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   258篇
  免费   6篇
财政金融   46篇
工业经济   11篇
计划管理   51篇
经济学   44篇
综合类   22篇
运输经济   6篇
旅游经济   7篇
贸易经济   31篇
农业经济   22篇
经济概况   24篇
  2023年   2篇
  2022年   10篇
  2021年   7篇
  2020年   15篇
  2019年   4篇
  2018年   3篇
  2017年   10篇
  2016年   6篇
  2015年   4篇
  2014年   14篇
  2013年   28篇
  2012年   23篇
  2011年   22篇
  2010年   19篇
  2009年   16篇
  2008年   19篇
  2007年   15篇
  2006年   19篇
  2005年   13篇
  2004年   4篇
  2003年   5篇
  2001年   2篇
  2000年   2篇
  1998年   1篇
  1995年   1篇
排序方式: 共有264条查询结果,搜索用时 14 毫秒
1.
Predicting consumption behavior is very important for adjusting supplier production plans and enterprise marketing activities. Conventional statistical methods are unable to accurately predict green consumption behavior because it is characterized by multivariate nonlinear interactions. The paper proposes an optimized fruit fly algorithm (FOA) and extreme learning machine (ELM) model for consumption behavior prediction. First, to address the problem of uneven search direction of FOA leading to insufficient search ability and low efficiency, the paper proposes a sector search mechanism instead of a random search mechanism to improve the global search ability and convergence speed of FOA. Second, to address the issue that the initial weights and hidden layer bias values of the ELM are randomly generated, which affects the learning efficiency and generalization of the ELM, the paper uses an improved FOA to optimize the weights and bias values of ELM for improving the prediction accuracy. Taking the green vegetable consumption behavior of Beijing residents as an example, the results show the optimization of the initial weight and threshold of ELM by the GA, PSO, FOA, and SFOA, the prediction accuracy of the GA-ELM, PSO-ELM, FOA-ELM, and SFOA-ELM models all surpass those of ELM. Compared with BPNN, GRNN, ELM, GA-ELM, PSO-ELM, and FOA-ELM models, the RMSE value of SFOA-ELM was decreased by 9.45%, 8.40%, 11.89%, 5.84%, 2.22%, and 2.69%, respectively. These findings demonstrate the effectiveness of the SFOA-ELM model in green consumption behavior prediction and provide new ideas for the accurate prediction of consumption behaviors of other green products with similar characteristics.  相似文献   
2.
仿制药专利挑战机制是我国药品专利链接制度的核心环节。在现有规范体系下进行制度构建,存在同现行《专利法》抵触的问题,通过立法或释法活动化解这种冲突具有必要性。在解释学范式下对仿制药品专利挑战侵权拟制、侵权解释两种立法进路进行推演和反思,并辅之以制度体系、国际比较、法律政策、经济分析等视角,可得出拟制进路更为可行的结论。在拟制进路下进行制度构建,应遵循法律拟制技术规范,并妥善处理制度配套问题。  相似文献   
3.
The exploration of option pricing is of great significance to risk management and investments. One important challenge to existing research is how to describe the underlying asset price process and fluctuation features accurately. Considering the benefits of ensemble empirical mode decomposition (EEMD) in depicting the fluctuation features of financial time series, we construct an option pricing model based on the new hybrid generalized autoregressive conditional heteroskedastic (hybrid GARCH)-type functions with improved EEMD by decomposing the original return series into the high frequency, low frequency and trend terms. Using the locally risk-neutral valuation relationship (LRNVR), we obtain an equivalent martingale measure and option prices with different maturities based on Monte Carlo simulations. The empirical results indicate that this novel model can substantially capture volatility features and it performs much better than the M-GARCH and Black–Scholes models. In particular, the decomposition is consistently helpful in reducing option pricing errors, thereby proving the innovativeness and effectiveness of the hybrid GARCH option pricing model.  相似文献   
4.
Abstract

This paper measures the degree of bank competition in India using a sample of 70 commercial banks over the period 1996–2016. To assess the degree of competition, we estimate the market power of each bank in our sample employing three nonstructural measures: the Lerner index, the adjusted Lerner index, and the Boone indicator. Bank-wise and year-wise estimates of the marginal cost required in all these measures are obtained using the semi-parametric method. The paper further attempts to undertake a comprehensive assessment of competition in Indian banking and identifies various bank-specific, macroeconomic, structural, and contestability indicators, which are supposed to explain level and variation of the degree of competition over time. Empirical findings reveal that public-sector banks in India exercise a relatively higher degree of bank competition compared to private and foreign-sector banks. However, aggregate results support that the Indian banking system is competitive in general. Unlike the structure-conduct-performance paradigm, which advocates that a concentrated banking system impairs competitiveness, our findings reveal that concentration measures hardly exert any effect on bank competition. Rather, contestability measures play a significant role in the determination of bank competition.  相似文献   
5.
