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   268篇
  免费   145篇
  国内免费   47篇
  460篇
  2023年   4篇
  2022年   3篇
  2021年   10篇
  2020年   9篇
  2019年   15篇
  2018年   13篇
  2017年   18篇
  2016年   15篇
  2015年   17篇
  2014年   18篇
  2013年   28篇
  2012年   18篇
  2011年   23篇
  2010年   13篇
  2009年   22篇
  2008年   8篇
  2007年   15篇
  2006年   18篇
  2005年   23篇
  2004年   7篇
  2003年   10篇
  2002年   11篇
  2001年   14篇
  2000年   10篇
  1999年   10篇
  1998年   7篇
  1997年   6篇
  1996年   6篇
  1995年   3篇
  1994年   4篇
  1993年   4篇
  1992年   6篇
  1991年   5篇
  1990年   5篇
  1989年   4篇
  1988年   11篇
  1987年   5篇
  1986年   6篇
  1985年   4篇
  1984年   2篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1979年   6篇
  1978年   4篇
  1977年   3篇
  1976年   5篇
  1975年   1篇
排序方式: 共有460条查询结果,搜索用时 0 毫秒
241.
In comparing open and closed economies, researchers often arrange shorter sessions under the former condition than under the latter. Several studies indicate that session length per se can affect performance and there are some data that indicate that this variable can influence demand functions. To provide further data, the present study exposed domestic hens to series of increasing fixed-ratio schedules with the length of the open-economy sessions varied over 10, 40, 60, and 120 min. Session time affected the total-session response rates and pause lengths. The shortest session gave the greatest response rates and shortest pauses and the longest gave the lowest response rates and longest pauses. The total-session demand functions also changed with session length: The shortest session gave steeper initial slopes (i.e., the functions were more elastic at small ratios) and smaller rates of change of elasticity than the longest session. Response rates, pauses, and demand functions were, however, similar for equivalent periods of responding taken from within sessions of different overall lengths (e.g., total-session data for 10-min sessions and the data for the first 10 min of 120-min sessions). These findings suggest that differences in session length can confound the results of studies comparing open and closed economies when those economies are arranged in sessions that differ substantially in length, hence data for equivalent-length periods of responding, rather than total-session data, should be of primary interest under these conditions.  相似文献   
242.
The present paper gives an overview of recent research on the association between 2D:4D and different types of economic behavior. Particular attention is given to the importance of context dependence of relationships between 2D:4D and economic as well as other, social, behavior. Patterns of results are discussed from the perspective that 2D:4D might serve as a biological marker of dispositional dominance. This overview hopes to stimulate research from an interactionist perspective which focuses at relationships between 2D:4D and behavior that only appear when specific situational pressures interact with individual differences in 2D:4D.  相似文献   
243.
Mean comparisons are of great importance in the application of statistics. Procedures for mean comparison with manifest variables have been well studied. However, few rigorous studies have been conducted on mean comparisons with latent variables, although the methodology has been widely used and documented. This paper studies the commonly used statistics in latent variable mean modeling and compares them with parallel manifest variable statistics. Our results indicate that, under certain conditions, the likelihood ratio and Wald statistics used for latent mean comparisons do not always have greater power than the Hotelling T2 statistics used for manifest mean comparisons. The noncentrality parameter corresponding to the T2 statistic can be much greater than those corresponding to the likelihood ratio and Wald statistics, which we find to be different from those provided in the literature. Under a fixed alternative hypothesis, our results also indicate that the likelihood ratio statistic can be stochastically much greater than the corresponding Wald statistic. The robustness property of each statistic is also explored when the model is misspecified or when data are nonnormally distributed. Recommendations and advice are provided for the use of each statistic. The research was supported by NSF grant DMS-0437167 and Grant DA01070 from the National Institute on Drug Abuse. We would like to thank three referees for suggestions that helped in improving the paper.  相似文献   
244.
The second-to-fourth digit ratio (2D:4D) is sexually differentiated and is a likely biomarker for the organisational (permanent) effects of prenatal testosterone on the human brain. Recent research has highlighted a possible role of prenatal testosterone levels in both the etiology of autism-spectrum disorders and in sex and individual differences in cognitive styles of the normal mind (Baron-Cohen’s Extreme Male Brain Theory of Autism and Empathising/Systemising Theory). Importantly, autistic children present lower (hypermasculinised) 2D:4D than healthy controls. Based on these accounts, we investigated the relation of 2D:4D with Baron-Cohen’s measures of empathising (“Reading the Mind in the Eyes” test, RMET; Empathy Quotient, EQ), systemising (Systemising Quotient, SQ), and autistic-like traits (Autism-Spectrum Quotient, AQ) in the general population (N = 423 Austrian adults). Whereas sex differences into the expected direction and of expected size were obtained for all variables and internal scale consistencies tallied to retrievable reference values, 2D:4D was unrelated to RMET, EQ, SQ, and AQ scores. Candidate explanations for this lack of correlation might be possible developmental timing differences in the expression of 2D:4D and empathising/systemising, qualitative (as opposed to quantitative) functional differences between the normal and the autistic mind, or the suboptimal psychometric properties of the measures.  相似文献   
245.
