全文获取类型
收费全文 | 1878篇 |
免费 | 117篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 103篇 |
妇产科学 | 18篇 |
基础医学 | 154篇 |
口腔科学 | 6篇 |
临床医学 | 211篇 |
内科学 | 925篇 |
皮肤病学 | 1篇 |
神经病学 | 18篇 |
特种医学 | 51篇 |
外科学 | 354篇 |
综合类 | 134篇 |
预防医学 | 15篇 |
眼科学 | 4篇 |
药学 | 21篇 |
中国医学 | 2篇 |
肿瘤学 | 6篇 |
出版年
2024年 | 3篇 |
2023年 | 55篇 |
2022年 | 85篇 |
2021年 | 153篇 |
2020年 | 117篇 |
2019年 | 151篇 |
2018年 | 85篇 |
2017年 | 45篇 |
2016年 | 27篇 |
2015年 | 65篇 |
2014年 | 122篇 |
2013年 | 87篇 |
2012年 | 64篇 |
2011年 | 77篇 |
2010年 | 57篇 |
2009年 | 65篇 |
2008年 | 53篇 |
2007年 | 52篇 |
2006年 | 60篇 |
2005年 | 50篇 |
2004年 | 33篇 |
2003年 | 24篇 |
2002年 | 42篇 |
2001年 | 28篇 |
2000年 | 36篇 |
1999年 | 33篇 |
1998年 | 36篇 |
1997年 | 26篇 |
1996年 | 29篇 |
1995年 | 38篇 |
1994年 | 20篇 |
1993年 | 21篇 |
1992年 | 20篇 |
1991年 | 21篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 17篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 2篇 |
排序方式: 共有2028条查询结果,搜索用时 15 毫秒
11.
12.
Tsutomu Saito Hiroyuki Horimi Tsuguo Hasegawa Toshiro Kamoshida 《Surgery today》1993,23(12):1081-1084
We report herein the case of a 42-year-old man in whom dyspnea on exertion was found to be caused by isolated tricuspid stenosis. Two-dimensional echocardiogram showed thickening of the tricuspid valve with a markedly enlarged right atrium. A color-flow Doppler examination-revealed severe tricuspid stenosis without regurgitation and a Doppler-derived tricuspid diastolic pressure gradient of 23 mmHg. At the time of surgery, the patient was noted to have a stenotic tricuspid valve with thickened leaflets, fused commissures, and almost normal chorda tendineae. The valve leaflets were teased apart to the scattered specimen, and tricuspid valve replacement was successfully performed. Microscopic examination of the specimen demonstrated infective endocarditis. Isolated acquired tricuspid stenosis is extremely rare and, to our knowledge, this is the first case of infective endocarditis being involved as the primary cause. 相似文献
13.
人工心瓣膜患者微栓子信号和凝血活性的相关性研究 总被引:1,自引:0,他引:1
目的 :研究人工心瓣膜患者脑动脉微栓子信号 (MES)的数量及相对强度与凝血活性的相关性。方法 :采用双门深经颅多普勒 (TCD)检测人工心瓣膜患者脑动脉MES ,同时检测患者凝血酶原时间国际通用比值 (INR) ,观察MES数量及相对强度与INR的相关性。结果 :MES阳性发现率 83 33% (2 5 30 ) ,MES出现频率 0~ 4 0 4 (中位数 4 0 )个 h ,MES平均相对强度 11~ 38(2 3 6 3±5 13)dB。INR1 12~ 3 5 1(1 95± 0 6 9)。MES数量及相对强度与INR无相关性。结论 :人工心瓣膜患者脑动脉MES与凝血活性无关 ,提示微栓子物质不是血栓性的 相似文献
14.
Surgically uncorrectable tricuspid valve disease in children is rare. However, when it happens the surgical options are very limited. Tricuspid valve replacement using a mechanical valve or stented bioprosthesis is impractical. Use of homografts in the “anatomic position” has its limitations. We report here the use of an extracardiac homograft connection between the right atrium and right ventricle in a 16-month-old boy in whom severe tricuspid valve stenosis developed after surgical repair of a complex ventricular septal defect associated with dextrocardia and anomalous systemic venous drainage. The patient remains well receiving no cardiac medication 12 months after the procedure. 相似文献
15.
16.
