收费全文 | 220987篇 |
免费 | 17020篇 |
国内免费 | 7146篇 |
耳鼻咽喉 | 1257篇 |
儿科学 | 7657篇 |
妇产科学 | 1553篇 |
基础医学 | 19488篇 |
口腔科学 | 3609篇 |
临床医学 | 23388篇 |
内科学 | 55914篇 |
皮肤病学 | 2720篇 |
神经病学 | 26132篇 |
特种医学 | 6325篇 |
外国民族医学 | 4篇 |
外科学 | 16795篇 |
综合类 | 30035篇 |
现状与发展 | 31篇 |
一般理论 | 9篇 |
预防医学 | 18685篇 |
眼科学 | 2392篇 |
药学 | 15217篇 |
195篇 | |
中国医学 | 10004篇 |
肿瘤学 | 3743篇 |
2024年 | 683篇 |
2023年 | 4653篇 |
2022年 | 8364篇 |
2021年 | 11859篇 |
2020年 | 11097篇 |
2019年 | 8402篇 |
2018年 | 8324篇 |
2017年 | 8234篇 |
2016年 | 8552篇 |
2015年 | 8249篇 |
2014年 | 15600篇 |
2013年 | 17034篇 |
2012年 | 12732篇 |
2011年 | 13777篇 |
2010年 | 10854篇 |
2009年 | 10433篇 |
2008年 | 10432篇 |
2007年 | 10095篇 |
2006年 | 8991篇 |
2005年 | 7417篇 |
2004年 | 6308篇 |
2003年 | 5423篇 |
2002年 | 4575篇 |
2001年 | 3950篇 |
2000年 | 3297篇 |
1999年 | 2820篇 |
1998年 | 2701篇 |
1997年 | 2382篇 |
1996年 | 2134篇 |
1995年 | 1929篇 |
1994年 | 1774篇 |
1993年 | 1516篇 |
1992年 | 1453篇 |
1991年 | 1278篇 |
1990年 | 1013篇 |
1989年 | 858篇 |
1988年 | 805篇 |
1987年 | 732篇 |
1986年 | 633篇 |
1985年 | 736篇 |
1984年 | 617篇 |
1983年 | 380篇 |
1982年 | 447篇 |
1981年 | 374篇 |
1980年 | 282篇 |
1979年 | 247篇 |
1978年 | 184篇 |
1977年 | 164篇 |
1976年 | 135篇 |
1975年 | 49篇 |
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献Background
Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19. 相似文献Background and aims
It is not known whether non alcoholic fatty liver disease (NAFLD) is a risk factor for diabetes in non obese, non centrally-obese subjects. Our aim was to investigate relationships between fatty liver, insulin resistance and a biomarker score for liver fibrosis with incident diabetes at follow up, in subjects who were neither obese nor centrally-obese.Methods and results
As many as 70,303 subjects with a body mass index (BMI) < 25 kg/m2 and without diabetes were followed up for a maximum of 7.9 years. At baseline, fatty liver was identified by liver ultrasound, insulin resistance (IR) by homeostatic model assessment of insulin resistance (HOMA-IR) ≥2.0, and central obesity by waist circumference (waist circumference ≥90 cm (men) and ≥85 cm (women). The Fibrosis-4 (FIB-4 score) was used to estimate extent of liver fibrosis. Cox proportional hazards models adjusted for confounders were used to estimate hazard ratios (aHRs) for incident diabetes. As many as 852 incident cases of diabetes occurred during follow up (median [IQR] 3.71 [2.03] years). Mean ± SD BMI was 22.8 ± 1.8 and 21.7 ± 2.0 kg/m2 in subjects with and without diabetes at follow up. In subjects without central obesity and with fatty liver, aHRs (95% CI) for incident diabetes at follow up were 2.17 (1.56, 3.03) for men, and 2.86 (1.50,5.46) for women. Similar aHRs for incident diabetes occurred with fatty liver, IR and the highest quartile of FIB-4 combined, in men; and there was a non significant trend toward increased risk in women.Conclusions
In normal weight, non-centrally obese subjects NAFLD is an independent risk factor for incident diabetes. 相似文献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Methods: This is a retrospective analysis of discharge records from the National Inpatient Sample database for patients receiving allo-HSCT between 1 January 2009 and 31 December 2013. Allo-HSCT discharges with an aGVHD diagnosis were included in the aGVHD group and those without any graft-versus-host disease (GVHD) diagnosis comprised the non-GVHD group. Mortality, LOS and costs were compared between the two groups, as well as within subgroups, including age (<18 vs. ≥18 years) and survival status (alive vs. deceased) at discharge.
Results: Overall, mortality (16.2% vs. 5.3%; p?<?.01), median hospital LOS (42.0 vs. 26.0 days; p?<?.01) and median total costs ($173,144 vs. $98,982; p?<?.01) were significantly increased in patients with aGVHD versus those without GVHD during hospitalizations for allo-HSCT, irrespective of age group. Patients with aGVHD who were <18 years of age had a lower mortality rate but greater hospital LOS and total costs versus patients aged ≥18 years. Patients who died during allo-HSCT hospitalization had longer LOS and incurred greater costs than those who survived in both the aGVHD and non-GVHD groups.
Conclusion: Occurrence of aGVHD during allo-HSCT admissions resulted in a tripling of the mortality rate and a near doubling of hospital LOS and total costs. In addition, death during allo-HSCT hospitalizations was associated with greater healthcare utilization and costs. Effectively mitigating aGVHD may improve survival and substantially reduce hospital LOS and costs for allo-HSCT. 相似文献