全文获取类型
收费全文 | 23845篇 |
免费 | 1896篇 |
国内免费 | 105篇 |
专业分类
耳鼻咽喉 | 259篇 |
儿科学 | 453篇 |
妇产科学 | 291篇 |
基础医学 | 3292篇 |
口腔科学 | 452篇 |
临床医学 | 2985篇 |
内科学 | 5451篇 |
皮肤病学 | 446篇 |
神经病学 | 2356篇 |
特种医学 | 736篇 |
外国民族医学 | 3篇 |
外科学 | 3519篇 |
综合类 | 254篇 |
现状与发展 | 1篇 |
一般理论 | 11篇 |
预防医学 | 1586篇 |
眼科学 | 377篇 |
药学 | 1576篇 |
中国医学 | 68篇 |
肿瘤学 | 1730篇 |
出版年
2023年 | 137篇 |
2022年 | 219篇 |
2021年 | 600篇 |
2020年 | 405篇 |
2019年 | 623篇 |
2018年 | 722篇 |
2017年 | 524篇 |
2016年 | 547篇 |
2015年 | 674篇 |
2014年 | 850篇 |
2013年 | 1140篇 |
2012年 | 1825篇 |
2011年 | 1977篇 |
2010年 | 953篇 |
2009年 | 911篇 |
2008年 | 1503篇 |
2007年 | 1509篇 |
2006年 | 1411篇 |
2005年 | 1440篇 |
2004年 | 1287篇 |
2003年 | 1150篇 |
2002年 | 1167篇 |
2001年 | 279篇 |
2000年 | 255篇 |
1999年 | 281篇 |
1998年 | 237篇 |
1997年 | 193篇 |
1996年 | 136篇 |
1995年 | 138篇 |
1994年 | 106篇 |
1993年 | 104篇 |
1992年 | 183篇 |
1991年 | 168篇 |
1990年 | 151篇 |
1989年 | 138篇 |
1988年 | 144篇 |
1987年 | 138篇 |
1986年 | 143篇 |
1985年 | 145篇 |
1984年 | 116篇 |
1983年 | 97篇 |
1982年 | 104篇 |
1981年 | 98篇 |
1980年 | 83篇 |
1979年 | 80篇 |
1978年 | 72篇 |
1977年 | 66篇 |
1976年 | 54篇 |
1975年 | 47篇 |
1974年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
991.
992.
Helen Hogan Frances Healey Graham Neale Richard Thomson Nick Black Charles Vincent 《Journal of the Royal Society of Medicine》2014,107(9):365-375
Objective
To determine if applying change analysis to the narrative reports made by reviewers of hospital deaths increases the utility of this information in the systematic analysis of patient harm.Design
Qualitative analysis of causes and contributory factors underlying patient harm in 52 case narratives linked to preventable deaths derived from a retrospective case record review of 1000 deaths in acute National Health Service Trusts in 2009.Participants
52 preventable hospital deaths.Setting
England.Main outcome measures
The nature of problems in care and contributory factors underlying avoidable deaths in hospital.Results
The change analysis approach enabled explicit characterisation of multiple problems in care, both across the admission and also at the boundary between primary and secondary care, and illuminated how these problems accumulate to cause harm. It demonstrated links between problems and underlying contributory factors and highlighted other threats to quality of care such as standards of end of life management. The method was straightforward to apply to multiple records and achieved good inter-rater reliability.Conclusion
Analysis of case narratives using change analysis provided a richer picture of healthcare-related harm than the traditional approach, unpacking the nature of the problems, particularly by delineating omissions from acts of commission, thus facilitating more tailored responses to patient harm. 相似文献993.
Philippe Alix Kumar Venkatesan Jacqueline Scuvée‐Moreau Laurent Massotte Mai‐Linh Nguyen Trung Charlotte A. Cornil Vincent Seutin 《The European journal of neuroscience》2014,39(2):186-196
Most serotonergic neurons display a prominent medium‐duration afterhyperpolarization (mAHP), which is mediated by small‐conductance Ca2+‐activated K+ (SK) channels. Recent ex vivo and in vivo experiments have suggested that SK channel blockade increases the firing rate and/or bursting in these neurons. The purpose of this study was therefore to characterize the source of Ca2+ which activates the mAHP channels in serotonergic neurons. In voltage‐clamp experiments, an outward current was recorded at ?60 mV after a depolarizing pulse to +100 mV. A supramaximal concentration of the SK channel blockers apamin or (‐)‐bicuculline methiodide blocked this outward current. This current was also sensitive to the broad Ca2+ channel blocker Co2+ and was partially blocked by both ω‐conotoxin and mibefradil, which are blockers of N‐type and T‐type Ca2+ channels, respectively. Neither blockers of other voltage‐gated Ca2+ channels nor DBHQ, an inhibitor of Ca2+‐induced Ca2+ release, had any effect on the SK current. In current‐clamp experiments, mAHPs following action potentials were only blocked by ω‐conotoxin and were unaffected by mibefradil. This was observed in slices from both juvenile and adult rats. Finally, when these neurons were induced to fire in an in vivo‐like pacemaker rate, only ω‐conotoxin was able to increase their firing rate (by ~30%), an effect identical to the one previously reported for apamin. Our results demonstrate that N‐type Ca2+ channels are the only source of Ca2+ which activates the SK channels underlying the mAHP. T‐type Ca2+ channels may also activate SK channels under different circumstances. 相似文献
994.
