全文获取类型
收费全文 | 94340篇 |
免费 | 5207篇 |
国内免费 | 2625篇 |
专业分类
耳鼻咽喉 | 279篇 |
儿科学 | 1646篇 |
妇产科学 | 280篇 |
基础医学 | 4324篇 |
口腔科学 | 131篇 |
临床医学 | 14238篇 |
内科学 | 23897篇 |
皮肤病学 | 297篇 |
神经病学 | 5705篇 |
特种医学 | 3640篇 |
外科学 | 5863篇 |
综合类 | 19977篇 |
预防医学 | 4186篇 |
眼科学 | 278篇 |
药学 | 10584篇 |
149篇 | |
中国医学 | 5242篇 |
肿瘤学 | 1456篇 |
出版年
2024年 | 43篇 |
2023年 | 1053篇 |
2022年 | 2117篇 |
2021年 | 3198篇 |
2020年 | 3558篇 |
2019年 | 3994篇 |
2018年 | 2241篇 |
2017年 | 2625篇 |
2016年 | 2943篇 |
2015年 | 2857篇 |
2014年 | 6954篇 |
2013年 | 6534篇 |
2012年 | 6102篇 |
2011年 | 6387篇 |
2010年 | 5205篇 |
2009年 | 4801篇 |
2008年 | 4753篇 |
2007年 | 4864篇 |
2006年 | 4623篇 |
2005年 | 3888篇 |
2004年 | 3075篇 |
2003年 | 2672篇 |
2002年 | 2201篇 |
2001年 | 2129篇 |
2000年 | 1814篇 |
1999年 | 1522篇 |
1998年 | 1246篇 |
1997年 | 1186篇 |
1996年 | 908篇 |
1995年 | 835篇 |
1994年 | 795篇 |
1993年 | 628篇 |
1992年 | 533篇 |
1991年 | 500篇 |
1990年 | 444篇 |
1989年 | 375篇 |
1988年 | 359篇 |
1987年 | 304篇 |
1986年 | 268篇 |
1985年 | 327篇 |
1984年 | 271篇 |
1983年 | 151篇 |
1982年 | 190篇 |
1981年 | 164篇 |
1980年 | 132篇 |
1979年 | 102篇 |
1978年 | 84篇 |
1977年 | 68篇 |
1976年 | 39篇 |
1975年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
Joseph Wheatley Zhengyang Liu Joel Loth Mark P. Plummer Jahan C. Penny-Dimri Reny Segal Julian Smith Luke A. Perry 《Acta anaesthesiologica Scandinavica》2023,67(2):131-141
Background
Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil–lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting.Methods
We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity.Results
Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18–1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50–3.72). Postoperative NLR measurements were not of prognostic significance.Conclusions
Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery. 相似文献3.
Rolf Svedjeholm Gabriele Ferrari Farkas Vanky Örjan Friberg Jonas Holm 《Acta anaesthesiologica Scandinavica》2023,67(10):1373-1382
Background
Glutamate plays a key role for post-ischaemic recovery of myocardial metabolism. According to post hoc analyses of the two GLUTAMICS trials, patients without diabetes benefit from glutamate with less myocardial dysfunction after coronary artery bypass surgery (CABG). Copeptin reflects activation of the Arginine Vasopressin system and is a reliable marker of heart failure but available studies in cardiac surgery are limited. We investigated whether glutamate infusion is associated with reduced postoperative rises of plasma Copeptin (p-Copeptin) after CABG.Methods
A prespecified randomised double-blind substudy of GLUTAMICS II. Patients had left ventricular ejection fraction ≤0.30 or EuroSCORE II ≥3.0 and underwent CABG ± valve procedure. Intravenous infusion of 0.125 M L-glutamic acid or saline at 1.65 mL/kg/h was commenced 10–20 min before the release of the aortic cross-clamp and then continued for another 150 min P-Copeptin was measured preoperatively and postoperatively on day one (POD1) and day three. The primary endpoint was an increase in p-Copeptin from the preoperative level to POD1. Postoperative stroke ≤24 h and mortality ≤30 days were safety outcomes.Results
We included 181 patients of whom 48% had diabetes. The incidence of postoperative mortality ≤30 days (0% vs. 2.1%; p = .50) and stroke ≤24 h (0% vs. 3.2%; p = .25) did not differ between the glutamate group and controls. P-Copeptin increased postoperatively with the highest values recorded on POD1 without significant inter-group differences. Among patients without diabetes, p-Copeptin did not differ preoperatively but postoperative rise from preoperative level to POD1 was significantly reduced in the glutamate group (73 ± 66 vs. 115 ± 102 pmol/L; p = .02). P-Copeptin was significantly lower in the Glutamate group on POD1 (p = .02) and POD 3 (p = .02).Conclusions
Glutamate did not reduce rises of p-Copeptin significantly after moderate to high-risk CABG. However, glutamate was associated with reduced rises of p-Copeptin among patients without diabetes. These results agree with previous observations suggesting that glutamate mitigates myocardial dysfunction after CABG in patients without diabetes. Given the exploratory nature of these findings, they need to be confirmed in future studies. 相似文献4.