高速铁路网的日趋完善,高速列车开行数量的进一步增加,对高速铁路动车组检修资源布局提出新的要求。为合理优化动车组检修资源布局,提高动车组检修效率,在分析我国动车段和动车运用所管理模式及布局方案的基础上,将动车组检修资源布局优化问题转化为基于多基地车辆路径运用的基地选址问题,基于"备选运用所-运输需求-动车组运用"间的关联关系构建动车组运用检修接续网络,建立动车组检修资源布局优化模型。以某区域的铁路网为例,利用近远期规划优化动车组检修资源布局,验证模型有效性,为今后动车组检修资源布局优化提供参考。  相似文献   
6.
2016年5月《国务院办公厅关于深入推行科技特派员制度的若干意见》发布实施,但其实施效果如何有待验证。构建科技特派员制度实施绩效评估指标体系,利用改进熵值法和官方统计数据,对中国省域科技特派员制度实施绩效进行实证评估,并对评估结果进行聚类分析。结果表明,中国大多数省份科技特派员制度实施绩效水平较低;根据实施科技开发项目、形成利益共同体、服务农民情况、推广服务和扶贫成效5个绩效评估维度,可以将中国内地31个省份划分为5种类型;即使是总绩效水平较高的地区,在科技特派员制度实施绩效方面也存在一些短板。  相似文献   
7.
任务型教学法实现了从教学思想到教学方法的变革,体现了“以学生为主体,教师为主导”的教学原则.在此原则的指导下,本文首先阐述了任务的相关概念、任务教学法的设计原则,然后论述了任务型教学法在大学英语教学中的具体实施过程.在当前英语课程改革不断深化的背景下,倡导运用任务型教学可以更好地实现英语课程的教学目标.  相似文献   
8.
江西省已在2005年进入人口老龄化社会。江西省统计局人口变动情况抽样调查资料显示,在省内居民生活水平上升、平均预期寿命提高,以及人口生育率持续保持较低水平等因素的综合作用下,江西省人口老龄化进程持续加快。妥善解决老年人的需求,将成为实现江西崛起的关键一步。文中通过对江西省内实地调研,针对现有居家养老模式存在的缺陷,提出合理建议。  相似文献   
9.
Despite widespread global efforts to promote clean cookstoves to achieve improvements in air and forest quality, and to reduce global climate change, surprisingly little is known about the degree to which these actually reduce biomass fuel consumption in real-world settings. Using data from in-house weighing of fuel conducted in rural India, we examine the impact of cleaner cookstoves ⿿ most of which are LPG stoves ⿿ on three key outcomes related to solid fuel use. Our results suggest that using a clean cookstove is associated with daily reductions of about 4.5 kg of biomass fuel, 160 fewer minutes cooking on traditional stoves, and 105 fewer minutes collecting biomass fuels. These findings of substantial savings are robust to the use of estimators with varying levels of control for selection, and to alternative data obtained from household self-reports. Our results support the idea that efforts to promote clean stoves among poor rural households can reduce solid fuel use and cooking time, and that rebound effects toward greater amounts of cooking on multiple stoves are not sufficient to eliminate these gains. We also find, however, that households who have greater wealth, fewer members, are in less marginalized groups, and practice other health-averting behaviors, are more likely to use these cleaner stoves, which suggests that socio-economic status plays an important role in determining who benefits from such technologies. Future efforts to capture social benefits must therefore consider how to promote the use of alternative technologies by poor households, given that these households are least likely to own clean stoves.  相似文献   
10.
钟文皓 《商业科技》2014,(31):104-108
我国正处于产业结构转型的关键时期,一二产业逐渐向第三产业转移。以往研究大多落脚于人力资本对产业结构的影响,而忽略了由于产业转型带来的对高技术人才的需求推动了人力资本的积累。作者认为,产业结构的优化将有助于人力资本的积累,同时,文化消费、教育投入等因素也会影响到人力资本。本文使用2005-2011年,我国31个省份的面板数据,建立了多元线性回归模型,运用工具变量的方法,以金融发展状况作为第三产业占比的工具变量,进行实证研究。在控制了年份和省份的固定效应后,我们发现第三产业占比对人均人力资本有显著的正向影响,产业结构向第三产业转移有利于人力资本积累。在此基础上,我们提出了若干建议来推动产业结构的优化。  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