全文获取类型
收费全文 | 61633篇 |
免费 | 4801篇 |
国内免费 | 1646篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 2206篇 |
妇产科学 | 570篇 |
基础医学 | 4336篇 |
口腔科学 | 153篇 |
临床医学 | 8721篇 |
内科学 | 19519篇 |
皮肤病学 | 65篇 |
神经病学 | 891篇 |
特种医学 | 1823篇 |
外科学 | 4641篇 |
综合类 | 12065篇 |
现状与发展 | 4篇 |
一般理论 | 3篇 |
预防医学 | 2797篇 |
眼科学 | 35篇 |
药学 | 6008篇 |
77篇 | |
中国医学 | 3973篇 |
肿瘤学 | 177篇 |
出版年
2024年 | 152篇 |
2023年 | 894篇 |
2022年 | 1606篇 |
2021年 | 2394篇 |
2020年 | 2593篇 |
2019年 | 2170篇 |
2018年 | 2073篇 |
2017年 | 1995篇 |
2016年 | 1858篇 |
2015年 | 1956篇 |
2014年 | 4162篇 |
2013年 | 4295篇 |
2012年 | 3487篇 |
2011年 | 3749篇 |
2010年 | 2964篇 |
2009年 | 2831篇 |
2008年 | 2792篇 |
2007年 | 2997篇 |
2006年 | 2590篇 |
2005年 | 2425篇 |
2004年 | 1970篇 |
2003年 | 1812篇 |
2002年 | 1589篇 |
2001年 | 1440篇 |
2000年 | 1175篇 |
1999年 | 1190篇 |
1998年 | 1023篇 |
1997年 | 970篇 |
1996年 | 764篇 |
1995年 | 715篇 |
1994年 | 713篇 |
1993年 | 534篇 |
1992年 | 514篇 |
1991年 | 462篇 |
1990年 | 372篇 |
1989年 | 354篇 |
1988年 | 298篇 |
1987年 | 276篇 |
1986年 | 254篇 |
1985年 | 290篇 |
1984年 | 252篇 |
1983年 | 147篇 |
1982年 | 175篇 |
1981年 | 155篇 |
1980年 | 132篇 |
1979年 | 110篇 |
1978年 | 101篇 |
1977年 | 79篇 |
1976年 | 72篇 |
1975年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Gilbert H. L. Tang Paul W. M. Fedak Terrence M. Yau Richard D. Weisel Alex Kulik Donald A. G. Mickle Ren-Ke Li 《European journal of cardio-thoracic surgery》2003,23(6):907-916
Current therapies for congestive heart failure are limited in efficacy or in applicability. Cardiac cell transplantation offers a novel therapeutic approach to improve heart function. Although significant progress has been made over the past decade in the development of cell transplantation, only recently have investigators studied the changes in ventricular function following cell transplantation. This review article describes the latest research developments, evaluates recent studies of ventricular function after cell transplantation, and discusses the future directions of cell transplantation as a new therapy to ‘repair broken hearts’. 相似文献
52.
E Baracca C Longhini S Aggio C Brunazzi A E Aubert R Pansini 《European heart journal》1991,12(2):249-261
The present study applies a non-invasive method to the quantitative evaluation of left ventricular stiffness in normal subjects and in patients with ischaemic heart disease (IHD). We have studied 20 patients with IHD and 25 healthy subjects. The third heart sound (S3) was detectable in all patients. We have correlated the energy spectrum of S3, divided into 15 Hz bands, with a series of echocardiographic parameters. The existence of a significant correlation between the spectrum energy and the diameter and thickness of the left ventricle at the moment of S3 allowed us to explore the possibility of interpreting the origin of S3 based on a mathematical model. Our hypothesis has been that, once the left ventricle starts vibrating, it behaves as a simple physical model composed of a mass and an elastic element. To this purely elastic model one can add a factor accounting for viscosity, with a damping effect, to obtain a more complex viscoelastic model. The stiffness coefficient 'k' was computed in both models from the peak frequency of S3 and the left ventricular mass at the moment of S3. Furthermore, in the viscoelastic model, the damping element 'c' was also computed. Both parameters--k and c--were significantly increased in the group with IHD compared with the control group. Although a simplification of the vibrating system, these models make it possible to obtain non-invasively information on the characteristics of the left ventricle through the combined use of echocardiography and spectral analysis of S3. 相似文献
53.
