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   29075篇
  免费   971篇
  国内免费   176篇
耳鼻咽喉   180篇
儿科学   466篇
妇产科学   413篇
基础医学   974篇
口腔科学   295篇
临床医学   4447篇
内科学   2193篇
皮肤病学   53篇
神经病学   1110篇
特种医学   323篇
外国民族医学   1篇
外科学   16390篇
综合类   1280篇
一般理论   6篇
预防医学   495篇
眼科学   98篇
药学   1020篇
  12篇
中国医学   76篇
肿瘤学   390篇
  2024年   26篇
  2023年   1030篇
  2022年   1329篇
  2021年   1586篇
  2020年   1603篇
  2019年   883篇
  2018年   834篇
  2017年   804篇
  2016年   878篇
  2015年   768篇
  2014年   1702篇
  2013年   1299篇
  2012年   1344篇
  2011年   1271篇
  2010年   1165篇
  2009年   1116篇
  2008年   1005篇
  2007年   1049篇
  2006年   977篇
  2005年   946篇
  2004年   824篇
  2003年   806篇
  2002年   829篇
  2001年   711篇
  2000年   679篇
  1999年   717篇
  1998年   259篇
  1997年   225篇
  1996年   211篇
  1995年   210篇
  1994年   171篇
  1993年   133篇
  1992年   465篇
  1991年   460篇
  1990年   439篇
  1989年   374篇
  1988年   333篇
  1987年   177篇
  1986年   79篇
  1985年   63篇
  1984年   56篇
  1983年   43篇
  1982年   42篇
  1981年   49篇
  1980年   38篇
  1979年   27篇
  1978年   31篇
  1977年   20篇
  1976年   28篇
  1974年   16篇
排序方式: 共有10000条查询结果,搜索用时 421 毫秒
1.
2.
3.
A total of 15 leaflets from 5 failed conduits (group F) and 12 leaflets from 5 nonfailed conduits (group non-F) were evaluated. Macroscopic and histopathologic examination revealed 4 remarkable findings: proliferation of collagenous neointima, existence of lymphocytic inflammation, proteinaceous infiltration into the leaflet, and calcification of the leaflet. There was a significant correlation between appearance probability of calcification in group F and that of proteinaceous infiltration in group non-F, suggesting that proteinaceous infiltration into the leaflet seems to be responsible for leaflet calcification. Modification of the ePTFE material against proteinaceous infiltration may reduce the calcification, and therefore improve the durability of the ePTFE-valved conduit.
  1. Download : Download high-res image (161KB)
  2. Download : Download full-size image
  相似文献   
4.
5.
This study used the National Survey of Ambulatory Surgery (NSAS) database to measure the incidence of and risk factors for symptoms in the ambulatory surgery center and problems within 24 h after isolated carpal tunnel release (CTR). The NSAS contained records on 400,000 adult patients with carpal tunnel syndrome who were treated with CTR in 2006, based on ICD-9 codes. The type of anesthesia used and factors associated with symptoms and problems were sought in bivariate and multivariable statistical analyses. The mean duration of the procedure was 16 ± 8.8 min. Only 5 % were performed under local anesthesia without sedation, 45 % with IV sedation, 28 % regional anesthesia, and 19 % general anesthesia. Symptoms in the ambulatory surgery center or a problem within 24 h after discharge were recorded in 10 % of patients, all of them minor and transient, including difficulties with pain and its treatment. The strongest risk factors were male sex, age of 45 years and older, and participation of an anesthesiologist. Local anesthesia and regional anesthesia were associated with more perioperative symptoms and postoperative problems. Most CTR are performed with some sedation in the United States. CTR is a safe procedure: one in 10 patients will experience a minor issue in the perioperative or immediate postoperative period.  相似文献   
6.
7.
8.
