全文获取类型
收费全文 | 20366篇 |
免费 | 2186篇 |
国内免费 | 614篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 559篇 |
妇产科学 | 89篇 |
基础医学 | 1169篇 |
口腔科学 | 41篇 |
临床医学 | 2365篇 |
内科学 | 6074篇 |
皮肤病学 | 59篇 |
神经病学 | 467篇 |
特种医学 | 384篇 |
外科学 | 1116篇 |
综合类 | 3896篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 410篇 |
眼科学 | 2818篇 |
药学 | 1778篇 |
9篇 | |
中国医学 | 1888篇 |
肿瘤学 | 29篇 |
出版年
2024年 | 85篇 |
2023年 | 505篇 |
2022年 | 626篇 |
2021年 | 1023篇 |
2020年 | 947篇 |
2019年 | 897篇 |
2018年 | 893篇 |
2017年 | 843篇 |
2016年 | 870篇 |
2015年 | 889篇 |
2014年 | 1500篇 |
2013年 | 1475篇 |
2012年 | 1161篇 |
2011年 | 1320篇 |
2010年 | 1003篇 |
2009年 | 937篇 |
2008年 | 978篇 |
2007年 | 921篇 |
2006年 | 798篇 |
2005年 | 776篇 |
2004年 | 612篇 |
2003年 | 518篇 |
2002年 | 439篇 |
2001年 | 400篇 |
2000年 | 324篇 |
1999年 | 304篇 |
1998年 | 255篇 |
1997年 | 248篇 |
1996年 | 173篇 |
1995年 | 147篇 |
1994年 | 135篇 |
1993年 | 126篇 |
1992年 | 111篇 |
1991年 | 85篇 |
1990年 | 80篇 |
1989年 | 85篇 |
1988年 | 70篇 |
1987年 | 80篇 |
1986年 | 60篇 |
1985年 | 81篇 |
1984年 | 65篇 |
1983年 | 40篇 |
1982年 | 64篇 |
1981年 | 47篇 |
1980年 | 43篇 |
1979年 | 20篇 |
1978年 | 19篇 |
1977年 | 16篇 |
1976年 | 10篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 512 毫秒
51.
Stability of the Defibrillation Probability Curve with the Development of Ventricular Dysfunction in the Canine Rapid Paced Model 总被引:1,自引:0,他引:1
PAUL A. FRIEDMAN DAVID A. FOLEY TIMOTHY F. CHRISTIAN MARSHALL S. STANTON 《Pacing and clinical electrophysiology : PACE》1998,21(2):339-351
Most patients with implantable defibrillators have diminished cardiac function. Progressive heart failure might impair defibrillation efficacy, leading to interpreted device, failure. This study sought to determine the effect of ventricular dysfunction on defibrillation energy using a biphasic endocardial system. Eleven dogs were ventricularly paced at 225 pulses/min for 2 weeks to induce ventricular dysfunction, and five control dogs remained unpaced. Dose response defibrillation probability curves were generated for each animal at baseline, after 2 weeks (at which time the pacemakers were turned off in the paced group), and then 1 week later. The defibrillation thresholds, ED20 , ED50 , and ED80 (the 20%, 50%, and 80% effective defibrillation energies, respectively) were determined for each dog at each study. In the paced dogs, the mean ejection fraction fell from 55% to 25% after pacing (P < 0.0001), and rose to 46% after its discontinuation (P = 0.0002). The defibrillation threshold, ED20, ED50 , and ED80 remained unchanged in both the control and paced groups for all three studies, even after adjustment for dog weight or left ventricular mass. Rapid pacing produced no change in left ventricular mass. It induced ventricular cavity dilatation and wall thinning, which had opposing effects on defibrillation energy requirements, resulting in no net change of the ED50 in heart failure. In conclusion, the defibrillation efficacy of a biphasic transvenous system is not changed by the development of heart failure using the rapid paced canine model. 相似文献
52.
I. Wiklund F. Waagstein K. Swedberg Å. Hjalmarsson 《Cardiovascular drugs and therapy / sponsored by the International Society of Cardiovascular Pharmacotherapy》1996,10(3):361-368
Summary Quality of life in heart failure patients is receiving increased attention as a reflection of a treatment's potential secondary
benefit of general well-being and daily functioning. The Metoprolol in Dilated Cardiomyopathy (MDC) trial was conducted as
a large, multicenter trial to establish the effects of metoprolol on mortality and need for heart transplantation in patients
with symptomatic idiopathic cardiomyopathy. It was found that metoprolol was well tolerated, improved symptoms and cardiac
function, and prevented clinical deterioration in patients with symptomatic idiopathic dilated cardiomyopathy. Quality of
life was evaluated as a secondary endpoint in 345 out of 383 randomized patients using a disease-specific questionnaire, the
Quality of Life in Heart Failure Questionnaire, depicting physical activity, somatic symptoms, emotions, and life satisfaction.
