全文获取类型
收费全文 | 2122篇 |
免费 | 124篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 109篇 |
妇产科学 | 36篇 |
基础医学 | 398篇 |
口腔科学 | 29篇 |
临床医学 | 244篇 |
内科学 | 397篇 |
皮肤病学 | 60篇 |
神经病学 | 163篇 |
特种医学 | 108篇 |
外科学 | 244篇 |
综合类 | 22篇 |
一般理论 | 3篇 |
预防医学 | 174篇 |
眼科学 | 21篇 |
药学 | 137篇 |
中国医学 | 4篇 |
肿瘤学 | 97篇 |
出版年
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 22篇 |
2019年 | 26篇 |
2018年 | 36篇 |
2017年 | 21篇 |
2016年 | 44篇 |
2015年 | 35篇 |
2014年 | 40篇 |
2013年 | 63篇 |
2012年 | 93篇 |
2011年 | 130篇 |
2010年 | 69篇 |
2009年 | 65篇 |
2008年 | 106篇 |
2007年 | 110篇 |
2006年 | 100篇 |
2005年 | 103篇 |
2004年 | 90篇 |
2003年 | 78篇 |
2002年 | 109篇 |
2001年 | 69篇 |
2000年 | 91篇 |
1999年 | 63篇 |
1998年 | 29篇 |
1997年 | 30篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 46篇 |
1991年 | 39篇 |
1990年 | 36篇 |
1989年 | 24篇 |
1988年 | 24篇 |
1987年 | 17篇 |
1986年 | 20篇 |
1985年 | 25篇 |
1984年 | 14篇 |
1983年 | 21篇 |
1982年 | 9篇 |
1980年 | 9篇 |
1979年 | 23篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1971年 | 8篇 |
1969年 | 10篇 |
1968年 | 8篇 |
1942年 | 10篇 |
排序方式: 共有2257条查询结果,搜索用时 8 毫秒
61.
S. Leone V. Ravasio E. Durante-Mangoni M. Crapis G. Carosi P. G. Scotton N. Barzaghi M. Falcone P. Chinello M. B. Pasticci P. Grossi R. Utili P. Viale M. Rizzi F. Suter 《Infection》2012,40(5):527-535
Background
The characteristics of patients with infective endocarditis (IE) vary significantly by region of the world. The aim of this study was to evaluate the contemporary epidemiology, characteristics, and outcome of IE in a large, nationwide cohort of Italian patients.Methods
We conducted a prospective, observational study at 24 medical centers in Italy, including all the consecutive patients with a definite or possible diagnosis of IE (modified Duke criteria) admitted from January 2004 through December 2009. A number of clinical variables were collected through an electronic case report form and analyzed to comprehensively delineate the features of IE. We report the data on patients with definite IE.Results
A total of 1,082 patients with definite IE were included. Of these, 753 (69.6?%) patients had infection on a native valve, 277 (25.6?%) on a prosthetic valve, and 52 (4.8?%) on an implantable electronic device. Overall, community-acquired (69.2?%) was more common than nosocomial (6.2?%) or non-nosocomial (24.6?%) health care-associated IE. Staphylococcus aureus was the most common pathogen (22.0?%). In-hospital mortality was 15.1?%. From the multivariate analysis, congestive heart failure (CHF), stroke, prosthetic valve infection, S. aureus, and health care-associated acquisition were independently associated with increased in-hospital mortality, while surgery was associated with decreased mortality.Conclusions
The current mortality of IE remains high, and is mainly due to its complications, such as CHF and stroke. 相似文献62.
63.
64.
Interactive 3D editing tools for image segmentation 总被引:4,自引:0,他引:4
Segmentation is an important part of image processing, which often has a large impact on quantitative image analysis results. Fully automated operator independent segmentation procedures that successfully work in a population with a larger biological variation are extremely difficult to design and usually some kind of operator intervention is required, at least in pathological cases.We developed a variety of 3D editing tools that can be used to correct or improve results of initial automatic segmentation procedures. Specifically we will discuss and show examples for three types of editing tools that we termed: hole-filling (tool 1), point-bridging (tool 2), and surface-dragging (tool 3). Each tool comes in a number of flavors, all of which are implemented in a truly 3D manner. We describe the principles, evaluate efficiency and flexibility, and discuss advantages and disadvantages of each tool. We further demonstrate the superiority of the 3D approach over the time-consuming slice-by-slice editing of 3D datasets, which is still widely used in medical image processing today. We conclude that performance criteria for automatic segmentation algorithms may be eased significantly by including 3D editing tools early in the design process. 相似文献
65.
