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   47508篇
  免费   3667篇
  国内免费   1616篇
耳鼻咽喉   141篇
儿科学   476篇
妇产科学   199篇
基础医学   2616篇
口腔科学   744篇
临床医学   6375篇
内科学   18906篇
皮肤病学   411篇
神经病学   1438篇
特种医学   2059篇
外国民族医学   3篇
外科学   2805篇
综合类   8568篇
预防医学   1474篇
眼科学   187篇
药学   3733篇
  44篇
中国医学   1913篇
肿瘤学   699篇
  2023年   785篇
  2022年   1133篇
  2021年   2077篇
  2020年   2045篇
  2019年   1612篇
  2018年   1619篇
  2017年   1469篇
  2016年   1516篇
  2015年   1604篇
  2014年   3393篇
  2013年   3356篇
  2012年   2775篇
  2011年   3037篇
  2010年   2421篇
  2009年   2253篇
  2008年   2420篇
  2007年   2550篇
  2006年   2168篇
  2005年   1893篇
  2004年   1504篇
  2003年   1304篇
  2002年   1076篇
  2001年   988篇
  2000年   730篇
  1999年   599篇
  1998年   599篇
  1997年   581篇
  1996年   431篇
  1995年   544篇
  1994年   437篇
  1993年   429篇
  1992年   348篇
  1991年   336篇
  1990年   254篇
  1989年   245篇
  1988年   237篇
  1987年   211篇
  1986年   167篇
  1985年   252篇
  1984年   235篇
  1983年   152篇
  1982年   173篇
  1981年   156篇
  1980年   141篇
  1979年   107篇
  1978年   77篇
  1977年   84篇
  1976年   81篇
  1975年   47篇
  1973年   43篇
排序方式: 共有10000条查询结果,搜索用时 31 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.
BackgroundRecent guidelines for the treatment of moderate or severe ischemic mitral regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) have changed. This study assessed the real-world impact of changing guidelines on the management of IMR during CABG over time. We hypothesized that the utilization of mitral valve repair for IMR would decrease over time, whereas mitral valve replacement for severe IMR would increase.MethodsPatients undergoing CABG in a statewide collaborative database (2011-2020) were stratified by severity of IMR. Trends in mitral valve repair or replacement were evaluated. To account for differences of the patients, propensity score–matched analyses were used to compare patients with and without mitral intervention.ResultsA total of 11,676 patients met inclusion criteria, including 1355 (11.6%) with moderate IMR and 390 (3.3%) with severe IMR. The proportion of patients undergoing mitral intervention for moderate IMR decreased over time (2011, 17.7%; 2020, 7.5%; Ptrend = .001), whereas mitral replacement for severe IMR remained stable (2011, 11.1%; 2020, 13.3%; Ptrend = .14). Major morbidity was higher for patients with moderate IMR who underwent mitral intervention (29.1% vs 19.9%; P = .005). In a propensity analysis of 249 well-matched pairs, there was no difference in major morbidity (29.3% with mitral intervention vs 23.7% without; P = .16) or operative mortality (1.2% vs 2.4%; P = .5).ConclusionsConsistent with recent guideline updates, patients with moderate IMR were less likely to undergo mitral repair. However, the rate of replacement for severe IMR did not change. Mitral intervention during CABG did not increase operative mortality or morbidity.  相似文献   
3.
BackgroundInflammation surrounding the coronary arteries can be non-invasively assessed using pericoronary adipose tissue attenuation (PCAT). While PCAT holds promise for further risk stratification of patients with low coronary artery disease (CAD) prevalence, its value in higher risk populations remains unknown.MethodsCORE320 enrolled patients referred for invasive coronary angiography with known or suspected CAD. Coronary computed tomography angiography (CCTA) images were collected for 381 patients for whom clinical outcomes were assessed 5 years after enrollment. Using semi-automated image analysis software, PCAT was obtained and normalized for the right coronary (RCA), left anterior descending (LAD), and left circumflex arteries (LCx). The association between PCAT and major adverse cardiovascular events (MACE) during follow up was assessed using Cox regression models.ResultsThirty-seven patients were excluded due to technical failure. For the remaining 344 patients, median age was 62 (interquartile range, 55–68) with 59% having ≥1 coronary artery stenosis of ≥50% by quantitative coronary angiography. Mean attenuation values for PCAT in RCA, LAD, and LCx were ?74.9, ?74.2, and ?71.2, respectively. Hazard ratios and 95% confidence intervals (CI) for normalized PCAT in the RCA, LAD, and LCx for MACE were 0.96 (CI: 0.75–1.22, p ?= ?0.71), 1.31 (95% CI: 0.96–1.78, p ?= ?0.09), and 0.98 (95% CI: 0.78–1.22, p ?= ?0.84), respectively. For death, stroke, or myocardial infarction only, hazard ratios were 0.68 (0.44–1.07), 0.85 (0.56–1.29), and 0.57 (0.41–0.80), respectively.ConclusionsIn patients referred for invasive coronary angiography with suspected CAD, PCAT did not predict MACE during long term follow up. Further studies are needed to understand the relationship of PCAT with CAD risk.  相似文献   
4.
