全文获取类型
收费全文 | 3398篇 |
免费 | 191篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 59篇 |
妇产科学 | 66篇 |
基础医学 | 533篇 |
口腔科学 | 62篇 |
临床医学 | 198篇 |
内科学 | 633篇 |
皮肤病学 | 430篇 |
神经病学 | 283篇 |
特种医学 | 54篇 |
外科学 | 371篇 |
综合类 | 11篇 |
预防医学 | 307篇 |
眼科学 | 84篇 |
药学 | 197篇 |
中国医学 | 3篇 |
肿瘤学 | 235篇 |
出版年
2023年 | 14篇 |
2022年 | 20篇 |
2021年 | 42篇 |
2020年 | 32篇 |
2019年 | 69篇 |
2018年 | 83篇 |
2017年 | 67篇 |
2016年 | 81篇 |
2015年 | 68篇 |
2014年 | 96篇 |
2013年 | 137篇 |
2012年 | 233篇 |
2011年 | 231篇 |
2010年 | 154篇 |
2009年 | 118篇 |
2008年 | 233篇 |
2007年 | 241篇 |
2006年 | 216篇 |
2005年 | 194篇 |
2004年 | 192篇 |
2003年 | 179篇 |
2002年 | 210篇 |
2001年 | 68篇 |
2000年 | 77篇 |
1999年 | 67篇 |
1998年 | 38篇 |
1997年 | 14篇 |
1996年 | 34篇 |
1995年 | 17篇 |
1994年 | 17篇 |
1993年 | 23篇 |
1992年 | 30篇 |
1991年 | 32篇 |
1990年 | 28篇 |
1989年 | 24篇 |
1988年 | 22篇 |
1987年 | 13篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 8篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1975年 | 5篇 |
1972年 | 4篇 |
1968年 | 4篇 |
1962年 | 6篇 |
1960年 | 4篇 |
1930年 | 4篇 |
1925年 | 4篇 |
1922年 | 4篇 |
排序方式: 共有3599条查询结果,搜索用时 15 毫秒
71.
Gilles Montalescot Stephen G. Ellis Mark A. de Belder Luc Janssens Olivier Katz Wladyslaw Pluta Patrick Ecollan Michal Tendera Ad J. van Boven Petr Widimsky Henning R. Andersen Amadeo Betriu Paul Armstrong Bruce R. Brodie Howard C. Herrmann Franz-Josef Neumann Mark B. Effron Jiandong Lu Elliot S. Barnathan Eric J. Topol 《JACC: Cardiovascular Interventions》2010,3(2):203-212
72.
A pedunculated aldosterone‐producing adenoma drained by an extra vein causing puzzling results of adrenal vein sampling 下载免费PDF全文
73.
Wouter G. Wieringa Chris P.H. Lexis Erik Lipsic Hindrik W. van der Werf Johannes G.M. Burgerhof Vincent E. Hagens G. Louis Bartels Alexander Broersen Remco A. Schurer Eng-Shiong Tan Pim van der Harst Ad F.M. van den Heuvel Tineke P. Willems Gabija Pundziute 《Journal of Cardiovascular Computed Tomography》2017,11(2):111-118
Background
In vitro studies have shown the feasibility of coronary lesion grading with computed tomography angiography (CTA), intravascular ultrasound (IVUS) and optical coherence tomography (OCT) as compared to histology, whereas OCT had the highest discriminatory capacity.Objective
We investigated the ability of CTA and IVUS to differentiate between early and advanced coronary lesions in vivo, OCT serving as standard of reference.Methods
Multimodality imaging was prospectively performed in 30 NSTEMI patients. Plaque characteristics were assessed in 1083 cross-sections of 30 culprit lesions, co-registered among modalities. Absence of plaque, fibrous and fibrocalcific plaque on OCT were defined as early plaque, whereas lipid rich-plaque on OCT was defined as advanced plaque. Odds ratios adjusted for clustering were calculated to assess associations between plaque types on CTA and IVUS with early or advanced plaque.Results
Normal findings on CTA as well as on IVUS were associated with early plaque. Non-calcified, calcified plaques and the napkin ring sign on CTA were associated with advanced plaque. On IVUS, fatty and calcified plaques were associated with advanced plaque.Conclusions
In vivo coronary plaque characteristics on CTA and IVUS are associated with plaque characteristics on OCT. Of note, normal findings on CTA and IVUS relate to early lesions on OCT. Nevertheless, multiple plaque features on CTA and IVUS are related to advanced plaques on OCT, which may make it difficult to use qualitative plaque assessment in clinical practice. 相似文献74.
