全文获取类型
| 收费全文 | 4073136篇 |
| 免费 | 301715篇 |
| 国内免费 | 10219篇 |
专业分类
| 耳鼻咽喉 | 57492篇 |
| 儿科学 | 130393篇 |
| 妇产科学 | 111160篇 |
| 基础医学 | 568651篇 |
| 口腔科学 | 116970篇 |
| 临床医学 | 375360篇 |
| 内科学 | 789401篇 |
| 皮肤病学 | 91257篇 |
| 神经病学 | 338170篇 |
| 特种医学 | 158637篇 |
| 外国民族医学 | 1438篇 |
| 外科学 | 610112篇 |
| 综合类 | 91179篇 |
| 现状与发展 | 6篇 |
| 一般理论 | 1720篇 |
| 预防医学 | 325320篇 |
| 眼科学 | 94708篇 |
| 药学 | 301382篇 |
| 11篇 | |
| 中国医学 | 7983篇 |
| 肿瘤学 | 213720篇 |
出版年
| 2018年 | 43686篇 |
| 2017年 | 33602篇 |
| 2016年 | 38185篇 |
| 2015年 | 43102篇 |
| 2014年 | 60669篇 |
| 2013年 | 92085篇 |
| 2012年 | 122375篇 |
| 2011年 | 129879篇 |
| 2010年 | 77888篇 |
| 2009年 | 74474篇 |
| 2008年 | 121874篇 |
| 2007年 | 129462篇 |
| 2006年 | 131223篇 |
| 2005年 | 126850篇 |
| 2004年 | 122248篇 |
| 2003年 | 117858篇 |
| 2002年 | 114691篇 |
| 2001年 | 187070篇 |
| 2000年 | 192550篇 |
| 1999年 | 163311篇 |
| 1998年 | 48497篇 |
| 1997年 | 43269篇 |
| 1996年 | 42913篇 |
| 1995年 | 41619篇 |
| 1994年 | 38640篇 |
| 1993年 | 36154篇 |
| 1992年 | 129771篇 |
| 1991年 | 125546篇 |
| 1990年 | 121350篇 |
| 1989年 | 117257篇 |
| 1988年 | 108382篇 |
| 1987年 | 106757篇 |
| 1986年 | 100843篇 |
| 1985年 | 96600篇 |
| 1984年 | 72644篇 |
| 1983年 | 62042篇 |
| 1982年 | 37361篇 |
| 1981年 | 33618篇 |
| 1979年 | 66758篇 |
| 1978年 | 47237篇 |
| 1977年 | 40036篇 |
| 1976年 | 37506篇 |
| 1975年 | 39600篇 |
| 1974年 | 47998篇 |
| 1973年 | 45819篇 |
| 1972年 | 43118篇 |
| 1971年 | 39937篇 |
| 1970年 | 37315篇 |
| 1969年 | 35283篇 |
| 1968年 | 32461篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
51.
J. Rodríguez-Carrio A. Martínez-Zapico I. Cabezas-Rodríguez L. Benavente Á.I. Pérez-Álvarez P. López J.B. Cannata-Andía M. Naves-Díaz A. Suárez 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):135-143
Background and aims
Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.Methods and results
In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.Conclusion
SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE. 相似文献52.
Leonardo Jönck Staub Roberta Rodolfo Mazzali Biscaro Erikson Kaszubowski Rosemeri Maurici 《The Journal of emergency medicine》2019,56(1):53-69
Background
Lung ultrasound can accelerate the diagnosis of life-threatening diseases in adults with respiratory symptoms.Objective
Systematically review the accuracy of lung ultrasonography (LUS) for emergency diagnosis of pneumonia, acute heart failure, and exacerbation of chronic obstructive pulmonary disease (COPD)/asthma in adults.Methods
PubMed, Embase, Scopus, Web of Science, and LILACS (Literatura Latino Americana e do Caribe em Ciências da Saúde; until 2016) were searched for prospective diagnostic accuracy studies. Rutter-Gatsonis hierarchical summary receiver operating characteristic method was used to measure the overall accuracy of LUS and Reitsma bivariate model to measure the accuracy of the different sonographic signs. This review was previously registered in PROSPERO (Centre for Reviews and Dissemination, University of York, York, UK; CRD42016048085).Results
Twenty-five studies were included: 14 assessing pneumonia, 14 assessing acute heart failure, and four assessing exacerbations of COPD/asthma. The area under the summary receiver operating characteristic curve of LUS was 0.948 for pneumonia, 0.914 for acute heart failure, and 0.906 for exacerbations of COPD/asthma. In patients suspected to have pneumonia, consolidation had sensitivity of 0.82 (95% confidence interval [CI] 0.74–0.88) and specificity of 0.94 (95% CI 0.85–0.98) for this disease. In acutely dyspneic patients, modified diffuse interstitial syndrome had sensitivity of 0.90 (95% CI 0.87–0.93) and specificity of 0.93 (95% CI 0.91–0.95) for acute heart failure, whereas B-profile had sensitivity of 0.93 (95% CI 0.72–0.98) and specificity of 0.92 (95% CI 0.79–0.97) for this disease in patients with respiratory failure. In patients with acute dyspnea or respiratory failure, the A-profile without PLAPS (posterior-lateral alveolar pleural syndrome) had sensitivity of 0.78 (95% CI 0.67–0.86) and specificity of 0.94 (95% CI 0.89–0.97) for exacerbations of COPD/asthma.Conclusion
Lung ultrasound is an accurate tool for the emergency diagnosis of pneumonia, acute heart failure, and exacerbations of COPD/asthma. 相似文献53.
