全文获取类型
收费全文 | 2060篇 |
免费 | 33篇 |
专业分类
公路运输 | 841篇 |
综合类 | 79篇 |
水路运输 | 540篇 |
铁路运输 | 65篇 |
综合运输 | 568篇 |
出版年
2023年 | 22篇 |
2022年 | 51篇 |
2021年 | 22篇 |
2020年 | 10篇 |
2019年 | 20篇 |
2018年 | 53篇 |
2017年 | 54篇 |
2016年 | 114篇 |
2015年 | 30篇 |
2014年 | 102篇 |
2013年 | 292篇 |
2012年 | 111篇 |
2011年 | 121篇 |
2010年 | 108篇 |
2009年 | 104篇 |
2008年 | 105篇 |
2007年 | 46篇 |
2006年 | 45篇 |
2005年 | 45篇 |
2004年 | 34篇 |
2003年 | 29篇 |
2002年 | 31篇 |
2001年 | 31篇 |
2000年 | 43篇 |
1999年 | 31篇 |
1998年 | 21篇 |
1997年 | 29篇 |
1996年 | 34篇 |
1995年 | 40篇 |
1994年 | 18篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 17篇 |
1989年 | 7篇 |
1988年 | 15篇 |
1987年 | 12篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 7篇 |
1977年 | 14篇 |
1976年 | 13篇 |
1975年 | 22篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有2093条查询结果,搜索用时 46 毫秒
81.
Ren-Yong GuoHai-Jun Huang S.C. Wong 《Transportation Research Part B: Methodological》2011,45(3):490-506
We present a method of predicting pedestrian route choice behavior and physical congestion during the evacuation of indoor areas with internal obstacles. Under the proposed method, a network is first constructed by discretizing the space into regular hexagonal cells and giving these cells potentials before a modified cell transmission model is employed to predict the evolution of pedestrian flow in the network over time and space. Several properties of this cell transmission model are explored. The method can be used to predict the evolution of pedestrian flow over time and space in indoor areas with internal obstacles and to investigate the collection, spillback, and dissipation behavior of pedestrians passing through a bottleneck. The cell transmission model is further extended to imitate the movements of multiple flows of pedestrians with different destinations. An algorithm based on generalized cell potential is also developed to assign the pedestrian flow. 相似文献
82.
83.
Alan H. Robinson 《Coastal management》2013,41(1-2):5-34
This article reviews the historical development of the category of national park known as “national seashore,”; and traces the evolution of basic planning and management policies that are applied to such areas. Also reviewed is the current sequential approach applied by the National Park Service in all its planning efforts, including a discussion of the impact of the National Environmental Policy Act on park planning. Several examples are provided to illustrate a variety of planning problems common to the sashore environment. Finally, comments are provided on the future promise of seashore and barrier island conservation and development, as well as the future role of other agencies and private organizations. 相似文献
84.
Y.H. Venus Lun Michael BrowneKee-hung Lai Christina W.Y. WongT.C.E. Cheng 《Research in Transportation Economics》2011,32(1):64-70
Container shipping and its related service sectors help accelerate globalization of the world economy. This industry has been experiencing rapid growth, prompting container terminal operators to increase their handling capacity in response. Providing container terminal services requires substantial capital investment in physical assets such as cargo handling facilities and information systems. On the other hand, operating container terminals is a long-term investment that typically spans several business cycles. Hence prudent asset management using appropriate tools is critical for container terminal operators to sustain their businesses. Generally, due to risk-adverseness, investors are unwilling to take more risk in their investment unless they can reap a higher return. Contrary to this argument, this study finds no direct influence of better firm performance as a proxy of higher return on business risk-taking by container terminal operators. Instead, scale of operations is positively associated with business risk-taking, suggesting that container terminal operators with a larger scale of operations are willing to take more business risk. 相似文献
85.
Timon H. Stasko H. Oliver Gao 《Transportation Research Part A: Policy and Practice》2012,46(8):1216-1226
The considerable cost of maintaining large fleets has generated interest in cost minimization strategies. With many related decisions, numerous constraints, and significant sources of uncertainty (e.g. vehicle breakdowns), fleet managers face complex dynamic optimization problems. Existing methodologies frequently make simplifying assumptions or fail to converge quickly for large problems. This paper presents an approximate dynamic programming approach for making vehicle purchase, resale, and retrofit decisions in a fleet setting with stochastic vehicle breakdowns. Value iteration is informed by dual variables from linear programs, as well as other bounds on vehicle shadow prices. Sample problems are based on a government fleet seeking to comply with emissions regulation. The model predicts the expected cost of compliance, the rules the fleet manager will use in deciding how to comply, and the regulation’s impact on the value of vehicles in the fleet. Stricter regulation lowers the value of some vehicle categories while raising the value of others. Such insights can help guide regulators, as well as the fleet managers they oversee. The methodologies developed could be applied more broadly to general multi-asset replacement problems, many of which have similar structures. 相似文献
86.
87.
This paper proposes the adoption of an integrated inventory and transportation system (IITS) to minimize the total costs of inventory and transportation. A non-linear programing is developed by analyzing transportation and inventory costs with one supplier and many retailers in the distribution environment. The paper compares the proposed model with the traditional approach in computing total costs with numerical data. The results indicate that the total costs can be optimized by adopting integrated programing rather than the traditional approach, along with achieving improved customer service levels. In particular, sensitivity analysis is applied to determine the performance of the IITS under various transportation costs, holding costs and shortage costs. It shows that the transportation cost per unit is most sensitive in the proposed model. In this situation, the IITS is more effective for cost saving when set-up cost, holding and shortage costs are high, but is less effective for situations involving high per-unit transportation costs. 相似文献
88.
Rutherford H. Platt 《Coastal management》2013,41(3):265-284
The ocean and Great Lakes coasts of the United States are experiencing widespread economic and environmental damage from coastal flooding and erosion. During this century, public response to such coastal hazards has evolved haphazardly in response to particular disasters. Over time, however, the range of response has broadened as research has helped to refine public understanding of physical coastal processes, and specific disasters have been studied before longer term forms of institutional response have been formulated. Earlier reliance on engineered shoreline protection has been supplemented by beach nourishment, flood insurance, building and land use regulations, coastal zone planning, and other approaches. This article interprets the evolution of such public policy innovations in terms of a model that depicts the interaction of spatially differentiated systems of physical, legal, and cultural phenomena in the coastal context. 相似文献
89.
John H. Mott 《先进运输杂志》2013,47(5):498-511
A method for modeling air carrier departure delays at commercial‐service airports as autoregressive random processes is presented. This method employs the correlation of a priori demand data to significantly reduce prediction error in the optimal least‐squares estimator for additive white noise. The reduction factor of the prediction error is demonstrated to be on the order of 102 over that of the unbiased estimator. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
90.
William H.K. Lam 《运输规划与技术》2013,36(4):245-258
This paper investigates the role of transport pricing in network design and describes two facts about flow pattern in a transportation system. The first, illustrated by an example of Braess paradox, is that adding a new link to the network does not necessarily minimize the total travel time. The second is that introducing of appropriate toll pricing may reduce not only the total network time but also the travel time for each individual traveller. It follows with the investigations of different system objectives and different pricing policies (only toll pricing and distance‐based pricing are considered), and shows how they affect the system performance and flow pattern. Lastly, a systematic optimization process is proposed for integrated planning of transport network and pricing policies. 相似文献