全文获取类型
收费全文 | 30704篇 |
免费 | 2108篇 |
国内免费 | 680篇 |
专业分类
耳鼻咽喉 | 201篇 |
儿科学 | 771篇 |
妇产科学 | 74篇 |
基础医学 | 1446篇 |
口腔科学 | 31篇 |
临床医学 | 5547篇 |
内科学 | 13192篇 |
皮肤病学 | 38篇 |
神经病学 | 639篇 |
特种医学 | 1014篇 |
外科学 | 3065篇 |
综合类 | 4170篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 454篇 |
眼科学 | 33篇 |
药学 | 2037篇 |
11篇 | |
中国医学 | 640篇 |
肿瘤学 | 126篇 |
出版年
2024年 | 45篇 |
2023年 | 486篇 |
2022年 | 762篇 |
2021年 | 1196篇 |
2020年 | 1134篇 |
2019年 | 1251篇 |
2018年 | 1162篇 |
2017年 | 748篇 |
2016年 | 671篇 |
2015年 | 879篇 |
2014年 | 1982篇 |
2013年 | 1815篇 |
2012年 | 1315篇 |
2011年 | 1564篇 |
2010年 | 1361篇 |
2009年 | 1271篇 |
2008年 | 1466篇 |
2007年 | 1528篇 |
2006年 | 1303篇 |
2005年 | 1222篇 |
2004年 | 997篇 |
2003年 | 900篇 |
2002年 | 793篇 |
2001年 | 817篇 |
2000年 | 662篇 |
1999年 | 656篇 |
1998年 | 601篇 |
1997年 | 597篇 |
1996年 | 483篇 |
1995年 | 418篇 |
1994年 | 401篇 |
1993年 | 328篇 |
1992年 | 330篇 |
1991年 | 311篇 |
1990年 | 260篇 |
1989年 | 202篇 |
1988年 | 197篇 |
1987年 | 194篇 |
1986年 | 172篇 |
1985年 | 167篇 |
1984年 | 184篇 |
1983年 | 126篇 |
1982年 | 124篇 |
1981年 | 83篇 |
1980年 | 74篇 |
1979年 | 72篇 |
1978年 | 55篇 |
1977年 | 31篇 |
1976年 | 36篇 |
1973年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
Dynamic LVOT Obstruction and Aortic Stenosis in the Same Patient: A Case of Challenging Doppler Hemodynamics
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Matthew W. Parker M.D. Francis J. Kiernan M.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1030-1032
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction. 相似文献
9.
Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
10.
《Journal of Cardiovascular Computed Tomography》2020,14(4):363-369
BackgroundData on left ventricular (LV) deformation imaging using CT angiography (CTA) are scarce and the feasibility of atrial deformation analysis by CT has not been addressed. We aimed to compare 2D echocardiographic and CT derived LV and left atrial (LA) global longitudinal strain (GLS) obtained by using a novel feature tracking algorithm in patients following transcatheter aortic valve implantation.MethodsTwenty-eight patients were included who underwent retrospectively-gated 256-slice CTA and speckle-tracking echocardiography (STE) on the same day. CT datasets in 10% increments were reconstructed throughout the cardiac cycle. LV GLS and LA global peak reservoir strain (LA GS) was measured.ResultsMedian absolute values for LV GLS were 19.9 [14.8–22.4] vs. 19.9 [16.8–24.7], as measured by CT vs STE, respectively (p = 0.017). We found good inter-modality correlation for LV GLS (ρ = 0.78, p < 0.05) with a mean bias of −1.6. Regarding atrial measurements, the median LA GS was 19.0 [13.5–27.3] for CT vs. 28.0 [17.5–32.6] for STE (p < 0.001) with a mean bias of −5.6 between CT and STE and a correlation coefficient of ρ = 0.87, p < 0.001. CT measurements were highly reproducible: intra-observer intra-class correlation coefficient was 0.96 for LV GLS and 0.95 for LA GS.ConclusionWe detected good correlation between CTA and echocardiography-based LV and LA longitudinal strain parameters. CTA provides accurate strain measurements with high reproducibility. Feature tracking-based deformation analysis could provide a clinically important addition to CT examinations by complementing anatomical information with functional data. 相似文献