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991.
合理的铁路运用车保有量,对满足铁路货运需求,提高货车运用效率,降低运营成本等有重要作用.考虑铁路运输系统复杂的内外部环境及其动态变化特性,对影响运用车保有量因素定性分析;提出了粗糙集属性约简、灰色关联分析、逐步回归方法相结合的主要影响因素识别方法.以此为基础,建立了基于 Box-Cox变换分位数回归(Box-Cox-TQR)和核密度估计相结合的概率密度预测模型.以国家铁路局运用车保有量实际数据为基础,进行预测试验.结果表明,利用主要因素识别的方法符合目标值的运动变化规律,预测结果具有良好的精度.此外,概率密度预测比点预测、区间预测传递出更多信息,为管理决策提供更多准确有用信息. 相似文献
992.
The purpose of this study is to understand the effects of the influential factors that affect the sustainable development of new energy vehicle in China, investigate the cause-effect relationships among them, and propose some appropriate policies and efficacious measures for the policy-makers to promote its sustainable development. Interpretative Structuring Modeling was used to identify the critical factors affecting the sustainability of China’s new energy vehicle industry and to find the potential relationships among the factors; subsequently, fuzzy Decision Making Trial and Evaluation Laboratory was employed to investigate the cause-effect relationships among the influential factors and to prioritize these factors. The results reveal that technological maturity, technological standards for new energy vehicles, and funds on R&D of new energy vehicles are the three most important driving factors for promoting the sustainable development of new energy vehicle industry of China. Some implications were also proposed for China’s authority. The success factors and strategic implications of new energy vehicles in China were investigated in a multi-criteria analysis approach. 相似文献
993.
The use of traffic sensors to acquire real‐time traffic information for intelligent transportation systems is becoming increasingly common. It is a challenge to determine where these sensors should be located to maximize the benefit of their use. This paper aims to illuminate the interaction of the sensor location problem (SLP) and its influencing factors, and to reveal the influencing mechanisms between those factors and the optimal sensor numbers. Firstly, we sum up the factors that influence the SLP for freeway corridors in detail and present the mathematical formulation of each factor. Then, given the parameters, which are derived from those influencing factors, the maximum integration value model (MIVM) and simplified MIVM are proposed for addressing the SLP. Finally, a real world case study, in which the simplified MIVM is used, is presented to illustrate how these factors influence the optimal sensor numbers and the maximum integration value, and also leads to the typical influencing patterns of those factors for freeway corridors. The results of the case study also demonstrate the effectiveness of the model and problem solving scheme. What is more, the suggestions for using the findings hereof in practical applications are put forward. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
994.
Port public–private partnerships (PPPs) are considered to be an important emerging mechanism for port development and improvement in port performance especially for developing countries. This paper empirically investigates the effect of institutional factors in the success of port’s PPPs; the latter defined as the attractiveness of the PPP project for private bidders and the market competitiveness of the facility. The empirical investigation of a large sample of ports finds that ‘regulatory quality’, ‘market openness’, ‘ease to start a business’ and ‘enforcing contracts’ are important institutional determinants of port PPP success and may ultimately contribute to port development and economic growth. The results are consistent with and add to the theoretical literature whereas practical implications for port authorities, managers and investors are discussed. 相似文献
995.
港口国监督检查的效率逐渐引起世界海事界的重视,如何提高PSC检查效率成为各港口国当局不得不面对的问题。本文介绍了效率的释义和PSC检查效率的内涵以及国际海事界对PSC检查效率的新要求,分析了PSC检查效率的影响因素,提出了提高我国港口国监督效率的几点建议。 相似文献
996.
The hypothesis of this paper is that some features of the built environment, particularly those concerned with the accessibility of the street network, could be associated with the proportion of pedestrians on all trips (modal split) found in different parts of a city. Quantitative analysis (bi-variate correlation and a multiple regression model) was used to establish the association between variables. The study area covered a substantial part of the metropolitan area in Madrid, Spain. Results showed a consistent influence of five particular indexes in the multi-variate model. Not surprisingly for this kind of research, four of them described density and mix of land uses. But perhaps more interestingly, the first one was a measure of the accessibility of the public space network, a less prominent variable in literature to date. This variable is called herein configurational accessibility, calculated using Space Syntax, an urban morphology theory. The relevance of configurational accessibility is probably related to its surprising ability to synthesize global and perceived properties of street networks at the same time. The findings introduce the idea that the configuration of the urban grid can influence the proportion of pedestrians (as a part of total trips in any transport mode) who choose to walk on single-journey trips. The discussion links with the current debate about walkability indexes and the need of empirical support for the chosen variables and also with transport planning. Because the relevance of the street network’s role is not so easy to grasp, inputs from configurational theory and the pedestrian potential underlying this fact are also discussed at the end of the paper. 相似文献
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In the context of sustainable urban transport in developing countries, individuals’ travel behavior faces multiple factors which influence their mobility patterns. Recognizing these factors could be a favorable method to organize more regular and sustainable trip patterns. This study aims to identify the less well-known lifestyle along with more popular built environment as the main factors which shape travel behaviors. Employing data from 900 respondents of 22 urban areas in city of Shiraz, Iran, this paper explores travel behaviors as non-working trip frequencies by different modes. Results of structural equation model indicate a strong significant effect of individual’s lifestyle patterns on their non-working trips. However, built environment impact on travel behavior is small compared to lifestyle. Besides, other variables such as travel attitudes and socio-economic factors stay crucial in the mode choice selection. These findings indicate the necessity of regarding lifestyle orientations in travel studies as well as objective factors such as land use attributes. 相似文献