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   3001篇
  免费   539篇
  国内免费   246篇
  3786篇
  2024年   9篇
  2023年   60篇
  2022年   69篇
  2021年   86篇
  2020年   187篇
  2019年   194篇
  2018年   186篇
  2017年   211篇
  2016年   209篇
  2015年   151篇
  2014年   159篇
  2013年   703篇
  2012年   104篇
  2011年   146篇
  2010年   86篇
  2009年   106篇
  2008年   114篇
  2007年   121篇
  2006年   103篇
  2005年   84篇
  2004年   76篇
  2003年   60篇
  2002年   52篇
  2001年   41篇
  2000年   40篇
  1999年   34篇
  1998年   21篇
  1997年   29篇
  1996年   20篇
  1995年   24篇
  1994年   18篇
  1993年   23篇
  1992年   16篇
  1991年   13篇
  1990年   9篇
  1989年   16篇
  1988年   10篇
  1987年   11篇
  1986年   14篇
  1985年   16篇
  1984年   13篇
  1983年   7篇
  1982年   10篇
  1981年   14篇
  1980年   16篇
  1979年   18篇
  1978年   17篇
  1977年   30篇
  1976年   18篇
  1975年   12篇
排序方式: 共有3786条查询结果,搜索用时 15 毫秒
91.
92.
The development of cognitive control enables children to better resist acting based on distracting information that interferes with the current action. Cognitive control improvement serves different functions that differ in part by the type of interference to resolve. Indeed, resisting to interference at the task‐set level or at the response‐preparation level is, respectively, associated with cognitive flexibility and inhibition. It is, however, unknown whether the same neural mechanism underlies these two functions across development. Studies in adults have revealed the contribution of midfrontal theta (MFT) oscillations in interference resolution. This study investigated whether MFT is involved in the resolution of different types of interference in two age groups identified as corresponding to different latent structures of executive functions. Preschool (4–6 years) and school children (6–8 years) were tested with a task involving interference at the response level and/or the task‐set level while (electroencephalogram) EEG was recorded. Behaviorally, response time and accuracy were affected by task‐set. Both age groups were less accurate when the interference occurred at the task‐set level and only the younger group showed decreased accuracy when interference was presented at the response‐preparation level. Furthermore, MFT power was increased, relative to the baseline, during the resolution of both types of interference and in both age groups. These findings suggest that MFT is involved in immature cognitive control (i.e., preschool and school‐ages), by orchestrating its different cognitive processes, irrespective of the interference to resolve and of the level of cognitive control development (i.e., the degree of differentiation of executive functions).  相似文献   
93.
IntroductionLevel 2 driving automation features, such as adaptive cruise control (ACC) combined with lane centering, primarily communicate their operating statuses through the instrument cluster. It remains unclear how interface-specific training and display content influence the ability to understand Level 2 activity in production vehicles.MethodsEighty participants viewed videos recorded from the driver’s point of view in a variety of driving scenarios with Level 2 activity displayed in the instrument cluster of a 2017 Mercedes-Benz E-Class. Half viewed one of two instrument cluster layouts (simple or complex), and half received an orientation to the interface before the experiment. After each video, they were asked about the scenario they had just seen. We then examined what information in the displays participants used to identify Level 2 activity and the usability of the displays.ResultsTraining improved recognition accuracy of when lane centering was temporarily inactive and understanding of why it was inactive. Neither training nor display content affected the ability to recognize when ACC had adjusted the vehicle’s speed or detected a vehicle ahead, or when ACC initially did not detect a lead vehicle and understanding of why it had not detected it. Both factors influenced which sources of information participants used to determine Level 2 activity. Recognition accuracy of system activity improved when participants used valid sources of information. Training, but not display content, improved lane centering usability, but not ACC usability.DiscussionBasic training improves detection of notifications that potentially require further driver action, but not of those that display persistent status information. Training does not result in full understanding of all system notifications or functional limitations, which reinforces the need for intuitive, salient communication about system behavior and its limitations.  相似文献   
94.
Recent evidence suggests humans have an automatic attraction to effort minimization. Yet, how this attraction is associated with response inhibition is still unclear. Here, we used go/no-go tasks to capture inhibitory control in response to stimuli depicting physical activity versus physical inactivity in 59 healthy young individuals. Higher commission errors (i.e., failure to refrain a response to a “no-go” stimulus) indicated lower inhibitory control. Based on the energetic cost minimization theory, we hypothesized that participants would exhibit higher commission errors when responding to physical inactivity stimuli rather than physical activity stimuli. Mixed effects models showed that, compared to physical activity stimuli, participants exhibited higher commission errors when responding to stimuli depicting physical inactivity (odds ratio = 1.59, 95% Confidence Interval = 1.18 to 2.16, p = .003). These results suggest that physical inactivity stimuli might require high response inhibition. This study lends support for the hypothesis that an attraction to effort minimization might affect inhibitory processes in the presence of stimuli related to this minimization. The study pre-registration form can be found at https://doi.org/10.17605/OSF.IO/RKYHB.  相似文献   
95.
隔代教育是指祖辈对孙辈的抚养和教育, 随着经济社会的发展, “隔代教育”已成为“亲代教育”的一种重要补充形式。隔代教育对祖孙两辈人的身心健康均存在“双刃剑”效应。生物进化论、社会交换理论和家庭系统理论为理解隔代教育对孙辈的影响提供了理论支持, 角色紧张和角色强化理论可以加深隔代教育对祖辈影响的认识。未来研究应明确隔代教育的定义和类型, 控制边界因素进行更为深入的综合性研究, 并进一步推进隔代教育的本土化研究。  相似文献   
96.
采用整群抽样法选取1967名青少年被试(平均年龄13.22±0.36岁,男生1018人)进行三年追踪,运用个体定向方法考察青少年早期身体攻击和关系攻击的异质性共发模式及其稳定性、与同伴关系间联系。结果发现三时间点均存在5个身体—关系攻击共发模式组:高身体—关系攻击组、中等身体—关系攻击组、中下身体且低关系攻击组、低身体且中下关系攻击组、低身体—关系攻击组,表明两类攻击总体上表现出水平一致或类似的共发模式,且具跨年龄一致性。各共发模式身份表现出有差异的跨时间稳定性,低攻击组稳定性最高,其次是高攻击组、中等攻击组,低身体且中下关系攻击组转变概率最高。高攻击组同伴拒绝水平最高、同伴接纳最低,低攻击组反之,其他组同伴拒绝水平均显著高于低攻击组,为两类攻击亚组共发模式提供了效度证据。  相似文献   
97.
本研究以281名老年人为研究对象,探讨了城市变迁中的老年人居住地情感认同、领悟社会支持和控制感的关系。研究使用居住地情感认同问卷、领悟社会支持问卷和控制感问卷为研究工具,采用每次间隔6个月,共3次的纵向追踪设计。结果发现:老年人的居住地情感认同可以正向预测领悟社会支持,老年人的领悟社会支持可以正向预测控制感,老年人的领悟社会支持在居住地情感认同和控制感之间起纵向中介作用。本研究结果揭示了城市老年居民的居住地情感认同对控制感的影响机制,也对提升城市老年居民的控制感具有一定的实践意义。  相似文献   
98.
Within the framework of modern evolutionary theory, arguments are reviewed that the nonlegal equivalent of aggressive criminal behavior may have evolved by natural selection among mammals, particularly primates, as part of their overall approach to reproduction. If so, the commission of aggressive crimes (or their nonlegal equivalent) by humans, and even efforts to prevent fellow social group members from being victimized by aggressive crimes, may also be partially explainable in natural selection terms. The plausibility of this deduction was explored, first, by specifying the three elements that a human act must have to be regarded as an aggressive crime. Summarily, these were that (1) injury to a victim must be a likely result of the act, (2) the act must be intended, and (3) the act must elicit negative responses from those witnessing it. The primate behavior literature was examined for evidence that some behavior of nonhumans met all three conditions. Affirmative results were obtained. Therefore, while further research is in order, human aggressive criminal behavior, as well as human efforts to control it, seem to have close parallels in other primates. This would be consistent with the notion that aggressive criminal behavior (along with its condemnation by fellow group members) is part of a social system produced and sustained by natural selection.  相似文献   
99.
100.
Integrity of both cerebral hemispheres is required to control in-phase or anti-phase coupling of ipsilateral hand and foot oscillations, as shown by the impairment of these tasks when performed on the healthy side of hemiplegic patients. On this basis, coupling of hand–foot movements was analysed in a right-handed subject (ME) who underwent a total resection of the corpus callosum. Oscillations of the prone hand and foot, paced by a metronome at different frequencies, as well as EMG activity in extensor carpi radialis (ECR) and tibialis anterior (TA) muscles were analysed by measuring the average phase difference between the hand and foot movements and EMG cycles.