75.
76.
77.
78.
Neocortical neurons in vivo are embedded in networks with intensive ongoing activity. How this network activity affects the neurons' integrative properties and what function this may imply at the network level remain largely unknown. Most of our knowledge regarding synaptic communication and integration is based on recordings in vitro, where network activity is strongly diminished or even absent. Here, we present results from two complementary series of experiments based on intracellular in vivo recordings in anesthetized rat frontal cortex. Specifically, we measured 1) the relationship between the excursions of a neuron's membrane potential and the spiking activity in the surrounding network and 2) how the summation of several inputs to a single neuron changes with the different levels of its membrane potential excursions and the associated states of network activity. The combination of these measurements enables us to assess how the level of network activity influences synaptic integration. We present direct evidence that integration of synaptic inputs in frontal cortex is linear, independent of the level of network activity. However, during periods of high network activity, the neurons' response to synaptic input is markedly reduced in both amplitude and duration. This results in a drastic shortening of its window for temporal integration, requiring more precise coordination of presynaptic spike discharges to reliably drive the neuron to spike under conditions of high network activity. We conclude that ongoing activity, as present in the active brain, emphasizes the need for neuronal cooperation at the network level, and cannot be ignored in the exploration of cortical function. 相似文献
79.
Failure to control an outbreak of qnrA1-positive multidrug-resistant Enterobacter cloacae infection despite adequate implementation of recommended infection control measures 下载免费PDF全文
Paauw A Verhoef J Fluit AC Blok HE Hopmans TE Troelstra A Leverstein-van Hall MA 《Journal of clinical microbiology》2007,45(5):1420-1425
A large outbreak with an aminoglycoside-resistant Enterobacter cloacae (AREC) clone occurred at the University Medical Center Utrecht beginning in 2001 and continued up through the time that this study was completed. This clone (genotype I) contains a conjugative R plasmid carrying the qnrA1, bla(CTX-M-9), and aadB genes, encoding resistance to quinolones, extended-spectrum beta-lactamases, and aminoglycosides, respectively. The aim of this study was to determine whether this clone was more transmissible than other AREC strains. Therefore, the dissemination of this genotype and of other E. cloacae strains was studied. In addition, infection control measures taken were evaluated. Pulsed-field gel electrophoresis analysis divided the 191 AREC strains into 42 different genotypes, of which 5 (12%) involved at least three patients. Aside from this outbreak (133 patients), only two other small outbreaks occurred, showing that the infection control measures were successful for all strains but one. Among 324 aminoglycoside-susceptible E. cloacae strains, 34/166 (20%) genotypes were identified from at least three patients, but only 4 involved small outbreaks. The outbreak strain was also detected in 11 of 15 other Dutch hospitals and caused outbreaks in at least 4. Evaluation of infection control measures showed that the outbreak strain disseminated throughout the hospital despite adequate implementation of internationally accepted guidelines on the control of multidrug-resistant Enterobacteriaceae (MRE). In conclusion, some MRE strains are better able to spread than others, and these strains may not be controlled by the current infection control guidelines. Strategies to identify such strains in an early phase and adapted guidelines for such "superbugs" are needed to prevent these clones from becoming endemic. 相似文献
80.
A recurrent chromosome translocation breakpoint in breast and pancreatic cancer cell lines targets the neuregulin/NRG1 gene 总被引:2,自引:0,他引:2