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   320篇
  免费   62篇
  国内免费   86篇
  2023年   8篇
  2022年   5篇
  2021年   16篇
  2020年   21篇
  2019年   19篇
  2018年   18篇
  2017年   37篇
  2016年   28篇
  2015年   15篇
  2014年   26篇
  2013年   48篇
  2012年   14篇
  2011年   22篇
  2010年   21篇
  2009年   17篇
  2008年   19篇
  2007年   13篇
  2006年   15篇
  2005年   16篇
  2004年   14篇
  2003年   9篇
  2002年   8篇
  2001年   7篇
  2000年   10篇
  1999年   4篇
  1998年   3篇
  1997年   1篇
  1996年   2篇
  1995年   5篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1983年   2篇
  1981年   2篇
  1980年   2篇
  1979年   3篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有468条查询结果,搜索用时 15 毫秒
461.
Outstanding advantages of OFDM helps high data rate communication systems such as Digital Video Broadcasting (DVB) and mobile worldwide interoperability for microwave access (mobile Wi-MAX). But, OFDM system grieves from grave issue of high PAPR. In OFDM system data output is superposition of multiple sub-carriers and leads to big data. In this case some instantaneous power output might increase greatly and become far higher than the mean power of system. In order to make Neutrosophic data for less PAPR criteria, Gaussian filter based Costas coding is proposed. This paper also proposes feeding the Orthogonal Frequency Division Multiplexed signal (OFDM) into a phase accumulator to obtain frequency modulation, with the aim of reducing the peak to average power ratio (PAPR). For associated radar with modulated waveform mentioned here can be used to enhance the performance. It is widely used to analyze the variation of the output waveform further, the implementation results using MATLAB show that the ratio of average power to peak power is reducing considerably in comparing with the conventional method. Consequently; the signal can assume to fade in a frequency selective channel without an equalizer.  相似文献   
462.
Posadzki, P., Stockl, A., Musonda, P. & Tsouroufli, M. (2010). A mixed‐method approach to sense of coherence, health behaviors, self‐efficacy and optimism: Towards the operationalization of positive health attitudes. Scandinavian Journal of Psychology, 51, 246–252. This study discusses the results of a cross‐sectional survey of healthy college students in Poland. More specifically, it describes, explores, and explains the relationships between psychological variables/models such as health behaviors (HB), sense of coherence (SOC), level of optimism (LOO), and self‐efficacy (SE) among college students. These separate constructs have also been used to operationalize a positive health attitude (PHA) as a novel construct. The social survey was carried out at three higher education institutions in Poland in January 2006. The random sample of 455 undergraduate students was taken from five different faculties: Physiotherapy, Physical Education, Tourism and Recreation, English Philology and Polish Philology. Four reliable and validated research tools were used to collect the data: Juczynsky’s Health Behaviour Inventory (HBI); Antonovsky’s Sense of Coherence Questionnaire (SOC‐29); Schwarzer & Jerusalem’s Generalized Self‐Efficacy Scale (GSES); and Seligman’s Scale (SS). The results indicate statistically significant differences (p < 0.001) between these four variables: for example, the healthier health behaviors the stronger the sense of coherence, level of optimism and self‐efficacy. It was also demonstrated that LOO, SOC, SE, and HB correlate with one another. Finally, these variables create an explicit empirical‐theoretical pattern. All the research results from REGWQ tests, Pearson’s correlation coefficient and cluster analysis suggest the existence of conceptual similarities between these four variables and/or the existence of some broader scientific construct such as PHA. However, this needs to be examined further. These results could be a good indicator for future research among different faculties or age groups.  相似文献   
463.
464.
陈寒  韩玉昌 《心理科学》2004,27(4):807-811
基于内插材料加工对内隐记忆的干扰的研究范式(Martens&Wohers.2002)所带来的启示,满足启动材料与目标词在语义线索上的匹配要求,根据启动材料的数量来控制语义加工水平(量)的大小,探索意识条件下和无意识条件下(阈限下)语义加工水平(量)对内隐记忆的影响。结果表明,无论是意识条件下.还是无意识条件下,内隐记忆成绩随语义加工水平的提高而提高。内插材料加工范式无疑是一种从更微观的角度探讨加工水平对内隐记忆的影响的较好的途径。  相似文献   
465.
466.
Furthering a prior research on two‐person bi‐level multi‐objective decision‐making problems of the leader‐follower Stackelberg game, we present an extended model of bi‐level multi‐objective decision‐making with multiple interconnected decision makers at the lower level. In the model, the upper level decision maker acts as a leader and the lower level decision makers behave as the followers, and inter‐connections and interactions exist among these followers in decision‐making scenarios. Following the rules of leader‐follower Stackelberg game, we develop an interactive algorithm of the model for solving multi‐objective decision‐making problems and reflecting the interactive natures among the decision makers. Finally, the authors exemplify the model and algorithm, and draw a conclusion on points of contributions and the significance of this study in decision‐making and support. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
467.
People differ. How and why they differ are the fundamental questions for personality psychologists. In this article we address three levels at which people differ: within individuals, between individuals, and between groups of individuals. A dynamic model of personality is considered where traits are seen as rates of change in states in response to environmental cues. Within individuals, motivational and behavioral states show inertial properties and lead to an analysis of rates of change and latencies of behavior. Between individuals, the analysis is one of frequency and duration of choices. When individuals self select into groups reflecting shared interests and abilities, the structure of these group differences reflects the consequences of the self selection. Examples of the dynamic model are given for each level of analysis.  相似文献   
468.
李垚锦  张微  扶蓓  周兵平 《心理学报》2020,52(6):777-785
在注意定向与维持上,注意缺陷多动障碍(ADHD)个体更容易受到外部刺激的干扰而导致目标任务加工进程受阻,表现出了注意定向反应的缺陷,但导致任务失败的原因是由于对突然出现的外部无关刺激的过度兴奋还是对内源性目标刺激的持续维持能力减弱,尚不清楚。研究采用反向眼跳范式、记忆导向眼跳范式和视觉导向眼跳范式,来探索成人ADHD内外源注意定向反应的情况,以及当二者发生冲突时,成人ADHD失败的可能机制。结果发现,在反向眼跳任务上,成人注意缺陷多动障碍组错误率更高,并且差异性显著。但在记忆导向眼跳任务中,成人注意缺陷多动障碍组与正常组的差异不显著。在视觉导向眼跳任务中,成人注意缺陷多动障碍组的正确眼跳潜伏期比正常组要短,且二者之间的差异显著。这说明,在内外源刺激反应的冲突导致的情境中,成人注意缺陷多动障碍的反应明显落后于正常个体,这种缺陷并非由于其维持内源性注意产生定向反应落后所导致的,而是与其外源注意定向反应过强有关。  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