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   2076篇
  免费   245篇
  国内免费   87篇
  2408篇
  2024年   4篇
  2023年   37篇
  2022年   17篇
  2021年   33篇
  2020年   90篇
  2019年   119篇
  2018年   81篇
  2017年   123篇
  2016年   97篇
  2015年   70篇
  2014年   77篇
  2013年   376篇
  2012年   57篇
  2011年   79篇
  2010年   41篇
  2009年   107篇
  2008年   112篇
  2007年   89篇
  2006年   64篇
  2005年   88篇
  2004年   75篇
  2003年   60篇
  2002年   57篇
  2001年   65篇
  2000年   41篇
  1999年   29篇
  1998年   42篇
  1997年   32篇
  1996年   24篇
  1995年   56篇
  1994年   19篇
  1993年   6篇
  1992年   12篇
  1991年   10篇
  1989年   6篇
  1988年   10篇
  1987年   4篇
  1986年   2篇
  1985年   8篇
  1984年   12篇
  1983年   11篇
  1982年   5篇
  1981年   7篇
  1980年   15篇
  1979年   12篇
  1978年   7篇
  1977年   8篇
  1976年   5篇
  1975年   2篇
  1974年   4篇
排序方式: 共有2408条查询结果,搜索用时 15 毫秒
51.
The acute and chronic effects of cocaine and d-amphetamine on food-reinforced behavior were investigated in pigeons responding on a two-component multiple schedule. In one component, the behavioral task consisted of the same chain of conditional discriminations each session (performance). In the other component, the chain of conditional discriminations was changed from session to session (learning). In comparison to control sessions, both acute cocaine and d-amphetamine increased errors in each component of the multiple schedule. Responding in the learning component, however, was generally disrupted at lower doses than those that affected responding in the performance component. At high doses, both drugs produced pauses in responding in each component in three of the four subjects. Pausing engendered by d-amphetamine was approximately twice as long as that under cocaine. Upon chronic administration, both the pausing and error-increasing effects of each drug diminished. Drug-induced changes in timeout responding, however, did not decrease during chronic administration. Redeterminations of the d-amphetamine dose-effect curves following chronic cocaine administration suggested the existence of cross-tolerance between cocaine and d-amphetamine. Both the acute and chronic data are consistent with the view that conditions of stimulus control may modulate the behavioral effects of drugs.  相似文献   
52.
53.
The current study investigates two recently identified threats to the construct validity of behavioral inhibition as a core deficit of attention-deficit/hyperactivity disorder (ADHD) based on the stop-signal task: calculation of mean reaction time from go-trials presented adjacent to intermittent stop-trials, and non-reporting of the stop-signal delay metric. Children with ADHD (n = 12) and typically developing (TD) children (n = 11) were administered the standard stop-signal task and three variant stop-signal conditions. These included a no-tone condition administered without the presentation of an auditory tone; an ignore-tone condition that presented a neutral (i.e., not associated with stopping) auditory tone; and a second ignore-tone condition that presented a neutral auditory tone after the tone had been previously paired with stopping. Children with ADHD exhibited significantly slower and more variable reaction times to go-stimuli, and slower stop-signal reaction times relative to TD controls. Stop-signal delay was not significantly different between groups, and both groups’ go-trial reaction times slowed following meaningful tones. Collectively, these findings corroborate recent meta-analyses and indicate that previous findings of stop-signal performance deficits in ADHD reflect slower and more variable responding to visually presented stimuli and concurrent processing of a second stimulus, rather than deficits of motor behavioral inhibition.  相似文献   
54.
实际应用中测验往往具有多维结构, 如果仍采用单维IRT方法进行等值, 会得到不准确的结果。因此对于多维结构的测验, 需要使用多维IRT等值方法来实现参数的转换。基于共同题设计, 文章通过模拟研究的方法, 考察了不同铆测验设计下几种多维IRT等值方法的表现, 同时考虑了测验长度、两个维度题目数量的比例、铆测验长度、铆测验的选择策略、两个维度之间的相关和等值群体的能力水平差异六个因素的影响。所比较的多维IRT等值方法有:均值/均值(MM)方法, 均值/标准差(MS)方法, Stoking-Lord (SL)方法, Haebara (HB)方法, 最小平方(LS)方法。结果显示:(1) SL, HB和LS方法得到的等值误差均方根最小, 且在各条件下表现较为稳定。(2) MM和MS方法在非等组条件下呈现出很大的误差均方根。(3)铆测验设计对SL, HB和LS方法的等值结果没有显著影响。(4)在两个维度之间的相关较高, 测验长度和铆测验长度较长, 等值群体的能力水平没有差异的条件下, SL, HB和LS方法得到的等值误差均方根最小。  相似文献   
55.
工作投入研究的现状   总被引:15,自引:0,他引:15  
工作投入指的是一种与工作相关的积极、完满的情绪与认知状态,具有持久性和弥散性的特点。工作投入对个体的工作绩效和某些工作态度及行为变量,以及顾客满意度、生产力、利润率和单位总体绩效等组织结果变量均具有一定的影响。工作投入的影响因素包括个体特征因素、与工作相关的因素以及与家庭相关的因素等3个方面。文章在对工作投入的相关研究进行全面述评的基础上,指出未来的研究有必要进一步加强对工作投入的干预机制等五方面问题的探讨  相似文献   
56.
