首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   796篇
  免费   59篇
  国内免费   7篇
耳鼻咽喉   6篇
儿科学   33篇
妇产科学   1篇
基础医学   99篇
口腔科学   6篇
临床医学   73篇
内科学   181篇
皮肤病学   19篇
神经病学   139篇
特种医学   35篇
外科学   114篇
综合类   4篇
预防医学   24篇
眼科学   2篇
药学   33篇
中国医学   1篇
肿瘤学   92篇
  2024年   1篇
  2023年   13篇
  2022年   27篇
  2021年   51篇
  2020年   19篇
  2019年   20篇
  2018年   40篇
  2017年   29篇
  2016年   37篇
  2015年   24篇
  2014年   36篇
  2013年   43篇
  2012年   64篇
  2011年   66篇
  2010年   27篇
  2009年   29篇
  2008年   43篇
  2007年   37篇
  2006年   59篇
  2005年   33篇
  2004年   35篇
  2003年   42篇
  2002年   42篇
  2001年   1篇
  2000年   4篇
  1999年   2篇
  1998年   4篇
  1997年   3篇
  1996年   9篇
  1995年   4篇
  1994年   3篇
  1993年   5篇
  1992年   1篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1978年   1篇
  1966年   1篇
  1935年   1篇
  1912年   1篇
排序方式: 共有862条查询结果,搜索用时 15 毫秒
21.
22.
While endovascular coil embolization has become one of the major therapeutic modalities for intracranial aneurysms, long-term imaging follow-up is required because of the higher rate of retreatment compared with surgical clipping. The purpose of this study was to show the usefulness of craniograms to discriminate coiled intracranial aneurysms that required retreatment. Under the study protocol approved by institutional review board, a retrospective review of the medical record was done regarding coil embolization for intracranial aneurysms performed between January 2014 and December 2018. Coil embolization performed as the initial treatment and followed up for more than 1 year without additional treatment, and those performed as retreatment after the initial coil embolization performed at our institution were recruited. Craniograms obtained just after the initial treatment were compared with those obtained just before the additional treatment in the retreated cases and compared with the latest ones in the non-recurrence cases. Correlation between the morphological changes in the coil mass on the craniograms and retreatments was evaluated. During the study period, 288 coil embolization procedures for intracranial aneurysms were performed. From these, 191 treatments that were followed up for more than 1 year without any additional treatments and 30 retreatments were included. Morphological change of the coil mass was observed in 4 of the 191 non-recurrence treatments and 26 of the 30 retreatments, which was significantly correlated with retreatments (p <0.001). Craniogram was a useful modality in following up the coiled intracranial aneurysms to detect those required retreatments.  相似文献   
23.
24.
The newly developed Ihara's genetically epileptic rat (IGER) is thought to be a useful tool for studying epilepsy of the limbic type. Morphological changes in the hip-pocampus, which is one of the characteristic findings in the brains of patients with temporal lobe epilepsy, were presumed to occur also in IGER during the course of epileptic activities. We investigated chronological changes in volume of the IGER hippocampal formation using mag-netic resonance (MR) imaging. The experiment consisted of two protocols. First, MR imaging was performed for volumetric measurement of the cerebrum and the hippocampus in four male IGER, each at 2, 4, 6, 8, 10 and 12 months of age. After MR examination, the brains were subjected to histological and morphometric examinations. Second, changes in the hippocampal volume were traced chronologically in three IGER at the ages of 2, 4, 6, 8 and 10 months. Age-matched Wistar rats were used as controls. In IGER, the volume of the cerebrum, especially of the hippocampus, and the ratio of the hippocampal to the cerebral volume increased, in concert with the increase in seizure activities. Histological and morphometric invest-igations revealed that there was mild astrogliosis and marked microgliosis with hypertrophic change in the hippocampal formation with aging, but no loss of neurons was observed. Neither an increase in volume nor gliosis was found in the brains of control rats. The enlargement of the hippocampal formation in IGER brains was assumed to be partially due to gliosis of astrocyte and microglia with hypertrophy.  相似文献   
25.
