全文获取类型
收费全文 | 267篇 |
免费 | 1篇 |
专业分类
公路运输 | 95篇 |
综合类 | 4篇 |
水路运输 | 104篇 |
铁路运输 | 1篇 |
综合运输 | 64篇 |
出版年
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 50篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 17篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 8篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 10篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 6篇 |
1972年 | 2篇 |
排序方式: 共有268条查询结果,搜索用时 0 毫秒
41.
James Bird 《Maritime Policy and Management》1982,9(2):83-102
This paper, in two parts, reports on the Seaport Development in the European Communities Research Project wherein forty interviews with decision-makers were held in European seaports, and another forty were held with shipowning organizations. This part of the paper reports on analysis of the open-ended tape-recorded responses of the interviewees to six separate sets of propositions they were shown. The first major conclusion is that decision-makers in the ports and shipping industries have a great deal to offer in helping to shape future EC policies about seaports. The second is that these decision-makers on the whole agree with students of the subject, but outside the industries, that a step-by-step approach is possible towards a Common Seaports Policy. Indeed, without prompting, some respondents even confirmed a previously published suggestion for the first stage of this process—the necessity for an agreed standard basis for ports' accounts. It is believed that a small secretariat within the Brussels Commission could weld representatives of the industries into a working group which could make real progress by consulting their colleagues through interviews similar to those successfully conducted for this project. 相似文献
42.
Using the concept of generalised costs to reflect quality in rail services, we consider the level of provision and quality of these services in the various forms they may take in a privatised environment within a model where we assume linear and separable demand and cost functions for analytical simplicity. Using the Pareto-efficient output and quality outcomes under a fully integrated system for reference (as well as those for a fully integrated profit-maximising monopolist) we show that if either bilateral monopoly or complementary monopoly emerge as a market structure the output of train services and their quality will generally fall. In the case of the emergence of both bilateral monopoly and complementary monopoly our analysis again suggests poor welfare outcomes. The implication that can be drawn from our analysis is that a regulator of a privatised rail system faces some severe problems if she is to attain the appropriate welfare targets. 相似文献
43.
To plan new bus routes in suburban areas, expected bus running times on these routes are needed. Using most readily available relevant variables, a regression model is developed for estimating bus running times. The model is conceptually reasonable and it was tested using data other than that used for estimation. 相似文献
44.
James P. Gander 《Transportation Research Part B: Methodological》1985,19(3):187-195
Highway automobile speed and uncertain enforcement of the speed limit are introduced into a standard household utility model having time and income constraints. Due to uncertainty, expected utility is maximized to obtain the optimal speed (in excess of the speed limit). The optimal amounts of all other commodities and travel are also obtained. The key feature of the model is the risk attitude of the driver and the effect on optimal speed of such attitude. A related feature is the effect of risk attitude on the amount of speed self-insurance. An important finding is that the risk avert (seeking, neutral) driver charges himself an insurance premium that is larger than (smaller than, equal to) what is actuarially sufficient. The relationship between speed, risk attitude, and efficient cost of automobile travel is developed and implications are explored. A parametric analysis is conducted to establish the effect on optimal speed (and other variables) of changes in such policy instruments as the price of gasoline, the probability of being caught exceeding the speed limit, the unit speed fine, and the speed limit. Policy implications of the theoretical results are part of the conclusions. 相似文献
45.
Kailash C. Kapur Assistant Professor 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1972,1(1):3-16
Automation of vehicular traffic in different forms has been considered by many people. It offers many advantages. Vehicular traffic dynamics for automated vehicle systems are developed here using calculus of variations and optimal control theory. Using such an optimization approach, the relationship of the traffic dynamics developed here and the traffic dynamics which have been used extensively before for non-automated systems is also shown. Such an approach considers multiple objective functions for the system. 相似文献
46.
