全文获取类型
收费全文 | 20543篇 |
免费 | 1250篇 |
国内免费 | 151篇 |
专业分类
耳鼻咽喉 | 174篇 |
儿科学 | 455篇 |
妇产科学 | 389篇 |
基础医学 | 2392篇 |
口腔科学 | 792篇 |
临床医学 | 1957篇 |
内科学 | 4468篇 |
皮肤病学 | 433篇 |
神经病学 | 1285篇 |
特种医学 | 473篇 |
外国民族医学 | 5篇 |
外科学 | 2707篇 |
综合类 | 530篇 |
一般理论 | 15篇 |
预防医学 | 1707篇 |
眼科学 | 778篇 |
药学 | 1949篇 |
中国医学 | 239篇 |
肿瘤学 | 1196篇 |
出版年
2024年 | 32篇 |
2023年 | 286篇 |
2022年 | 773篇 |
2021年 | 1184篇 |
2020年 | 787篇 |
2019年 | 954篇 |
2018年 | 1109篇 |
2017年 | 801篇 |
2016年 | 861篇 |
2015年 | 859篇 |
2014年 | 1174篇 |
2013年 | 1331篇 |
2012年 | 1846篇 |
2011年 | 1868篇 |
2010年 | 1089篇 |
2009年 | 863篇 |
2008年 | 1193篇 |
2007年 | 1074篇 |
2006年 | 904篇 |
2005年 | 747篇 |
2004年 | 598篇 |
2003年 | 491篇 |
2002年 | 426篇 |
2001年 | 49篇 |
2000年 | 61篇 |
1999年 | 62篇 |
1998年 | 54篇 |
1997年 | 46篇 |
1996年 | 45篇 |
1995年 | 36篇 |
1994年 | 19篇 |
1993年 | 33篇 |
1992年 | 24篇 |
1991年 | 17篇 |
1990年 | 19篇 |
1989年 | 20篇 |
1988年 | 18篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 16篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A. J. Pijl K. A. Solen† S. F. Mohammad R. Monson† L. S. Yu J. M. T. van Griensven D. B. Olsen W. J. Kolff 《Artificial organs》1990,14(2):125-129
Device-induced thrombogenesis was studied in an in vitro model using human blood circulated through an artificial ventricle. A new constant pressure filtration technique was used to detect circulating microemboli, the activated partial thromboplastin time (APTT) test was used to monitor the blood for the presence of anticoagulant activity of heparin, and hemolysis was quantified by measuring the plasma free hemoglobin level. Circulation of blood through a 20-ml stroke volume pneumatically driven ventricle for 6-9 h resulted in a significant reduction of APTT, indicating the loss of the anticoagulant effect of heparin. Microemboli concentration was minimal until the APTT decreased below 125 s, at which time the microemboli concentration increased rapidly. This was presumed to be due to the formation of thrombi following a decrease in heparin activity. A significant increase in hemolysis was also noted when blood was pumped. None of these changes was noted in the nonpumped control blood. Spontaneous loss of heparin activity in blood circulated by a pneumatically driven pump may have clinical implications and may help understanding of the problems associated with device-induced thrombogenesis. 相似文献
42.
43.
44.
45.
Mohammad Nasri-Sebdani Flavien Traoré Christian Cognard Daniel Potreau Jean -Pierre Poindessault Guy Raymond 《Pflügers Archiv : European journal of physiology》1990,416(1-2):106-112
The effects of tetracaine (10–50 M) and ryanodine (0.1–10 M) were tested on the slow outward K+ current (I
so) and the mechanical tension of isolated frog muscle fibres in a voltage-clamp device (double mannitol-gap) connected to a mechanoelectric transducer. In the concentration range tested, both drugs induced a simultaneous inhibition of tension and current. In all cases the effect on tension was twice that on current. The tetracaine-induced current and tension blocks were fully reversible and dose-dependent. In contrast the ryanodine effects on current and tension were not reversible and did not exhibit a dose dependence except for the delay before the onset of the response, which was shortened when the concentration was raised. Linear regression analysis of the time-dependent and dose-dependent effects of both drugs indicated a strong correlation between the decreases in tension and current. It is concluded that the slow outward current is partly under the control of the Ca2+ release from sarcoplasmic reticulum during contraction. 相似文献
46.
