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   124篇
  免费   51篇
临床医学   97篇
内科学   72篇
神经病学   1篇
特种医学   1篇
外科学   2篇
药学   1篇
肿瘤学   1篇
  2023年   4篇
  2020年   9篇
  2019年   1篇
  2018年   16篇
  2017年   17篇
  2016年   6篇
  2015年   14篇
  2014年   10篇
  2013年   11篇
  2012年   7篇
  2011年   9篇
  2010年   8篇
  2009年   17篇
  2008年   3篇
  2007年   4篇
  2006年   4篇
  2005年   6篇
  2004年   2篇
  2003年   3篇
  2002年   4篇
  2001年   6篇
  2000年   3篇
  1999年   3篇
  1998年   1篇
  1997年   2篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
排序方式: 共有175条查询结果,搜索用时 46 毫秒
31.
Congenital coronary arteriovenous fistulas are rare anomalies. Patients may present with congestive heart failure, ischemic chest pain, or endocarditis. In this case, transesophageal echocardiography provided valuable additional information to that obtained from cardiac catheterization, which was essential for the diagnosis and planning of surgical correction.  相似文献   
32.
33.

Objective

Trans‐catheter (TC) pulmonary valve replacement (PVR) has become common practice for patients with right ventricular outflow tract obstruction (RVOTO) and/or pulmonic insufficiency (PI). Our aim was to compare PVR and right ventricular (RV) function of patients who received TC vs surgical PVR.

Design

Retrospective review of echocardiograms obtained at three time points: before, immediately after PVR, and most recent.

Patients

Sixty‐two patients (median age 19 years, median follow‐up 25 months) following TC (N = 32) or surgical (N = 30) PVR at Yale‐New Haven Hospital were included.

Outcome Measures

Pulmonary valve and right ventricular function before, immediately after, and most recently after PVR.

Results

At baseline, the TC group had predominant RVOTO (74% vs 10%, P < .001), and moderate‐severe PI was less common (61% vs 100%, P < .001). Immediate post‐procedural PVR function was good throughout. At last follow‐up, the TC group had preserved valve function, but the surgical group did not (moderate RVOTO: 6% vs 41%, P < .001; >mild PI: 0% vs 24%, P = .003). Patients younger than 17 years at surgical PVR had the highest risk of developing PVR dysfunction, while PVR function in follow‐up was similar in adults. Looking at RV size and function, both groups had a decline in RV size following PVR. However, while RV function remained stable in the TC group, there was a transient postoperative decline in the surgical group.

Conclusions

TC PVR in patients age <17 years is associated with better PVR function in follow‐up compared to surgical valves. There was a transient decline in RV function following surgical but not TC PVR. TC PVR should therefore be the first choice in children who are considered for PVR, whenever possible.  相似文献   
34.
35.
36.
Objective. There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range. Methods. Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Association's criteria and 23 age‐matched individuals as a control group with cognitive function within normal limits. Results. The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean ± SD, 0.67 ± 14) when compared with the control individuals (0.79 ± 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end‐diastolic diameter were significantly higher in the AD group (P ≤ 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time‐velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018). Conclusions. Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with age‐matched control individuals.  相似文献   
37.
Background  Apical hypertrophy cardiomyopathy (ACM) is a rare condition characterized by asymmetric myocardial hypertrophy of the apex of the left ventricle. When two-dimensional echocardiography is limited by a poor acoustic window, patients are often referred for MRI. Our hypothesis is that a cheaper and more widely available diagnostic modality like myocardial perfusion single photon emission computed tomography (SPECT) may be helpful in the diagnosis of ACM. Objective  The purpose of this prospective study was to define the characteristics of rest and stress SPECT studies in patients with known ACM, and whether SPECT may be helpful in the diagnosis of ACM. Methods  Adult patients with ACM were enrolled in the study. Diagnosis was made with 2-D echo. A rest and exercise or dipyridamole stress SPECT study was performed in all patients with Tc-99m sestamibi. Results  We enrolled 20 patients (mean age 60 ± 16 years), 9 were female, with ACM. SPECT at rest revealed in 15 patients (75%) an increased apical tracer uptake, a spade-like deformity of the left ventricular chamber, and the “Solar Polar” map pattern consistent with ACM. The sensitivity, specificity, positive predictive value, and negative predictive value of SPECT for detecting ACM were 75%, 100%, 100%, and 80%, respectively. Conclusion  Three-fourths of adult patients with ACM showed, on myocardial perfusion SPECT, characteristic findings which were not seen in age-matched control subjects, such as a significant increased apical tracer uptake, a spade-like deformity of the left ventricle, and the “Solar Polar” map. Nuclear physicians should be aware of these SPECT findings because many ACM patients may first end up in the nuclear labs due to their markedly abnormal ECG for exclusion of obstructive coronary artery disease. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. T. F. Cianciulli, M. C. Saccheri, and O. H. Masoli are researchers of the Secretary of Health, Government of the City of Buenos Aires.  相似文献   
38.
Traditionally, performing myocardial contrast echocardiography with OPTISON required maximal bolus dosing. However, sustained and consistent opacification of the myocardium would be preferable for perfusion imaging. METHODS: Images of 5 anesthetized dogs and 6 human volunteers were obtained with a second harmonic ultrasound system during bolus administration of OPTISON and 2 infusion techniques. One infusion technique used diluted OPTISON, and the other used the buoyant properties of OPTISON microspheres by placing the contrast agent between an infusion source and the intravenous site in a vertically oriented extension line (ELT). Myocardial intensities and in vitro microsphere characteristics were analyzed to assess the consistency of microsphere delivery over time. RESULTS: In addition to providing higher myocardial opacification intensity than diluted infusions, ELT infusions provided consistent microsphere concentration, phantom enhancement, and near-peak bolus-level myocardial opacification for 7 to 15 minutes. The myocardial intensity at 3 and 5 minutes in human subjects during ELT infusions (30 mL/h; 2.5 mL) was lower (220 arbitrary units [au] and 165 au, respectively) but not significantly different (P =.3 and.1, respectively) than the peak myocardial intensity (265 au) after bolus administration. CONCLUSION: This new ELT infusion method provides an acceptable alternative to bolus administration of OPTISON for prolonged myocardial opacification.  相似文献   
39.
Study Objective . To evaluate the effect of cimetidine, famotidine, ranitidine, and placebo on left ventricular systolic function, aerobic metabolic performance, and exercise capacity in patients with chronic, stable heart failure. Design . Double-blind, randomized, placebo-controlled, four-way crossover study. Setting . Outpatient, university-affiliated cardiology clinic. Patients . Twelve men with stable New York Heart Association class II or III heart failure secondary to ischemic heart disease or hypertension. Interventions . Patients received in random sequence cimetidine 400 mg twice/day, famotidine 40 mg/day, ranitidine 150 mg twice/day, and placebo. Each treatment was administered for 7 days, and the periods were separated by a 1-week washout. Measurements and Main Results . Before and after each treatment, patients underwent a bicycle stress echocardiogram with aerobic metabolic assessment. Left ventricular function was evaluated by calculating ejection phase indexes from Doppler echocardiographic measurements. All 12 patients successfully completed the study. No patient reported any adverse effect attributed to study drugs. None of the treatments was associated with significant changes in any measure of left ventricular systolic function, aerobic metabolic performance, or exercise capacity, nor were placebo-subtracted differences for the agents significantly different for any of the three measures.  相似文献   
40.
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