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   4340篇
  免费   180篇
  国内免费   23篇
管理学   189篇
劳动科学   2篇
民族学   22篇
人口学   56篇
丛书文集   431篇
理论方法论   228篇
综合类   2900篇
社会学   264篇
统计学   451篇
  2023年   25篇
  2022年   16篇
  2021年   24篇
  2020年   50篇
  2019年   59篇
  2018年   66篇
  2017年   89篇
  2016年   71篇
  2015年   82篇
  2014年   369篇
  2013年   406篇
  2012年   205篇
  2011年   316篇
  2010年   402篇
  2009年   346篇
  2008年   339篇
  2007年   246篇
  2006年   237篇
  2005年   223篇
  2004年   169篇
  2003年   185篇
  2002年   180篇
  2001年   129篇
  2000年   90篇
  1999年   38篇
  1998年   28篇
  1997年   29篇
  1996年   31篇
  1995年   17篇
  1994年   10篇
  1993年   12篇
  1992年   8篇
  1991年   8篇
  1990年   7篇
  1989年   7篇
  1988年   6篇
  1987年   7篇
  1986年   1篇
  1985年   5篇
  1984年   1篇
  1981年   2篇
  1976年   1篇
  1973年   1篇
排序方式: 共有4543条查询结果,搜索用时 15 毫秒
1.
文章提出具有卖空总量限制、阈值约束和V型交易成本的多阶段均值—半绝对偏差(M-SAD)投资组合优化模型。该模型分别运用均值和半绝对偏衡量资产的收益率和风险。由于交易成本的存在,该模型不满足无后效性的动态优化问题。文章将该模型近似为一般动态规划问题,提出一种新的离散迭代方法,并证明该算法是线性收敛的。最后,文章通过实证研究比较分析卖空总量限制和风险偏好系数取不同值时对投资组合最优策略的影响,验证模型和算法的有效性。  相似文献   
2.
Strong orthogonal arrays (SOAs) were recently introduced and studied as a class of space‐filling designs for computer experiments. An important problem that has not been addressed in the literature is that of design selection for such arrays. In this article, we conduct a systematic investigation into this problem, and we focus on the most useful SOA(n,m,4,2 + )s and SOA(n,m,4,2)s. This article first addresses the problem of design selection for SOAs of strength 2+ by examining their three‐dimensional projections. Both theoretical and computational results are presented. When SOAs of strength 2+ do not exist, we formulate a general framework for the selection of SOAs of strength 2 by looking at their two‐dimensional projections. The approach is fruitful, as it is applicable when SOAs of strength 2+ do not exist and it gives rise to them when they do. The Canadian Journal of Statistics 47: 302–314; 2019 © 2019 Statistical Society of Canada  相似文献   
3.
I conducted a trust game in the field within a natural experiment paradigm to test the effects of urbanization on both in- and out-group trust. I found that urbanization has a larger positive effect on out-group trust than on in-group trust. My findings provide new knowledge to the literature on the intricacy of the urbanization-trust relationship and contribute to the ongoing discourse on the different foundations underpinning in-group and out-group trust.  相似文献   
4.
对初始情境中受难者“陷困”功能的探讨,是“动物叙事”叙事语法研究中不容忽视的一环,其中贯穿了一个最为基础的叙事功能指向——“抉择之痛”。强调“动物与人”两类受难者角色在身体、心理抑或情感维度陷入某种矛盾与纠结的状态,并且彼此间时常呈现出一定的矛盾悖反性。这一角色身份由动物形象与人类形象分别或共同承担,均指向一种叙事伦理层面的现代境遇的表达。在题材范畴方面,这一功能指涉涵盖了家养类与野生类“动物叙事”各自的叙事范畴。其效力边际已不仅仅局限在单纯生态视域与人性指涉的层面,而是凸显现代语境下人类所面临的共通性的伦理困境:一种挥之不去的矛盾、困惑与不安的情感和心境的写照。  相似文献   
5.
In social research, the use of agree/disagree (A/D) questions is a popular method for measuring attitudes. Research has shown that A/D questions require complex cognitive processing and are susceptible to response bias. Thus, some researchers recommend the use of item-specific (IS) questions. This study examines the processing of A/D and IS questions, using eye-tracking methodology. By recording respondents’ eye movements, how respondents process survey questions can be evaluated. The results reveal that IS questions cause more and longer fixations. However, this only applies to the response categories. There are no differences regarding the question stems. Altogether, it seems that IS response categories trigger deeper cognitive processing than A/D response categories.  相似文献   
6.