Breast core biopsies are a standard component of the triple approach that includes clinical examination, imaging and tissue sampling. Conventional cores, diagnostic vacuum assisted biopsy and vacuum assisted excisions are established methods for sampling and managing breast lesions. It is important to be aware of the potential pitfalls in the technical handling and interpretation of the limited core biopsy samples. Here, we present a clinically oriented, well illustrated overview of the common diagnostic pitfalls based on the author's diagnostic and second opinion practice, emphasize the value of clinicopathological correlation and provide histological tips and clues with useful immunohistochemistry to aid the reporting pathologists in their daily interpretation of breast core biopsies.  相似文献   
5.
Acute coronary syndrome (ACS) remains one of the leading causes of death in the United States. With its heightened prevalence, considerable variabilities in the disease process exist across ethnicities, sex, and age. This creates substantial disparities in the recognition and management of ACS, which consequently contributes to poor outcomes. It is of utmost importance that nurse practitioners remain vigilant, cognizant, and maintain a high index of suspicion to accurately identify ACS presentations and thus efficaciously intervene to successfully manage the disease process.  相似文献   
6.
目的 探讨应用EBU系列指引导管行右冠状动脉复杂病变介入治疗( PCI) 的可行性。 方法 前瞻性分析2020年1月至2021年12月首都医科大学附属北京友谊医院及平谷区医院心内科应用EBU指引导管介入治疗右冠状动脉复杂病变25例患者的临床资料、 影像资料和术后恢复情况,对该技术的可行性和安全性进行评价。 结果 25例患者经冠状动脉造影确诊为冠心病,且均存在右冠状动脉复杂病变,有对右冠状动脉行PCI的指征。所有患者均经桡动脉入路使用EBU指引导管行PCI。25例患者的EBU指引导管全部输送到位,经调整进入右冠状动脉开口,EBU导管使用的成功率为100%。25例患者全部行右冠状动脉PCI,24例成功,PCI成功率为96%,无患者出现指引导管相关并发症。结论 经桡动脉应用EBU指引导管行右冠PCI具有很好的可行性和安全性,可作为部分经选择患者行右冠复杂病变PCI的首选方法。  相似文献   
7.
目的:分析我院2020年1月1日至2020年9月中旬近4万余例女性HPV感染情况,为HPV疫苗接种、宫颈病变预防、治疗、随访提供流行病学数据。方法:选取我院2020年1月1日至2020年9月中旬之间,于我院妇科门诊及病房、皮肤科门诊及体检中心的37 325接受HPV分型检测的患者的临床资料,分析检测结果。结果:HPV感染率为13.91%(5 193/37 325),单一感染率11.46%(4 276/37 325),阳性构成比82.34%(4 276/5 193),高危亚型感染以HPV16最多见,其次52、58,低危型以6最多见,其次为11、44,与5年前HPV感染情况分析中最常见的低危亚型为cp8304不同。不同年龄段感染率不同。结论:近年沈阳地区妇女HPV感染率为13.91%,较5年前感染率18.60%有所下降,以单一、高危亚型感染为主,多重感染并存为特征。  相似文献   
8.
Vascular injuries that occur during traffic accidents are a commonly neglected aspect that can add more detail to the framework of a case. In this study, we analysed a case series of 150 traffic accidents, 39 of which were marked by microscopically identifiable vascular lesions. The purpose was to identify the presence of carotid injuries in individuals who died due to traffic accidents and had nonpenetrating trauma of the neck. We focused on the discrepancies regarding the macroscopical aspect and the histology and demonstrated how histological analysis of the carotids in cases of trauma can reveal injuries that are attributable to the trauma itself. We conducted a histological analysis of the lesions to describe their distribution and type and investigate potential correlations. The study offers insight on how to examine road accidents that involve traumatic injury of the carotid arteries. Indeed the main task of the forensic pathologist in the case of death is to establish the existence of a causal relationship between the micro- or macroscopic alterations observed in the autopsy and the traumatic event that led to the death of the subject. Thus, further morphological elements were provided to the forensic practitioners that may reveal injuries attributable to the trauma itself and should be evaluated in cases of trauma in traffic accidents.  相似文献   
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