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   1679篇
  免费   40篇
  国内免费   15篇
耳鼻咽喉   745篇
儿科学   33篇
妇产科学   1篇
基础医学   212篇
口腔科学   116篇
临床医学   101篇
内科学   17篇
皮肤病学   1篇
神经病学   324篇
特种医学   11篇
外科学   30篇
综合类   53篇
预防医学   25篇
药学   23篇
  1篇
中国医学   24篇
肿瘤学   17篇
  2023年   19篇
  2022年   38篇
  2021年   59篇
  2020年   40篇
  2019年   42篇
  2018年   55篇
  2017年   60篇
  2016年   59篇
  2015年   58篇
  2014年   74篇
  2013年   361篇
  2012年   89篇
  2011年   91篇
  2010年   64篇
  2009年   81篇
  2008年   79篇
  2007年   67篇
  2006年   57篇
  2005年   45篇
  2004年   37篇
  2003年   28篇
  2002年   19篇
  2001年   14篇
  2000年   14篇
  1999年   26篇
  1998年   16篇
  1997年   13篇
  1996年   10篇
  1995年   7篇
  1994年   12篇
  1993年   4篇
  1992年   7篇
  1991年   8篇
  1990年   4篇
  1989年   9篇
  1988年   6篇
  1987年   3篇
  1986年   10篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   7篇
  1980年   10篇
  1979年   5篇
  1978年   7篇
  1977年   3篇
  1975年   1篇
  1974年   3篇
  1973年   2篇
排序方式: 共有1734条查询结果,搜索用时 15 毫秒
121.
Epilepsy is a frequent neurologic disease in childhood, characterized by recurrent seizures and sometimes with major effects on social, behavioral, and cognitive development. Childhood focal epilepsies particularly are age-related diseases mainly occurring during developmental critical periods. A complex interplay between brain development and maturation processes and susceptibility genes may contribute to the development of various childhood epileptic syndromes associated with language and cognitive deficits. Indeed, the Landau-Kleffner syndrome (LKS), the continuous spike-and-waves during sleep syndrome (CSWS), and the benign childhood epilepsy with centrotemporal spikes (BCECTS) or benign rolandic epilepsy, are different entities that are considered as part of a single continuous spectrum of disorders. Genetic predisposition with simple to complex modes of inheritance has long been suspected for this wide group of childhood focal epilepsies. Recent reports on the involvement of the SRPX2 and ELP4 genes with possible roles in cell motility, migration, and adhesion have provided first insights into the complex molecular bases of childhood focal epilepsies.  相似文献   
122.
Single pulse transcranial magnetic stimulation (TMS) was applied to the hand area of the left primary motor cortex or, as a control, to the vertex (STIMULATION: TMS(M1) vs. TMS(vertex)) while right-handed volunteers silently read verbs related to hand actions. We examined three different tasks and time points for stimulation within the same experiment: subjects indicated with their left foot when they (i) had finished reading, (ii) had judged whether the corresponding movement involved a hand rotation after simulating the hand movement, and (iii) had judged whether they would frequently encounter the action verb in a newspaper (TASK: silent reading, motor imagery, and frequency judgment). Response times were compared between TMS(M1) and TMS(vertex), both applied at different time points after stimulus onset (DELAY: 150, 300, 450, 600, and 750 ms). TMS(M1) differentially modulated task performance: there was a significant facilitatory effect of TMS(M1) for the imagery task only (about 88 ms), with subjects responding about 10% faster (compared to TMS(vertex)). In contrast, response times for silent reading and frequency judgments were unaffected by TMS(M1). No differential effect of the time point of TMS(M1) was observed. The differential effect of TMS(M1) when subjects performed a motor imagery task (relative to performing silent reading or frequency judgments with the same set of verbs) suggests that the primary motor cortex is critically involved in processing action verbs only when subjects are simulating the corresponding movement. This task-dependent effect of hand motor cortex TMS on the processing of hand-related action verbs is discussed with respect to the notion of embodied cognition and the associationist theory.  相似文献   
123.
In schizophrenia, speech production deficits in patients with positive formal thought disorder (FTD e.g. loosening of associations and derailment) have been attributed to impairments in the semantic network. The brain area implicated in the retrieval of associated (i.e. relational) concepts is the hippocampus, a key region in the psychopathology of schizophrenia. However, its role in schizophrenic speech production and FTD in particular is yet little understood.

