全文获取类型
收费全文 | 22649篇 |
免费 | 1859篇 |
国内免费 | 104篇 |
专业分类
耳鼻咽喉 | 307篇 |
儿科学 | 719篇 |
妇产科学 | 572篇 |
基础医学 | 2773篇 |
口腔科学 | 690篇 |
临床医学 | 1735篇 |
内科学 | 4943篇 |
皮肤病学 | 749篇 |
神经病学 | 1272篇 |
特种医学 | 850篇 |
外国民族医学 | 10篇 |
外科学 | 3873篇 |
综合类 | 275篇 |
现状与发展 | 2篇 |
一般理论 | 7篇 |
预防医学 | 1660篇 |
眼科学 | 595篇 |
药学 | 1912篇 |
中国医学 | 136篇 |
肿瘤学 | 1532篇 |
出版年
2023年 | 214篇 |
2022年 | 666篇 |
2021年 | 989篇 |
2020年 | 646篇 |
2019年 | 957篇 |
2018年 | 1228篇 |
2017年 | 839篇 |
2016年 | 858篇 |
2015年 | 786篇 |
2014年 | 1060篇 |
2013年 | 1465篇 |
2012年 | 1731篇 |
2011年 | 1796篇 |
2010年 | 1120篇 |
2009年 | 992篇 |
2008年 | 1162篇 |
2007年 | 1129篇 |
2006年 | 1070篇 |
2005年 | 963篇 |
2004年 | 857篇 |
2003年 | 665篇 |
2002年 | 596篇 |
2001年 | 355篇 |
2000年 | 363篇 |
1999年 | 298篇 |
1998年 | 135篇 |
1997年 | 102篇 |
1996年 | 98篇 |
1995年 | 68篇 |
1994年 | 55篇 |
1993年 | 58篇 |
1992年 | 64篇 |
1991年 | 63篇 |
1990年 | 54篇 |
1989年 | 65篇 |
1988年 | 63篇 |
1987年 | 57篇 |
1986年 | 47篇 |
1985年 | 60篇 |
1984年 | 100篇 |
1983年 | 88篇 |
1982年 | 56篇 |
1981年 | 41篇 |
1980年 | 57篇 |
1979年 | 67篇 |
1978年 | 55篇 |
1977年 | 46篇 |
1976年 | 48篇 |
1975年 | 55篇 |
1973年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Shwikar AbdelSalam Ahmed Azza Mahmoud Elhefnawy Hanan Galal Azouz Yara Safwat Roshdy Mona Hamdy Ashry Ahmed Elsayed Ibrahim Marwa Ahmed Meheissen 《Journal of molecular neuroscience : MN》2020,70(6):887-896
The role of gut microbiome was recently raised in the pathogenesis of neurodevelopmental disorders including autism spectrum disorder (ASD). The aim of this study was to elucidate changes in gut microbiome in Egyptian autistic children and its possible correlation with the severity of autism and gastrointestinal (GI) symptoms. The gut bacterial microbiome of 41 ASD children, 45 siblings, and 45 healthy controls were analyzed using quantitative SYBR Green real-time PCR technique targeting 16S rRNA of selected bacteria. The gut microbiome of ASD children and their siblings contained a higher relative abundance of Bacteroides as well as Ruminococcus than controls. Prevotella/Bacteroides (P/B) ratio and Firmicutes/Bacteroidetes (F/B) were significantly lower in both ASD cases and their siblings. The only difference between the autistic cases and their siblings was the significantly higher level of Bifidobacterium in siblings, which appears to offer them a protective role. There was no correlation between the altered gut microbiome and the severity of autism or GI symptoms. The current study showed an evidence of changes in the gut microbiome of autistic children compared to the unrelated control. However, the microbiome profile of siblings was more like that of autistic children than that of unrelated controls indicating that gut microbiota is affected by dietary habits, living conditions together with host genetic factors. 相似文献
992.
Simona Schiavi Maria Petracca Matteo Battocchio Mohamed M. El Mendili Swetha Paduri Lazar Fleysher Matilde Inglese Alessandro Daducci 《Human brain mapping》2020,41(11):2951-2963
Graph theory and network modelling have been previously applied to characterize motor network structural topology in multiple sclerosis (MS). However, between‐group differences disclosed by graph analysis might be primarily driven by discrepancy in density, which is likely to be reduced in pathologic conditions as a consequence of macroscopic damage and fibre loss that may result in less streamlines properly traced. In this work, we employed the convex optimization modelling for microstructure informed tractography (COMMIT) framework, which, given a tractogram, estimates the actual contribution (or weight) of each streamline in order to optimally explain the diffusion magnetic resonance imaging signal, filtering out those that are implausible or not necessary. Then, we analysed the topology of this ‘COMMIT‐weighted sensory‐motor network’ in MS accounting for network density. By comparing with standard connectivity analysis, we also tested if abnormalities in network topology are still identifiable when focusing on more ‘quantitative’ network properties. We found that topology differences identified with standard tractography in MS seem to be mainly driven by density, which, in turn, is strongly influenced by the presence of lesions. We were able to identify a significant difference in density but also in network global and local properties when accounting for density discrepancy. Therefore, we believe that COMMIT may help characterize the structural organization in pathological conditions, allowing a fair comparison of connectomes which considers discrepancies in network density. Moreover, discrepancy‐corrected network properties are clinically meaningful and may help guide prognosis assessment and treatment choice. 相似文献
993.
