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   26943篇
  免费   2357篇
  国内免费   1335篇
耳鼻咽喉   252篇
儿科学   406篇
妇产科学   340篇
基础医学   2656篇
口腔科学   322篇
临床医学   2714篇
内科学   5093篇
皮肤病学   404篇
神经病学   1658篇
特种医学   1091篇
外国民族医学   11篇
外科学   3515篇
综合类   4965篇
现状与发展   6篇
预防医学   565篇
眼科学   1257篇
药学   2680篇
  11篇
中国医学   1370篇
肿瘤学   1319篇
  2024年   73篇
  2023年   407篇
  2022年   688篇
  2021年   967篇
  2020年   958篇
  2019年   893篇
  2018年   865篇
  2017年   837篇
  2016年   939篇
  2015年   1034篇
  2014年   1658篇
  2013年   1935篇
  2012年   1527篇
  2011年   1644篇
  2010年   1470篇
  2009年   1401篇
  2008年   1486篇
  2007年   1489篇
  2006年   1444篇
  2005年   1308篇
  2004年   1110篇
  2003年   962篇
  2002年   847篇
  2001年   674篇
  2000年   607篇
  1999年   453篇
  1998年   383篇
  1997年   317篇
  1996年   292篇
  1995年   276篇
  1994年   211篇
  1993年   173篇
  1992年   166篇
  1991年   169篇
  1990年   107篇
  1989年   100篇
  1988年   92篇
  1987年   94篇
  1986年   72篇
  1985年   90篇
  1984年   71篇
  1983年   45篇
  1982年   53篇
  1981年   73篇
  1980年   36篇
  1979年   37篇
  1978年   30篇
  1977年   21篇
  1976年   15篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Valvular heart disease affects patients of all ages, with the highest incidence in patients older than 75 years. The nurse practitioner, whether in the primary or acute care setting, plays a vital role in the detection, monitoring, and shared decisions in treatment options. Assessment skills in conjunction with appropriate testing can identify patients early in the trajectory of the disease. The purpose of this article is to provide tips for history-taking and physical exam techniques, identify appropriate diagnostic testing, and review treatment options for adults with valvular heart disease.  相似文献   
2.
3.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
4.
5.
Central illustration: cumulative major adverse cardiac events (MACE) and bioresorbable vascular scaffold (BVS) thrombosis rates after 1, 2, 3, 4 and 5 years.
  相似文献   
6.
7.
8.
9.
Purpose: To describe how central venous access devices (CVADs) are utilized for ambulatory oncology patients and to evaluate the rate of complications. Method: Single institution retrospective study of oncology patients with CVADs who received systemic treatment at the Walker Family Cancer Centre (WFCC) between 1 January and 31 December 2018. Results: A total of 480 CVADS were placed in 305 patients, of which 408 (85%) were peripherally inserted central catheters (PICCs) and 72 (15%) were implanted vascular access devices (PORTs). The incidence of early and late complications was 9% and 24%, respectively. For the entire cohort, the rate of venous thromboembolism (VTE) was 16%, of which 9% were CVAD-related thrombosis (CRTs) and 7% were distant VTE. The CRT rates were similar for PICCs and PORTs (9% vs. 7%). A total of 6% of CVADs were complicated by infection (i.e., localized infections and bacteremia), with a total infection rate of 0.43 and 0.26 per 1000 indwelling days for PICCs and PORTs, respectively. The incidence of central line associated bloodstream infections (CLABSI) was greater for PICCs than PORTs, at a rate of 0.22 compared with 0.08 per 1000 indwelling days, respectively. The premature catheter removal rate was 26% for PICCs and 18% for PORTs. PORTs required more additional hospital visits. Conclusions: PICCs were utilized more frequently than PORTs and had a higher rate of premature removal. The rates of VTE and CRT were similar for both CVAD types. PORTs had a lower rate of infection per 1000 indwelling days. However, the management of PORT related complications required more visits to the hospital and oncology clinic.  相似文献   
10.
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.  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