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   284篇
  免费   21篇
  国内免费   41篇
  2023年   11篇
  2022年   3篇
  2021年   10篇
  2020年   15篇
  2019年   23篇
  2018年   14篇
  2017年   27篇
  2016年   11篇
  2015年   17篇
  2014年   12篇
  2013年   50篇
  2012年   11篇
  2011年   21篇
  2010年   5篇
  2009年   11篇
  2008年   13篇
  2007年   11篇
  2006年   8篇
  2005年   6篇
  2004年   6篇
  2003年   5篇
  2002年   6篇
  2001年   5篇
  2000年   8篇
  1999年   2篇
  1998年   3篇
  1997年   2篇
  1996年   4篇
  1994年   2篇
  1993年   2篇
  1991年   2篇
  1990年   2篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   4篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   3篇
  1976年   1篇
  1975年   2篇
排序方式: 共有346条查询结果,搜索用时 15 毫秒
301.
对临床72例急性期脑出血分别进行CT及MR检查,通过脑内血肿量测定及两住有经验诊断医生的分析诊断,比较两项检查的诊断敏感性,探讨高场强MR在诊断急性脑出血中的价值。测量所得MR各序列和CT血肿量差异无统计学意义。敏感性比较T2*WI和CT组差异无统计学意义,P〈0.01。T1WI和T2WI序列的敏感性相对较差,与CT组比较差异有统计学意义,P〈0.01。MR梯度回波T2*WI对诊断急性脑内血肿的敏感性和CT检查相当,结合常规扫描序列在急性期脑内血肿的诊断和鉴别诊断中具有实际应用价值。  相似文献   
302.
Environmental stimuli during neonatal periods play an important role in the development of cognitive function. In this study, we examined the long-term effects of neonatal tactile stimulation (TS) on spatial working memory (SWM) and related mechanisms. We also investigated whether TS-induced effects could be counteracted by repeated short periods of maternal separation (MS). Wistar rat pups submitted to TS were handled and marked transiently per day during postnatal days 2–9 or 10–17. TS/MS pups were stimulated in the same way as TS pups and then individually separated from their mother for 1 h/day. Their nontactile stimulated (NTS) siblings served as controls. In adulthood, TS and TS/MS rats showed better performance in two versions of the delayed alternation task and superior in vivo long-term potentiation of the hippocampo–prefrontal cortical pathway when compared with controls. Furthermore, there were more doses of A77636 (a selective dopamine D1 agonist) to significantly improve SWM performance in TS and TS/MS rats than in NTS rats, suggesting that activation of prefrontal D1 receptors in TS and TS/MS rats is more optimal for SWM function than in NTS rats. MS did not counteract TS-induced effects because no significant difference was found between TS/MS and TS animals. These data indicate that in early life, external tactile stimulation leads to long-term facilitative effects in SWM-related neural function.  相似文献   
303.
Previous neuroimaging studies have suggested that the neural activity associated with truthful recall, with false memory, and with feigned memory impairment are different from one another. Here, we report a functional magnetic resonance imaging (fMRI) study that addressed an important but yet unanswered question: Is the neural activity associated with intentional faked responses and with errors differentiable? Using a word list learning recognition paradigm, the findings of this mixed event-related fMRI study clearly indicated that the brain activity associated with intentional faked responses was different to the activity associated with errors committed unintentionally. For intentional faked responses, significant activation was found in the ventrolateral prefrontal cortex, the posterior cingulate region, and the precuneus. However, no significant activation was observed for unintentional errors. The results suggest that deception, in terms of feigning memory impairment, is not only more cognitively demanding than making unintentional errors but also utilizes different cognitive processes.  相似文献   
304.
捡了西瓜,就该丢掉芝麻吗——浅谈医源性Wernicke脑病   总被引:3,自引:0,他引:3  
探讨医源性Wernicke脑病(WE)的病因、临床及磁共振图像特点,回顾性分析6例医源性WE病例。医源性WE病前均有禁食史,其临床表现多样。磁共振图像为中脑导水管周围T2WI及Flair高信号。大部分病例补充维生素B1后可好转。提示医源性禁食导致体内维生素B1耗竭是医源性WE的病因,及时补充维生素B1是预防及治疗本病的关键。  相似文献   
305.