Christopher N. Cooley Tyler J. Beranek Matthew A. Warpinski Robert Alexander Amanda O. Esquivel 《The American journal of emergency medicine》2019,37(2):199-203
Introduction
In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.Methods
We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.Results
A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.Conclusion
The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department. 相似文献54.
55.
Anand Dayama Nikolaos Tsilimparis Stephen Kolakowski Nathaniel M. Matolo Misty D. Humphries 《Journal of vascular surgery》2019,69(1):156-163.e1
Background
Chronic limb-threatening ischemia (CLTI), defined as ischemic rest pain or tissue loss secondary to arterial insufficiency, is caused by multilevel arterial disease with frequent, severe infrageniculate disease. The rise in CLTI is in part the result of increasing worldwide prevalence of diabetes, renal insufficiency, and advanced aging of the population. The aim of this study was to compare a bypass-first with an endovascular-first revascularization strategy in patients with CLTI due to infrageniculate arterial disease.Methods
We reviewed the American College of Surgeons National Surgical Quality Improvement Program targeted lower extremity revascularization database from 2012 to 2015 to identify patients with CLTI and isolated infrageniculate arterial disease who underwent primary infrageniculate bypass or endovascular intervention. We excluded patients with a history of ipsilateral revascularization and proximal interventions. The end points were major adverse limb event (MALE), major adverse cardiovascular event (MACE), amputation at 30 days, reintervention, patency, and mortality. Multivariable logistic regression was used to determine the association of a bypass-first or an endovascular-first intervention with outcomes.Results
There were 1355 CLTI patients undergoing first-time revascularization to the infrageniculate arteries (821 endovascular-first revascularizations and 534 bypass-first revascularizations) identified. There was no significant difference in adjusted rate of 30-day MALE in the bypass-first vs endovascular-first revascularization cohort (9% vs 11.2%; odds ratio [OR], 0.73; 95% confidence interval [CI], 0.50-1.08). However, the incidence of transtibial or proximal amputation was lower in the bypass-first cohort (4.3% vs 7.4%; OR, 0.60; CI, 0.36-0.98). Patients with bypass-first revascularization had higher wound complication rates (9.7% vs 3.7%; OR, 2.75; CI, 1.71-4.42) compared with patients in the endovascular-first cohort. Compared with the endovascular-first cohort, the incidence of 30-day MACE was significantly higher in bypass-first patients (6.9% vs 2.6%; adjusted OR, 3.88; CI, 2.18-6.88), and 30-day mortality rates were 3.23% vs 1.8% (adjusted OR, 2.77; CI, 1.26-6.11). There was no difference in 30-day untreated loss of patency, reintervention of treated arterial segment, readmissions, and reoperations between the two cohorts. In subgroup analysis after exclusion of dialysis patients, there was also no significant difference in MALE or amputation between the bypass-first and endovascular-first cohorts.Conclusions
CLTI patients with isolated infrageniculate arterial disease treated by a bypass-first approach have a significantly lower 30-day amputation. However, this benefit was not observed when dialysis patients were excluded. The bypass-first cohort had a higher incidence of MACE compared with an endovascular-first strategy. These results reaffirm the need for randomized controlled trials, such as the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL-2) trial and Best Endovascular vs Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI), to provide level 1 evidence for the role of endovascular-first vs bypass-first revascularization strategies in the treatment of this population of challenging patients. 相似文献56.
N. SUVAJD
I&#x; V. EMERIKI&#x;‐MARTINOVI&#x; &#x;. &#x;ARANOVI&#x; M. PETROVI&#x; M. POPOVI&#x; V. ARTIKO M. &#x;UPI&#x; I. ELEZOVI&#x; 《International journal of laboratory hematology》2006,28(5):317-320
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed. 相似文献
57.
58.
59.
60.