To investigate the neural correlates of associative verbal retrieval, twelve patients with schizophrenia with varying degrees of FTD and twelve matched healthy control subjects underwent a free verbal association (FVA), a semantic (SVF) and a phonological verbal fluency (PVF) task while brain activity was measured with fMRI. The tasks varied in the relational binding operations needed for linking the stimulus to the respective response.

Compared to control subjects, patients revealed attenuated left hippocampal activity during both semantic word generation tasks (FVA, SVF). Contrasting verbal fluency with FVA, a failure in recruiting the anterior cingulate gyrus emerged in the patient group. A negative correlation was found between right middle temporal activity and the severity of FTD during FVA.

The hippocampus seems to play a major role in word generation. In schizophrenia, attenuated hippocampal activity during semantic tasks strengthens the hypothesis of impaired relational memory processes, affecting thought and language.  相似文献   

124.
Pierre Robin Sequence (PRS) is a congenital craniofacial anomaly distinguished by the presence of micrognathia, glossoptosis, and upper airway obstruction. Cleft palate occurs in over 3/4 of patients with PRS. The wide U-shape cleft and airway dysfunction create challenges in clinical management. Currently, disputes exist on the treatment protocol and prognosis of cleft palate management among patients with PRS. This review is focused on the deformity features, intervention timing, technique selection, airway support, and outcome evaluation of cleft palate among patients with PRS, aiming to provide reference to further evolution in the management of PRS-related cleft palate.  相似文献   
125.
Aims: Many fMRI protocols for localizing speech comprehension have been described, but there has been little quantitative comparison of these methods. We compared five such protocols in terms of areas activated, extent of activation, and lateralization. Methods: fMRI BOLD signals were measured in 26 healthy adults during passive listening and active tasks using words and tones. Contrasts were designed to identify speech perception and semantic processing systems. Activation extent and lateralization were quantified by counting activated voxels in each hemisphere for each participant. Results: Passive listening to words produced bilateral superior temporal activation. After controlling for prelinguistic auditory processing, only a small area in the left superior temporal sulcus responded selectively to speech. Active tasks engaged an extensive, bilateral attention, and executive processing network. Optimal results (consistent activation and strongly lateralized pattern) were obtained by contrasting an active semantic decision task with a tone decision task. There was striking similarity between the network of brain regions activated by the semantic task and the network of brain regions that showed task‐induced deactivation, suggesting that semantic processing occurs during the resting state. Conclusions: fMRI protocols for mapping speech comprehension systems differ dramatically in pattern, extent, and lateralization of activation. Brain regions involved in semantic processing were identified only when an active, nonlinguistic task was used as a baseline, supporting the notion that semantic processing occurs whenever attentional resources are not controlled. Identification of these lexical‐semantic regions is particularly important for predicting language outcome in patients undergoing temporal lobe surgery.  相似文献   
126.
Purpose: To evaluate cortical auditory function, including speech recognition, in children with benign rolandic epilepsy (BRE).
Methods: Fourteen children, seven patients with BRE and seven matched controls, underwent audiometric and behavioral testing, simultaneous EEG recordings, and auditory-evoked potential recordings with speech and tones. Speech recognition was tested under multiple listening conditions.
Results: All participants demonstrated normal speech recognition abilities in quiet, as well as normal peripheral and subcortical auditory function. BRE patients performed significantly worse than controls when speech recognition was tested under adverse listening conditions, including background noise. Five BRE patients who were impaired on two or more tests had centrotemporal spiking on awake EEG. There were no significant group differences in the latency or amplitude of early N100 cortical responses to speech or tones. Conversely, the mismatch negativity, a preattentive index of cortical processing that is elicited passively, was absent or prolonged for speech, but not tones, in BRE patients as compared to controls.
Discussion: Children with BRE demonstrated specific speech recognition impairments. Our evoked potential findings indicate that these behavioral impairments reflect dysfunction of nonprimary auditory cortex and cannot be attributed solely to attention difficulties. A possible association between auditory impairments and centrotemporal spiking (>1/min) on awake EEG was identified. The pattern of speech recognition impairments observed is a known risk factor for academic difficulties in school-age children. Our results underscore the importance of comprehensive auditory testing, using behavioral and electrophysiological measures, in children with BRE.  相似文献   
127.
