收费全文 | 3238422篇 |
免费 | 249780篇 |
国内免费 | 5615篇 |
耳鼻咽喉 | 47387篇 |
儿科学 | 102799篇 |
妇产科学 | 89746篇 |
基础医学 | 460711篇 |
口腔科学 | 93095篇 |
临床医学 | 291247篇 |
内科学 | 628782篇 |
皮肤病学 | 66891篇 |
神经病学 | 266629篇 |
特种医学 | 128586篇 |
外国民族医学 | 1170篇 |
外科学 | 491002篇 |
综合类 | 74397篇 |
现状与发展 | 2篇 |
一般理论 | 1209篇 |
预防医学 | 256127篇 |
眼科学 | 76089篇 |
药学 | 243640篇 |
61篇 | |
中国医学 | 6014篇 |
肿瘤学 | 168233篇 |
2018年 | 32209篇 |
2016年 | 27382篇 |
2015年 | 31112篇 |
2014年 | 44357篇 |
2013年 | 67859篇 |
2012年 | 91822篇 |
2011年 | 97292篇 |
2010年 | 57223篇 |
2009年 | 54599篇 |
2008年 | 92709篇 |
2007年 | 99444篇 |
2006年 | 100594篇 |
2005年 | 98167篇 |
2004年 | 94703篇 |
2003年 | 91354篇 |
2002年 | 90330篇 |
2001年 | 146449篇 |
2000年 | 151341篇 |
1999年 | 128252篇 |
1998年 | 37392篇 |
1997年 | 33663篇 |
1996年 | 33593篇 |
1995年 | 32369篇 |
1994年 | 30448篇 |
1993年 | 28333篇 |
1992年 | 103728篇 |
1991年 | 100922篇 |
1990年 | 98229篇 |
1989年 | 94924篇 |
1988年 | 88201篇 |
1987年 | 86792篇 |
1986年 | 82445篇 |
1985年 | 78972篇 |
1984年 | 59709篇 |
1983年 | 51136篇 |
1982年 | 31016篇 |
1981年 | 27602篇 |
1980年 | 25875篇 |
1979年 | 56359篇 |
1978年 | 39853篇 |
1977年 | 33753篇 |
1976年 | 31902篇 |
1975年 | 34098篇 |
1974年 | 41472篇 |
1973年 | 39528篇 |
1972年 | 37365篇 |
1971年 | 34605篇 |
1970年 | 32474篇 |
1969年 | 30486篇 |
1968年 | 28221篇 |
Background
Liver transplantation from donors after either controlled or uncontrolled cardiac death (DCD) is associated with considerable rates of primary nonfunction (PNF) and ischemic cholangiopathy (IC). Normothermic regional perfusion (NRP) could significantly reduce such rates.Methods
Retrospective study to analyze short-term (mortality, PNF, vascular complications) and long-term (IC, survival) complications in 11 liver transplants from controlled DCDs using NRP with extracorporeal membrane oxygenation (ECMO) (group 1). They were compared with 51 patients transplanted with grafts from donors after brain death (DBD) (group 2). Mean recipient age, sex, and Model for End-stage Liver Disease (MELD) score were not significantly different.Results
In group 1, mean functional warm ischemia time was 15.8 (range, 7–40) minutes and 94.1 (range, 20–150) minutes on NRP. The ischemic damage was minimal, as shown by the slight alanine aminotransferase (ALT) and aspartate aminotransferase (AST) rises in the donor serum after 1 hour on NRP and similar rises 24 hours after transplantation in both groups. No patient had IC or acute renal failure. No significant difference was found between the groups for vascular or biliary complications. One group 1 patient had PNF (9.1%), resulting in death. Overall retransplantation and in-hospital death rates were 8.1% and 4.8%, respectively, with no significant difference between groups. Estimated mean survival was 24.6 (95% confidence interval [CI], 20.2–29.1) months in group 1 and 32.3 (95% CI, 30.4–34.2) months in group 2 (not a statistically significant difference).Conclusion
In our experience, liver transplants from controlled DCDs using NRP with ECMO is associated with a low risk of PNF and IC, with short- and long-term results comparable to those in DBD transplants. 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Background
There are conflicting data regarding the relative effectiveness of renal sympathetic denervation (RSD) in patients with hypertension.Objectives
The purpose of this study was to evaluate the blood pressure (BP) response after RSD in sham-controlled randomized trials.Methods
Databases were searched through June 30, 2018. Randomized trials (RCTs) with ≥50 patients comparing catheter-based RSD with a sham control were included. The authors calculated summary treatment estimates as weighted mean differences (WMD) with 95% confidence intervals (CIs) using random-effects meta-analysis.Results
The analysis included 977 patients from 6 trials. The reduction in 24-h ambulatory systolic blood pressure (ASBP) was significantly greater for patients treated with RSD than sham procedure (WMD ?3.65 mm Hg, 95% CI: ?5.33 to ?1.98; p < 0.001). Compared with sham, RSD was also associated with a significant decrease in daytime ASBP (WMD ?4.07 mm Hg, 95% CI: ?6.46 to ?1.68; p < 0.001), office systolic BP (WMD ?5.53 mm Hg, 95% CI: ?8.18 to ?2.87; p < 0.001), 24-h ambulatory diastolic BP (WMD ?1.71 mm Hg, 95% CI: ?3.06 to ?0.35; p = 0.01), daytime ambulatory diastolic BP (WMD ?1.57 mm Hg, 95% CI: ?2.73 to ?0.42; p = 0.008), and office diastolic BP (WMD ?3.37 mm Hg, 95% CI: ?4.86 to ?1.88; p < 0.001). Compared with first-generation trials, a significantly greater reduction in daytime ASBP was observed with RSD in second-generation trials (6.12 mm Hg vs. 2.14 mm Hg; p interaction = 0.04); however, this interaction was not significant for 24-h ASBP (4.85 mm Hg vs. 2.23 mm Hg; p interaction = 0.13).Conclusions
RSD significantly reduced blood pressure compared with sham control. Results of this meta-analysis should inform the design of larger, pivotal trials to evaluate the long-term efficacy and safety of RSD in patients with hypertension. 相似文献Background
Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.Methods
We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).Results
Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.Conclusions
Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation. 相似文献Abbreviations: CONCEA: National Council for the Control of Animal Experimentation; GEPR: genetically epilepsy-prone rats; WAR: Wistar Audiogenic Rat. 相似文献
Background
Nutrition specialists are considered key members of multicomponent pediatric weight management intervention teams, but to date, their contribution has not been quantified.Objective
The purpose of this systematic review was to estimate the effectiveness of interventions provided by treatment teams that include a nutrition specialist on pediatric weight management outcomes, including body mass index (BMI), BMI z score, and waist circumference when compared with treatment teams that do not include a nutrition specialist.Methods
The results of a comprehensive literature search and a systematic and more targeted update of that search were included in the meta-analyses: a search of controlled trials published between July 2005 and April 2012, conducted during the 2015 Pediatric Weight Management Update Project of the Academy of Nutrition and Dietetics Evidence Analysis Library, and an update search of controlled trials published between May 2012 and December 2015 focusing on a more specific topic within the previous search. Studies included overweight and/or obese patients aged 6 to 18 years receiving outpatient weight management treatment. Data extraction of all studies identified was performed using a standardized tool. The resulting data from the search and the systematic update were merged. Ninety-nine studies and 209 study arms were included in the analysis. An exploratory meta-analysis using alternative meta-analytic methods designed for complex, heterogenous interventions was conducted to identify relative contributions by intervention provider category at selected time points. Meta-regression analyses were used to evaluate significant differences from the reference category for each provider category.Results
The nutrition specialist-only condition resulted in increased reductions in BMI z score compared with behavioralist-only, combined nutrition specialist and behavioralist, and neither nutrition specialist or behavioralist category (reference) throughout the analysis. Meta-regression analysis indicated that the difference in BMI z score between the nutrition specialist-only category and the reference category was significant at 3 to <6 months, 6 months to <1 year, and 1-year to 2-year time points (P=0.01, P=0.05, and P=0.01, respectively). There were smaller increases in BMI over time for the nutrition specialist-only provider category compared with reference categories, and this difference was significant at the 3 to <6 months and 1-year to 2-years time points (P=0.001 and P=0.05, respectively). There were no significant differences among provider categories for waist circumference at any time point.Conclusions
Indirect evidence indicated that pediatric weight management outcomes for BMI z score and BMI at selected time points appeared to be better when a nutrition specialist was involved in delivering care. 相似文献Methods: Attributes were defined from a literature search, clinician and patient interviews: shape, dose insertion, dose preparation, dose release, dose confirmation, dose counter and reusability. An online DCE was conducted in respondents with self-reported COPD stage 2–4 recruited through a panel. The study questionnaire included twelve choice scenarios per respondent and questions on patient characteristics, treatment and disease severity. Statistical analyses used a mixed logit regression model with random effects. Utility scores were estimated for four types of inhalers: Inhaler A – soft mist inhaler; Inhaler B – reusable soft mist inhaler; Inhaler C – multi-dose dry powder inhaler; and Inhaler D – single dose dry powder inhaler.
Results: The study was completed by 153 patients (50 females); respondents were 50.4?years old on average; 13 different inhaler devices were reported. The most preferred inhaler is L-shaped, has dose preparation with capsule insertion and a dose counter, and is reusable. Inhaler profiles A and B had the highest utilities (mean of 1.2533 and 0.9578 respectively) compared to inhaler C (0.6315) and D (0.2200).
Conclusions: This study showed statistically significant results that the strongest drivers of preference in French users of inhalation devices for COPD are shape, dose counter and reusability. Convenience-related characteristics are important to patients and should be taken into account by clinicians prescribing these devices. 相似文献