全文获取类型
收费全文 | 5967篇 |
免费 | 554篇 |
国内免费 | 110篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 142篇 |
妇产科学 | 30篇 |
基础医学 | 301篇 |
口腔科学 | 3篇 |
临床医学 | 936篇 |
内科学 | 2626篇 |
皮肤病学 | 4篇 |
神经病学 | 197篇 |
特种医学 | 212篇 |
外国民族医学 | 2篇 |
外科学 | 919篇 |
综合类 | 647篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 249篇 |
眼科学 | 9篇 |
药学 | 192篇 |
1篇 | |
中国医学 | 101篇 |
肿瘤学 | 52篇 |
出版年
2024年 | 5篇 |
2023年 | 137篇 |
2022年 | 148篇 |
2021年 | 284篇 |
2020年 | 325篇 |
2019年 | 357篇 |
2018年 | 322篇 |
2017年 | 247篇 |
2016年 | 188篇 |
2015年 | 211篇 |
2014年 | 438篇 |
2013年 | 371篇 |
2012年 | 257篇 |
2011年 | 323篇 |
2010年 | 236篇 |
2009年 | 255篇 |
2008年 | 294篇 |
2007年 | 282篇 |
2006年 | 225篇 |
2005年 | 227篇 |
2004年 | 198篇 |
2003年 | 161篇 |
2002年 | 131篇 |
2001年 | 110篇 |
2000年 | 69篇 |
1999年 | 77篇 |
1998年 | 75篇 |
1997年 | 71篇 |
1996年 | 56篇 |
1995年 | 67篇 |
1994年 | 40篇 |
1993年 | 53篇 |
1992年 | 50篇 |
1991年 | 45篇 |
1990年 | 39篇 |
1989年 | 33篇 |
1988年 | 31篇 |
1987年 | 29篇 |
1986年 | 24篇 |
1985年 | 27篇 |
1984年 | 24篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1974年 | 4篇 |
排序方式: 共有6631条查询结果,搜索用时 183 毫秒
1.
《介入医学杂志(英文)》2022,5(4):196-199
ObjectiveThis study aimed to analyze and evaluate the results of mid-term follow-up after fetal pulmonary valvuloplasty (FPV) in fetuses with pulmonary atresia with intact ventricular septum (PA/IVS).MethodsFrom August 31, 2018, to May 31, 2019, seven fetuses with PA/IVS and hypoplastic right heart were included in this study. All underwent echocardiography by the same specialist and were operated on by the same team. Intervention and echocardiography data were collected, and changes in the associated indices noted during follow-up were analyzed.ResultsAll seven fetuses successfully underwent FPV. The median gestational age at FPV was 27.54 weeks. The average FPV procedural time was 6 ?min. Persistent bradycardia requiring treatment occurred in 4/7 procedures. Finally, five pregnancies were successfully delivered, and the other two were aborted. Compared to data before fetal cardiac interventions (FCI), tricuspid valve annulus diameter/mitral valve annulus diameter (TV/MV) and right ventricle diameter/left ventricle diameter (RV/LV) of all fetuses had progressively improved. The maximum tricuspid regurgitation velocity decreased from 4.60 ?m/s to 3.64 ?m/s. The average follow-up time was 30.40 ?± ?2.05 months. During the follow-up period, the diameter of the tricuspid valve ring in five children continued to improve, and the development rate of the tricuspid valve was relatively obvious from 6 months to 1 year after birth. However, the development of the right ventricle after birth was relatively slow. It was discovered that there were individual variations in the development of the right ventricle during follow-up.ConclusionThe findings support the potential for the development of the right ventricle and tricuspid valve in fetuses with PA/IVS who underwent FCI. Development of the right ventricle and tricuspid valve does not occur synchronously during pregnancy. The right ventricle develops rapidly in utero, but the development of tricuspid valve is more apparent after birth than in utero. 相似文献
2.
3.
4.
5.
《Journal of Cardiovascular Computed Tomography》2021,15(6):492-498
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.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):449-459.e4
ObjectiveThe objective of this study was to investigate the association between morphological variation and postsurgical pulmonary vein (PV) stenosis (PPVS) in patients with cardiac total anomalous pulmonary venous connection (TAPVC).MethodsThis single-center, retrospective study included 168 pediatric patients who underwent surgical repair of cardiac TAPVC from 2013 to 2019 (connection to the coronary sinus [CS], n = 136; connection directly to the right atrium [RA], n = 32). Three-dimensional computed tomography modeling and geometric analysis were performed to investigate the morphological features; their relevance to the PPVS was examined.ResultsThe connection type had no association with PPVS (CS type: 18% vs right atrial type: 19%; P = .89) but there was a higher incidence of PPVS in patients with a single PV orifice than > 1 orifice (P < .001). Confluence-to-total PV area ratio (hazard ratio, 4.78, 95% CI, 1.86-12.32; P = .001) and length of drainage route (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < .001) had a 4- and 1-fold increase in the risk for PPVS in the CS type after adjustment for age and preoperative pulmonary venous obstruction. In the right atrial type, those with anomalous PV return to the RA roof were more likely to develop PPVS than to the posterior wall of the RA (P < .001).ConclusionsThe number of inter-junction PV orifice correlated with PPVS development in cardiac TAPVC. The confluence-to-total PV ratio, length of drainage route, and anomalous PV return to the RA roof are important predictors for PPVS. Morphological subcategorization in this clinical setting can potentially assist in surgical decision-making. 相似文献
7.
