全文获取类型
收费全文 | 1301篇 |
免费 | 38篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 25篇 |
妇产科学 | 19篇 |
基础医学 | 135篇 |
口腔科学 | 9篇 |
临床医学 | 118篇 |
内科学 | 363篇 |
皮肤病学 | 4篇 |
神经病学 | 111篇 |
特种医学 | 55篇 |
外科学 | 265篇 |
综合类 | 4篇 |
预防医学 | 68篇 |
眼科学 | 7篇 |
药学 | 52篇 |
中国医学 | 8篇 |
肿瘤学 | 78篇 |
出版年
2023年 | 10篇 |
2022年 | 29篇 |
2021年 | 65篇 |
2020年 | 22篇 |
2019年 | 44篇 |
2018年 | 51篇 |
2017年 | 25篇 |
2016年 | 23篇 |
2015年 | 37篇 |
2014年 | 53篇 |
2013年 | 86篇 |
2012年 | 123篇 |
2011年 | 112篇 |
2010年 | 57篇 |
2009年 | 35篇 |
2008年 | 85篇 |
2007年 | 70篇 |
2006年 | 64篇 |
2005年 | 55篇 |
2004年 | 51篇 |
2003年 | 50篇 |
2002年 | 58篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 7篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1973年 | 7篇 |
1972年 | 3篇 |
1969年 | 2篇 |
排序方式: 共有1345条查询结果,搜索用时 15 毫秒
91.
Cognitive control and brain resources in major depression: an fMRI study using the n-back task 总被引:8,自引:0,他引:8
Harvey PO Fossati P Pochon JB Levy R Lebastard G Lehéricy S Allilaire JF Dubois B 《NeuroImage》2005,26(3):860-869
Several neuroimaging studies have reported 'hypofrontality' in depressed patients performing a cognitive challenge compared to control subjects. Hypofrontality in depression is likely associated with an impaired behavioral performance. It is unclear whether this impaired performance is the consequence or the cause of hypofrontality. Consequently, we proposed to compare the cerebral activity of depressed patients and healthy subjects while controlling for the level of performance. Ten individuals meeting DSM-IV criteria for Major Depression and 10 healthy controls were tested with a verbal version of the n-back task during fMRI scanning. The working memory load was manipulated across the experiment (1,2,3-back) to increase the cognitive demands. fMRI data were acquired on a 1.5-T GE scanner and analyzed using SPM99 software. We did not find any difference between groups in both performance and reaction times for each level of complexity of the n-back task. Depressed patients and control subjects showed bilateral activation of the lateral prefrontal cortex, anterior cingulate and parietal cortex. Activation of these regions was modulated by the complexity of the task. Within this n-back neural network, depressed patients showed greater activation of the lateral prefrontal cortex and the anterior cingulate compared to healthy subjects. This study provides evidence that depressed patients need greater activation within the same neural network to maintain a similar level of performance as controls during a working memory task. Our findings suggest that depression may impair the cognitive capacity of depressed patients by recruiting more brain resources than controls during cognitive control. 相似文献
92.
93.
Boselli E Breilh D Djabarouti S Guillaume C Rimmelé T Gordien JB Xuereb F Saux MC Allaouchiche B 《Intensive care medicine》2007,33(9):1519-1523
Objective To evaluate the reliability of mini-bronchoalveolar lavage (mini-BAL) for the measurement of tobramycin concentrations in
epithelial lining fluid (ELF) in comparison with conventional bronchoscopic bronchoalveolar lavage (BAL).
Design Prospective, open-label study.
Setting An intensive care unit and research ward in a university hospital.
Patients Twelve critically ill adult patients with ventilator-associated pneumonia (VAP).
Interventions All subjects received intravenous infusions of tobramycin 7–10 mg/kg once daily. After 2 days of therapy, the steady-state
serum and ELF concentrations (obtained from BAL and mini-BAL) of tobramycin were determined by means of high-performance liquid
chromatography.
Measurements and results We observed poor penetration of tobramycin in ELF of ≈ 12% with ELF peak concentrations of ≈ 3 mg/l with both methods. Good
agreement in Bland–Altman analysis (mean ± SD bias = 0.04 ± 0.38 mg/l) was observed between the two methods of sampling.
Conclusion Our results suggest that tobramycin 7–10 mg/kg once daily in critically ill patients with VAP might provide insufficient lung
concentrations in the case of difficult-to-treat pathogens. Besides, mini-BAL, which is simple, non-invasive and easily repeatable
at the bedside, appears to be a reliable method for the measurement of antibiotic concentrations in ELF in comparison with
bronchoscopic BAL in critically ill patients with VAP.
This article is discussed in the editorial available at: .
Support was provided only by institutional sources. 相似文献
94.
