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1.
田波  杨爱峰 《物流科技》2007,30(8):66-69
本文在分析现有的供应商评价方法的基础上,提出一种基于改进的模糊综合评价模型,使得评价的结果更为客观、科学,而且计算较为简便,为供应商的选择提供了一种全新的思路。最后用一个简单的案例进行了分析和讨论。  相似文献   
2.
为了提升民航运行效率、准确预测客运量,促进其可持续发展,采用分类学方法将民航客运量预测方法划分为传统统计学、机器学习、组合模型3大类.详述各类方法的改进原理、效果和应用,通过数据处理、权重调整、参数优化和结构改进提高准确性,并总结组合模型相对单一模型的优势.实证研究结果表明,组合预测模型相较于单一模型具有更高的准确性,并指出结合人工智能和大数据技术的发展趋势,构建优秀的组合预测模型将是提高准确性的潜在研究方向.  相似文献   
3.
企业财务管理的目标在于实现企业价值最大化,实现这一目标在于科学、合理的分配收益:兼顾消费与 积累的关系、确保息税按期足额支付、前置人力资本的收益分配、优化现金股利和股票股利的结构。  相似文献   
4.
We consider the problem of estimating a probability density function based on data that are corrupted by noise from a uniform distribution. The (nonparametric) maximum likelihood estimator for the corresponding distribution function is well defined. For the density function this is not the case. We study two nonparametric estimators for this density. The first is a type of kernel density estimate based on the empirical distribution function of the observable data. The second is a kernel density estimate based on the MLE of the distribution function of the unobservable (uncorrupted) data.  相似文献   
5.
    
Few would contest that teachers are a very important determinant of how much students learn in school, and how to improve teacher performance has been the focus of lively policy debate in both rich and poor countries. This paper examines how teacher incentives, both pecuniary and non‐pecuniary, correlate with teacher effort. Using school survey data from Lao PDR, we estimate measures of teacher effort, including the number of hours that teachers spend preparing for classes and teacher provision of private tutoring outside of class hours, which are not the typical measures used in previous research. Estimation results fit well under the standard labour supply framework and indicate that greater teacher effort is associated with non‐pecuniary incentives such as more teacher autonomy over teaching materials and monitoring as measured by the existence of an active parent – teacher association and the ability of school principals to dismiss teachers. Methodologically, this paper provides a detailed derivation of a simultaneous OLS‐probit model with school random effects that can jointly estimate teacher work hours and tutoring provision.  相似文献   
6.
    
Estimation in the interval censoring model is considered. A class of smooth functionals is introduced, of which the mean is an example. The asymptotic information lower bound for such functionals can be represented as an inner product of two functions. In case 1, i.e. one observation time per unobservable event time, both functions can be given explicitly. We mainly consider case 2, with two observation times for each unobservable event time, in the situation that the observation times can not become arbitrarily close to each other. For case 2, one of the functions in the inner product can only be given implicitly as solution to a Fredholm integral equation. We study properties of this solution and, in a sequel to this paper, prove that the nonparametric maximum likelihood estimator of the functional asymptotically reaches the information lower bound.  相似文献   
7.
    
Are low wages a way for the unemployed to switch to higher-paying jobs? Using data from the British Household Panel Survey, the labour market dynamics of unemployed, low-paid and higher-paid employed men are analysed. Moreover, the respective (un)employment duration and occupational skill level are accounted for. Results show that in general low wages significantly reduce the risk of future unemployment and increase the chances of ascending the salary ladder, especially in the case of long-term unemployment (>360 days). Furthermore, the occupational skill level has a substantial influence on the upward mobility of low-paid jobs: individuals working in the initial period in a low-paid and higher-skilled occupation have on average an 11 percentage points higher probability of entering higher pay compared to when working in a low-paid and low-skilled occupation.  相似文献   
8.
    
Airport terminals are facilities that provide a variety of activities related to both the preparation of the passengers for their air trip (aeronautical) and their free time inside the terminal (non-aeronautical). In the last years, the number of non-aeronautical activities has substantially increased and significantly diversified both before and after the security checkpoint. The established role of non-aeronautical activities forces planners and managers to better understand passenger behavior. The potential of discrete choice models for the exploration of passenger behavior is analyzed in this paper. For the demonstration of the methodology, Lisbon Humberto Delgado International airport is used as a case study. Data is collected through a revealed and stated preference survey inside the terminal at the area before the security checkpoint. Activity-choice models are developed to identify the factors that affect the choices of the passengers over the area where they conduct non-aeronautical activities. Forecasts show that when increasing the percentage of passengers who conduct the check-in online and have planned their activities before arriving at the airport, the passengers’ preferences to conduct non-aeronautical activities only after the security checkpoint increase. This paper shows the contribution of developing discrete choice models in the better comprehension of passenger decisions over the activities they perform in an airport terminal.  相似文献   
9.
Airlines design their initial schedules under the assumption that all resources will be available on time and flights will operate as planned. However, some disruptions occur due to mechanical failures and unexpected delays of maintenance, making the aircraft unavailable for a certain period of time. These deviations from the initial plan result in high operational costs in addition to the serious inconveniences experienced by passengers. In order to handle aircraft and passenger recovery problems simultaneously, we work on integrated networks at which aircraft routings and passenger itineraries are superimposed. Consequently, we could calculate the actual profit and cancellation cost by evaluating each passenger itinerary while considering the seat capacity limitations. In our computational results, we use a daily schedule of a major U.S. airline and clearly demonstrate that there is an optimal trade-off between operating and passenger-related costs.  相似文献   
10.
本文讨论了一类新的加工时间可控的单机排序问题,其目标函数为正则函数与最大不满意程度函数之和,不满意函数刻划了对工件实际加工时间偏离其额定加工时间不满意的程度,本文对这类问题提出了几个多项式算法。  相似文献   
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