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101.
Demand projections for civil aviation have forecast increases in operations in future decades. Increases in demand are beneficial to the growth and advancement of the aviation industry, but also come with the threat of significant increase in environmental impacts. In response, the industry is focusing on programs to develop technologies for reductions in fuel burn, NOx emissions, and noise. While aircraft-level impacts are an obvious metric of success, it is difficult to make informed robust technology investment decisions with respect to noise without understanding the fleet-level impacts. Fleet-level predictions of noise for technology explorations are especially complicated because it is computationally expensive, highly combinatorial, and airport-specific. Recently, rapid automated airport noise models have been developed, which can be simulated using Design of Experiments (DOE). The results of these simulations are used to generate surrogate models for airport noise contour area, which can be summed to yield a fleet-level impact. These models make use of simplifying assumptions to provide estimates of airport-level noise that are substantially cheaper to compute. They can be used to perform parametric trade-off analyses in conjunction with the equivalency assumption. Equivalency asserts that environmental impacts of a technology infused aircraft can be represented by scaled operations of the baseline aircraft in the same class. This simple assumption allows for the modeling of technology and market penetration factors under the same units: operations. This research uses surrogate models in conjunction with the equivalency assumption to examine two potential technology scenarios in a target forecast year, simulating technology and market performance factors to identify vehicle classes that could have the greatest impact in reducing contour area. Results show that technology and market performance of future notional Small Single Aisle and Large Single Aisle vehicle aircraft have the highest positive correlations with potential reductions in contour area.  相似文献   
102.
The objective of this study was to identify the hypothesized relationships amongst emotional experience, cognition, and behavioural intention in battlefield tourism. A face-to-face questionnaire survey was administered and 655 valid questionnaires were collected at heritage site related to the Sino-French War in Keelung, Taiwan. The results revealed significant positive relationships between emotional experience and cognition as well as between cognition and behavioural intention. Structural equation modelling verified that cognition fully mediated the effects of emotional experience on behavioural intention. Moreover, this study suggests that cognition may be an accurate predictor of behavioural intention, particularly in regard to battlefield tourism.  相似文献   
103.
当前,我国正处于利率市场化改革的关键时期。利率市场化改革要求中央银行有完善的价格调控手段,并体现在基准利率体系的完善和利率传导机制的畅通上。本文对我国主要利率品种之间的关系进行实证研究发现,我国货币市场利率、央票利率、贷款利率等相关性不断增强。据此,本文对我国进一步推进利率市场化改革提出了政策建议。  相似文献   
104.
近几年来,"省直管县"财政体制在各省陆续实施,其主要目的在于克服既有的市管县体制存在的各种弊端。可以预期,这项改革措施有减少行政管理成本、解决县乡财政困难、促进县域经济增长等多种潜在作用。但可能存在的问题是,该财政体制如何促进经济增长?文章利用江苏省51个县(市)2004-2009年的空间面板数据进行分析发现,"省直管县"财政体制对经济增长的作用主要是通过县(市)扩权而产生的"政府竞争效应"实现的。  相似文献   
105.
This study investigates the correlation and interdependence between and within the U.S. and Canadian corporate bond markets. The empirical framework adopted allows credit spreads to depend on common systematic risk factors derived from structural models and incorporates dynamic conditional correlations (DCC) between spreads. Results show that there is a surprisingly weak correlation between the two markets in normal times. However, during crises, there is a sudden and strong increase in the correlation between U.S. and Canadian credit spreads. The analysis of credit spread correlation within each market also shows an unusual increase in credit spread correlations between sectors and between risk classes in the U.S. during the 2007–2009 global financial crisis. This increase persists over the post-crisis period. By contrast, in Canada, credit spread correlations between sectors remain remarkably stable over time, suggesting an interdependence of credit spreads within the Canadian market.  相似文献   
106.
This article analyzes the relationships among trade, the economy, and environmental quality in China. First, in the context of these relationships, the Super-SBM model is used to calculate the environmental efficiencies of thirty Chinese provinces and cities to obtain the degrees of regional disparity. Second, China’s provincial panel data from 2003 and 2012 are used to establish an influential factor indicator system of environmental efficiency. A section-weighted fixed effect model then provides insights about influential factors such as spatial heterogeneity. Third, the article establishes a variable coefficient model to identify the relationships among the objects of the study and divides the Chinese regions into four types. The suggestions include enhancing environmental and business regulations to ensure equilibrium between trade, the environment, and local economies.  相似文献   
107.