J. M. Nolde M. P. Schlaich D. I. Sessler A. Mian T. B. Corcoran C. K. Chow M. T. V. Chan F. K. Borges M. H. McGillion P. S. Myles N. L. Mills P. J. Devereaux G. S. Hillis 《Anaesthesia》2023,78(7):853-860
Myocardial injury due to ischaemia within 30 days of non-cardiac surgery is prognostically relevant. We aimed to determine the discrimination, calibration, accuracy, sensitivity and specificity of single-layer and multiple-layer neural networks for myocardial injury and death within 30 postoperative days. We analysed data from 24,589 participants in the Vascular Events in Non-cardiac Surgery Patients Cohort Evaluation study. Validation was performed on a randomly selected subset of the study population. Discrimination for myocardial injury by single-layer vs. multiple-layer models generated areas (95%CI) under the receiver operating characteristic curve of: 0.70 (0.69–0.72) vs. 0.71 (0.70–0.73) with variables available before surgical referral, p < 0.001; 0.73 (0.72–0.75) vs. 0.75 (0.74–0.76) with additional variables available on admission, but before surgery, p < 0.001; and 0.76 (0.75–0.77) vs. 0.77 (0.76–0.78) with the addition of subsequent variables, p < 0.001. Discrimination for death by single-layer vs. multiple-layer models generated areas (95%CI) under the receiver operating characteristic curve of: 0.71 (0.66–0.76) vs. 0.74 (0.71–0.77) with variables available before surgical referral, p = 0.04; 0.78 (0.73–0.82) vs. 0.83 (0.79–0.86) with additional variables available on admission but before surgery, p = 0.01; and 0.87 (0.83–0.89) vs. 0.87 (0.85–0.90) with the addition of subsequent variables, p = 0.52. The accuracy of the multiple-layer model for myocardial injury and death with all variables was 70% and 89%, respectively. 相似文献
5.
《Revista portuguesa de cardiologia》2022,41(7):573-582
IntroductionThe management of acute coronary syndrome (ACS) in malignancy is challenging due to higher bleeding risk.MethodsWe analyzed patients with cancer (active or in the previous five years) prospectively included in the ProACS registry between 2010 and 2019. Our aim was to assess safety (major bleeding, primary endpoint) and secondary efficacy endpoints (in-hospital mortality and combined in-hospital mortality, reinfarction and ischemic stroke) of ACS treatment. Propensity score matching analysis (1:1) was further performed to better understand predictors of outcomes.ResultsWe found 934 (5%) cancer patients out of a total of 18 845 patients with ACS. Cancer patients had more events: major bleeding (2.9% vs. 1.5%), in-hospital mortality (5.8% vs. 3.4%) and the combined endpoint (7.4% vs. 4.9%). The primary endpoint was related to cancer diagnosis (OR 1.97), previous bleeding (OR 7.09), hemoglobin level (OR 4.94), atrial fibrillation (OR 3.50), oral anticoagulation (OR 3.67) and renal dysfunction. Mortality and the combined secondary endpoint were associated with lower use of invasive coronary angiography and antiplatelet and neurohormonal blocker therapy. After propensity score matching (350 patients), there were no statistically significant differences in endpoints between the populations.ConclusionBleeding risk was not significant higher in the cancer population compared to patients with similar characteristics, nor were mortality or ischemic risk. The presence of cancer should not preclude simultaneous ACS treatment. 相似文献
6.