目的 分析学龄前听障儿童助听后言语流畅性的特征,探讨辅听装置、年龄、性别、语训时长对其言语流畅性的影响.方法 以109例3.5~6.5岁学龄前健听及听障儿童为研究对象,其中健听儿童30例(健听组),双耳佩戴助听器的听障儿童28例(助听器组),右耳植入人工耳蜗的听障儿童26例(人工耳蜗组),同时佩戴助听器和人工耳蜗双耳双模式助听的听障儿童25例(双模式组),通过主题对话的形式分别采集各组儿童的语音样本,比较各组儿童在自发性言语语言任务下的语速、停顿、重复和拖延差异;分析辅听装置、年龄、性别、语训时长等因素对听障儿童言语流畅性的影响.结果 ①健听组儿童的语速显著高于其他三组(P<0.05),健听组停顿次数显著低于人工耳蜗组(P=0.001)和双模式组(P=0.032);健听组拖延次数显著低于助听器组(P=0.001)和双模式组(P=0.001),极显著低于人工耳蜗组(P<0.001);②不同性别听障儿童语速、停顿、重复次数和拖延次数差异无统计学意义(P>0.05),而助听器组语速显著高于人工耳蜗组(P=0.045),人工耳蜗组停顿次数显著高于助听器组(P=0.028);3.5~5岁听障儿童语速显著低于5.1~6.5岁组(P=0.042);语训0~2.5年听障儿童语速显著低于语训>2.5年者(P=0.002),停顿及重复次数均高于语训>2.5年者(分别P=0.047,P=0.02).结论 听障儿童的语速低于健听儿童,停顿次数、拖延次数高于健听儿童;年龄、辅听装置、语训时长影响学龄前听障儿童的言语流畅性,性别影响不大.  相似文献   
128.
Being related to the adoption of new beliefs, attitudes and, ultimately, behaviors, analyzing online communication is of utmost importance for medicine. Multiple health care, academic communities, such as information seeking and dissemination and persuasive technologies, acknowledge this need. However, in order to obtain understanding, a relevant way to model online communication for the study of behavior is required. In this paper, we propose an automatic method to reveal process models of interrelated speech intentions from conversations. Specifically, a domain-independent taxonomy of speech intentions is adopted, an annotated corpus of Reddit conversations is released, supervised classifiers for speech intention prediction from utterances are trained and assessed using 10-fold cross validation (multi-class, one-versus-all and multi-label setups) and an approach to transform conversations into well-defined, representative logs of verbal behavior, needed by process mining techniques, is designed. The experimental results show that: (1) the automatic classification of intentions is feasible (with Kappa scores varying between 0.52 and 1); (2) predicting pairs of intentions, also known as adjacency pairs, or including more utterances from even other heterogeneous corpora can improve the predictions of some classes; and (3) the classifiers in the current state are robust to be used on other corpora, although the results are poorer and suggest that the input corpus may not sufficiently capture varied ways of expressing certain speech intentions. The extracted process models of interrelated speech intentions open new views on grasping the formation of beliefs and behavioral intentions in and from speech, but in-depth evaluation of these conversational models is further required.  相似文献   
129.
一组普通话音位平衡单音节字表的文字编撰   总被引:4,自引:2,他引:4  
目的编写一组适用于言语识别率测试的音位平衡的单音节测听词表。方法为兼顾测试的可靠性与临床实践中的效率,本课题将简短原则、音位平衡原则、常用字原则、覆盖原则、表间等价性等作为词表编写的主要原则。共设计了30张词表、每张词表包含25个单音节测试项。参照《声学手册》中的汉语音位一维概率分布,计算得到汉语拼音的22个声母(含零声母)、36个韵母、4个声调在30张词表、750个单音节测试项中的分布频次。基于音位平衡原则,通过计算机辅助编程和手动调整,从现代汉语常用字表的一级最常用汉字2500字和常用词表4000词中的单字词表中进行音节编选。结果形成了30张包含声母、韵母、声调在内的音位分配表。选取了489个音节,编撰了30张遵循音位平衡的单音节字表,每张表25字。结论该表文字稿是今后制作汉语音位平衡的单音节语音测试录音材料的基础。  相似文献   
130.
宋秋桂 《实用医技杂志》2006,13(22):3931-3932
目的尽快建立腭裂术后正确的发音部位与发音方法,去除过度鼻音,提高患者的语音清晰度。方法对18例腭成形术后且腭咽闭合良好的患者进行语音训练。包括训练前后语音清晰度测试与评定。结果患者语音清晰度从训练前的47.33%提高到训练后93.67%,平均提高45.97%,经t检验,差异具有显著性(P<0.05)。结论集中系统并辅以个性化语音训练,可以使腭裂术后腭咽闭合功能良好的患者,语音清晰度提高到与正常人基本一致。  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