In a comparison of patients treated with metoprolol or placebo, patients treated with metoprolol noted a significantly more
favorable response than those treated with placebo in terms of the overall treatment evaluation (p<0.05). Additionally, an
analysis of the changes from baseline to 18 months, using 95% confidence intervals, revealed that patients treated with metoprolol
showed a significant improvement from baseline to 18 months in life satisfaction, physical activity, and the total score,
while patients treated with placebo did not change at all. The improvement in quality of life was supported by the correlations
with improvement in traditional clinical parameters. 相似文献
53.
CHRISTOPH STELLBRINK KLAUS-PETER KUNZE PETER HANRATH 《Pacing and clinical electrophysiology : PACE》1995,18(9):1717-1720
STELLBRINK, C., et al .: Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber . A patient with hypertrophic cardiomyopathy (HCM) who presented with preexcitation pattern on the surface ECG suggestive of the Wolff-Parkinson-White (WPW) syndrome is described. Intracardiac electrophysiological study revealed a fixed anomalous QRS complex and a short fixed His-ventricular interval indicating a fasciculoventricular Mahaim fiber. As this specific form of accessory connection does not cause reentrant tachycardias, no treatment was required. It is important to distinguish this entity from atriofascicular or nodoventricular Mahaim fibers or the WPW syndrome in patients with HCM showing a preexcitation pattern in the surface ECG, as these may cause life-threatening arrhythmias in this patient population. 相似文献
54.
55.
56.
G. RAYMAN S. A. WILLIAMS J. GAMBLE J. E. TOOKE 《European journal of clinical investigation》1994,24(12):830-836
Abstract. The effect of lowering the foot on the factors governing fluid filtration in the foot were studied in 12 male insulin-dependent diabetic subjects and 10 controls. Toe skin blood flow, measured by laser Doppler flowmetry, was significantly higher during dependency in the diabetic group. In the control subjects, the colloid osmotic pressure of venous blood sampled from the foot rose to 47·7 mmHg (range 45·1–53·8) after 50 min of foot dependency. In the diabetic group, colloid osmotic pressure failed to rise to the same extent (median 36·7 mmHg; range 28·6–43·0; P < 0·001). Capillary pressure, measured directly by the Landis microinjection technique, was significantly higher in the diabetic group (85·3±1·7 ( n = 6) vs. 92·2±4·6 cm H2 O ( n = 6); P < 0·007), as was foot swelling rate determined by mercury strain gauge plethysmography (0·069±0·022 vs. 0·099±0·025 ml min-1 100ml-1 ; P < 0·02). These results suggest an impairment of the oedema-preventing mechanisms in diabetic subjects which may contribute to the risks of ulceration in the diabetic foot. 相似文献
57.
Summary This study describes reduced motor nerve conduction velocity and increased resistance to hypoxia-induced conduction failure in sciatic nerves of rats after four weeks of streptozotocin-induced diabetes (both effects were significant at p <0.05). These changes occurred in the absence of any deficit in the steady-state ouabain-sensitive adenosine triphosphatase (ATPase) activity of sciatic nerve endoneurial homogenates. The addition of 10 nmol/l insulin to endoneurial homogenates from control animals resulted in a 34% increase in ouabain-sensitive ATPase activity and a 19% reduction in ouabain-insensitive ATPase activity (both p <0.01). This stimulation of ouabain-sensitive ATPase activity by insulin did not occur in homogenates from diabetic rats. Treating diabetic rats daily with the aldose reductase inhibitor, imirestat (1 mg/kg) improved nerve conduction velocity (p <0.05) but was without effect upon the resistance to hypoxic conduction blockade or the deficit in insulin-stimulated oubain-sensitive ATPase activity. These data suggest that in streptozotocin-diabetic rats the functional disorders of reduced motor nerve conduction velocity and increased resistance to hypoxic conduction blockade do not share a common aetiology and that impaired nerve conduction is not related to reduced maximal potential oubain-sensitive ATPase activity. 相似文献
58.
对病理学确诊的25例病毒性心肌炎(VMC)和10例扩张型心肌病(DCM)患者心内膜心肌活检标本,运用ABC技术,进行了免疫球蛋白IgG、IgM、IgA和补体C3的检测。结果:20例VMC和9例DCM的标本中,发现了IgG和IgM的沉积,主要分布于心肌肌膜和毛细血管内皮,IgG的肌膜沉积与同步做的病理切片中观察到的心肌细胞坏死和炎性细胞浸润有病理形态学联系。两组患者中均未发现IgA和C3沉积。结果显示,IgG是参与VMC和DCM心肌损伤的主要免疫球蛋白,心肌病变与抗体诱导的免疫反应有关。 相似文献
59.
胰激肽原酶治疗糖尿病足38例疗效分析 总被引:3,自引:0,他引:3
目的 观察胰激肽原酶改善微循环干预治疗糖尿病足的疗效。方法 选择38例确诊为糖尿病足的患者,结合下肢血管多普勒超声显像、肌电图、血液流变学检测,确定疗效。结果 胰激肽原酶治疗后,肢体影色多普勒超声显像显示下肢血管血流明显加快(P<0.01);神经电生理异常均有不同程度改善;血液粘度明显下降(P<0.01);足部症状明显缓解。结论 胰激肽原酶是一种干预糖尿病足进展的有效药物。 相似文献
60.