Christophe Demoulin Damien Baeri Geoffrey Toussaint Barbara Cagnie Axel Beernaert Jean-François Kaux Marc Vanderthommen 《Joint, bone, spine : revue du rhumatisme》2018,85(2):239-242
Objectives
To examine beliefs about cracking sounds heard during high-velocity low-amplitude (HVLA) thrust spinal manipulation in individuals with and without personal experience of this technique.Methods
We included 100 individuals. Among them, 60 had no history of spinal manipulation, including 40 who were asymptomatic with or without a past history of spinal pain and 20 who had nonspecific spinal pain. The remaining 40 patients had a history of spinal manipulation; among them, 20 were asymptomatic and 20 had spinal pain. Participants attended a one-on-one interview during which they completed a questionnaire about their history of spinal manipulation and their beliefs regarding sounds heard during spinal manipulation.Results
Mean age was 43.5 ± 15.4 years. The sounds were ascribed to vertebral repositioning by 49% of participants and to friction between two vertebras by 23% of participants; only 9% of participants correctly ascribed the sound to the formation of a gas bubble in the joint. The sound was mistakenly considered to indicate successful spinal manipulation by 40% of participants. No differences in beliefs were found between the groups with and without a history of spinal manipulation.Conclusions
Certain beliefs have documented adverse effects. This study showed a high prevalence of unfounded beliefs regarding spinal manipulation. These beliefs deserve greater attention from healthcare providers, particularly those who practice spinal manipulation. 相似文献95.
Benjamin Darnis Kayvan Mohkam François Cauchy Jean-Baptiste Cazauran Brigitte Bancel Agnès Rode Christian Ducerf Mickaël Lesurtel Jean-Yves Mabrut 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2018,20(11):985-991
Background
Multiple gallbladders (MG) are a rare malformation, with no clear data on its clinical impact, therapeutic indications or risk for malignancy.Methods
A systematic review of all published literature between 1990 and 2017 was performed using the PRISMA guidelines.Results
Data of 181 patients extracted from 153 studies were reviewed. MG were diagnosed during the treatment of a gallstone-related disease in 83% of patients, of which 13% had previous cholecystectomy and had a recurrence of biliary stone disease. The sensitivity of ultrasound scan was 66%, and that of magnetic resonance imaging cholangio-pancreatography, 97%. The cystic duct was common to both gallbladders (type1) in 43% and separated (type 2) in 50% of patients. In the latter case, there was no way to differentiate preoperatively an accessory gallbladder from a Todani II bile duct cyst. Cholecystectomy was performed in 129 patients by laparotomy (43%) or laparoscopy (56%). MG was undiagnosed before surgery in 24% of the patients. The postoperative biliary leakage rate was 0.7%. In two patients, gallbladder cancers were detected.Conclusion
MG are difficult to diagnose and share a common natural history with single gallbladders, without evidence of increased risk for malignancy. Excision of both gallbladders is indicated in symptomatic stone disease. However, prophylactic cholecystectomy must be considered for type 2 MG, since it cannot be preoperatively differentiated from a Todani II bile duct cyst, which is associated with a risk of malignant transformation. 相似文献96.
97.
Grange C Létourneau J Forget MA Godin-Ethier J Martin J Liberman M Latour M Widmer H Lattouf JB Piccirillo CA Cailhier JF Lapointe R 《Journal of immunological methods》2011,372(1-2):119-126
Multi-parametric flow cytometry analysis is a reliable method for phenotypic and functional characterization of tumor infiltrating immune cells (TIIC). The isolation of infiltrating leukocytes from solid tumors can be achieved through various methods which can be both enzymatic and mechanical; however, these methods may alter cell biology. The aim of this study was to compare the effects of three tissue disaggregation techniques on TIIC biology in breast, kidney and lung tumor specimens. We therefore compared two enzymatic treatments using either collagenase type IA alone or in combination with collagenase type IV and DNase I type II, and one mechanical system (Medimachine?). We evaluated the impact of treatments on cell viability, surface marker integrity and proliferative capacity. We show that cell viability was not significantly altered by treatments. However, enzymatic treatments decreased cell proliferation; specifically collagenases and DNase provoked a significant decrease in detection of surface markers such as CD4, CD8, CD45RA and CD14, indicating that results of phenotypic studies employing these techniques could be affected. In conclusion, mechanical tissue disaggregation by Medimachine? appears to be optimal to maintain phenotypic and functional TIIC features. 相似文献
98.
99.
100.
Milea D Lobel E Lehéricy S Leboucher P Pochon JB Pierrot-Deseilligny C Berthoz A 《Neuroreport》2007,18(12):1221-1224
Deciding where to look is mandatory to explore the visual world. To study the neural correlates subserving the cognitive phase of self-initiated eye movements in humans, we tested 12 healthy participants, using event-related functional MRI. Changes in the frontal-cortical activity preceding voluntary saccades were studied when the participants freely decided the direction of a forthcoming saccade, compared with a condition in which they had only to prepare an externally cued saccade. Self-initiation of saccades, before their execution, was specifically associated with frontal-lobe activation in the dorsolateral prefrontal cortex, and in the right presupplementary eye field and frontal eye fields, suggesting the roles of these areas in the decision process of where to look when facing two possible visual targets. 相似文献