This editorial summarizes and comments on the papers published in issue 11(4) so as to raise the bar in applied spatial economic research and highlight new trends. The first paper deals with common factors and spatial dependence in the error term specification of a production function model. The second paper sets forth a New Economic Geography (NEG) model with production activities that vary in their complexity, so as to analyse the impact on specialization patterns across different regions. The third paper measures the efficiency of local public investments using a relatively unknown econometric technique in which the time span over which the variables in the regression equation are measured is increased by one time period every run. The fourth paper adopts a conditional quantile regression approach to determine the impact of people employed in informal jobs on the wage distribution in Colombia and five of its regions. Finally, the last paper proposes and tests two new Bayesian variable selection approaches for spatial econometric models.  相似文献   
108.
农业旅游空间布局研究   总被引:8,自引:1,他引:8  
卢亮  陶卓民 《商业研究》2005,(19):171-173
农业旅游是农业与旅游业的交叉行业,也是一种新兴的专项旅游活动,由于具有贴近自然、参与性强等诸多优点,深受城市旅游者的青睐。通过对农业旅游空间布局的理论基础进行探寻,分析影响农业旅游空间布局的因素,提出农业旅游空间布局模式及其演化规律,并对农业旅游空间布局的优化提出了建议。  相似文献   
109.
厘清并量化电力市场与碳市场间的关联关系,是深化电力市场改革与实现"双碳"目标的重要抓手。本文基于2006—2018年中国100个地级及以上城市的面板数据,使用似不相关回归模型评估了电力市场效率,在此基础上研究了电、碳市场关联条件下碳价对电价的传导率,并对不同场景下全国碳市场的碳价进行了优化设计。研究发现:(1)与非试点地区相比,碳市场试点地区中电力市场的无谓损失率更低,并且市场效率的提高具有更高的碳减排作用。(2)电、碳市场关联条件下,碳价对电力市场中居民电价的传导率高于对工业电价的传导率,但均远低于完全竞争条件下的传导率水平。(3)传导率的提升能够缓解"降电价"与"碳减排"之间的矛盾。当前传导率下电力市场效率目标与碳减排目标的协同实现需要碳价的大幅提升,而在完全传导的理想情况下最优碳价约为40元/吨。(4)长期而言,当前传导率下碳排放总量下降场景、经济增速放缓场景对应的最优碳价分别为255.05元/吨、173.63元/吨,而人口老龄化场景并未对最优碳价的设置形成约束。本文的研究不仅为电力市场与碳市场之间的关联奠定了理论基础,也为全国碳市场价格机制的优化设计提供了政策参考。  相似文献   
110.
"双评价"(资源环境承载能力评价和国土空间开发适宜性评价)作为构建国土空间基本战略格局的科学基础尚未延伸至海洋层面。海域"双评价"作为沿海地区国土空间规划工作的重要内容,存在理论缺失、技术方法不完善等问题。文章以海域功能理论为基础,从人类海洋活动出发,探索海域"双评价"的实践方案,建立"双评价"到海域利用优化的科学逻辑,指出基于"双评价"的海域利用冲突识别是海洋空间规划的关键。以温州市海域为例,基于本底资源从空间、渔业、环境和生态四方面进行单要素承载力测算,以此获得海域综合承载力作为监测预警的标志。选择渔业用海和建设用海两类典型用海进行适宜性分析,确定海洋空间利用的最优布局,判断海域利用空间冲突。结果表明:温州市沿海区县的海洋承载能力差异较大,资源环境分化严重,龙湾区与洞头区渔业资源开发超载;乐清市与龙湾区的海洋环境超载。渔业用海适宜面积占比较低且分布于远海地带。不适宜区域集中于瓯江、飞云江、鳌江三江入海口岸海域。建设用海适宜区域集中于近岸海域,远海区域距离城镇与交通较远,自然条件中水深较深,成本较高。苍南县和平阳县海域利用冲突较少,用海布局合理。乐清市、龙湾区与洞头区存在显著冲突。"双评价"的实践与应用是指导沿海地区海洋经济发展与海洋资源保护的关键,能够综合识别海洋利用的冲突,有助于沿海地区海洋空间规划。  相似文献   
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