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   1211篇
  免费   247篇
  国内免费   150篇
  2024年   3篇
  2023年   22篇
  2022年   25篇
  2021年   53篇
  2020年   69篇
  2019年   67篇
  2018年   61篇
  2017年   67篇
  2016年   82篇
  2015年   54篇
  2014年   70篇
  2013年   199篇
  2012年   56篇
  2011年   64篇
  2010年   34篇
  2009年   51篇
  2008年   60篇
  2007年   51篇
  2006年   55篇
  2005年   33篇
  2004年   42篇
  2003年   48篇
  2002年   34篇
  2001年   37篇
  2000年   24篇
  1999年   21篇
  1998年   14篇
  1997年   11篇
  1996年   13篇
  1995年   18篇
  1994年   18篇
  1993年   23篇
  1992年   16篇
  1991年   11篇
  1990年   10篇
  1989年   5篇
  1988年   6篇
  1987年   2篇
  1986年   8篇
  1985年   12篇
  1984年   4篇
  1983年   2篇
  1982年   6篇
  1981年   4篇
  1980年   4篇
  1979年   6篇
  1978年   12篇
  1977年   10篇
  1976年   8篇
  1975年   3篇
排序方式: 共有1608条查询结果,搜索用时 15 毫秒
281.
Abstract: An experiment was conducted to examine the effects of time uncertainty and instructed muscle tension on the reaction time of elbow flexion. Twenty-two right-handed subjects were asked to respond to an audio stimulus by flexing their right elbow under four conditions (2 time uncertainty × 2 instructed muscle tension). Electromyograms (EMGs) were recorded from the biceps and triceps on the subject's right side. Reaction time was divided into premotor time and motor time, based on the difference between the EMG and elbow flexion response. Analysis of reaction time showed that the effects of time uncertainty and instructed muscle tension were additive. Time uncertainty affected premotor time only, and instructed muscle tension affected motor time only. These results are discussed in terms of the assumption that premotor time is a reflection of the central nervous system and motor time is a reflection to the peripheral muscle system.  相似文献   
282.
信息加工的阶段及其年龄差异源   总被引:4,自引:0,他引:4  
选择7—19岁的被试140名,对四种不同任务进行操作。结果表明,相同图形的空间调整过程速度除7岁年龄段以外,其余年龄段变化较小;不同图形调整过程速度、不同字母转换过程速度和不同字母的转换差异速度到了11岁以后,基本保持不变,而且,图形调整速度和字母转换速度基本相同;指数函数能较好地描述选择和反应过程速度随年龄增长而变化的特性,不能较好地描述字母转换过程速度随年龄增长而变化的特性,直线方程则不能很好地描述不同任务加工速度随年龄增长而变化的特性;最后,本研究对信息加工阶段及其年龄差异源进行了讨论。  相似文献   
283.
Direct observation was used to examine multiple aspects of care provided in a proprietary nursing home. The samples were taken at random intervals, 7 days per week for 5 weeks, across several categories of environmental and resident conditions as well as staff and resident activity. Results showed a high degee of compliance with predefined standards (based on current federal regulations) for environmental and resident conditions. Overall distributions of resident and staff activity showed results similar to those found in previous studies, with residents spending most of their time engaged in nonsocial activity and staff spending the majority of their time engaged in nonresident work. When data were analyzed across areas of the facility, times of day, and weekdays versus weekends, some differences were noted. Weekend versus weekday comparisons showed higher resident:staff ratios on weekends and more resident inactivity, but no significant differences in environmental or resident conditions. In addition, more frequent resident care, resident interaction, and resident activity were observed in Medicare units than in non-Medicare units. Results are discussed in terms of federal requirements for monitoring the quality of care in nursing homes and the potential use of time sampling expressly for this purpose.  相似文献   
284.
Three experimentally sophisticated chimpanzees (Pan), Akira, Chloe, and Ai, were trained on visual search performance using a modified multiple-alternative matching-to-sample task in which a sample stimulus was followed by the search display containing one target identical to the sample and several uniform distractors (i.e., negative comparison stimuli were identical to each other). After they acquired this task, they were tested for transfer of visual search performance to trials in which the sample was not followed by the uniform search display (odd-item search). Akira showed positive transfer of visual search performance to odd-item search even when the display size (the number of stimulus items in the search display) was small, whereas Chloe and Ai showed a transfer only when the display size was large. Chloe and Ai used some nonrelational cues such as perceptual isolation of the target among uniform distractors (so-called pop-out). In addition to the odd-item search test, various types of probe trials were presented to clarify the controlling relations in multiple-alternative matching to sample. Akira showed a decrement of accuracy as a function of the display size when the search display was nonuniform (i.e., each "distractor" stimulus was not the same), whereas Chloe and Ai showed perfect performance. Furthermore, when the sample was identical to the uniform distractors in the search display, Chloe and Ai never selected an odd-item target, but Akira selected it when the display size was large. These results indicated that Akira's behavior was controlled mainly by relational cues of target-distractor oddity, whereas an identity relation between the sample and the target strongly controlled the performance of Chloe and Ai.  相似文献   
285.
