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   955篇
  免费   123篇
  国内免费   279篇
  2024年   2篇
  2023年   18篇
  2022年   47篇
  2021年   42篇
  2020年   54篇
  2019年   31篇
  2018年   46篇
  2017年   54篇
  2016年   52篇
  2015年   39篇
  2014年   55篇
  2013年   83篇
  2012年   64篇
  2011年   78篇
  2010年   71篇
  2009年   51篇
  2008年   68篇
  2007年   76篇
  2006年   101篇
  2005年   84篇
  2004年   60篇
  2003年   51篇
  2002年   24篇
  2001年   17篇
  2000年   17篇
  1999年   12篇
  1998年   9篇
  1997年   6篇
  1996年   5篇
  1995年   6篇
  1994年   5篇
  1993年   7篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   5篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   4篇
  1982年   2篇
  1979年   2篇
排序方式: 共有1357条查询结果,搜索用时 31 毫秒
91.
随着民航行业的快速发展,飞机登机牌的使用率越来越高,而不同航空公司所采用的登机牌在信息内容和布局设计等方面均缺乏相关的设计规范,因此有必要从可用性角度对登机牌进行系统的研究.首先,采用KANO问卷法对登机牌上的文字信息要素进行研究,并基于研究结果设计出新登机牌;然后,从搜索绩效和主观偏好两个方面对新旧登机牌进行比较评价研究.结果显示:①登机牌上必须呈现的信息主要包括登机时间、登机口、航班号、座位号、姓名、日期和目的地七项必要信息,以及可提高旅客使用体验的预计飞行时间信息,但登机牌上不能呈现旅客身份证号码等个人隐私信息;②基于信息要素研究结果重新布局设计的新登机牌在搜索绩效和主观偏好方面均显著优于现有登机牌.本研究结果可为将来的登机牌设计提供科学依据.  相似文献   
92.
93.
The primary purpose of this study was to investigate whether the theory of planned behavior (TPB) mediated the relationship between dialectical thinking and health behaviors. A sample of 285 undergraduates was tested with a dialectical thinking styles scale, health promoting lifestyle profiles, and TPB questionnaires. Structural equation modeling was used for data analysis. Results indicated that all the three dimensions of thinking styles (belief in the connection, acceptance of change, and acceptance of contradiction) exerted significant effects on TPB constructs. Specifically, the connection and the change dimensions had positive effects on health behaviors mediated by TPB, whereas the contradiction dimension had a negative effect. Model 2 showed a satisfactory fit, demonstrating the influential pathways between dialectical thinking and health behaviors. Implications in issues of health promotion and future research are discussed.  相似文献   
94.
It is known that electromyostimulation (EMS) alone or superimposed over voluntary contraction (EV) can effectively improve muscle strength. However, the effect of this type of training on the ability to control force production at submaximal levels is unknown. The authors examined the effects of EV training on steadiness in force production of knee extensors and flexors in older adults. Forty participants, including 20 men and 20 women, 60–77 years of age, were randomly allocated into a control group (CG) and an electromyostimulation superimposed over voluntary contraction (EVG) group. The EVG performed 30 bilateral isometric knee extension and flexion contractions per session, 3 training sessions per week, for 6 weeks. The variations in force production, expressed in absolute (standard deviation [SD]) and relative (coefficient of variation [CV]) terms, were assessed in isometric contractions at 5%, 15% and 25% maximal voluntary contraction (MVC) levels. Results indicated that MVC increased in knee extension and flexion in EVG (p < .05) after the training; steadiness CV also improved at 15% MVC in knee flexion (p < .05) but no significant changes were found in knee extension and steadiness SD. The training-induced changes in MVC were not correlated to steadiness CV that might indicate different mechanisms underlying these adaptations.  相似文献   
95.
In this study, we examine when creativity is positively or negatively related to firm performance. Building on the creation–implementation tension theorized in the literature and the attention capacity perspective, we argue that the relationship between creativity and firm performance is contingent on riskiness orientation, firm size, and realized absorptive capacity. Data were collected from 761 core knowledge employees, 148 CEOs, and 148 HR executives from 148 high‐technology firms. The results indicated that core knowledge employee creativity was negatively related to firm performance when riskiness orientation was high. The relationship was positive when realized absorptive capacity was high. Finally, the relationship was more positive in small firms than in large firms. We discuss the implications of our findings for creativity research and managerial practices.  相似文献   
96.