7.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(2):469-478
Background and aimsThe relationship between hemoglobin glycation index (HGI) and the diagnosis and prognosis of cardiovascular disease (CVD) has been verified by previous studies. However, it remains unknown whether HGI has a predictive effect on subclinical myocardial injury (SC–MI). The purpose of the present study was to explore the relationship between HGI and SC–MI in the general population free from CVD.Methods and resultsThe present study included 6009 participants free of CVD from the third National Health and Nutrition Examination Survey. Binary Logistic regression analysis was used to tested the association between HGI and SC–MI. As results, the HGI was significantly higher in participants with SC–MI compared with those without, and the HGI was positively correlated with SC–MI and other metabolic disorder parameters. Each 1-unit increase of HGI and glycated hemoglobin A1c (HbA1c) was independently associated with higher risk of SC–MI (P < 0.05), while fasting plasma glucose (FPG) was no longer a predictive indicator of SC–MI with the increase of confounding factors [OR (95% CI): 1.001 (0.999–1.003), P = 0.305]. And in the subgroup analysis, HGI, only in participants without diabetes, was independently associated with higher risk of SC–MI, while HbA1c and FPG had no independent predictive role in both diabetic and non-diabetic participants.ConclusionsHGI was a significant predictor of SC–MI in the general population free from CVD. 相似文献
8.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(3):641-647
Background and aimsHyperuricemia is widely thought as a risk factor for myocardial infarction (MI) and all-cause mortality; however, the relation of serum uric acid (sUA) and subclinical myocardial injury (SCeMI) remains unclear. We hypothesize that sUA is associated with subclinical myocardial injury.Methods and resultsA total of 5880 adult individuals (57.9 ± 13.0 years, 54.23% women) without known cardiovascular disease from National Health and Nutrition Examination Survey (NHANES) III were included. Determined by Cardiac Infarction Injury Score (CIIS) from 12-lead electrocardiogram, SCeMI was defined by CIIS ≥10 units. The relationship between sUA and SCeMI was analyzed by using logistic regression models and the smooth curve fitting. Subgroup analyses were conducted. After adjusting for potential confounding variables, the smooth curve fitting revealed a non-linear relationship between sUA level and SCeMI. When sUA was above the inflection point 266.5 μmol/L, each 100 unit increase in sUA increase the risk of SCeMI by 15%. In women group, when sUA>340.3 μmol/L, each 100 unit increase in sUA increase the risk of SCeMI by 71%, but no significant correlation was observed in men group.ConclusionsOur findings confirm that sUA is an independent risk factor for subclinical myocardial injury after adjusting for potential confounding variables, and existence of such an association in women only, which require more random control trials to confirm the strategy of cardiovascular disease prevention based on sUA reduction in female. 相似文献
9.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(7):1583-1589
Elevated serum uric acid (SUA) levels have been associated with several cardiovascular risk factors and the progression of coronary artery disease. In the setting of acute myocardial infarction, increasing evidence suggests that high SUA levels could be related to adverse outcomes. Interestingly elevated SUA levels have been linked to endothelial dysfunction, inflammation and oxidative stress. The aim of this review is to discuss the potential negative effects of SUA in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention, analyzing the possible underlying pathophysiological mechanisms. 相似文献
10.
目的评估CHA2DS2-VASc评分对急性心肌梗死(AMI)患者院内结局事件的预测价值。方法回顾性分析冠心病医疗结果评价和临床转化研究(China PEACE)回顾性急性心肌梗死研究中23728例AMI患者的病历信息,按CHA2DS2-VASc评分分为低(0~3分)、中(4~6分)、高(7~9分)分值组。院内结局包括主要不良心血管事件、死亡、死亡或放弃治疗、再发心肌梗死、缺血性卒中等。采用多因素Cox回归分析CHA2DS2-VASc评分对AMI患者院内结局的影响。通过受试者工作特征(ROC)曲线,评估CHA2DS2-VASc评分对AMI患者院内死亡与死亡或放弃治疗的预测价值。结果入组患者年龄66(56,75岁)岁,女性占30.7%。CHA2DS2-VASc评分高分值组患者院内结局事件发生率更高,基础疾病更多(P值均<0.001);多因素logistic回归中,院内病死率(OR=6.13,95%CI 4.77~7.87,P<0.001)、院内死亡或放弃治疗率(OR=6.43,95%CI 5.16~8.00,P<0.001)、主要心血管事件发生率(OR=4.94,95%CI 4.06~6.01,P<0.001)明显高于其他两组。ROC曲线分析显示,无论院内病死率,还是死亡或放弃治疗率,CHA2DS2-VASc评分与简化版全球急性冠状动脉事件登记(global registry of acute coronary events,mini-GRACE)评分相比差异无统计学意义(ROC曲线下面积:0.699与0.696,P=0.752;0.708与0.713,P=0.489)。结论CHA2DS2-VASc评分是一种有效预测AMI患者院内风险的评估工具,该评分操作简单,预测价值与mini-GRACE评分相当。 相似文献