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   3875篇
  免费   53篇
  国内免费   2篇
财政金融   705篇
工业经济   113篇
计划管理   1003篇
经济学   836篇
综合类   211篇
运输经济   64篇
旅游经济   86篇
贸易经济   490篇
农业经济   196篇
经济概况   226篇
  2025年   10篇
  2024年   35篇
  2023年   73篇
  2022年   37篇
  2021年   80篇
  2020年   178篇
  2019年   158篇
  2018年   132篇
  2017年   152篇
  2016年   150篇
  2015年   95篇
  2014年   221篇
  2013年   460篇
  2012年   172篇
  2011年   245篇
  2010年   173篇
  2009年   175篇
  2008年   193篇
  2007年   166篇
  2006年   166篇
  2005年   139篇
  2004年   104篇
  2003年   77篇
  2002年   85篇
  2001年   83篇
  2000年   53篇
  1999年   70篇
  1998年   40篇
  1997年   48篇
  1996年   29篇
  1995年   26篇
  1994年   17篇
  1993年   15篇
  1992年   10篇
  1991年   10篇
  1990年   4篇
  1988年   5篇
  1987年   4篇
  1986年   2篇
  1985年   13篇
  1984年   12篇
  1983年   6篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
排序方式: 共有3930条查询结果,搜索用时 15 毫秒
101.
    
There is increased interest in greater localization of food supply chains but little evidence about the effects of localization on supply-chain costs. Assessing these effects is complex in multiple-product, multi-process supply chains such as the dairy industry. In this study, we develop a spatially-disaggregated transshipment model for the US dairy sector that minimizes total supply-chain costs, including assembly, processing, interplant transportation and final product distribution. We employ the cost-minimizing solution as benchmark to compare alternative scenarios of increased supply chain localization. Our results indicate: (1) short-run limits to increased localization, (2) modest impacts on overall supply-chain costs, and (3) large cost re-allocations across supply chain segments, regions and products. We find that increased localization reduces assembly costs while increase processing and distribution costs. Cost increases are larger in regions with smaller raw milk supplies and during the season when less raw milk is produced. Minimizing distances traveled by all dairy products results in tradeoffs across products in terms of cost and distance traveled. The relationship between increased localization and costs appears to be nonlinear.  相似文献   
102.
余金龙 《价值工程》2011,30(21):236-237
心理问题在中学生群体中普遍存在,并对他们的学习和生活产生很多不良的影响。本文详细讲述了中学生的一些心理问题在中学生物实验中的表现及危害,以及在中学生物实验教学中渗透心理健康教育的重要作用和相关策略。  相似文献   
103.
    
We develop models for examining possible predictors of growth of China's foreign exchange reserves that embrace Chinese and global trade, financial and risk (uncertainty) factors. Specifically, by comparing with other alternative models, we show that the dynamic model averaging (DMA) and dynamic model selection (DMS) models outperform not only linear models (such as random walk, recursive OLS-AR(1) models, recursive OLS with all predictive variables models) but also the Bayesian model averaging (BMA) model for examining possible predictors of growth of those reserves. The DMS is the best overall across all forecast horizons. While some predictors matter more than others over the forecast horizons, there are few that stand the test of time. The US–China interest rate differential has a superior predictive power among the 13 predictors considered, followed by the nominal effective exchange rate and the interest rate spread for most of the forecast horizons. The relative predictive prowess of the oil and copper prices alternates, depending on the commodity cycles. Policy implications are also provided.  相似文献   
104.
期权定价模型在物流企业价值评估中的新思路   总被引:1,自引:0,他引:1  
曹秀娟  刘卫东 《物流科技》2006,29(9):124-125
现代物流企业与传统企业一样,其终极财务管理的目标都是使企业的价值实现最大化。对现代物流企业价值进行评估,评估结果固然重要,评估过程中也包含着许多有益的信息,评估过程有助于我们理解实现现代物流企业价值的决定因素,本文基于此,通过利用一种新的价值评估体系——期权定价模型进行对物流企业的价值评估,从而可以帮助现代物流企业更好地认识自身的价值及其提升途径。  相似文献   
105.
106.
    
In this paper, we consider portmanteau tests for testing the adequacy of multiplicative seasonal autoregressive moving‐average models under the assumption that the errors are uncorrelated but not necessarily independent. We relax the standard independence assumption on the error terms in order to extend the range of applications of the seasonal autoregressive moving‐average models. We study the asymptotic distributions of residual and normalized residual empirical autocovariances and autocorrelations under weak assumptions on noise. We establish the asymptotic behavior of the proposed statistics. A set of Monte Carlo experiments and an application to monthly mean total sunspot number are presented.  相似文献   
107.
There is by now a long tradition of using the EM algorithm to find maximum‐likelihood estimates (MLEs) when the data are incomplete in any of a wide range of ways, even when the observed‐data likelihood can easily be evaluated and numerical maximisation of that likelihood is available as a conceptually simple route to the MLEs. It is rare in the literature to see numerical maximisation employed if EM is possible. But with excellent general‐purpose numerical optimisers now available free, there is no longer any reason, as a matter of course, to avoid direct numerical maximisation of likelihood. In this tutorial, I present seven examples of models in which numerical maximisation of likelihood appears to have some advantages over the use of EM as a route to MLEs. The mathematical and coding effort is minimal, as there is no need to derive and code the E and M steps, only a likelihood evaluator. In all the examples, the unconstrained optimiser nlm available in R is used, and transformations are used to impose constraints on parameters. I suggest therefore that the following question be asked of proposed new applications of EM: Can the MLEs be found more simply and directly by using a general‐purpose numerical optimiser?  相似文献   
108.
109.
    
This study develops a novel agent-based model of the interbank market with endogenous credit risk formation mechanisms. We allow banks to exchange funds through unsecured and secured transactions, which facilitates the flow of funds to the most profitable investment projects. Risk premiums result from banks׳ forecasting rules and depend on past performance of the benchmark risk factors and interest rates. Our model confirms basic stylized facts of the interbank interest rates and volumes. We also find that network structures within the secured market segment are characterized by the presence of dealer banks, while we do not observe similar patterns in the unsecured market. We perturb the model with exogenous shocks and policy scenarios which correspond to unconventional monetary policies.  相似文献   
110.
In order to aid organisations in the adoption of enterprise architecture (EA) best practices, maturity models have been proposed in the literature. These models offer organisational roadmaps and assessment frameworks for increasing EA maturity. However, key questions concerning the implied meaning of the term maturity in the context of these models have been left unexplored by previous research. This research, aided by the field of organisational learning, offers new insights into the implied assumptions of current EA maturity models and offers initial concepts and constructs to guide the conceptualisation, construction and refinement of enterprise maturity models.  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