Decision-making consists of several stages of information processing, including an anticipation stage and an outcome evaluation stage. Previous studies showed that the ventral striatum (VS) is pivotal to both stages, bridging motivation and action, and it works in concert with the ventral medial prefrontal cortex (vmPFC) and the amygdala. However, evidence concerning how the VS works together with the vmPFC and the amygdala came mainly from neuropathology and animal studies; little is known about the dynamics of this network in the functioning human brain. Here we used fMRI combined with dynamic causal modeling (DCM) to investigate the information flow along amygdalostriatal and corticostriatal pathways in a facial attractiveness guessing task. Specifically, we asked participants to guess whether a blurred photo of female face was attractive and to wait for a few seconds (“anticipation stage”) until an unblurred photo of feedback face, which was either attractive or unattractive, was presented (“outcome evaluation stage”). At the anticipation stage, the bilateral amygdala and VS showed higher activation for the “attractive” than for the “unattractive” guess. At the outcome evaluation stage, the vmPFC and the bilateral VS were more activated by feedback faces whose attractiveness was congruent with the initial guess than by incongruent faces; however, this effect was only significant for attractive faces, not for unattractive ones. DCM showed that at the anticipation stage, the choice-related information entered the amygdalostriatal pathway through the amygdala and was projected to the VS. At the evaluation stage, the outcome-related information entered the corticostriatal pathway through the vmPFC. Bidirectional connectivities existed between the vmPFC and VS, with the VS-to-vmPFC connectivity weakened by unattractive faces. These findings advanced our understanding of the reward circuitry by demonstrating the pattern of information flow along the amygdalostriatal and corticostriatal pathways at different stages of decision-making.  相似文献   
97.
焦虑与注意偏向的研究是近年来情绪与认知领域的热点。为探讨特质焦虑个体的注意偏向特点及其返回抑制能力是否受不同线索的调节, 采用特质焦虑量表筛选高特质焦虑大学生29名, 低特质焦虑大学生28名完成线索-靶子任务。要求被试在提示线索消失后, 对位置进行快而准地辨别反应, 分别探索中性和情绪性提示线索下被试的返回抑制。结果发现:(1)在中性线索条件下, 高焦虑个体平均反应时慢于低焦虑个体。(2) 在情绪线索条件下, 高焦虑个体在负性线索下的反应时小于在正性线索下的反应时; 高、低焦虑个体在各种SOA条件下均出现了返回抑制, 但各组返回抑制量受到情绪线索的调节:在正性情绪线索条件下, 两组返回抑制量没有显著差异; 在负性情绪线索下, 高焦虑个体返回抑制量显著小于低焦虑个体。这表明, (1)焦虑个体的注意偏向受到刺激信息的影响:只对负性情绪线索出现注意警觉; (2)只有在涉及负性情绪信息时高、低焦虑个体返回抑制能力才有差异, 高焦虑个体存在对负性情绪线索的抑制困难。  相似文献   
98.
Abstract

Superconducting and mechanical properties of Y1 Ba2Cu3 O7 can be improved by the use of sintering aids. 0·2 wt% of finely divided laser-ablated platinum powder has been mixed with the parent material and produced a dense product with exaggerated grain growth and improved critical current density and Vickers hardness. At higher concentrations of platinum, while the mechanical properties are further improved, the increased density appeared to inhibit access of oxygen for the tetragonal to orthorhombic phase transition and the current density was reduced.  相似文献   
99.
In this study, (Gd1? x Nd x )2(Zr1? x Ce x )2O7 (0 ≤ x ≤ 0.5) ceramics have been prepared by pressureless sintering at 1973 K to investigate the influence of Nd and Ce co-doping on their electrical conductivity. The electrical conductivity of the ceramics was investigated by impedance spectroscopy measurements from 723 to 1173 K over the frequency range of 20 Hz to 2 MHz in air. The measured values obey the Arrhenius relation. For each composition, the grain conductivity gradually increases with increasing temperature from 723 to 1173 K. At a given temperature, it gradually decreases with increasing neodymium and cerium contents from x = 0 to 0.3; thereafter, the grain conductivity exhibits a slight increase with further increasing neodymium and cerium contents up to x = 0.5.  相似文献   
100.
The aim of the present study was to investigate the time course of the positive advantage in the expression classification of faces by recording event-related potentials (ERPs). Although neutral faces were classified more quickly than either happy or sad faces, a significant positive classification advantage (PCA)—that is, faster classification for happy than for sad faces—was found. For ERP data, as compared with sad faces, happy faces elicited a smaller N170 and a larger posterior N2 component. The P3 was modulated by facial expressions with higher amplitudes and shorter latencies for both happy and neutral stimuli than for sad stimuli, and the reaction times were significantly correlated with the amplitude and latency of the P3. Overall, these data showed robust PCA in expression classification, starting when the stimulus has been recognized as a face revealed by the N170 component.  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