The aim of this study was to analyze correlations among the annual rate of gray matter volume change, age, gender, and cerebrovascular risk factors in 381 healthy community‐dwelling subjects with a large age range by applying a longitudinal design over 6 years using brain magnetic resonance images (MRIs). Brain MRI data were processed with voxel‐based morphometry using a custom template by applying diffeomorphic anatomical registration using the exponentiated lie algebra procedure. The annual rate of regional gray matter volume change showed significant positive correlations with age in several regions, including the bilateral temporal pole, caudate nucleus, ventral and dorsolateral prefrontal cortices, insula, hippocampus, and temporoparietal cortex, whereas significant negative correlations with age were observed in several regions including the bilateral cingulate gyri and anterior lobe of the cerebellum. Additionally, a significant age‐by‐gender interaction was found for the annual rate of regional gray matter volume change in the bilateral hippocampus. No significant correlations were observed between the annual rate of regional gray matter volume change and body mass index or systolic blood pressure. A significant positive correlation between the annual rate of gray matter volume change and age indicates that the region shows not linear but accelerated gray matter loss with age. Therefore, evaluating the annual rate of the gray matter volume change with age in healthy subjects is important in understanding how gray matter volume changes with aging in each brain region and in anticipating what cognitive functions are likely to show accelerated decline with aging. Hum Brain Mapp 34:2292–2301, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
26.
We successfully treated a case of mitral regurgitation due to chest trauma in Barlow's disease. A 71‐year‐old man was admitted with severe mitral regurgitation after blunt compression of the chest by a heavy object 5 months earlier. Preoperative examination revealed wide chordae tendineae rupture and myxomatous changes to the bileaflets. Neo‐chordae reconstruction of the anterior mitral leaflet using loop technique, triangular resection of the posterior mitral leaflet, and ring annuloplasty was performed via surgical robot. Robotic mitral valve plasty for severe mitral regurgitation due to chest trauma in Barlow's disease was achieved safely with good clinical and excellent cosmetic results.  相似文献   
27.
The construction of three-dimensional images of the primary current density (PCD) produced by neuronal activity is a problem of great current interest in the neuroimaging community, though being initially formulated in the 1970s. There exist even now enthusiastic debates about the authenticity of most of the inverse solutions proposed in the literature, in which low resolution electrical tomography (LORETA) is a focus of attention. However, in our opinion, the capabilities and limitations of the electro and magneto encephalographic techniques to determine PCD configurations have not been extensively explored from a theoretical framework, even for simple volume conductor models of the head. In this paper, the electrophysiological inverse problem for the spherical head model is cast in terms of reproducing kernel Hilbert spaces (RKHS) formalism, which allows us to identify the null spaces of the implicated linear integral operators and also to define their representers. The PCD are described in terms of a continuous basis for the RKHS, which explicitly separates the harmonic and non-harmonic components. The RKHS concept permits us to bring LORETA into the scope of the general smoothing splines theory. A particular way of calculating the general smoothing splines is illustrated, avoiding a brute force discretization prematurely. The Bayes information criterion is used to handle dissimilarities in the signal/noise ratios and physical dimensions of the measurement modalities, which could affect the estimation of the amount of smoothness required for that class of inverse solution to be well specified. In order to validate the proposed method, we have estimated the 3D spherical smoothing splines from two data sets: electric potentials obtained from a skull phantom and magnetic fields recorded from subjects performing an experiment of human faces recognition.  相似文献   
28.
29.
Acute liver failure (ALF) with macrophage activation syndrome (MAS) is well known as a complication of systemic-onset juvenile idiopathic arthritis (S-JIA). However, liver failure without overt MAS is rare in S-JIA. We encountered two Japanese children with S-JIA in whom ALF developed during the remission of clinical manifestations. ALF without MAS was improved with plasma exchange and cyclosporine A combined with pulse methylprednisolone.  相似文献   
30.
The recent advent of neuroimaging techniques provides an opportunity to examine brain regions related to a specific memory process such as episodic memory encoding. There is, however, a possibility that areas active during an assumed episodic memory encoding task, compared with a control task, involve not only areas directly relevant to episodic memory encoding processes but also areas associated with other cognitive processes for on-line information. We used positron emission tomography (PET) to differentiate these two kinds of regions. Normal volunteers were engaged in deep (semantic) or shallow (phonological) processing of new or repeated words during PET. Results showed that deep processing, compared with shallow processing, resulted in significantly better recognition performance and that this effect was associated with activation of various brain areas. Further analyses revealed that there were regions directly relevant to episodic memory encoding in the anterior part of the parahippocampal gyrus, inferior frontal gyrus, supramarginal gyrus, anterior cingulate gyrus, and medial frontal lobe in the left hemisphere. Our results demonstrated that several regions, including the medial temporal lobe, play a role in episodic memory encoding.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号