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   5248篇
  免费   281篇
  国内免费   67篇
财政金融   286篇
工业经济   215篇
计划管理   1357篇
经济学   1188篇
综合类   487篇
运输经济   50篇
旅游经济   158篇
贸易经济   439篇
农业经济   937篇
经济概况   479篇
  2024年   56篇
  2023年   145篇
  2022年   194篇
  2021年   212篇
  2020年   277篇
  2019年   219篇
  2018年   154篇
  2017年   208篇
  2016年   189篇
  2015年   202篇
  2014年   286篇
  2013年   490篇
  2012年   428篇
  2011年   531篇
  2010年   426篇
  2009年   262篇
  2008年   274篇
  2007年   203篇
  2006年   196篇
  2005年   143篇
  2004年   109篇
  2003年   82篇
  2002年   69篇
  2001年   58篇
  2000年   46篇
  1999年   23篇
  1998年   14篇
  1997年   24篇
  1996年   15篇
  1995年   10篇
  1994年   7篇
  1993年   4篇
  1992年   3篇
  1991年   4篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1987年   4篇
  1986年   2篇
  1985年   7篇
  1984年   6篇
  1983年   4篇
  1982年   2篇
  1981年   2篇
排序方式: 共有5596条查询结果,搜索用时 234 毫秒
101.
We develop an iterative and efficient information-theoretic estimator for forecasting interval-valued data, and use our estimator to forecast the SP500 returns up to five days ahead using moving windows. Our forecasts are based on 13 years of data. We show that our estimator is superior to its competitors under all of the common criteria that are used to evaluate forecasts of interval data. Our approach differs from other methods that are used to forecast interval data in two major ways. First, rather than applying the more traditional methods that use only certain moments of the intervals in the estimation process, our estimator uses the complete sample information. Second, our method simultaneously selects the model (or models) and infers the model’s parameters. It is an iterative approach that imposes minimal structure and statistical assumptions.  相似文献   
102.
This paper contributes to the growing literature on spatial prices in large heterogeneous countries. While the literatures on spatial variation and temporal movement in prices have grown in parallel, this study marks a departure by providing a unified treatment and proposing a comprehensive framework that allows both approaches. The proposed model is based on twin extensions of the household version of the “country product dummy model” by allowing for a dynamic stochastic specification and interdependence of spatial prices of geographically adjacent regions. Tests of temporal stability and regional independence of the estimated spatial prices are proposed and applied in this paper. The paper shows that the introduction of an autoregressive error process of order one, AR(1), improves the efficiency of the estimates of parameters, urban‐rural and temporal price indices under certain conditions. The Indian application points to a rich potential for using the proposed framework in cross country comparisons such as the International Comparison Program (ICP) exercises.  相似文献   
103.
ABSTRACT

Land market regulations are often justified by the assumption that activities of foreign and non-agricultural investors drive up prices in domestic land markets. However, empirical knowledge about the dynamics of agricultural land prices across borders is sparse. Using the German reunification as a natural experiment, we study the effect of the former inner German border on the dynamics of agricultural land prices in East and West Germany. We apply a land price diffusion model with an error correction specification to analyse spatial agricultural land markets. A novel feature of our model is its ability to distinguish price diffusion within states and across state borders. We provide evidence for a persistent border effect given that the fraction of spatially integrated counties is larger within states than across the former border. Moreover, we observe non-significant error correction terms for many counties along the former border. From a policy perspective, it is striking to realize that even 25 years after German reunification, pronounced land price differences persist. It is quite likely that price diffusion through existing borders within the EU would take even more time given language barriers, different institutional frameworks, and information asymmetries between domestic and foreign market participants.  相似文献   
104.
The concept of the ‘polycentric urban region’ has been popularised both as a theoretical concept for understanding regional urban systems in an era of reduced transport and communication costs, and as a normative policy objective in its own right. This paper explores its relevance to the rapidly urbanising Cape Town city-region. First, empirical evidence for the emergence of polycentric regional development patterns was considered. Shifts in relative settlements sizes (morphological polycentrism) over the period 1991–2011 were examined using population data, and patterns of inter-settlement interactions (functional polycentrism) were explored by analysing commuting information. Contrary to expectations, trends toward polycentric development were found to be weak. Second, the paper considers the relevance and value of polycentric development thinking for regional economic and spatial planning policy, concluding that there are insufficient grounds for policy intervention aimed at encouraging polycentric regional development or countering the dominance of Cape Town in the region.  相似文献   
105.
106.
Stephen Bazen 《Applied economics》2018,50(47):5110-5121
Generic Bordeaux red wine (basic claret) can be regarded as being similar to an agricultural commodity. Production volumes are substantial, they are traded at high frequency and the quality of the product is relatively homogeneous. Unlike other commodities and the top-end wines (which represent only 3% of the traded volume), there is no futures market for generic Bordeaux wine. Reliable forecasts of prices can to large extent replace this information deficiency and improve the functioning of the market. We use state-space methods with monthly data to obtain a univariate forecasting model for the average price. The estimates highlight the stochastic trend and the seasonality present in the evolution of the price over the period 1999 to 2016. The model predicts the path of wine prices out of sample reasonably well, suggesting that this approach is useful for making reasonably accurate forecasts of future price movements.  相似文献   
107.
吴晓晨 《价值工程》2015,34(16):106-108
由玻璃纤维增强塑料夹砂管的环刚度、刚度等级概念分析了环刚度设计与检测的基本方法,探讨挠曲水平、轴向拉伸强力和环向拉伸强力检测方法,比较分析了各种方法的优缺点与适用范围,对理解及掌握玻璃纤维增强塑料夹砂管初始力学性能的概念及相关检测方法具有一定参考意义。  相似文献   
108.
王莺鹤 《价值工程》2015,(10):85-87
对于球形单层网壳结构进行考虑初始缺陷的几何非线性的有限元分析即荷载-位移全过程分析。  相似文献   
109.
This article looks at successive attempts to create new spatial imaginaries around three estuary‐based city regions in England: the London–Thames Gateway, the Atlantic Gateway/Mersey Belt (Manchester and Liverpool), and Hull and the Humber ports. We develop a framework of analysis for new planning and regeneration spaces that takes forward debates on relational and territorial geographies, spatial imaginaries and the creation of new regional identities as governance objects. Specifically, we adopt a long‐term and comparative perspective that allows an examination of how successive efforts at regional building are both path‐dependent and context‐specific, as new approaches reflect emerging ideas about how best to construct successful regions in a changing global economy.  相似文献   
110.
Varying coefficient regression models are known to be very useful tools for analysing the relation between a response and a group of covariates. Their structure and interpretability are similar to those for the traditional linear regression model, but they are more flexible because of the infinite dimensionality of the corresponding parameter spaces. The aims of this paper are to give an overview on the existing methodological and theoretical developments for varying coefficient models and to discuss their extensions with some new developments. The new developments enable us to use different amount of smoothing for estimating different component functions in the models. They are for a flexible form of varying coefficient models that requires smoothing across different covariates' spaces and are based on the smooth backfitting technique that is admitted as a powerful technique for fitting structural regression models and is also known to free us from the curse of dimensionality.  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