ME performed in-phase movements (right-hand extension coupled to right-foot dorsal flexion) at frequencies up to 3 Hz, though the hand cycle progressively lagged the foot cycle as the frequency increased. At 3 Hz the hand lag reached −142° (as compared to about 25° in healthy subjects). The lag increased even further after application of an inertial load to the hand, reaching 180° at 1.8 Hz (about 50° in healthy subjects). ME's hand lag is caused by the lack of any anticipatory reaction in hand movers. In contrast to healthy subjects, which activate the ECR earlier than the TA when the frequency increases, ME activated the ECR later than TA at all frequencies higher than 0.9 Hz.

Anti-phase movements (hand extension coupled to foot plantar flexion) were performed only upto 1 Hz in unloaded conditions. At 0.6 Hz, movements were in tight phase-opposition (3°), but at 1 Hz, the hand lag reached −34° because of a delayed ECR activation. After hand loading ME was unable to couple movements in anti-phase. In contrast, normal subjects maintain a tight anti-phase coupling up to 2.0 Hz, both with an unloaded or loaded hand. Similar deficits were observed by ME when performing in-phase and anti-phase coupling on the left side, as well as when he was blindfolded.

In normal subjects, an anticipated muscular activation of hand movers compensates for hand loading. Since this compensation must depend on monitoring the hand delay induced by loading, the absence in ME of such compensatory reaction suggests that callosal division had apparently compromised the mechanisms sustaining feedback compensation for differences in the biomechanical limb properties. They also confirm and reinforce the idea that elaboration of the afferent message, aiming at controlling the phase of the movement association, needs the co-operation of both cerebral hemispheres.  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