通心络胶囊对冠心病治疗效果的临床对照观察 总被引:1,自引:0,他引:1
欧宁 《中西医结合心脑血管病杂志》2007,5(7):575-576
目的观察通心络胶囊对冠心病(CHD)常见临床症状的改善效果。方法对照组维持原有药物治疗不变,治疗组在此基础上加服通心络胶囊4粒/次,3次/日,疗程4周。病人接受观察前进行常规化验检查,检测心率、血压、心功能等指标。疗程结束时对上述指标再进行检查,并观察病人的临床症状改善情况。结果两组病人的胸痛、胸闷、气憋、心悸、乏力等常见临床症状均有改善,且治疗组明显优于对照组(P〈0.05);治疗组每搏量和心排血量的较对照组提高较为明显(P〈0.01)。结论加服通心络胶囊治疗CHD能增强西药的治疗效果,进一步改善CHD病人的常见临床症状。 相似文献
54.
R. K. Vesalainen K. U. O. Tahvanainen T. J. Kaila I. M. Kantola T. A. Kuusela D. L. Eckberg 《Clinical physiology and functional imaging》1997,17(2):135-133
We studied how posture influences the effects of transdermal scopolamine on autonomic cardiovascular regulation in a randomized, double-blind, placebo-controlled crossover study of 10 healthy young volunteers. We recorded the electrocardiogram and auscultatory sphygmomanometric and continuous non-invasive finger arterial pressure (Finapres device) to obtain signals for the beat-by-beat R–R interval and systolic, mean and diastolic pressures. R–R interval and arterial pressure variabilities were characterized by power spectral analysis. Scopolamine increased the mean R–R intervals and reduced arterial pressure in both the supine and the standing positions, but did not affect blood pressure variability. Scopolamine increased the total variability of R–R interval and its mid- (0·07–0·15 Hz) and high- (0·15–0·40 Hz) frequency band power in the standing position during controlled breathing at 0·25 Hz. In the supine position, scopolamine did not affect R–R interval variability. In the deep breathing test, scopolamine increased the maximal expiratory–inspiratory R–R interval ratio. This study showed that low-dose scopolamine increases vagal cardiac inhibition in both supine and standing positions in healthy volunteers. However, scopolamine increases heart rate variability only in the standing position during partial vagal withdrawal. The study also demonstrates that transdermal scopolamine decreases blood pressure in healthy young subjects. 相似文献
55.
Charles Seydoux Danièle Gillard Berguer Eric Eeckhout Frank Stumpe Michel Hurni Patrick Ruchat Hossein Sadeghi Jean-Jacques Goy 《Transplant international》1996,9(4):433-436
Transplant atherosclerotic coronary disease remains the leading cause of death in heart transplant recipients. We report the first case of coronary stent implantation in a heart graft for epicardial focal stenosis. Due to the lower rate of restenosis after stenting in the native coronary artery, we suggest that coronary stenting be considered an acceptable, first intention therapeutic option instead of angioplasty alone whenever possible. 相似文献
56.
15例肺心病血液高粘滞患者自体血250ml用XZY-Ⅰ型量子血液治疗机进行紫外线照射和充以纯氧后再输入,每周一次,最多连续做三次(平均1.86±0.71次)后,作者发现血液全血高切、低切粘度,全血高切、低切还原粘度,血浆比粘度,血浆纤维否白原含量,红细胞聚集指数,红细胞电泳率等有显著性改变,单纯常规治疗组15例患者血液流变无此变化,分析认为,这些变化可能与红细胞聚集性降低、纤维蛋白源溶解度提高及血氧饱和度增加有关。 相似文献
57.
