全文获取类型
收费全文 | 5675篇 |
免费 | 453篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 141篇 |
妇产科学 | 91篇 |
基础医学 | 479篇 |
口腔科学 | 58篇 |
临床医学 | 655篇 |
内科学 | 1202篇 |
皮肤病学 | 29篇 |
神经病学 | 1085篇 |
特种医学 | 115篇 |
外科学 | 267篇 |
综合类 | 646篇 |
预防医学 | 464篇 |
眼科学 | 87篇 |
药学 | 483篇 |
12篇 | |
中国医学 | 244篇 |
肿瘤学 | 99篇 |
出版年
2024年 | 23篇 |
2023年 | 142篇 |
2022年 | 252篇 |
2021年 | 318篇 |
2020年 | 312篇 |
2019年 | 223篇 |
2018年 | 221篇 |
2017年 | 234篇 |
2016年 | 213篇 |
2015年 | 185篇 |
2014年 | 428篇 |
2013年 | 414篇 |
2012年 | 274篇 |
2011年 | 323篇 |
2010年 | 270篇 |
2009年 | 251篇 |
2008年 | 267篇 |
2007年 | 209篇 |
2006年 | 219篇 |
2005年 | 173篇 |
2004年 | 130篇 |
2003年 | 129篇 |
2002年 | 115篇 |
2001年 | 82篇 |
2000年 | 78篇 |
1999年 | 70篇 |
1998年 | 55篇 |
1997年 | 55篇 |
1996年 | 48篇 |
1995年 | 46篇 |
1994年 | 36篇 |
1993年 | 36篇 |
1992年 | 43篇 |
1991年 | 29篇 |
1990年 | 27篇 |
1989年 | 27篇 |
1988年 | 27篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 38篇 |
1984年 | 30篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 5篇 |
1974年 | 6篇 |
排序方式: 共有6203条查询结果,搜索用时 11 毫秒
81.
82.
Enes Elvin Gul MD Rajiv A. Kabadi MD Santosh K. Padala MD Paula Sanchez Somonte MD Jordana Kron MD Richard K. Shepard MD Jayanthi N. Koneru MD Gautham Kalahasty MD Maria Terricabras MD Bernice Tsang MD Yaariv Khaykin MD Zaev Wulffhart MD Alfredo Pantano MD Kenneth A. Ellenbogen MD Atul Verma MD 《Journal of cardiovascular electrophysiology》2021,32(9):2515-2521
83.
84.
BACKGROUND: Patent foramen ovale (PFO) with or without atrial septal aneurysm (ASA) is highly associated with cerebral ischemic events in young patients. The prevalence of PFO and ASA in elderly patients with cerebral ischemic events is not well described. OBJECTIVE: Our study is to evaluate the frequencies of PFO with right-to-left shunt (RLS) and ASA in elderly patients and to determine whether age is a predictor of flow-reversed PFO with RLS in cerebral ischemic events. METHODS: A prospective registry for all consecutive patients with cerebral ischemic events who were evaluated by transesophageal echocardiography (TEE) for the detection of possible cardiac source of embolization was established and maintained in a university hospital. Patients' demographics including age, gender, ethnic origin, cerebrovascular risk factors, and all positive TEE data were collected from July 2000 to August 2001 for statistical analysis. A univariate and multivariate stepwise logistic regression analysis was performed. RESULTS: In older patients the prevalence of PFO with RLS, PFO, and ASA was 25/118 (20%), 28/118 (24%), and 38/118 (32%), respectively, as opposed to younger patients, in whom it was 35/119 (30%), 39/119 (33%), and 38/119 (32%), respectively. Older patients had higher frequencies of hypertension (59; 69%), CAD (25; 21%), and prior history of stroke (23; 20%) as opposed to younger patients. Younger age (<60 years), gender, smoking history, hypertension, hyperlipidemia, CAD, and prior history of stroke were not associated with higher prevalence of PFO with RLS. Patent foramen ovale was associated with ASA (P < 0.001) and LVH (P < 0.019) in patients with TIA and stroke. In multivariate analysis only ASA (P < 0.001) remained significant with PFO, with RLS controlling for age, gender, and LVH. CONCLUSIONS: PFO with RLS and ASA are frequently present in elderly stroke and/or TIA patients and age is not a predictor for PFO. Transesophageal echocardiography should be considered for all stroke and/or TIA patients irrespective of their age. 相似文献
85.