提出两种认知诊断计算机自适应测验下平衡属性收敛的新方法(MABI、RTA),模拟研究系统探讨和比较了此二者与已有方法(ABI、IABI和RABI)的表现。结果发现:(1)新方法较不考虑属性收敛的方法有更高的准确率以及更均衡的题目使用率;(2)新方法较ABI和RABI有稍低的准确性,但有更平衡的题目使用率;(3)新方法与IABI的准确性和题目使用率在不同选题策略下各有合优势。总之,两种新方法较好地兼顾测量准确性、题目使用率以及题库曝光情况。  相似文献   
246.
本研究探讨同一品类两个强势品牌广告竞争对弱势品牌产生的影响, 研究尝试将广告重复、广告长度作为操控广告竞争强度的具体手段, 运用感知到的广告竞争水平来表示广告竞争强度。研究结果表明, 同一品类两个品牌同时进行广告重复的水平不同, 可以导致被试感知到的广告竞争水平有显著差异, 广告重复次数越多, 被试感知到的广告竞争强度越高, 广告长度对感知到的广告竞争作用不显著。研究同时发现:随着两个强势品牌广告竞争强度的提高, 消费者对弱势品牌的品牌态度降低, 这表明强势品牌广告竞争对弱势品牌具有溢出效应。另外, 研究还发现产品涉入度和产品属性相似性对强势品牌广告竞争的溢出效应具有调节作用, 涉入度低的产品和属性相似性高的产品溢出效应更大。本研究丰富了溢出效应理论, 增加了溢出效应类别, 同时对同一品类内部的广告实践具有重要的指导意义。  相似文献   
247.
The Don’t Know (DK) response – taking the form of an omitted response or not-reached at the end of a cognitive test, or explicitly presented as a response option in a social survey – contains important information that is often overlooked. Direct psychometric modeling efforts for DK responses are few and far between. In this article, the linear logistic test model (LLTM) is proposed for delineating the impacts of cognitive operations for a test that contains DK responses. We assume that the DK response is a valid response. The assumption is reasonable for many situations, including low-stakes cognitive tests and attitudinal assessments. By extracting information embedded in the DK response, the method shows how DK can inform the latent construct of interest and the cognitive operations underlying the response to stimuli. Using a proven recoding scheme, the LLTM could be implemented through commonly used programs such as PROC GLIMMIX. Two simulation experiments to evaluate how well the parameters can be recovered were conducted. In addition, two real data examples, from a noncognitive test of health belief assessment and a cognitive test of knowledge in diabetes, are also presented as case studies to illustrate the LLTM for DK response.  相似文献   
248.
In the accumulation paradigm animals press one manipulandum to accumulate pellets or seconds of access to food, and then press another manipulandum, or run some distance, to collect it. The accumulation may be interpreted as delay discounting, with the animals adjusting the distal amount to compensate for its distance or delay. The amount accumulated before being collected is a linear function of the distance or time that the experimental paradigm stipulates for collecting it. That linear function follows from the Unit‐Price/Unit‐Amount axiom. The inverse of the linear compensation functions gives a delay‐discount hyperbola. The advantages of the accumulation paradigm and analytic framework for delay discounting studies are noted. Compensation functions are then derived from a behavioral regulation model, which generalizes them to contexts where the individual's budget for response cost becomes over‐taxed. In turn, such compensation/regulation models lead directly to representative demand functions. In sum, regulation models provide a theoretical grounding for demand functions, compensation functions, and delay discounting hyperbolas. The parameter that links them is the unit amount k, the slope of the compensation function and of the discount function, the setpoint for consumption in a regulation model, and the ideal quantity consumed at minimal price in a demand analysis.  相似文献   
249.
本研究用绝对辨认法与信号清晰度和响度适宜性主观评价测试了60、70和 80dB(A)三种噪声水平下与言语通讯同时呈现的高优先权音调信号的最小强度增量要求。研究结果表明 :在本实验设置的强度范围内 ,音调信号的辨认正确性主要取决于信号的相对强度 ;而音调信号的清晰度和响度适宜性与信号的绝对强度和相对强度都有关。对于采用信号强度自动增益控制的告警系统 ,这是一个值得注意的问题。  相似文献   
250.
Six male Wistar rats were exposed to different orders of reinforcement schedules to investigate if estimates from Herrnstein's (1970) single-operant matching law equation would vary systematically with schedule order. Reinforcement schedules were arranged in orders of increasing and decreasing reinforcement rate. Subsequently, all rats were exposed to a single reinforcement schedule within a session to determine within-session changes in responding. For each condition, the operant was lever pressing and the reinforcing consequence was the opportunity to run for 15 s. Estimates of k and R(O) were higher when reinforcement schedules were arranged in order of increasing reinforcement rate. Within a session on a single reinforcement schedule, response rates increased between the beginning and the end of a session. A positive correlation between the difference in parameters between schedule orders and the difference in response rates within a session suggests that the within-session change in response rates may be related to the difference in the asymptotes. These results call into question the validity of parameter estimates from Herrnstein's (1970) equation when reinforcer efficacy changes within a session.  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