A sample of 250 people completed a questionnaire where they rated 30 statements describing their behavior and experiences during a recent time pressure situation. A factor analysis resulted in three factors: Personal Burden, Work Problems and Difficulties, and Challenge Orientation. People high on this last factor liked the excitement of being under pressure, were very absorbed in the task, and showed signs of being effective in dealing with the situation. Such individuals were having what has been identified as a flow experience often observed in sports and the arts. The results of this study suggest that effective coping with time pressure is related to taking a task-oriented attitude, avoiding self-preoccupation, and using time management skills to focus on successful achievement.  相似文献   
286.
The ability to represent emotions is an important capacity for the understanding of discourse. In the current literature, it is unclear whether older adults represent emotion information in the course of language processing, in particular as it relates to developing an adequate mental model of characters in narratives. We addressed this issue in two studies, one assessing emotion activation at the word level and the other at the mental model level. In the first experiment, subjects performed a lexical decision task in which words were drawn from both logic- and emotion-based categories. For both category types, priming was evident for young and old. In the second experiment, subjects read passages with emotion information that was consistent or inconsistent with the implied emotional tone. Both age groups showed an increase in reading time in response to inconsistent emotion information, indicating that the protagonist's emotional state was represented while reading. Results of these studies generally suggest age preservation in the activation of emotion information in language processing.  相似文献   
287.
人体系统的非优性与疾病的时空特征   总被引:1,自引:1,他引:0  
人体系统并非完美,生命抛物线是由生理年龄、社会年龄、人体熵三大要素在非线性作用下相干的结果,从而呈现一种复杂的网状“大X构架”。每一个交叉点都具有阶段性态变的意义和对生命质量的表征。疾病是人体系统非优的必然。熵压决定了熵的退行性运动,从而也决定了生命时间的有限性。疾病是熵增过程造成机体不同程度封闭的结果。每次疾病都是对熵的增压,造成机体的物质丢失、时间丢失与跳跃,出现熵运动方面的引力偏折,从而在局  相似文献   
288.
This study examined the percentage time estimates of momentary time sampling against the real time obtained with handheld computers in a natural setting. Twenty-two concurrent observations were conducted in elementary schools by one observer who used 15-s momentary time sampling and a second who used a handheld computer. Results for the six behaviors showed a close correspondence between the momentary time sampling percentage observation intervals and the real time percentage observation time, although 15-s momentary time sampling tended not to sample low-frequency short-duration behaviors. The results confirmed laboratory findings that short-interval momentary time sampling estimates percentage time accurately for a wide range of behavior frequencies and durations, and suggested that observers using momentary time sampling in a natural setting are able to obtain accurate data.  相似文献   
289.
Abstract. This paper outlines some major ideas concerning cosmogony and cosmogony and cosmology that pervade the Hindu conceptual world. The basic source for this discussion is the philosophical literature of some of the principal schools of Hindu thought, such as VaiVaiśika, Sānkhya, and Advaita Vedānta, focusing on the themes of cosmology, time, and soteriology. The core of Hindu philosophical thinking regarding these issues is traced back to the Rk Vedic cosmogonical speculations, analyzed, and contrasted with the "views of the opponent." The relevance of the Hindu worldview for overcoming the conflict between science and religion is pointed out.  相似文献   
290.
Computer simulations of behavior and event records of a child's visual fixation on an adult person were generated and sampled using a modified time sampling procedure. The modified approach required making two independent scoring judgments per observation interval: if the behavior was initiated within the interval, the interval was scored; if the behavior was ongoing precisely at the end of the interval, the interval was again scored. The results showed that the within-interval and end-of-interval scores yielded, respectively, estimates of behavioral frequency and duration. The accuracy of the estimates was a function of the number of observations. Several field studies demonstrated high agreement among observers who employed the measurement system.  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