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   208721篇
  免费   18394篇
  国内免费   6107篇
耳鼻咽喉   1447篇
儿科学   4011篇
妇产科学   2197篇
基础医学   28117篇
口腔科学   4648篇
临床医学   20783篇
内科学   26446篇
皮肤病学   2169篇
神经病学   11369篇
特种医学   4847篇
外国民族医学   26篇
外科学   16999篇
综合类   30676篇
现状与发展   15篇
一般理论   27篇
预防医学   18778篇
眼科学   4846篇
药学   25336篇
  42篇
中国医学   12805篇
肿瘤学   17638篇
  2023年   2810篇
  2022年   3773篇
  2021年   7062篇
  2020年   6823篇
  2019年   7161篇
  2018年   7090篇
  2017年   6838篇
  2016年   6767篇
  2015年   6686篇
  2014年   11750篇
  2013年   12886篇
  2012年   10740篇
  2011年   12221篇
  2010年   10236篇
  2009年   9996篇
  2008年   10410篇
  2007年   11485篇
  2006年   10422篇
  2005年   10019篇
  2004年   8676篇
  2003年   7769篇
  2002年   5780篇
  2001年   5606篇
  2000年   4628篇
  1999年   4177篇
  1998年   2858篇
  1997年   2684篇
  1996年   2633篇
  1995年   2726篇
  1994年   2370篇
  1993年   2110篇
  1992年   1886篇
  1991年   1638篇
  1990年   1419篇
  1989年   1299篇
  1988年   1257篇
  1987年   976篇
  1986年   768篇
  1985年   903篇
  1984年   921篇
  1983年   581篇
  1982年   731篇
  1981年   607篇
  1980年   528篇
  1979年   449篇
  1978年   351篇
  1977年   306篇
  1976年   335篇
  1975年   220篇
  1973年   174篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.  相似文献   
2.
3.
A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on modal energy coefficients is proposed to detect troubled cells, where discontinuities exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR method. Numerical investigations show that the proposed subcell limiting strategy on unstructured quadrilateral meshes is robust in shock-capturing.  相似文献   
4.
目的:探讨ICU护士执行身体约束缩减行动的障碍因素,为制定身体约束标准化管理方案提供依据。方法:基于理论域框架(TDF)制定访谈提纲,采用目的抽样法对天津市某三级甲等医院的12名ICU护士进行半结构式访谈,按照TDF的相关领域对转录后的资料进行归类,用内容分析法对访谈资料进行分析。结果:ICU护士对身体约束缩减行动理解存在偏差、对约束替代措施内容的不熟悉是其执行身体约束缩减行动的障碍因素之一;身体约束缩减方案评估工具、决策流程的不规范对缩减约束行动的开展造成了一定阻碍;环境因素的限制及对缩减约束结果的担忧,使ICU护士没有足够的信心去执行;科室缺乏支持缩减约束的组织氛围,难以引起护士对执行约束缩减行动的重视,进而削减执行的动力。结合理论域框架将上述因素分别归属为知识、自我效能、环境背景和资源、社会影响、行为规范5个领域。结论:知识、自我效能、环境背景和资源、社会影响及行为规范为ICU护士执行身体约束缩减行动的障碍因素。科室要在明确障碍因素的基础上,加强领导层对执行缩减约束的重视和支持。制定缩减约束评估决策规范化流程以及培训方案,倡导团队协作,创造支持身体约束缩减行动的组织氛围,坚定ICU护士执行缩减约束的信心,促进身体约束缩减行动的持续实施。  相似文献   
5.
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations.  相似文献   
6.
BackgroundDespite high rate of cure in acute promyelocytic leukemia (APL) in clinical trials, outcomes in real-world practice are dismal. We utilized National Cancer Database (NCDB) to explore utilization of multiagent therapy in APL and identify any disparities in treatment in real-world practices.Patients and MethodsNCDB categorizes use of systemic chemotherapy into single agent versus multiagent therapy. Some patients received hormonal therapy, immunotherapy, and unknown therapy; details of these treatments could not be ascertained. We therefore used multiple logistic regression analysis to evaluate effects of covariates on the probability of multiagent therapy use in 6678 patients.ResultsCompared to patients >60 years, patients aged 0 to 18 years (hazard ratio[HR] 3.2, 95% confidence interval [CI] 1.8-5.5, P< .0001), 19 to 40 years (HR 1.6, 95% CI 1.03-2.54, P= .03), and 41 to 60 years (HR 1.6, 95% CI 1.3-1.9, P< .0001) were more likely to receive multiagent therapy. Patients with Charlson comorbidity index (CCI) of 0 (HR 1.6, 95% CI 1.2-2.3, P= .001) and CCI of 1 (HR 1.4, 95% CI 1.0-1.9, P= .04) had a higher likelihood of receiving multiagent therapy than patients with CCI ≥ 3. Patients treated at academic cancer centers, compared to those treated at community cancer center (HR 0.5, 95% CI 0.3-0.7, P= .001), comprehensive community cancer center (HR 0.7, 95% CI 0.6-0.8, P< .0001), and integrated network cancer center (HR 0.8, 95% CI 0.6-0.9, P= .02) were more likely to be treated with multiagent therapy. Compared to the patients with private insurance, those with Medicaid had increased likelihood (HR 1.2, 95% CI 1.0-1.4, P= .04) whereas uninsured patients had a lower likelihood of receiving multiagent therapy (HR 0.6, 95% CI 0.5-0.8, P= .0005).ConclusionTo our knowledge, this study is the first and the largest scale analysis of treatment practices in APL in real-world practices. Our findings highlight significant disparities in treatment of APL based on age, insurance, and health-system factors.  相似文献   
7.
8.
9.
10.
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