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   6642篇
  免费   491篇
  国内免费   707篇
耳鼻咽喉   3篇
儿科学   52篇
妇产科学   17篇
基础医学   815篇
口腔科学   44篇
临床医学   870篇
内科学   3043篇
皮肤病学   7篇
神经病学   369篇
特种医学   286篇
外科学   274篇
综合类   1114篇
预防医学   239篇
眼科学   4篇
药学   456篇
  5篇
中国医学   225篇
肿瘤学   17篇
  2024年   4篇
  2023年   47篇
  2022年   121篇
  2021年   211篇
  2020年   172篇
  2019年   128篇
  2018年   165篇
  2017年   211篇
  2016年   216篇
  2015年   239篇
  2014年   660篇
  2013年   508篇
  2012年   426篇
  2011年   565篇
  2010年   438篇
  2009年   430篇
  2008年   513篇
  2007年   416篇
  2006年   363篇
  2005年   331篇
  2004年   252篇
  2003年   212篇
  2002年   179篇
  2001年   127篇
  2000年   117篇
  1999年   93篇
  1998年   87篇
  1997年   70篇
  1996年   73篇
  1995年   70篇
  1994年   73篇
  1993年   47篇
  1992年   44篇
  1991年   35篇
  1990年   21篇
  1989年   18篇
  1988年   16篇
  1987年   17篇
  1986年   16篇
  1985年   25篇
  1984年   10篇
  1983年   6篇
  1982年   4篇
  1981年   13篇
  1980年   11篇
  1979年   10篇
  1978年   11篇
  1977年   4篇
  1974年   3篇
  1969年   3篇
排序方式: 共有7840条查询结果,搜索用时 31 毫秒
1.
2.
社区动脉粥样硬化风险(ARIC)研究是1987年由美国心、肺和血液研究所资助的关注非洲裔美国人心血管健康的最大研究。旨在调查心脏病的危险因素以及心血管疾病与认知之间的联系。ARIC研究的许多发现加深了对动脉粥样硬化性心血管病病因的了解,在心血管病预防领域做出了重大贡献,证明了以人群为基础的研究对改善健康和预防疾病的重要性。主要概述ARIC研究的起源、目的、研究设计、对心血管医学的贡献以及未来的发展方向。  相似文献   
3.
4.
目的 分析内囊预警综合征(capsular warning syndrome,CWS)的临床特点、影像学特征及治疗预后,
以提高对此病的认识。
方法 回顾性分析战略支援部队特色医学中心神经内科2013年1月-2018年12月收住院治疗的CWS的
临床资料、影像学特征及治疗预后情况。
结果 共12例患者,男性8例(66.67%),中位年龄为60岁。高脂血症9例(75.0%),高血压8例
(66.67%),糖尿病4例(33.33%),肿瘤病史3例(25.0%)。纯运动性卒中4例(33.33%),运动伴有构
音障碍者4例(33.33%),运动及感觉性障碍3例(25.00%),纯感觉障碍1例(8.33%)。影像学示豆纹
动脉供血区新发脑梗死6例(50%)。所有患者给予口服双联抗血小板治疗,其中3例症状复发患者又
给予静脉溶栓和静脉抗血小板治疗。3个月随访,所有患者均未再出现症状发作,10例mRS评分为0
分,2例mRS评分分别为4分及3分。
结论 CWS主要表现为运动障碍,发作刻板,常见原因为动脉粥样硬化性。在本组病例中发现双重
抗血小板治疗有效,静脉溶栓效果不肯定。  相似文献   
5.
BackgroundCompared with invasive fractional flow reserve (FFR), coronary CT angiography (cCTA) is limited in detecting hemodynamically relevant lesions. cCTA-based FFR (CT-FFR) is an approach to overcome this insufficiency by use of computational fluid dynamics. Applying recent innovations in computer science, a machine learning (ML) method for CT-FFR derivation was introduced and showed improved diagnostic performance compared to cCTA alone. We sought to investigate the influence of stenosis location in the coronary artery system on the performance of ML-CT-FFR in a large, multicenter cohort.MethodsThree hundred and thirty patients (75.2% male, median age 63 years) with 502 coronary artery stenoses were included in this substudy of the MACHINE (Machine Learning Based CT Angiography Derived FFR: A Multi-Center Registry) registry. Correlation of ML-CT-FFR with the invasive reference standard FFR was assessed and pooled diagnostic performance of ML-CT-FFR and cCTA was determined separately for the following stenosis locations: RCA, LAD, LCX, proximal, middle, and distal vessel segments.ResultsML-CT-FFR correlated well with invasive FFR across the different stenosis locations. Per-lesion analysis revealed improved diagnostic accuracy of ML-CT-FFR compared with conventional cCTA for stenoses in the RCA (71.8% [95% confidence interval, 63.0%–79.5%] vs. 54.8% [45.7%–63.8%]), LAD (79.3 [73.9–84.0] vs. 59.6 [53.5–65.6]), LCX (84.1 [76.0–90.3] vs. 63.7 [54.1–72.6]), proximal (81.5 [74.6–87.1] vs. 63.8 [55.9–71.2]), middle (81.2 [75.7–85.9] vs. 59.4 [53.0–65.6]) and distal stenosis location (67.4 [57.0–76.6] vs. 51.6 [41.1–62.0]).ConclusionIn a multicenter cohort with high disease prevalence, ML-CT-FFR offered improved diagnostic performance over cCTA for detecting hemodynamically relevant stenoses regardless of their location.  相似文献   
6.
7.
《Drug discovery today》2022,27(10):103317
  1. Download : Download high-res image (137KB)
  2. Download : Download full-size image
  相似文献   
8.
Objective: Hesperidin, an abundant flavonoid in citrus fruit, and its aglycone, hesperetin, have been reported to possess various physiological activities, including antioxidant, anti-inflammatory, hypolipidemic, and antihypertensive activities. In this study, we investigated whether α-glucosyl hesperidin and water-dispersible hesperetin have protective effects on atherosclerotic progression in apolipoprotein E knockout (Apo-E KO) mice.