This study evaluated the effectiveness of fine motor physical activity with tactile stimulation during two conditions of math problem solving, visual and auditory. Eight 4th and 5th grade students with attention problems participated. Using an alternating treatments design, students solved as many math story problems as they could, presented on worksheets or verbally during two conditions, with and without tactile stimulation during 20 min. Motor behavior, recorded from videotape, and number of correctly completed word problems were measured. Results suggest that fine motor manipulation of a tactile stimulation object reduced excessive motor movement and increased task completion of students with attention problems.  相似文献   
306.
乐国安  李安 《心理科学》2007,30(5):1026-1028
在社会认知中,由于所呈现的刺激都具有复杂的社会意义,其必然会在被试的心理上引起复杂的反应。实验通过对刺激时间的控制来了解个体在知觉阶段与记忆阶段所进行的责任推论是否存在差异。结果表明,工读生在刺激快速呈现时的责任判断与刺激缓慢呈现时的责任推论存在显著差异。  相似文献   
307.
本项工作尝试将人类思维的神经生物学基础研究与人工智能的研究成果相结合, 利用类比生成模型的原理, 开发了一个计算机辅助设计系统“多源类比人脸生成系统”, 并运用此平台开展了fMRI实验, 对人类大脑创造性思维的神经生物学机制进行了探索。实验采用open-ends模式下的“design task”和problem solving模式下的“control task”作为对照, 共采得15名健康成人被试的有效数据。数据结果显示design task与control task相比更为显著地激活了内侧前额叶、额中回、右侧颞上回、前扣带回、双侧海马、楔前叶这些脑区。综合以往研究推测, 内侧前额叶可能更多地与即兴自由创作中对自我信息的表征有关, 颞叶可能与不断产生和输出新颖性的观点有关, 边缘系统则可能主要与创造性活动中的动力驱动作用有关。总的来说, 创造性思维是多个脑区同时参与的高度分布式加工的结果。  相似文献   
308.
Rehabilitation options to promote neuroplasticity may be enhanced when patients are engaged in motor practice during repetitive transcranial magnetic stimulation (rTMS). Twelve participants completed 3 separate sessions: motor practice, motor practice with rTMS, and rTMS only: motor practice consisted of 30 isometric contractions and subthreshold rTMS was 30, 3-s trains at 10 Hz. Assessments included the Box and Block Test (BBT), force steadiness (10% of the maximum voluntary contraction), and TMS (cortical excitability, intracortical inhibition, and intracortical facilitation). Participants significantly increased BBT scores following the combined condition. Force steadiness improved after all 3 conditions (p < .05). TMS outcomes depended on intervention condition with significant increases in facilitation following the motor practice plus rTMS condition. All interventions influenced motor control, yet are likely modulated differently when combining motor practice plus rTMS. These results help guide the clinical utility of rTMS as an intervention to influence motor control.  相似文献   
309.
The authors' aim was to investigate the changes of corticospinal excitability during kinesthetic illusions induced by tendon vibration. Motor-evoked potentials in response to transcranial magnetic stimulation were recorded from the vibrated flexor carpi radialis and its antagonist, extensor carpi radialis. The illusions were evoked under vision conditions without feedback for the position of the wrist (open or closed eyes). In these two conditions motor-evoked potential changes during vibration in the antagonist were not identical. This discrepancy may be a result of 2 simultaneously acting, different and opposite influences and the balance between them depends on visual conditions. Thus, the illusion was accompanied by the facilitation of corticospinal excitability in both vibrated muscle and its antagonist.  相似文献   
310.
The magnetic, mechanical and thermodynamic properties of LaMO3 (M = Ti~Fe) have been systematically investigated using the first-principles calculations. The total magnetic moments of LaMO3 are mainly from the M atom, and the contributions from La and O are very small. For LaTiO3, LaVO3, LaCrO3 and LaMnO3 the total magnetic moments agree well with experiment, while with somewhat larger disagreement for LaFeO3. Using the GGA + U (U = 5.6 eV), the calculated magnetic moment of LaFeO3 is 4.98μB, which is in agreement with experiment data. The elastic constants and Vickers hardness suggest that LaMO3 are mechanically stable and soft materials. The B/G ratios indicate that all of LaMO3 are ductile except LaVO3 and LaCrO3.The LaCrO3 has the highest Debye temperature, while LaVO3 has the lowest Debye temperature.  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