A. Boussuges P. Ambrosi M. Gainnier V. Quenee J.-M. Sainty 《Intensive care medicine》1997,23(6):702-703
We describe a case of left-sided superior vena cava. The diagnosis was suggested by chest radiograph after central venous
catheter placement. This was subsequently confirmed by magnetic resonance imaging.
Received: 4 March 1997 Accepted: 21 March 1997 相似文献
58.
目的探讨低血流期间无销对再灌注心脏功能恢复的影响。方法采用等客收缩大鼠灌流心脏模型,低血流期以无钠的Krebs-Henseleit(K-H)液灌注.San-ei362型多道重理记录仪,测定再灌注不同时刻左心宝功能及乳酸脱氨酶活性.结果再灌注30min.在各相应时刻,缺钠组左心室收缩压(LVSP)、心率(HR)、左心室内压最大上升速率(dp/dtmax)的恢复均显著高于对照组(P<0.001),左心室舒张期末压(LVEDP)显著低于对照组(P<0.001),乳酸脱氢酶数据低于对照组。结论低血流缺血间无销减轻了心脏血液动力学的损害,心肌乳酸脱氢酶的漏出减少,这可能与因低血流期间无销细胞内钠超负荷减轻有关。 相似文献
59.
Da-Nian Zhu, Long-Mei Xue, Peng Li. Effect of central muscarine receptor blockade. with DKJ-21 on the blood pressure and heart rote in stress-induced hypertensive rats.
The experiments were performed on Wistar or Sprague-Dawley rats of both sexes divided at random into stress and control groups. The rats in the stress groups were put into cages and subjected to electric foot-shocks and noises for 9-15 days, which caused an increase in blood pressure (BP) and heart rate (HR). In hypertensive rats DKJ-21 (4mg/lml) was injected intravenously (i.v.), and 0.5-1.0h after administration the BP and HR dropped from the high level to normotensive level. In normotensive rats, however, administration of DKJ-21 had no effect on BP or HR. In separate groups of normotensive rats, pretreatment of DKJ-21 (4 mg/l ml, i.v.) blocked the pressor and tachycardiac effect induced by microinjection of physostigmine (0.4μg/0.1 /μl/site), corticosterone (40μg/0.1μl/site) or aldosterone (40 μg/0.1 μl/site) into the rostral ventrolateral medulla (rVLM). Furthermore, DKJ-21 also attenuated the enhancement of the pressor response to stimulation of the defense area in the midbrain, which was induced by microinjection of drugs (mentioned above) into the rVLM. These results indicate that i.v. DKJ-21 can selectively block the muscarinic receptors in the rVLM in stress-induced hypertensive rats, which suggests that abnormal enhancement of cholinergic mechanism in the rVLM may be related to hypertensive effects of corticoids in this area. 相似文献
The experiments were performed on Wistar or Sprague-Dawley rats of both sexes divided at random into stress and control groups. The rats in the stress groups were put into cages and subjected to electric foot-shocks and noises for 9-15 days, which caused an increase in blood pressure (BP) and heart rate (HR). In hypertensive rats DKJ-21 (4mg/lml) was injected intravenously (i.v.), and 0.5-1.0h after administration the BP and HR dropped from the high level to normotensive level. In normotensive rats, however, administration of DKJ-21 had no effect on BP or HR. In separate groups of normotensive rats, pretreatment of DKJ-21 (4 mg/l ml, i.v.) blocked the pressor and tachycardiac effect induced by microinjection of physostigmine (0.4μg/0.1 /μl/site), corticosterone (40μg/0.1μl/site) or aldosterone (40 μg/0.1 μl/site) into the rostral ventrolateral medulla (rVLM). Furthermore, DKJ-21 also attenuated the enhancement of the pressor response to stimulation of the defense area in the midbrain, which was induced by microinjection of drugs (mentioned above) into the rVLM. These results indicate that i.v. DKJ-21 can selectively block the muscarinic receptors in the rVLM in stress-induced hypertensive rats, which suggests that abnormal enhancement of cholinergic mechanism in the rVLM may be related to hypertensive effects of corticoids in this area. 相似文献
60.
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