Methods: Ten-week-old male Apo-E KO mice were randomly assigned a regular high-fat diet, a high-fat diet with 0.5% α-glucosyl hesperidin, or a high-fat diet with 0.1% water-dispersible hesperetin for 12?weeks. Measurement of plasma total cholesterol levels, histological staining of aortic root, and immunohistochemistry for macrophages were performed to evaluate atherosclerotic plaque formation. Vascular reactivity of mouse aortic rings was also measured.

Results: Both α-glucosyl hesperidin and water-dispersible hesperetin reduced plasma total cholesterol level. They also reduced plaque formation area, adipose deposition, and macrophage infiltration into atherosclerotic lesion. Vascular-endothelium-dependent relaxation in response to acetylcholine was improved in both experimental diet groups compared to the high-fat diet group.

Conclusions: Our study suggests that both α-glucosyl hesperidin and water-dispersible hesperetin exert protective effects on atherosclerotic progression in Apo-E KO mice because they exhibit hypolipidemic activity, reduce inflammation through macrophages, and prevent endothelial dysfunction.  相似文献   

9.
BackgroundTrial and observational evidence is conflicting in terms of the association of blood lipids, atherosclerosis and statin use with dementia and cognitive impairment in the general population. It is uncertain whether the associations occur in stroke patients, who are at known higher risk of cognitive decline. This systematic review was to synthesize the evidence for these associations among stroke patients.MethodsMEDLINE, EMBASE, the Cochrane Library and trial registries were searched. We included randomized controlled trials (RCTs) or observational cohort studies conducted among patients with stroke and reported on the association of blood lipids, atherosclerosis or statin use with dementia or cognitive impairment. Meta-analysis was conducted separately for crude and maximally adjusted odds ratios (ORs) and hazard ratios (HRs).ResultsOf 18,026 records retrieved, 56 studies (one RCT and 55 cohort studies) comprising 38,423 stroke patients were included. For coronary heart disease, the pooled OR of dementia and cognitive impairment was 1.32 (95%CI 1.10–1.58, n = 15 studies, I2 = 0%) and 1.23 (95%CI 0.99–1.54, n = 14, I2 = 26.9%), respectively. Peripheral artery disease was associated with dementia (OR 3.59, 95%CI 1.47–8.76, n = 2, I2 = 0%) and cognitive impairment (OR 2.70, 95%CI 1.09–6.69, n = 1). For carotid stenosis, the pooled OR of dementia and cognitive impairment was 2.67 (95%CI 0.83–8.62, n = 3, I2 = 77.9%) and 3.34 (95%CI 0.79–14.1, n = 4, I2 = 96.6%), respectively. For post-stroke statin use, the pooled OR of dementia and cognitive impairment was 0.89 (95%CI 0.65–1.21, n = 1) and 0.56 (95%CI 0.46-0.69, n = 3, I2 = 0%), respectively. No association was observed for hypercholesterolemia. These results were mostly consistent with adjusted ORs or HRs, which were reported from limited evidence.ConclusionAtherosclerosis was associated with an increased risk of post-stroke dementia. Post-stroke statin use was associated with decreased risk of cognitive impairment. To confirm whether or not statins confer advantages in the post-stroke population in terms of preventing cognitive decline over and above their known effectiveness in reducing risk of further vascular events, further stroke trials including cognitive assessment and observational analyses adjusted for key confounders, focusing on key subgroups or statin use patterns are required.  相似文献   
10.
徐子奇 《中国卒中杂志》2020,15(10):1123-1127
中国是颅内动脉粥样硬化疾病的高发地区,多种危险因素与之有关。前后循环颅内动脉 狭窄/闭塞在危险因素分布上存在一定的差异性,同时后循环动脉的解剖结构具有自身独特的特点且 具有较多的解剖变异性。本综述回顾了基于颅内动脉粥样硬化的Mori分型、LMA分型,并对复杂后循 环颅内段动脉粥样硬化性病变进行了临床定义。由于复杂后循环颅内段动脉粥样硬化性病变药物治 疗效果往往不佳,卒中复发率高,同时血管内治疗又较困难,因此,本文从解剖结构、危险因素、卒中 病理生理特点、侧支循环、影像学评估及临床治疗进展多个方面对复杂后循环病变进行了综述。  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