全文获取类型
收费全文 | 844篇 |
免费 | 40篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 17篇 |
妇产科学 | 12篇 |
基础医学 | 143篇 |
口腔科学 | 12篇 |
临床医学 | 51篇 |
内科学 | 132篇 |
皮肤病学 | 26篇 |
神经病学 | 127篇 |
特种医学 | 35篇 |
外科学 | 117篇 |
预防医学 | 97篇 |
眼科学 | 19篇 |
药学 | 35篇 |
肿瘤学 | 61篇 |
出版年
2023年 | 9篇 |
2022年 | 16篇 |
2021年 | 24篇 |
2020年 | 7篇 |
2019年 | 20篇 |
2018年 | 38篇 |
2017年 | 20篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 28篇 |
2013年 | 43篇 |
2012年 | 56篇 |
2011年 | 78篇 |
2010年 | 46篇 |
2009年 | 24篇 |
2008年 | 56篇 |
2007年 | 51篇 |
2006年 | 42篇 |
2005年 | 47篇 |
2004年 | 40篇 |
2003年 | 24篇 |
2002年 | 36篇 |
2001年 | 21篇 |
2000年 | 19篇 |
1999年 | 19篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1979年 | 3篇 |
1975年 | 2篇 |
1972年 | 3篇 |
1971年 | 7篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1965年 | 3篇 |
1959年 | 1篇 |
1943年 | 1篇 |
1942年 | 1篇 |
排序方式: 共有893条查询结果,搜索用时 0 毫秒
1.
2.
Eugenio Neri Lucio Barabesi Dimitrios Buklas Luca A. Vricella Antonio Benvenuti Enrico Tucci Carlo Sassi Massimo Massetti 《European journal of cardio-thoracic surgery》2005,28(6):857-863
Objective: Increased dimension of the aortic root and proximal aorta is considered a significant risk factor for catastrophic events that involve the ascending aorta. The objective of this study was to determine the possible correlation between pre-dissection aortic diameter and the occurrence of Stanford type A aortic dissection. Methods: Samples of dissected ascending aortas were obtained from 220 patients at the time of their operation. Two groups were identified: patients with connective tissue disorders (Group 1, n = 94) and those without (Group 2, n = 126). Measurements of the true (intimal) lumen were conducted and extrapolated as reliable approximation of pre-dissection aortic diameter. The possible association of intimal diameter with anthropometric and demographic data was analyzed. Results: Median aortic diameter was, respectively, 41.8 and 41.3 mm for patients with and without connective tissue disorders (41.4 mm for the entire cohort). Data analysis indicated that 57% of patients had aortic diameter above 40 mm, while patients with frank aneurysm accounted only for 10%; this proportion was higher in Group 1 compared to Group 2 (17.2% vs 4.7%). Poor or no correlation was demonstrated between aortic size and any of the anthropometric or demographic variables essayed. Significant subgroup differences were found among patients with a history of cigarette smoking, hypertension, diabetes, chronic renal insufficiency, and bicuspid aortic valve. Conclusion: Although aortic diameter remains a strong indication for preventive surgery in patients with inherited connective tissue disorders, acute aortic dissection occurs rarely in the setting of true ascending aortic aneurysms, and despite normal or near-normal aortic size in more than one-third of subjects. Dissection superimposing on small aortic diameters can be regarded as an expression of substantial functional tissue susceptibility to aortic catastrophic events. 相似文献
3.
Folate deficiency is a common unpleasant secondary effect of anticonvulsant therapy. In order to contribute to the knowledge of biochemical mechanisms leading to this condition, the effects of two i.p. high doses of phenobarbitone administered to the rat (acute treatment) on the distribution of hepatic folate derivatives have been studied. A significant decrease of unsubstituted tetrahydro- and dihydropteroylpentaglutamates and 5,10-methylenetetrahydropentaglutamates was observed. The hypothesis that a lower availability of NADPH, which is utilized for hydroxylation reactions in phenobarbitone metabolism, may limit folate reduction is proposed. 相似文献
4.