注意缺陷多动障碍(ADHD)的发病群体多为5岁以后的儿童,主要临床表现是多动、冲动,注意力无法集中,对一项任务不能够有规划进行下去,而且脾气暴躁、易怒。近年来,心理学界、神经科学界和教育学界等对ADHD的研究取得了很多进展。本文概括性地介绍了ADHD病症的基本特征,目前对于患者脑机制损害的研究,并从药理学和行为学等方面讨论了ADHD的治疗方法和手段。  相似文献   
57.
图形项目记忆与位置来源提取的ERP研究   总被引:1,自引:0,他引:1  
采用事件相关电位(ERP)方法研究大学生图形项目记忆与位置来源提取新/旧效应的时、空分布特征。学习屏幕左侧(或右侧)呈现的图形后在屏幕中央呈现某一测验项目(已学图形或新图形),对受试者进行两类测验:其一是判断该项目是否已学过;其二是将从某侧学过的测验项目判断为目标,而将其它测验项目判断为非目标的来源测验(排除任务)。实验结果表明:图形位置来源提取比项目再认新/旧效应的头皮分布更广,持续时程更长;与前人相同实验范式的研究结果相比,本研究位置来源提取效应的头皮分布范围较广;非目标-旧图形与目标图形新/旧效应的头皮激活程度不同。上述结果说明:图形位置来源提取比项目再认激活的大脑区域更多,这与双重加工模型的观点一致;实验范式和来源知觉的特性共同调节来源记忆新/旧效应的时、空分布特征;意识水平对来源信息提取的新/旧效应存在一定的影响  相似文献   
58.
This study examined the contributions of several important domains of functioning to attention‐deficit/hyperactivity disorder (ADHD) symptoms and conduct problems. Specifically, we investigated whether cognitive inhibition, emotion regulation, emotionality, and disorganized attachment made independent and specific contributions to these externalizing behaviour problems from a multiple pathways perspective. The study included laboratory measures of cognitive inhibition and disorganized attachment in 184 typically developing children (M age = 6 years, 10 months, SD = 1.7). Parental ratings provided measures of emotion regulation, emotionality, and externalizing behaviour problems. Results revealed that cognitive inhibition, regulation of positive emotion, and positive emotionality were independently and specifically related to ADHD symptoms. Disorganized attachment and negative emotionality formed independent and specific relations to conduct problems. Our findings support the multiple pathways perspective on ADHD, with poor regulation of positive emotion and high positive emotionality making distinct contributions to ADHD symptoms. More specifically, our results support the proposal of a temperamentally based pathway to ADHD symptoms. The findings also indicate that disorganized attachment and negative emotionality constitute pathways specific to conduct problems rather than to ADHD symptoms.  相似文献   
59.
Reliability has become an integral component of the design intent of embedded cyber-physical systems. Safety-critical embedded systems are designed with specific reliability targets, and design practices include the appropriate allocation of both spatial and temporal redundancies in the implementation to meet such requirements. With increasing complexity of such systems and considering the large number of components in such systems, redundancy allocation requires a formal scientific basis. In this work, we profess the analysis of the redundancy requirement upfront with the objective of making it an integral part of the specification. The underlying problem is one of synthesizing a formal specification with built-in redundancy artifacts, from the formal properties of the error-free system, the error probabilities of the control components, and the reliability target. We believe that upfront formal analysis of redundancy requirements is important in budgeting the resource requirements from a cost versus reliability perspective. Several case-studies from the automotive domain highlight the efficacy of our proposal.  相似文献   
60.
Decision making is a two‐stage process, consisting of, first, consideration set construction and then final choice. Decision makers can form a consideration set from a choice set using one of two strategies: including the options they wish to further consider or excluding those they do not wish to further consider. The authors propose that decision makers have a relative preference for an inclusion (vs. exclusion) strategy when choosing from large choice sets and that this preference is driven primarily by a lay belief that inclusion requires less effort than exclusion, particularly in large choice sets. Study 1 demonstrates that decision makers prefer using an inclusion (vs. exclusion) strategy when faced with large choice sets. Study 2 replicates the effect of choice set size on preference for consideration set construction strategy and demonstrates that the belief that exclusion is more effortful mediates the relative preference for inclusion in large choice sets. Studies 3 and 4 further support the importance of perceived effort, demonstrating a greater preference for inclusion in large choice sets when decision makers are primed to think about effort (vs. accuracy; Study 3) and when the choice set is perceived as requiring more effort because of more information being presented about each alternative (vs. more alternatives in the choice set; Study 4). Finally, Study 5 manipulates consideration set construction strategy, showing that using inclusion (vs. exclusion) in large choice sets leads to smaller consideration sets, greater confidence in the decision process, and a higher quality consideration set.  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