Vicente Molina Alba Lubeiro Rodrigo de Luis Garcia Javier Gomez-Pilar Oscar Martín-Santiago María Iglesias-Tejedor Pedro Holgado-Madera Rafael Segarra-Echeverría María Recio-Barbero Pablo Núez Mahmoud Karim Haidar Jessica Fernndez-Sevillano Javier Sanz-Fuentenebro 《Journal of psychiatry & neuroscience : JPN》2020,45(5):322
BackgroundThe synchronized activity of distributed neural assemblies — reflected in the electroencephalogram (EEG) — underpins mental function. In schizophrenia, modulation deficits of EEG spectral content during a P300 task have been replicated. The effects of treatment, chronicity and specificity in these deficits and their possible relationship with anatomic connectivity remain to be explored.MethodsWe assessed spectral entropy modulation of the EEG during a P300 task in 79 patients with schizophrenia (of those, 31 were in their first episode), 29 patients with bipolar disorder and 48 healthy controls. Spectral entropy values summarize EEG characteristics by quantifying the irregularity of spectral content. In a subsample, we calculated the network architecture of structural connectivity using diffusion tensor imaging and graph-theory parameters.ResultsWe found significant spectral entropy modulation deficits with task performance in patients with chronic or first-episode schizophrenia and in patients with bipolar disorder, without significant pre-stimulus spectral entropy differences. The deficits were unrelated to treatment doses, and spectral entropy modulation did not differ between patients taking or not taking antipsychotics, lithium, benzodiazepines or antidepressants. Structural connectivity values were unrelated to spectral entropy modulation. In patients with schizophrenia, spectral entropy modulation was inversely related to negative symptoms and directly related to verbal memory.LimitationsAll patients were taking medication. Patients with bipolar disorder were euthymic and chronic. The cross-sectional nature of this study prevented a more thorough analysis of state versus trait criteria for spectral entropy changes.ConclusionSpectral entropy modulation with task performance is decreased in patients with schizophrenia and bipolar disorder. This deficit was not an effect of psychopharmacological treatment or structural connectivity and might reflect a deficit in the synchronization of the neural assemblies that underlie cognitive activity. 相似文献
994.
Riëm El Tahry Susana Ferrao Santos Pascal Vrielynck Marianne de Tourtchaninoff Thierry Duprez Geraldo Ribeiro Vaz Christian Raftopoulos Joon Yul Choi Zhong Irene Wang 《Epileptic Disord》2020,22(2):156-164
Aims: Magnetic resonance imaging is of paramount importance in the presurgical evaluation of drug resistant epilepsy. Detection of a potentially epileptogenic lesion significantly improves seizure outcome after surgery. To optimize the detection of subtle lesions, MRI post‐processing techniques may be of essential help. Methods: In this study, we aimed to evaluate the detection rate of the voxel‐based morphometric analysis program (MAP) in a prospective trial. We aimed to study the MAP+ findings in terms of their clinical value in the decision‐making process of the presurgical evaluation. Results: We included, prospectively, 21 patients who had negative MRI by visual analysis. In a first step, results of the conventional non‐invasive presurgical evaluation were discussed, blinded to the MAP results, in multidisciplinary patient management conferences to determine the possible seizure onset zone and to set surgical or invasive evaluation plans. Thereafter, MAP results were presented, and the change of initial clinical plan was recorded. All MAP detections were reaffirmed by a neuroradiologist with epilepsy expertise. For the 21 patients included, mean age at the time of patient management conference was 26 years (SD 15 +/‐ years, range: 5–54 years). In total, 4/21 had temporal lobe epilepsy and 17/21 had extra‐temporal lobe epilepsy. MAP was positive in 10/21 (47%) patients and in 6/10 (60%) a diagnosis of focal cortical dysplasia was confirmed after neuroradiologist review, corresponding to a 28% detection rate. MAP+ findings had a clear impact on the initial management in 7/10 patients (7/21, 33% of all patients), which included an adaptation of the intracranial EEG plan (6/7 patients), or the decision to proceed directly to surgery (1/7 patients). Conclusion: MRI post‐processing using the MAP method yielded an increased detection rate of 28% for subtle dysplastic lesions in a prospective cohort of MRI‐negative patients, indicating its potential value in epilepsy presurgical evaluation. 相似文献
995.
Tantawy Azza Abdel Gawad Adly Amira Abdel Moneam Abdeen Mai Seif El Din Salah Nouran Yousef 《Neurogenetics》2020,21(3):159-167
neurogenetics - Evidence about the link between glucocerebrosidase (GCase) and parkinsonism is growing. Parkinsonism was described in adult type 1 Gaucher disease (GD); few case reports described... 相似文献
996.
997.
998.
999.
Deepa Jagadeesh MD Navneet S. Majhail MD Yizeng He MS Kwang W. Ahn PhD Carlos Litovich MS Sairah Ahmed MD Mahmoud Aljurf MD Ulrike Bacher MD Sherif M. Badawy MD Nelli Bejanyan MD Mitchell Cairo MD Jan Cerny MD Narendranath Epperla MD Nosha Farhadfar MD César O. Freytes MD Robert Peter Gale MD Bradley Haverkos MD Nasheed Hossain MD David Inwards MD Rammurti T. Kamble MD Vaishalee P. Kenkre MD Hillard M. Lazarus MD Aleksandr Lazaryan MD Lazaros Lekakis MD Matthew Mei MD Hemant S. Murthy MD Alberto Mussetti MD Sunita Nathan MD Taiga Nishihori MD Richard F. Olsson MD Praveen Ramakrishnan Geethakumari MD Bipin N. Savani MD Jean A. Yared MD Timothy S. Fenske MD Mohamed A. Kharfan-Dabaja MD Anna Sureda MD Mehdi Hamadani 《Cancer》2020,126(10):2279-2287