首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   292053篇
  免费   17513篇
  国内免费   7830篇
耳鼻咽喉   5805篇
儿科学   9078篇
妇产科学   4983篇
基础医学   18531篇
口腔科学   7315篇
临床医学   33362篇
内科学   45658篇
皮肤病学   3718篇
神经病学   13354篇
特种医学   13445篇
外国民族医学   42篇
外科学   58168篇
综合类   29298篇
现状与发展   32篇
一般理论   9篇
预防医学   17332篇
眼科学   8773篇
药学   26605篇
  240篇
中国医学   5309篇
肿瘤学   16339篇
  2023年   3856篇
  2022年   6021篇
  2021年   12407篇
  2020年   9271篇
  2019年   14350篇
  2018年   9069篇
  2017年   7808篇
  2016年   9771篇
  2015年   12663篇
  2014年   23482篇
  2013年   20819篇
  2012年   23127篇
  2011年   20166篇
  2010年   17946篇
  2009年   17374篇
  2008年   15790篇
  2007年   15753篇
  2006年   13393篇
  2005年   9416篇
  2004年   5576篇
  2003年   4727篇
  2002年   3802篇
  2001年   3192篇
  2000年   2835篇
  1999年   2087篇
  1998年   2289篇
  1997年   2076篇
  1996年   1677篇
  1995年   1666篇
  1994年   1561篇
  1993年   1221篇
  1992年   1377篇
  1991年   1266篇
  1990年   1211篇
  1989年   1176篇
  1988年   1101篇
  1987年   1000篇
  1986年   818篇
  1985年   1735篇
  1984年   1877篇
  1983年   1353篇
  1982年   1442篇
  1981年   1417篇
  1980年   1212篇
  1979年   1022篇
  1978年   787篇
  1977年   783篇
  1976年   684篇
  1975年   448篇
  1974年   457篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
IntroductionOur aim was to describe practices in multimodal pain management at US children's hospitals and evaluate the association between non-opioid pain management strategies and pediatric patient-reported outcomes (PROs).MethodsData were collected as part of the 18-hospital ENhanced Recovery In CHildren Undergoing Surgery (ENRICH-US) clinical trial. Non-opioid pain management strategies included use of preoperative and postoperative non-opioid analgesics, regional anesthetic blocks, and a biobehavioral intervention. PROs included perioperative nervousness, pain-related functional disability, health-related quality of life (HRQoL). Associations were analyzed using multinomial logistic regression models.ResultsAmong 186 patients, 62 (33%) received preoperative analgesics, 186 (100%) postoperative analgesics, 81 (44%) regional anesthetic block, and 135 (73%) used a biobehavioral intervention. Patients were less likely to report worsened as compared to stable nervousness following regional anesthetic block (relative risk ratio [RRR]:0.31, 95% confidence interval [CI]:0.11–0.85), use of a biobehavioral technique (RRR:0.26, 95% CI:0.10–0.70), and both in combination (RRR:0.08, 95% CI:0.02–0.34). There were no associations of non-opioid pain control modalities with pain-related functional disability or HRQoL.ConclusionUse of postoperative non-opioid analgesics have been largely adopted, while preoperative non-opioid analgesics and regional anesthetic blocks are used less frequently. Regional anesthetic blocks and biobehavioral interventions may mitigate postoperative nervousness in children.Level of evidenceIII.  相似文献   
4.

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   
5.
认知障碍是指记忆、语言、理解和判断等一个或多个方面的功能障碍,包括轻度认知障碍和各种类型的痴呆症。痴呆症是认知障碍最严重的表现,是一种导致患者日常生活、社会交往和工作能力发生显著变化的综合征。阿尔茨海默病(AD)是最常见的痴呆症类型,其次是血管性痴呆(VD)和其他神经退行性痴呆[1]。已知年龄与认知功能的退化密切相关。  相似文献   
6.
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area.  相似文献   
7.
温婷  刘汉娇  易云霞 《全科护理》2022,20(2):199-202
综述女性压力性尿失禁(stress urinary incontinence,SUI)风险预测的研究进展。指出女性SUI风险预测相关文献普遍存在风险预测工具和指标缺乏临床大样本验证,指标、纳入人群不统一的现象,风险预测模型存在构建过程未按报告规范进行,未进行完整的模型验证以及模型性能评价指标不规范的情况。未来研究可以在现有风险预测工具或模型的基础上进行改进、完善,以期为女性SUI风险预测提供参考。  相似文献   
8.
Background and objectiveMinimally invasive surgery of benign middle ear tumours is possible by using the endoscope. The optimal lighting and the broadest vision it offers, allow a transcanal approach to these rare tumours. The objective of this work is to summarize its key points through a case series.Materials and methodsRetrospective study of benign middle ear tumours that underwent exclusive endoscopic surgery in a third-level adult university hospital between June 2018 and June 2020. Postoperative follow-up was performed by otoendoscopy and audiometry.ResultsSix patients underwent surgery during the study period. Five patients were female and one male, with an average age of 57.8 years (± 21.9). Four tumours were in the left ear and 2 in the right ear. These included 4 tympanic paragangliomas (3 type I and one type II), a chorda tympani neuroma, and a congenital cholesteatoma. There were no serious postoperative complications. At present, no tumour recurrence has been found in either case, with a minimum follow-up of 7 months.ConclusionsThe present study adds evidence on the safety and efficacy of endoscopic transcanal ear surgery, as a minimally invasive technique, for the treatment of benign middle ear tumours confined to the tympanic cavity.  相似文献   
9.
10.
ObjectiveNew-onset postoperative atrial fibrillation (POAF) after cardiac surgery is common, with rates up to 60%. POAF has been associated with early and late stroke, but its association with other cardiovascular outcomes is less known. The objective was to perform a meta-analysis of the studies reporting the association of POAF with perioperative and long-term outcomes in patients with cardiac surgery.MethodsWe performed a systematic review and a meta-analysis of studies that presented outcomes for cardiac surgery on the basis of the presence or absence of POAF. MEDLINE, EMBASE, and the Cochrane Library were assessed; 57 studies (246,340 patients) were selected. Perioperative mortality was the primary outcome. Inverse variance method and random model were performed. Leave-one-out analysis, subgroup analyses, and metaregression were conducted.ResultsPOAF was associated with perioperative mortality (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.58-2.33), perioperative stroke (OR, 2.17; 95% CI, 1.90-2.49), perioperative myocardial infarction (OR, 1.28; 95% CI, 1.06-1.54), perioperative acute renal failure (OR, 2.74; 95% CI, 2.42-3.11), hospital (standardized mean difference, 0.80; 95% CI, 0.53-1.07) and intensive care unit stay (standardized mean difference, 0.55; 95% CI, 0.24-0.86), long-term mortality (incidence rate ratio [IRR], 1.54; 95% CI, 1.40-1.69), long-term stroke (IRR, 1.33; 95% CI, 1.21-1.46), and longstanding persistent atrial fibrillation (IRR, 4.73; 95% CI, 3.36-6.66).ConclusionsThe results suggest that POAF after cardiac surgery is associated with an increased occurrence of most short- and long-term cardiovascular adverse events. However, the causality of this association remains to be established.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号