Placement of refugees and subsequent labour market integration within a host country represents a key challenge for policymakers and has emerged as one of the most divisive topics in the public debate. Immigration policy in Switzerland adopts random placement of asylum seekers across its different language regions. Hence, this policy allows to estimate the causal effect of language skills on employment chances, as refugees are exogenously placed across regions where the spoken language could either match or deviate from individual language skills. The results of this ‘natural experiment’ indicate substantially higher probabilities of finding employment when asylum seekers are placed in regions with a lingua franca that matches their individual language skills. Additionally, the findings suggest that language course participation can offset the reduced likelihood of employment in cases of a language mismatch. While random placement of refugees may be desirable for political reasons, it is detrimental to the economic integration process. Thereby, the study draws relevant conclusions for a larger European immigration policy.  相似文献   
7.
ABSTRACT

Games can be a powerful tool for learning about statistical methodology. Effective game design involves a fine balance between caricature and realism, to simultaneously illustrate salient concepts in a controlled setting and serve as a testament to real-world applicability. Striking that balance is particularly challenging in response surface and design domains, where real-world scenarios often play out over long time scales, during which theories are revised, model and inferential techniques are improved, and knowledge is updated. Here, I present a game, borrowing liberally from one first played over 40 years ago, which attempts to achieve that balance while reinforcing a cascade of topics in modern nonparametric response surfaces, sequential design, and optimization. The game embeds a blackbox simulation within a shiny app whose interface is designed to simulate a realistic information–availability setting, while offering a stimulating, competitive environment wherein students can try out new methodology, and ultimately appreciate its power and limitations. Interface, rules, timing with course material, and evaluation are described, along with a “case study” involving a cohort of students at Virginia Tech. Supplementary materials for this article are available online.  相似文献   
8.
Dominance hierarchies play an important role in governing the social interactions of humans and other species of social animals. In a social group, dominance relations can be inferred from the directed network of matchups between actors. Methodologists have proposed different ways to measure social dominance in directed networks. One such measure, the “β-measure” (van den Brink and Gilles, 2000), emphasizes the quality of defeated opponents in a way that an actor is seen as being more dominant when s/he defeats opponents who are more rarely defeated. While insightful in theory, the validity of the measure in people’s perception remains questionable, considering the cognitive complexity imposed by this measure, compared to a simpler measure that merely counts the number of defeated opponents. We conducted a vignette experiment with human subjects (professional athletes) to test their judgments of the dominance relation in a hypothetical tournament. Fitting our parametric model to peoples’ evaluations in the experiment, we found strong evidence in support of the β-measure: Although, in general, contestants who win more in the tournament are regarded as being more dominant, the contents of the winning records matter, such that those who beat more victorious opponents are further regarded as more dominant than those who defeat less victorious opponents. We also found a gender difference, in that men have a stronger propensity than women to adopt the β-measure when judging social dominance.  相似文献   
9.
ABSTRACT

Web surveys are an established data collection mode that use written language to provide information. The written language is accompanied by visual elements, such as presentation formats and shapes. However, research has shown that visual elements influence response behavior because respondents sometimes use interpretive heuristics to make sense of the visual elements. One such heuristic is the ‘left and top means first’ (LTMF) heuristic, which suggests that respondents tend to believe that a response scale consistently runs from left to right or from top to bottom. We conducted a web survey experiment to investigate how violations of the LTMF heuristic affect response behavior and data quality. For this purpose, a random half of respondents received response options that followed a consistent order and the other half received response options that followed an inconsistent order. The results reveal significantly different response distributions between the two groups. We also found that inconsistently ordered response options significantly increase response times and decrease data quality in terms of criterion validity. We, therefore, recommend using options that follow the design strategies of the LTMF heuristic.  相似文献   
10.
Computerized versions of population inferred cheating tasks (C-PICT)—i.e., tasks in which dishonesty is statistically determined on the aggregate by comparing self-reported outcomes with a known probability distribution—have become increasingly popular. To this date no study has investigated whether non-computerized population inferred cheating tasks (PICT) and C-PICT as well as different implementations of C-PICT produce similar results. The current study tackles both issues via a well-powered pre-registered online experiment (N = 3,645) with four conditions. Participants played either a non-computerized coin toss task (CTT) (C1) or one of three computerized CTT: a computerized CTT provided via an external website (C2), a computerized CTT provided within the survey framework of the study in which participants were explicitly informed that the actual outcome of the CTT was not monitored (C3), or a computerized CTT provided within the survey framework of the study in which participants were explicitly informed that the actual outcome of the CTT was monitored (C4). A priori we expected the probability of dishonesty to be higher in C1 compared to C2, C3, and C4, as well as lower in C4 compared to C3 and C2. Results show that the probability of dishonesty is higher in C1 and C2 compared to C3 and C4. Conversely, no significant difference was observed between C1 and C2, nor between C3 and C4. Taken together, our results indicate that C-PICT produce results similar to PICT when they are provided via an external website, but not when they are implemented within the survey framework of the study.  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