995.
Regionally selective atrophy of subcortical structures in prodromal HD as revealed by statistical shape analysis 下载免费PDF全文
Laurent Younes J. Tilak Ratnanather Timothy Brown Elizabeth Aylward Peg Nopoulos Hans Johnson Vincent A. Magnotta Jane S. Paulsen Russell L. Margolis Roger L. Albin Michael I. Miller Christopher A. Ross PREDICT‐HD Investigators Coordinators of the Huntington Study Group 《Human brain mapping》2014,35(3):792-809
Huntington disease (HD) is a neurodegenerative disorder that involves preferential atrophy in the striatal complex and related subcortical nuclei. In this article, which is based on a dataset extracted from the PREDICT‐HD study, we use statistical shape analysis with deformation markers obtained through “Large Deformation Diffeomorphic Metric Mapping” of cortical surfaces to highlight specific atrophy patterns in the caudate, putamen, and globus pallidus, at different prodromal stages of the disease. On the basis of the relation to cortico‐basal ganglia circuitry, we propose that statistical shape analysis, along with other structural and functional imaging studies, may help expand our understanding of the brain circuitry affected and other aspects of the neurobiology of HD, and also guide the most effective strategies for intervention. Hum Brain Mapp 35:792–809, 2014. © 2012 Wiley Periodicals, Inc. 相似文献
996.
How do we process event‐based and time‐based intentions in the brain? an fMRI study of prospective memory in healthy individuals 下载免费PDF全文
Julie Gonneaud Géraldine Rauchs Mathilde Groussard Brigitte Landeau Florence Mézenge Vincent de La Sayette Francis Eustache Béatrice Desgranges 《Human brain mapping》2014,35(7):3066-3082
Prospective memory (PM) refers to the ability to remember to do something in the future, either in response to an event (event‐based) or after a certain amount of time has elapsed (time‐based). While the distinction between event‐ and time‐based PM is widely acknowledged in the literature, little is known about the processes they share and those they do not. This is particularly true concerning their brain substrates, as almost all neuroimaging studies so far have focused on event‐based PM. We proposed a functional magnetic resonance imaging paradigm assessing both event‐based and time‐based PM to 20 healthy young individuals. Analyses revealed that event‐ and time‐based PM both induced activation in the posterior frontal and parietal cortices, and deactivation in the medial rostral prefrontal cortex. In addition, activation more specific to each condition, which may underlie differences in strategic monitoring, was highlighted. Thus, occipital areas were more activated during event‐based PM, probably reflecting target‐checking, while a network comprising the dorsolateral prefrontal cortex, the cuneus/precuneus and, to a lesser extent, the inferior parietal lobule, superior temporal gyrus, and the cerebellum, was more activated in time‐based PM, which may reflect the involvement of time‐estimation processes. These results confirm the allocation of attentional resources to the maintenance of intention for event‐based and time‐based PM, as well as the engagement of distinct mechanisms reflecting the monitoring strategies specific to each condition. Hum Brain Mapp 35:3066–3082, 2014. © 2013 Wiley Periodicals, Inc. 相似文献
997.
