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   4682篇
  免费   174篇
  国内免费   21篇
管理学   144篇
民族学   35篇
人才学   1篇
人口学   60篇
丛书文集   456篇
理论方法论   111篇
综合类   3337篇
社会学   108篇
统计学   625篇
  2024年   2篇
  2023年   15篇
  2022年   19篇
  2021年   34篇
  2020年   34篇
  2019年   47篇
  2018年   77篇
  2017年   84篇
  2016年   79篇
  2015年   82篇
  2014年   384篇
  2013年   510篇
  2012年   222篇
  2011年   351篇
  2010年   427篇
  2009年   361篇
  2008年   353篇
  2007年   264篇
  2006年   228篇
  2005年   187篇
  2004年   250篇
  2003年   221篇
  2002年   152篇
  2001年   152篇
  2000年   109篇
  1999年   41篇
  1998年   32篇
  1997年   26篇
  1996年   20篇
  1995年   20篇
  1994年   15篇
  1993年   19篇
  1992年   12篇
  1991年   6篇
  1990年   5篇
  1989年   7篇
  1988年   11篇
  1987年   7篇
  1986年   1篇
  1985年   4篇
  1984年   3篇
  1983年   1篇
  1979年   2篇
  1977年   1篇
排序方式: 共有4877条查询结果,搜索用时 15 毫秒
1.
This paper proposes a new hysteretic vector autoregressive (HVAR) model in which the regime switching may be delayed when the hysteresis variable lies in a hysteresis zone. We integrate an adapted multivariate Student-t distribution from amending the scale mixtures of normal distributions. This HVAR model allows for a higher degree of flexibility in the degrees of freedom for each time series. We use the proposed model to test for a causal relationship between any two target time series. Using posterior odds ratios, we overcome the limitations of the classical approach to multiple testing. Both simulated and real examples herein help illustrate the suggested methods. We apply the proposed HVAR model to investigate the causal relationship between the quarterly growth rates of gross domestic product of United Kingdom and United States. Moreover, we check the pairwise lagged dependence of daily PM2.5 levels in three districts of Taipei.  相似文献   
2.
An accurate procedure is proposed to calculate approximate moments of progressive order statistics in the context of statistical inference for lifetime models. The study analyses the performance of power series expansion to approximate the moments for location and scale distributions with high precision and smaller deviations with respect to the exact values. A comparative analysis between exact and approximate methods is shown using some tables and figures. The different approximations are applied in two situations. First, we consider the problem of computing the large sample variance–covariance matrix of maximum likelihood estimators. We also use the approximations to obtain progressively censored sampling plans for log-normal distributed data. These problems illustrate that the presented procedure is highly useful to compute the moments with precision for numerous censoring patterns and, in many cases, is the only valid method because the exact calculation may not be applicable.  相似文献   
3.
ABSTRACT

The circular economy (CE) has become a matter of urban development. A literature review shows that the CE debate is biased toward technology-driven industrial change, while bracketing broader socio-political interests. We address this gap by exploring the political economy of scale of the CE. Looking into the case of Brussels (Belgium), a city that has recently adopted the CE as part of its socio-economic strategy, we explore how the anticipated transition to a ‘circular city’ chimes with long-standing urban development agendas. While there is little evidence of stable growth coalitions between corporate and political elites, we argue that the CE provides an ‘urban sustainability fix’ by selectively incorporating ecological goals in urban governance strategies. We further scrutinise the landscape of diverse and heterogenous CE practices in food and transport, highlighting how they are regulated and organised, what labour conditions they offer, and how they are anchored in urban space.  相似文献   
4.
Abstract

Based on the value of children theory, the purpose of this study was to develop and establish the factor structure and internal consistency reliability of the Advantages of Children Scale (ACS), a self-report measure of a modification of Hoffman and Hoffman’s value scheme of the psychological needs children meet for their parents. Data were collected from 685 emerging adult men identifying as Latino or Caucasian who were not parents. Results of the confirmatory factor analysis found a good fit for the six hypothesized subscales on the ACS: connectedness, expansion of self, family heritage, adult status and social identity, development of self, and family maintenance. We discuss potential applications of the measure in research and practice.  相似文献   
5.
政府是污染减排的重要主体,了解其行为对污染减排的作用对提升污染减排效果及实现中国绿色发展具有重要意义。创造性地将政府减排目标纳入研究框架,构建面板门槛模型,从工业污染排放总量的角度分析政府减排目标、产业结构、经济规模等因素对地方污染减排的影响,并用工业污染物强度进行稳健性检验。结果显示,政府减排目标对污染减排的作用存在阶段性不同:经济发展初级阶段,政府减排目标对污染排放总量的作用方向为正; 经济发展水平较高时,作用方向为负; 两者之间存在适应性调整阶段,作用方向具有不确定性,但总体由正向作用向负向作用转变。产业结构对工业污染排放总量的作用方向因污染物种类而异,经济规模对工业污染排放总量作用方向为正。  相似文献   
6.
This article looks at the representation of scale in the 2014 film The Theory of Everything, identifying moments that relate to three concerns: firstly, how disabled people experience scale issues at an all too practical level in daily life; secondly, how Hawking’s experience of scale at the level of both body and mind is (a)typical of the way it is experienced by disabled people generally; and, thirdly, how a focus on the film can prompt some rethinking of perspectives both within disability studies and within the conceptualisation of scale more broadly.  相似文献   
7.
随着金融资产在居民家庭资产结构中的地位上升,金融投资活动对居民主观幸福感的影响日趋显著,这种主观幸福感可以用生活满意程度和未来信心程度来刻画。来自中国家庭追踪调查数据的经验证据表明,家庭金融投资规模对居民生活满意程度和未来信心程度都会产生负向影响;家庭金融投资绝对收益对居民生活满意程度存在正向影响,而家庭金融投资相对收益则对居民未来信心程度存在负向影响。这些情形可能源自于金融投资市场在市场机制、公平程度、投资者教育等方面的欠缺,需要管理者采取措施来改变这种幸福感损失。  相似文献   
8.
在犹豫直觉模糊语言集和语言尺度函数的基础上定义了均值-标准差偏好的Hamming距离,并提出了基于犹豫直觉模糊语言集距离TOPSIS和TODIM的多属性决策方法,进一步利用这两种方法对实例问题建筑商的招标方案进行排序,并讨论了偏好参数对排序结果的灵敏度分析。为验证上述方法的有效性,与已有方法对同一实例的排序结果进行了比较分析。  相似文献   
9.
Recently, Kambo and his co-researchers (2012) proposed a method of approximation for evaluating the one-dimensional renewal function based on the first three moments. Their method is simple and elegant, which gives exact values for well-known distributions. In this article, we propose an analogous method for the evaluation of bivariate renewal function based on the first two moments of the variables and their joint moment. The proposed method yields exact results for certain widely used bivariate distributions like bivariate exponential distribution, bivariate Weibull distributions, and bivariate Pareto distributions. An illustrative example in the form of a two-dimensional warranty problem is considered and comparisons of our method are made with the results of other models.  相似文献   
10.
In this paper, we consider the problem of estimating the Laplace transform of volatility within a fixed time interval [0,T] using high‐frequency sampling, where we assume that the discretized observations of the latent process are contaminated by microstructure noise. We use the pre‐averaging approach to deal with the effect of microstructure noise. Under the high‐frequency scenario, we obtain a consistent estimator whose convergence rate is , which is known as the optimal convergence rate of the estimation of integrated volatility functionals under the presence of microstructure noise. The related central limit theorem is established. The simulation studies justify the finite‐sample performance of the proposed estimator.  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