《Journal of vascular and interventional radiology : JVIR》2019,30(8):1265-1272
PurposeTo evaluate the safety and efficacy of balloon pulmonary angioplasty (BPA) for nonoperable chronic thromboembolic pulmonary hypertension (CTEPH) patients during the initial experience of a single center.MethodsA total of 18 CTEPH patients (5 with residual pulmonary hypertension after pulmonary endarterectomy) were treated with BPA during the period 2014–2018 and were retrospectively reviewed. Mean age was 61 ± 19 years; 55% were female; mean pulmonary artery pressure was 44 ± 12 mmHg; cardiac output was 4.3 ± 1.0 l/min; and pulmonary vascular resistance was 8.4 ± 3.6 WU. Patients were evaluated by New York Heart Association functional class, 6-minute walk distance, N-terminal pro b-type natriuretic peptide, echocardiography, right heart catheterization, and before and after completions of BPA.ResultsA total of 91 procedures were performed, with a median number of 4 BPA sessions per patient (range, 2–8). There were no deaths or major complications requiring extracorporeal support or (non)invasive ventilation. The most common complication was self-limiting hemoptysis (3%). According to Society of Interventional Radiology classification, 4 mild, 4 moderate, and 1 severe adverse events were noted. Invasive hemodynamics significantly improved, with a cardiac index increase of 15% (P = .0333), decrease of mean pulmonary artery pressure of 30% (P = .0013), and decrease of pulmonary vascular resistance of 45% (P = .0048). Stroke volume index (P = .0171) and pulmonary arterial compliance (P = .0004) were also significantly enhanced.ConclusionsBPA significantly improves cardiopulmonary hemodynamics with an acceptable safety profile. Further studies assessing the long-term efficacy of BPA are required. 相似文献
8.
9.
Chrystalle Katte Carreon Annachiara Benini Christopher Baird David Hoganson Michele Borisuk Sitaram Emani Sophie Hofferberth Robert F. Padera Stephen P. Sanders 《The Journal of thoracic and cardiovascular surgery》2019,157(1):342-350.e3
Objectives
Although valved venous homografts (VVHs) are used for establishing right ventricle-to-pulmonary artery continuity in some complex heart defects, the tissue changes that occur in situ have not been described. We review the gross and microscopic changes observed in explanted VVH conduits and their effects on functionality.Methods
In total, 20 explanted VVH conduits were evaluated for valve integrity, presence of thrombus, and stenosis. Hematoxylin and eosin– and trichrome-stained sections were reviewed for neointima formation, wall remodeling, inflammation, and calcification. Regurgitation and narrowing were assessed on pre-explant echocardiogram, and angiographic video clips were correlated with tissue findings. The source of the proliferating cells within the conduits was investigated by fluorescent in situ hybridization.Results
Thirteen male and 7 female infants underwent VVH implantation either as part of a composite Sano shunt (65%) or to establish right ventricle-to-pulmonary artery continuity in biventricular hearts (35%). The median duration of conduits in situ was 140 days (range: 98-340 days). Conduits were predominantly explanted for staged conversion to bidirectional Glenn (60%) and conduit upsizing (20%). The valves remained intact and functional in 75% of cases. Occlusive thrombosis was absent in all. Wall thickening due to neointima formation and wall remodeling was uniformly present and appeared to be driven by smooth muscle actin–expressing cells, which by fluorescent in situ hybridization are predominantly of recipient origin. Minimal calcification and mild adventitial chronic inflammation were present.Conclusions
Vein wall thickening is a uniform finding and can cause stenosis. The valves remain functional in most, and vein walls undergo remodeling with only minimal inflammation and calcification. 相似文献10.
Intracardiac thrombi are commonly encountered as a complication of a recent myocardial infarction, heart failure, atrial fibrillation, or intracardiac devices. The prevalence of atrial thrombi in the absence of these risk factors is not well‐described, but seems to be low. We present a case of a 51‐year‐old man with a massive mobile thrombus in the right heart extending through the tricuspid valve, diagnosed on echocardiography after presenting with a presyncopal episode. 相似文献