8 (SD 10.1) and did not improve after implementation of VA Notes.ConclusionsVA Notes users were different than patients with portal access who did not view their notes online, and they had higher rates of healthcare service use prior to and after VA Notes implementation. Opportunities exist to improve clinical note access and readability. 相似文献
48.
49.
50.
Transoesophageal echocardiographic assessment of primum, secundum and sinus venosus atrial septal defects 总被引:2,自引:0,他引:2
J P Gnanapragasam A B Houston D B Northridge M P Jamieson J C Pollock 《International journal of cardiology》1991,31(2):167-174
We compared the ability of transthoracic and transoesophageal echocardiography to determine the presence and site of an atrial septal defect and associated anomalous pulmonary venous connexions in 13 school age children (aged 5 to 15 years) and 12 adults (aged 25 to 68 years). Transthoracic echocardiography detected atrial septal defects in 12 children and 6 adults. Transoesophageal echocardiography confirmed the position of 16 (13 secundum, 3 primum) of these 18 defects but altered the diagnosis from a secundum defect to a sinus venosus defect in one and from a sinus venosus defect to a high secundum defect in another. In addition to these 18, transoesophageal echocardiography diagnosed a defect in 5 adults (3 secundum and 2 sinus venosus defects) and 1 child (secundum defect). In an adult with inconclusive transthoracic findings, transoesophageal echocardiography enabled clear visualisation of the atrial septum and excluded an atrial septal defect. Transoesophageal echocardiography showed anomalous attachment of a pulmonary vein into the region of a sinus venosus defect (n = 3) but did not show anomalous connexions to the superior caval vein (n = 3) or the inferior caval vein (n = 1). Transoesophageal echocardiography provides a reliable method of diagnosing or excluding an atrial septal defect in patients with inconclusive transthoracic findings and is of particular diagnostic value in sinus venosus defects. 相似文献