Edwina J. Popek R. Weslie Tyson Gary J. Miller Sherrie A. Caldwell 《Fetal and pediatric pathology》1991,11(1):1-29
Prune belly syndrome (PBS) has been recognized since 1950 as the triad of absent abdominal wall musculature, undescended testes, and urinary tract anomalies. The etiology, however, remains uncertain. Theories of mesenchymal maldevelopment, obstruction, and genetic origin have been proposed. To evaluate the role of lower urinary tract obstruction as it relates to prostatic development and PBS, we studied the lower urinary tract of 15 cases of PBS, 8 cases of posterior urethral values (PUV), and 34 age-matched controls. It is generally accepted that prostatic growth and development are dependent on mesenchymal-epithelial interactions. We evaluated the mesenchymal and epithelial differentiation and relationships, and found distinctly different and consistent abnormalities between PBS and PUV as compared with one another and controls. The findings suggest that in PBS, prostatic growth and development are hindered because of destruction or absence of the appropriate primitive mesenchyme. Our studies could not definitely exclude very early obstruction as a cause of the findings because of lack of appropriate fetal material. 相似文献
17.
Michael S. Sacks David B. Smith Erik D. Hiester 《Annals of biomedical engineering》1997,25(4):678-689
The planar fibrous connective tissues of the body are composed of a dense extracellular network of collagen and elastin fibers
embedded in a ground matrix, and thus can be thought of as biocomposites. Thus, the quantification of fiber architecture is
an important step in developing an understanding of the mechanics of planar tissues in health and disease. We have used small
angle light scattering (SALS) to map the gross fiber orientation of several soft membrane connective tissues. However, the
device and analysis methods used in these studies required extensive manual intervention and were unsuitable for largescale
fiber architectural mapping studies. We have developed an improved SALS device that allows for rapid data acquisition, automated
high spatial resolution specimen positioning, and new analysis methods suitable for large-scale mapping studies. Extensive
validation experiments revealed that the SALS device can accurately measure fiber orientation for up to a tissue thickness
of at least 500 μm to an angular resolution of∼1o and a spatial resolution of±254 μm. To demonstrate the new device’s capabilities, structural measurements from porcine aortic
valve leaflets are presented. Results indicate that the new SALS device provides an accurate method for rapid quantification
of the gross fiber structure of planar connective tissues. 相似文献
18.
Yoko Matsumura Hiromi Kurosawa Kiyozo Morita Koji Nomura Shogo Shimizu Akira Tatara 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2002,50(4):173-177
Optimal initial palliation and a subsequent staged approach is mandatory for high-risk Fontan candidates. We describe the case of mitral atresia with severe tricuspid regurgitation and pulmonary hypertension successfully managed by repeated palliation from the neonatal period and 2-stage Fontan surgery. A 1-month-old boy diagnosed with mitral atresia and double-outlet right ventricle underwent pulmonary artery banding at 1 month of age, followed by repeated pulmonary artery banding accompanied by tricuspid annuloplasty and atrial septal defect enlargement at 6 months. Because of the presence of pulmonary artery distortion, right ventricular dysfunction, and borderline pulmonary vascular resistance, a hemi-Fontan procedure was conducted with extended pulmonary artery plasty when the boy was 3 years and 8 months old. Cardiac catheterization done 3 months after showed improvement in risk factors, and the final Fontan operation (total cavopulmonary connection) was successfully done in conjunction with repeated tricuspid annuloplasty when the boy was 4 years and 5 months old. The patient remains in excellent clinical condition at the last follow-up 5 years after the final Fontan procedure with sinus rhythm and good ventricular function. 相似文献
19.
Disorders of conduction occurring simultaneously in both normal and accessory pathways of patients with Wolff-Parkinson-White (WPW) syndrome have only rarely been observed. To our knowledge this is the first report of impaired conduction in both pathways in WPW syndrome due to mitral annulus calcification (MAC). This case of WPW syndrome type A presented the following conduction abnormalities: (1) right bundle-branch block; (2) transient second-degree AV block with prolonged PR interval of the conducted beats; (3) during electrophysiological study, induction of tachycardia, dependent (phase 3) second-degree AV block, and occasionally conduction of two consecutive beats, the second showing an increased H-V interval (from 25 to 60 ms) and left bundle-branch block (LBBB) pattern, due to (4) infrahisian conduction abnormality. 相似文献
20.
Heinz Schurawitzki M.D. Paul C. Hajek Josef Kramer Florian Grabenwöger Walter Klepetko Anton Moritz 《Cardiovascular and interventional radiology》1989,12(1):10-13
In a radiologic search for embolized leaflets of Edwards-Duromedics bileaflet valves in 2 patients, the embolized fragments were localized in the iliac vessels using computed tomography. Sonography was successful in one case and standard X-ray films of the abdomen were negative in both cases.In vitro investigations with Björk-Shiley and Edwards-Duromedics leaflets suggested that standard X-ray films of the abdomen and pelvis should be considered as the first investigational technique. If negative, computed tomography of the lower abdomen should be done. 相似文献