《Sleep medicine》2021
Current diagnostics of sleep apnea relies on the time-consuming manual analysis of complex sleep registrations, which is impractical for routine screening in hospitalized patients with a high probability for sleep apnea, e.g. those experiencing acute stroke or transient ischemic attacks (TIA). To overcome this shortcoming, we aimed to develop a convolutional neural network (CNN) capable of estimating the severity of sleep apnea in acute stroke and TIA patients based solely on the nocturnal oxygen saturation (SpO2) signal.The CNN was trained with SpO2 signals derived from 1379 home sleep apnea tests (HSAT) of suspected sleep apnea patients and tested with SpO2 signals of 77 acute ischemic stroke or TIA patients. The CNN's performance was tested by comparing the estimated respiratory event index (REI) and oxygen desaturation index (ODI) with manually obtained values.Median estimation errors for REI and ODI in patients with stroke or TIA were 1.45 events/hour and 0.61 events/hour, respectively. Furthermore, based on estimated REI and ODI, 77.9% and 88.3% of these patients were classified into the correct sleep apnea severity categories. The sensitivity and specificity to identify sleep apnea (REI > 5 events/hour) were 91.8% and 78.6%, respectively. Moderate-to-severe sleep apnea was detected (REI > 15 events/hour) with sensitivity of 92.3% and specificity of 96.1%.The CNN analysis of the SpO2 signal has great potential as a simple screening tool for sleep apnea. This novel automatic method accurately detects sleep apnea in acute cerebrovascular disease patients and facilitates their referral for a differential diagnostic HSAT or polysomnography evaluation. 相似文献
86.
87.
MATERIAL AND METHODS: Data from the Göteborg myocardial infarction register wereused to investigate trends in attack rate, incidence of non-fatalmyocardial infarction and mortality from coronary heart diseasein persons aged 64 and below during the period 19751994. RESULTS: Myocardial infarction was defined according to strict criteriawhich remained the same throughout the study period. Attackrate and incidence were 35 times higher among men thanwomen. The ratio of recurrent infarcts out of all attacks increasedwith increasing age and was 14%, 20% and 24% for men aged 3544,4554, and 5564, respectively. Corresponding ratesfor women were 8%, 14%, and 22%, respectively. Both attack rateand incidence decreased significantly by 2·13·9%per year during the study period for most age groups. The 28-dayfatality rate (hospitalized as well as non-hospitalized cases)tended to decline, but significantly so only in the oldest men.The same was true for 28-day fatality among hospitalized patients.The majority of all coronary heart disease deaths occurred outsidehospital in people unaware they had coronary heart disease.Mortality from coronary heart disease decreased by 2·068%per year during the study period. In-hospital treatment of myocardialinfarction with intravenous beta-blockers followed by oral treatment,nitroglycerin and thrombolytics increased during the study period.Coronary surgery and angioplasty were used in less than 5% ofpatients during the study period, but increased substantiallyin 1994. CONCLUSION: Coronary heart disease and mortality in ages below 65 yearsare now decreasing in Sweden. Decreasing short-term mortalityis almost certainly due to more efficient treatment in hospital,but as the majority of coronary heart disease deaths occur outsidehospital and in people unaware they have coronary heart disease,primary prevention is still very important. 相似文献
88.
89.
P-wave dispersion in patients with stable coronary artery disease and its relationship with severity of the disease 总被引:7,自引:0,他引:7
AIM: P-wave dispersion (PD) has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. The purpose of this study was to investigate the PD in patients with stable coronary artery disease (CAD) and to determine its relationship with severity of the disease. METHODS: We prospectively analyzed 66 subjects with normal coronary angiogram (group 1) and 68 patients with significant (> or =50%) coronary stenosis; 25 had 1-vessel disease (group 2), 27 had 2-vessel disease (group 3), and 16 had 3-vessel disease (group 4). The maximum and minimum P-wave duration (Pmax and Pmin) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed. Angiographic vessel score and Gensini score were used to evaluate the severity of CAD. RESULTS: Pmax was longer in groups 3 and 4 compared with group 1 (P = .001 for both comparison). PD was greater in groups 2, 3, and 4 compared with group 1 ( P < .001 for all comparison), and also in group 4 compared with group 2 (P = .001). However, there was no statistically significant difference among the groups regarding Pmin. In bivariate correlation, increased PD was correlated with presence of hypertension (r = 0.278, P = .013), left ventricular ejection fraction (r = -0.231, P = .044), left atrial diameter (r = 0.223, P = .032), presence of moderate to severe mitral regurgitation (r = 0.284, P = .017), vessel score (r = 0.465, P < .001), and Gensini score (r = 0.338, P = .005). Multiple linear regression analysis showed that only vessel score was independently associated with PD (beta = .471, P = .01). CONCLUSIONS: PD was found to be greater in patients with stable CAD than in controls and to be associated with severity of the disease. 相似文献
90.