Brain networks disconnection in early multiple sclerosis cognitive deficits: An anatomofunctional study 下载免费PDF全文
Céline Louapre Vincent Perlbarg Daniel García‐Lorenzo Marika Urbanski Habib Benali Rana Assouad Damien Galanaud Léorah Freeman Benedetta Bodini Caroline Papeix Ayman Tourbah Catherine Lubetzki Bruno Stankoff 《Human brain mapping》2014,35(9):4706-4717
Severe cognitive impairment involving multiple cognitive domains can occur early during the course of multiple sclerosis (MS). We investigated resting state functional connectivity changes in large‐scale brain networks and related structural damage underlying cognitive dysfunction in patients with early MS. Patients with relapsing MS (3–5 years disease duration) were prospectively assigned to two groups based on a standardized neuropsychological evaluation: (1) cognitively impaired group (CI group, n = 15), with abnormal performances in at least 3 tests; (2) cognitively preserved group (CP group, n = 20) with normal performances in all tests. Patients and age‐matched healthy controls underwent a multimodal 3T magnetic resonance imaging (MRI) including anatomical T1 and T2 images, diffusion imaging and resting state functional MRI. Structural MRI analysis revealed that CI patients had a higher white matter lesion load compared to CP and a more severe atrophy in gray matter regions highly connected to networks involved in cognition. Functional connectivity measured by integration was increased in CP patients versus controls in attentional networks (ATT), while integration was decreased in CI patients compared to CP both in the default mode network (DMN) and ATT. An anatomofunctional study within the DMN revealed that functional connectivity was mostly altered between the medial prefrontal cortex (MPFC) and the posterior cingulate cortex (PCC) in CI patients compared to CP and controls. In a multilinear regression model, functional correlation between MPFC and PCC was best predicted by PCC atrophy. Disconnection in the DMN and ATT networks may deprive the brain of compensatory mechanisms required to face widespread structural damage. Hum Brain Mapp 35:4706–4717, 2014. © 2014 Wiley Periodicals, Inc . 相似文献
998.
999.
Vincent M Tutino Max Mandelbaum Hoon Choi Liza C Pope Adnan Siddiqui John Kolega Hui Meng 《Journal of cerebral blood flow and metabolism》2014,34(3):415-424
Carotid occlusions are associated with de novo intracranial aneurysm formation in clinical case reports, but this phenomenon is not widely studied. We performed bilateral carotid ligation (n=9) in rabbits to simulate carotid occlusion, and sham surgery (n=3) for control. Upon euthanasia (n=3 at 5 days, n=6 at 6 months post ligation, and n=3 at 5 days after sham operation), vascular corrosion casts of the circle of Willis (CoW) were created. Using scanning electron microscopy, we quantified gross morphologic, macroscopic, and microscopic changes on the endocasts and compared findings with histologic data. At 5 days, CoW arteries of ligated animals increased caliber. The posterior communicating artery (PCom) increased length and tortuosity, and the ophthalmic artery (OA) origin presented preaneurysmal bulges. At 6 months, calibers were unchanged from 5 days, PComs further increased tortuosity while presenting segmental dilations, and the OA origin and basilar terminus presented preaneurysmal bulges. This exploratory study provides evidence that flow increase after carotid occlusion produces both compensatory arterial augmentation and pathologic remodeling such as tortuosity and saccular/fusiform aneurysm. Our findings may have considerable clinical implications, as these lesser-known consequences should be considered when managing patients with carotid artery disease or choosing carotid ligation as a therapeutic option. 相似文献
1000.
Agnès Jacquin Vincent Deramecourt Serge Bakchine Claude-Alain Maurage Florence Pasquier 《Journal of neurology》2014,261(4):696-701
Sporadic Creutzfeldt–Jakob disease (sCJD) generally manifests itself by cognitive or rapidly progressive motor symptoms. An atypical onset or an unusual evolution may delay the diagnosis. Among patients with a confirmed diagnosis of sCJD following a post-mortem neuropathological examination at the Neuropathology Centre of Lille, France, those who had presented with atypical cognitive disorders at onset were included in the study. Four patients were included. The first patient (64-years-old) presented early language disorders, later accompanied by apathy and behavioral disorders. The prolonged course suggested a diagnosis of progressive primary aphasia. The second patient (68-years-old) presented with aphasia, apraxia, and ataxia of the right upper limb with parkinsonian syndrome, suggesting corticobasal degeneration. In the two last patients (58- and 61-years-old), the onset was marked by an anxiety–depression syndrome, falls, visual hallucinations, extra-pyramidal syndrome, and fluctuating cognitive decline. The diagnosis raised was probable Lewy body dementia. The 14.3.3 protein was found in two of the four cases. The clinical elements found may initially suggest focal atrophy or Lewy body dementia. A very rapid clinical deterioration generally suggests sCJD, but in the last case, the evolution was particularly slow. The diagnosis of sCJD must be considered in cases of rapid-onset dementia, even if all of the clinical criteria are not present. The detection of the 14.3.3 protein and multifold increase in total-Tau with normal or slightly increased phosphorylated-Tau in the CSF are additional arguments to reinforce the diagnosis. The post-mortem neuropathological examination is important to confirm the diagnosis. 相似文献