Mohammad Hassanzadeh Hassan Gilanpour Saied Charkhkar Johan Buyse Eddy Decuypere 《Avian pathology》2005,34(3):188-193
The present study was designed to compare the anatomical parameters of the cardiopulmonary system in three different lines of chickens with different susceptibility to ascites syndrome. Eggs from three different genetic lines-commercial broiler and layer lines and one native to Iran--were incubated and hatched, and 1-day-old chicks used. The relative heart and lung weights, the volumes of the heart, lung and thorax cavity, the incidence of ascites, and the related physiological parameters in these chickens were followed. Lung weight as a percentage of body weight, the relative lung and heart volume, and the volumes of the thorax cavity, before and after removing heart and lung tissues, were lower in fast-growing broiler chickens compared with the layer and native chickens. Additionally, most of these parameters (e.g. relative lung weight, lung volume and thorax cavity) were significantly decreased with age in broiler chickens but were increased in layer and native chickens, which was concomitant with the incidence of ascites in broiler chickens. Our data indicate that all cardiopulmonary parameters investigated are extremely unfavourable to broiler chickens and suggest a reduction in gas exchange area in broilers, and therefore higher susceptibility to pulmonary hypertension and ascites. 相似文献
47.
Ryoichi?Inaba Seyed?Mohammad?Mirbod Haruo?SugiuraEmail author 《BMC complementary and alternative medicine》2005,5(1):8
Background
Maharishi Amrit Kalash (MAK) 5, one of the Ayurvedic food supplements, belongs to a group of substances known as Rasayana. MAK5 and other Rasayanas are believed to enhance the body's resistance to infections and disease, and enhance longevity. In this study, we determined the effects of administration of MAK5, one of the Ayurvedic food supplements on immune functions in young and old mice. 相似文献48.
A novel in vivo lecithin-cholesterol acyltransferase (LCAT)-deficient mouse expressing predominantly LpX is associated with spontaneous glomerulopathy 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zhu X Herzenberg AM Eskandarian M Maguire GF Scholey JW Connelly PW Ng DS 《The American journal of pathology》2004,165(4):1269-1278
Complete lecithin cholesterol acyltransferase (LCAT) deficiency is a rare genetic cause of extreme reduction in high density lipoproteins and there is a high prevalence of chronic renal dysfunction that may progress to renal failure. Previous in vitro studies suggest the vesicular lipoprotein X (LpX) particles commonly seen in LCAT-deficient plasmas may be causative. To test this hypothesis, we have generated a novel murine model that selectively accumulate LpX in the circulation by cross breeding the sterol regulatory element binding protein (SREBP) 1a transgenic mice (S+) with the LCAT knockout (lcat-/-) mice. Fast protein liquid chromatography fractionation of pooled plasma lipids revealed that virtually all cholesterol is concentrated in the very low density lipoprotein (VLDL)-sized fractions. These fractions are enriched in free cholesterol and phospholipid but extremely poor in triglyceride. Electron microscopy of the d <1.063 g/ml fraction of the S+lcat-/- mice revealed abnormal large vesicular particles, suggestive of LpX. The S+lcat-/- mice developed glomerular lesions spontaneously evident at 6 months with glomerular and tubulointerstitial lipid-deposits. Immunohistochemical staining with RhoA showed marked positive focal staining in glomeruli in the S+lcat-/- mice and undetectable in the S+/lcat+/+ control. By 10 months of age, the kidneys showed progressive glomerular injury including segmental foam cell infiltrates, mesangial expansion, and hyalinosis. Renal abnormalities are very similar to those seen in human LCAT deficiency. We conclude that the selective high-level accumulation of plasma LpX in the S+lcat-/- mice is strongly associated with a spontaneous glomerulopathy, providing in vivo evidence that LpX contributes to the LCAT deficiency-related nephropathy. 相似文献
49.
Mechanical Analysis of Atherosclerotic Plaques Based on Optical Coherence Tomography 总被引:8,自引:0,他引:8
Chau AH Chan RC Shishkov M MacNeill B Iftimia N Tearney GJ Kamm RD Bouma BE Kaazempur-Mofrad MR 《Annals of biomedical engineering》2004,32(11):1494-1503
Finite element analysis is a powerful tool for investigating the biomechanics of atherosclerosis and has thereby provided an improved understanding of acute myocardial infarction. Structural analysis of arterial walls is traditionally performed using geometry contours derived from histology. In this paper we demonstrate the first use of a new imaging technique, optical coherence tomography (OCT), as a basis for finite element analysis. There are two primary benefits of OCT relative to histology: 1) imaging is performed without excessive tissue handling, providing a more realistic geometry than histology and avoiding structural artifacts common to histologic processing, and 2) OCT imaging can be performed in vivo, making it possible to study disease progression and the effect of therapeutic treatments in animal models and living patients. Patterns of mechanical stress and strain distributions computed from finite element analysis based on OCT were compared with those from modeling based on "gold standard" histology. Our results indicate that vascular structure and composition determined by OCT provides an adequate basis for investigating the biomechanical factors relevant to atherosclerosis and acute myocardial infarction. 相似文献
50.