收费全文 | 5971篇 |
免费 | 343篇 |
国内免费 | 82篇 |
耳鼻咽喉 | 122篇 |
儿科学 | 90篇 |
妇产科学 | 115篇 |
基础医学 | 1079篇 |
口腔科学 | 100篇 |
临床医学 | 473篇 |
内科学 | 1025篇 |
皮肤病学 | 223篇 |
神经病学 | 432篇 |
特种医学 | 562篇 |
外科学 | 751篇 |
综合类 | 28篇 |
一般理论 | 3篇 |
预防医学 | 211篇 |
眼科学 | 111篇 |
药学 | 442篇 |
中国医学 | 44篇 |
肿瘤学 | 585篇 |
2023年 | 25篇 |
2022年 | 88篇 |
2021年 | 157篇 |
2020年 | 82篇 |
2019年 | 119篇 |
2018年 | 143篇 |
2017年 | 125篇 |
2016年 | 156篇 |
2015年 | 225篇 |
2014年 | 254篇 |
2013年 | 335篇 |
2012年 | 483篇 |
2011年 | 466篇 |
2010年 | 258篇 |
2009年 | 241篇 |
2008年 | 341篇 |
2007年 | 354篇 |
2006年 | 280篇 |
2005年 | 278篇 |
2004年 | 229篇 |
2003年 | 251篇 |
2002年 | 199篇 |
2001年 | 200篇 |
2000年 | 195篇 |
1999年 | 141篇 |
1998年 | 77篇 |
1997年 | 68篇 |
1996年 | 50篇 |
1995年 | 41篇 |
1994年 | 35篇 |
1993年 | 34篇 |
1992年 | 59篇 |
1991年 | 49篇 |
1990年 | 46篇 |
1989年 | 40篇 |
1988年 | 46篇 |
1987年 | 33篇 |
1986年 | 26篇 |
1985年 | 20篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 17篇 |
1976年 | 11篇 |
1974年 | 9篇 |
1970年 | 5篇 |
Objective
The aims of this study were to compare opening and closing angles of normally functioning mechanical aortic valves measured on dual-source computed tomography (CT) with the manufacturers'' values and to compare CT-measured opening angles according to valve function.Materials and Methods
A total of 140 patients with 10 different types of mechanical aortic valves, who underwent dual-source cardiac CT, were included. Opening and closing angles were measured on CT images. Agreement between angles in normally functioning valves and the manufacturer values was assessed using the interclass coefficient and the Bland-Altman method. CT-measured opening angles were compared between normal functioning valves and suspected dysfunctioning valves.Results
The CT-measured opening angles of normally functioning valves and manufacturers'' values showed excellent agreement for seven valve types (intraclass coefficient [ICC], 0.977; 95% confidence interval [CI], 0.962-0.987). The mean differences in opening angles between the CT measurements and the manufacturers'' values were 1.2° in seven types of valves, 11.0° in On-X valves, and 15.5° in ATS valves. The manufacturers'' closing angles and those measured by CT showed excellent agreement for all valve types (ICC, 0.953; 95% CI, 0.920-0.972). Among valves with suspected dysfunction, those with limitation of motion (LOM) and an increased pressure gradient (PG) had smaller opening angles than those with LOM only (p < 0.05).Conclusion
Dual-source cardiac CT accurately measures opening and closing angles in most types of mechanical aortic valves, compared with the manufacturers'' values. Opening angles on CT differ according to the type of valve dysfunction and a decreased opening angle may suggest an elevated PG. 相似文献Spinal arteriovenous fistula (AVF) is treated by embolization or surgery. However, transarterial embolization or surgery is difficult in rare cases when the fistula site is very complicated to access especially as in fistular nidus supplied by posterior and anterior spinal artery. We present the case which was treated with intraoperative direct puncture and embolization (IOPE) using glue material, since the usual transarterial or transvenous neurointerventional approach was difficult to embolize the AVF.
MethodsA 36-year-old woman presented with progressive leg weakness and pain after a 20-year history of lower back pain. She had pelvic and spinal AVF combined with arteriovenous malformation (AVM). Despite prior treatment of the pelvic lesion with radiotherapy and coil embolization, the spinal lesion persisted and caused repeated subarachnoid hemorrhages. A spinal angiogram revealed a tortuous and long feeder of the AVF which had growing venous sac, as well as AVM. Two embolization trials failed because of the long tortuosity and associated anterior spinal artery. Four months later, drastic leg weakness and pain occurred, and IOPE was performed using a glue material.
ResultsThe subsequent recovery of the patient was rapid. One month later, the use of a strong opioid could be discontinued, and the patient could walk with aid. A follow-up spinal angiogram revealed that the venous sac of the AVF had disappeared.
ConclusionIn spinal AVF which is not feasible to access by usual intervention approach and to dissect surgically, IOPE with glue material can be considered for the treatment.
相似文献