BackgroundCoronary artery bypass grafting (CABG) improves survival in patients with heart failure and severely reduced left ventricular systolic function (LVEF). Limited data exist regarding adverse cardiovascular event rates after CABG in patients with heart failure with midrange ejection fraction (HFmrEF; LVEF > 40% and < 55%).MethodsWe analyzed data on isolated CABG patients from the Veterans Affairs national database (2010-2019). We stratified patients into control (normal LVEF and no heart failure), HFmrEF, and heart failure with reduced LVEF (HFrEF) groups. We compared all-cause mortality and heart failure hospitalization rates between groups with a Cox model and recurrent events analysis, respectively.ResultsIn 6533 veterans, HFmrEF and HFrEF was present in 1715 (26.3%) and 566 (8.6%) respectively; the control group had 4252 (65.1%) patients. HFrEF patients were more likely to have diabetes mellitus (59%), insulin therapy (36%), and previous myocardial infarction (31%). Anemia was more prevalent in patients with HFrEF (49%) as was a lower serum albumin (mean, 3.6 mg/dL). Compared with the control group, a higher risk of death was observed in the HFmrEF (hazard ratio [HR], 1.3 [1.2-1.5)] and HFrEF (HR, 1.5 [1.2-1.7]) groups. HFmrEF patients had the higher risk of myocardial infarction (subdistribution HR, 1.2 [1-1.6]; P = .04). Risk of heart failure hospitalization was higher in patients with HFmrEF (HR, 4.1 [3.5-4.7]) and patients with HFrEF (HR, 7.2 [6.2-8.5]).ConclusionsHeart failure with midrange ejection fraction negatively affects survival after CABG. These patients also experience higher rates myocardial infarction and heart failure hospitalization.  相似文献   
9.
目的 探讨丙泊酚复合瑞芬太尼喉罩全身麻醉(全麻)的效果。方法 62例腹腔镜、泌尿科、骨科、肛肠科、妇科等手术治疗的患者,随机分为实验组和对照组,每组31例。对照组采用常规气管插管静脉复合全麻,实验组给予靶控输注丙泊酚复合瑞芬太尼喉罩全麻。比较两组患者插入喉罩(插管)、插管1 min、插管3 min、拔出喉罩(拔管)1 min、拔管3 min时心率(HR)和平均动脉压(MAP)水平;不良反应发生情况、麻醉效果;全麻起效时间、维持全麻时间、术后苏醒时间。结果 实验组插管时、插管1 min、插管3 min、拔管1 min、拔管3 min的HR水平分别为(77.52±6.36)、(73.26±5.56)、(72.01±4.69)、(75.35±7.63)、(72.34±6.79)次/min,均低于对照组的(92.34±7.85)、(87.97±5.25)、(78.85±5.20)、(95.69±9.21)、(85.63±7.43)次/min,差异均具有统计学意义(P<0.05)。实验组插管时、插管1 min、插管3 min、拔管1 min、拔管3 min的MAP水平分别为(90.25±6.73)、(87.65±7.98)、(88.79±7.65)、(88.09±5.61)、(88.52±5.16)mm Hg(1 mm Hg=0.133 kPa),均低于对照组的(109.51±7.85)、(103.27±12.43)、(102.52±8.21)、(106.74±7.68)、(104.62±7.71)mm Hg,差异均具有统计学意义(P<0.05)。实验组不良反应发生率3.23%低于对照组的19.35%,差异具有统计学意义(P<0.05)。实验组麻醉总有效率96.77%均高于对照组的80.65%,差异均具有统计学意义(P<0.05)。实验组全麻起效、维持全麻、术后苏醒时间分别为(1.61±0.23)、(100.59±6.72)、(17.99±3.52)min,均短于对照组的(2.93±0.41)、(123.61±7.85)、(36.87±4.16)min,差异均具有统计学意义(P<0.05)。结论 针对腹腔镜等手术患者应用丙泊酚复合瑞芬太尼喉罩全麻对血液动力学影响小,不良反应发生率低,麻醉效果良好,降低对机体损伤,值得推广应用。  相似文献   
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