Detection of clastogenic compounds in the peripheral blood micronucleus test (MNT) in rats is a well-established methodology. However, the results obtained on the induction of micronuclei by aneugens in rat peripheral blood are controversial. Our aim was a comparative evaluation of the peripheral blood flow cytometry MNT in Wistar Han rat and CD1 mouse exposed to three aneugens (vinblastine, vincristine and colchicine) after single-dose applications. In addition, the same compounds were tested in the rat bone marrow MNT. The treatment with vinblastine (0.25, 0.5, 1, mg/kg), vincristine (0.025, 0.05, 0.1 mg/kg) or colchicine (0.7, 1, 1.3 mg/kg) induced no statistically significant increase in MN-PCEs (micronucleated polychromatic erythrocytes or reticulocytes) in rat peripheral blood. In rat bone marrow, a clear statistically significant increase in MN-PCE was found with vincristine and vinblastine. However, colchicine showed a clear increase in MN-PCE frequency without reaching statistically significant level only at 1 mg/kg. The positive effect in the bone marrow MNT shows that the target organ was exposed to the appropriate concentration levels of the respective aneugens. In mouse, the peripheral blood flow cytometry analysis after the treatment with vinblastine, vincristine and colchicine showed clear statistically significant increase in MN-PCE with all three compounds. The experiments with splenectomized rats treated with vincristine and colchicine were performed and statistically significant increases in MN-PCE were found with 0.05, 0.1, 0.15 mg/kg of vincristine and 0.7 and 1 mg/kg of colchicine. Our results demonstrate that micronucleated cells induced by aneugens are removed from rat peripheral blood by the spleen due to the large size of micronuclei. Based on our data, it is concluded that the flow cytometry peripheral blood MNT after single-dose applications is an appropriate test system for evaluating the genotoxic effects of aneugens in mice. However, in rats peripheral blood MNT aneugen detection might require multiple-dose applications to overwhelm the spleen effect. 相似文献
66.
The purpose of this study was to estimate the number of transgender men (transmen) adults living in San Francisco. We integrated two population size estimation methods into a community-based health survey of transmen (n = 122) in the San Francisco Bay Area in 2014–2015: the service multiplier and wisdom of the crowds. The median estimate was 806 transmen adults in San Francisco (0.11% of adults) and 4027 in the Bay Area. Considering potential biases, we believe our estimates are conservative. Knowing the denominator of persons at risk for health conditions is necessary for public health planning, surveillance, and impact evaluation. 相似文献
67.
Pulsed versus continuous wave CO2 laser excisions of 100 oral fibrous hyperplasias: A randomized controlled clinical and histopathological study
下载免费PDF全文
![点击此处可从《Lasers in surgery and medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
68.
69.
70.
Proteolytic inactivation of alpha 1-proteinase inhibitor in infected bronchial secretions from patients with cystic fibrosis 总被引:1,自引:0,他引:1
The chronic, progressively destructive bronchitis of patients with cystic fibrosis (CF) is characterized by an important imbalance between tissue destroying granulocyte proteases such as granulocyte elastase (GE) and its physiological inhibitors in bronchial secretions. Recent in vitro studies suggest, that proteases derived from bacteria or endogenous proteases may contribute to inactivation of physiological inhibitors of GE. Since only trypsin-unreactive alpha 1-proteinase inhibitor (alpha 1-PI) was detected in CF bronchial secretions, we attempted to identify the mechanism of inactivation of alpha 1-PI. We found a heat stable, serine protease-like enzymatic activity capable of degrading 125I-labelled alpha 1-PI extensively in 22 infected but not in one non-infected CF bronchial secretion. In infected secretions, only degraded alpha 1-PI, which did not migrate like oxidized alpha 1-PI in tandem-crossed immunoelectrophoresis, was detectable. We conclude, that free GE in excess as well as GE bound to bronchial mucosal inhibitor may partly account for the alpha 1-PI-cleaving activity, but that other yet unknown bacterial or host serine proteases also contribute to alpha 1-PI inactivation. 相似文献