James H. Banks 《先进运输杂志》1984,18(3):207-228
The amount of time required to pick up and discharge passengers is an important issue in the planning and modeling of urban bus systems. Several past studies have employed models of this component of bus travel time which are based, in part, on a model of the number of stoppings the bus makes to pick up or discharge passengers. Most past versions of this model have assumed that expected demand does not vary from stop to stop or from trip to trip, but that the number of passengers demanding service at any given stop during any given trip follows a Poisson distribution. An alternative model is derived, based on the assumption that expected demand varies among stops and times of day but is fixed from day to day at any given stop and time of day. Boarding and alighting survey data are used to verify that the “average-demand” Poisson model consistently overestimates the number of stoppings and to calibrate an approximate version of the alternative model. A stop-spacing optimization model previously developed by Kikuchi and Vuchic is reevaluated using the alternative stopping model in place of the average demand model used in the original version. The results are found to be considerably different, thus indicating that transit route optimization models are sensitive to the way in which stopping processes are modeled. 相似文献
47.
Edge C. Yeh Professor Guan Kae Roan Graduate Student I Hsien Yun Graduate Student 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(4):427-444
An Anti-Lock Brake System (ABS) system is developed for motorcycles using different control laws to improve the safety during emergent braking conditions. The mechanical design problem is first investigated so as to modify a scooter to be equipped with the proposed ABS brake system and to set up experimental test stand. For ABS control, the slip control, P1R3, and P2R4 methods are used to implement the controller using an Intel 80196KC single chip microcomputer. The hard-ware-in-the-loop (HITL) simulation is also performed in PC to check the performance in various road conditions including dry and wet roads. It is found experimentally that both P1R3 and P2R4 can both achieve ABS function, but P2R4 performs more desirably than P1R3 method. 相似文献
48.
This paper summarizes the interim Phase II results of the Arctic Tanker Risk Analysis Project, which examined the risk of oil shipment by tankers in the Canadian Arctic. The objectives were to identify the hazards most likely to produce an oil spill on the MV Arctic, and to institute measures to reduce that risk. Phase I indicated that a high potential exists for a shipping accident at the terminals, the St. Lawrence River and in the High Arctic. However, environmental sensitivity was shown to be greatest along the coastal zone of the Gulf of St. Lawrence and the St. Lawrence River. Phase II involved further examination of environmental sensitivity and the task of ice navigation. These results resulted in a revised risk profile. Three spill scenarios were then designed to estimate clean-up costs and other economic impacts. A cost effectiveness analysis was conducted which compared spill costs to risk mitigation. As the project enters Phase III, the scope has widened to include all product tankers operating in the Arctic. A new Canadian Standards Association Risk Management Standard Q850 is being implemented with the objective of providing prototype tanker Bridge Risk Management System software. 相似文献
49.
It has long been recognized that the compressive behavior of primary ship structural components plays a vital role in the design of surface ship hulls. This is equally as true for the new advanced double hull concept as it is for the more conventional surface ship configurations. What is different, however, is the nature of the structural mechanics phenomena which must be addressed due to the double hull's more radical departure from conventional design and construction practices. With increasing interest and attention being shown in this new concept, the David Taylor Model Basin has over the past few years initiated a number of research efforts which have and are continuing to address various aspects of the behavior of double hulls and their components to primary compressive loadings. These studies have as their ultimate goal the development of practical, user oriented design methods for double hull structure and as such currently focus on more approximate, rather than mathematically rigorous, approaches to the various structural phenomena being considered. This paper is in essence a progress report on a selected number of these efforts and describes the results achieved to date as well as the ongoing efforts and those planned for the future. This report focuses primarily on three recent studies: (1) a preliminary look at the relative significance of local versus general instability failure of double hull structure; (2) small scale experimental analysis of double hull sections using rigid vinyl modelling; and (3) the application of beam-on-elastic-foundation analysis methods for high aspect stiffened plates as it relates to double hull structure. In addition to these major topics, the report also includes a brief discussion of other ongoing and planned efforts relevant to the advanced double hull. 相似文献
50.
James R. Jones Lu Qu Kenneth L. Casavant Won W. Koo 《Maritime Policy and Management》1995,22(1):63-80
A mathematical spatial programming model developed to analyse changes in international and hinterland commodity flows through a regional port system is applied to wheat shipments through the U.S. Pacific Northwest port system. Two scenarios, one focusing on a Chinese quarantine on wheat shipments from the Pacific Northwest and the other on possible closure of barge transportation on the Columbia-Snake River, illustrate the capacity of the model to evaluate the impacts of international and hinterland shocks on the regional port system. 相似文献