Diagnosis of scaphoid fractures:A prospective multicenter study of 1,052 patients with 160 fractures
Bo Munk Johnny Fr kj r Claus Falck Larsen Hans Gad Johannsen Lars Lundager Rasmussen Annette Edal Lilla Demeney Rasmussen 《Acta orthopaedica》1995,66(4):359-360
In a prospective multicenter study of 1,052 patients with clinical signs of a scaphoid fracture, mammo-graphic films and fine intensifying screens were used at the radiographic examination. 5 standardized projections including 3 special projections focused on the scaphoid were taken. 150 fractures were diagnosed at the first examination but in 10 cases the fracture was first diagnosed at a second radiographic examination after 10-14 days.
The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections. 相似文献
The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections. 相似文献
5.
6.
Mansouri D Mrad K Sassi S Driss-Fourati M Abbes I Koubaa-Mahjoub W Hechiche M Ben Romdhane K 《Annales de pathologie》2004,24(2):179-182
Pseudo-angiomatous hyperplasia of mammary stroma (PASH) is a histopathological entity which is a microscopic fortuitous finding in mammary biopsies performed for different reasons. It may be symptomatic and appears then as a palpable lump. The term pseudo-angiomatous emphasizes the characteristic aspect of the stroma simulating a vascular tumor. We report a case of PASH in a 71 year-old woman who presented a recurring breast mass with rapid swelling of the mammary gland (70 x 60 x 20 cm) treated by mastectomy. PASH must be distinguished from a well-differentiated angiosarcoma. It is ruled out by immunohistochemistry. 相似文献
7.
Lesauskaite V Tanganelli P Sassi C Neri E Diciolla F Ivanoviene L Epistolato MC Lalinga AV Alessandrini C Spina D 《Human pathology》2001,32(9):1003-1011
The etiopathogenesis of thoracic aortic aneurysms is currently an issue of debate. The present study investigated ultrastructural, morphometric, and immunohistochemical aspects of smooth muscle cells (SMCs) in chronic aneurysm of the thoracic aorta (aneurysm group), aortic dilatation associated with valvular disease (valvular group), and dissection of the thoracic aorta (dissection group). Fragments of the ascending aorta that had been taken from the patients during coronary bypass surgery were used as controls. No significant difference was observed in the density of SMCs between the 3 pathologic groups put together and the controls. Only separate analysis of SMC density in each of the pathologic groups showed that the valvular group samples had significantly smaller amounts of SMCs in the internal layer of the media than the dissection group samples and controls. Ultrastructural analysis, in situ end labeling, propidium iodide assay, and DNA laddering did not show apoptosis of SMCs in the samples investigated. Ultrastructure of SMCs characteristic of the synthetic phenotype, together with increased expression of osteopontin in the media of pathologic thoracic aortas indicated the transition of SMCs from the contractile to the synthetic phenotype. Immunohistochemical investigation showed that medial SMCs in the samples taken from aortas of all 3 pathologic groups expressed stronger immunoreactivity for matrix metalloproteinase 1, 2, and 9 and tissue inhibitor of metalloproteinase 1 and 2 than the controls. The present study shows that during the formation of aneurysms, dissection of the thoracic aorta, or aortic dilatation associated with valvular disease, loss of SMCs was not of great importance with respect to their transition from the contractile to the synthetic type in leading to increased production of matrix metalloproteinases. 相似文献
8.
Summary An increased base binding power of the blood induced by alkali administration to subjects performing a supramaximal exercise has no appreciable effect neither on the maximal performance time nor on the total amount of lactic acid or its rate of appearance in blood.This work has been supported by a grant from the Italian National Research Council. Thanks are due also to Laboratory Glaxo, S.p.A. for facilities and financial support in the course of the experiments. 相似文献
9.
Davide Gibellini Paola Monari Monica Sassi Maria Carla Re 《Journal of clinical virology》2003,28(3):341-343
A hemi-nested PCR approach was adopted to detect HTLV-1 infection in clinical samples of peripheral blood mononuclear cells (PBMCs) from subjects with positive or indeterminate serological results. Our results showed that the hemi-nested PCR quickly solved the diagnostic query, detecting the presence of proviral HTLV-1 DNA in two of the 252 patients with inconclusive serological results. The main advantage of this method are the typology of DNA extraction, allowing a consistent DNA recovery without amplification problems, the rapidity (4-5 hours), the performance of the assay and its comparable or better sensitivity than other HTLV-1 PCR formats. 相似文献
10.
Inadequate venous drainage may represent a major problem in operations on the descending thoracic aorta performed with the aid of cardiopulmonary bypass. We herein describe an alternative technique of venous cannulation, which allows steady performances and high pump flows. 相似文献