全文获取类型
收费全文 | 273篇 |
免费 | 3篇 |
专业分类
公路运输 | 29篇 |
综合类 | 7篇 |
水路运输 | 89篇 |
铁路运输 | 3篇 |
综合运输 | 148篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 65篇 |
2012年 | 9篇 |
2011年 | 16篇 |
2010年 | 20篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有276条查询结果,搜索用时 15 毫秒
201.
Hilde Meersman Eddy Van de Voorde Thierry Vanelslander 《Maritime Policy and Management》2013,40(3):175-177
Due to the capital-intensive nature of the modern shipping industry, loan finance plays a major role in vessel-acquisition cost. In this paper, J. B. Yolland discusses government-guaranteed finance, ancillary and commercial new building finance and finance for second-hand tonnage. He also examines a new source of funding found in the Euro-market. 相似文献
202.
This paper synthesizes evidence from the workshop on risk and reward in public transport contracting. It broadens the usual risk/reward framework to encompass strategic/tactical level issues, identifying high level community goals as the ultimate risk/reward pay-off. The evolution of tactical level public transport planning is reviewed, noting considerable change in functional roles between purchaser and provider in some jurisdictions. No single “best” approach is evident but an emerging interest in relational contracting founded on trust is apparent. Risk allocation between purchaser and provider is considered, a key debate concerning the extent to which providers should be exposed to revenue risk. 相似文献
203.
Juan de Dios Ortúzar Gonzalo Rodríguez 《Transportation Research Part D: Transport and Environment》2002,7(6):2519
A stated preference ranking experiment is designed to estimate the willingness-to-pay (WTP) for reducing the amount of atmospheric pollution in a group-based residential location context. Important issues are the proper definition of the context and the variable metric for the environmental attribute. Sample members were asked to rank 10 options arising from variations in the attributes travel time to work and to study, rent of the house and an environmental attribute (the number of days of Alert, in terms of concentration of PM10, at a dwelling’s location). Multinomial logit models based on a consistent microeconomic framework were estimated for various stratifications of the data (income, pollution sensitivity, and type of dwelling currently inhabited). From these subjective values of time and WTP were derived for reductions in the number of days of alert and hence the amount of pollutant concentration at a given location. The WTP came out at about 1% of the family income for reducing one contingence day per year; this is approximately 60% higher than an estimate reported for the city of Edmonton, Canada, but the average PM10 concentration in Santiago is about six times higher. 相似文献
204.
M. A. H. Van Der J. H. E. A. Muijderman F. E. Veldpaus 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1997,28(4):307-323
Controllers for semi-active suspensions have to account for constraints on damper range, tire force and suspension travel. Two approaches to incorporate these constraints in the design of controllers to minimize peak values in the chassis acceleration are considered. It is assumed that information on the oncoming road elevations (preview) is available. In the soft constraint approach, the constraints on tire force and suspension travel are included in a quadratic performance index. Two clipped optimal control laws, which deal with preview in a different way, are presented. Simulation results with a 2-DOF vehicle model on some rounded pulses show that these laws do not work satisfactorily with respect to the constraints. Therefore, the control problem is reformulated as a constrained optimization problem with hard constraints on tire force and suspension travel. Simulations with the same model on the same rounded pulses show that the hard constraint approach handles the constraints more properly. 相似文献
205.
Preview Estimation and Control for (Semi-) Active Suspensions 总被引:3,自引:0,他引:3
R.G.M. Huisman F.E. Veldpaus J.G.A.M. Van Heck J.J. Kok 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1993,22(5):335-346
An active suspension with preview is tested for rounded pulses and a stochastic road surface, and is compared to a passive suspension. The spectacular performance improvement obtained for a step function as road surface is not achieved but the improvement is still significant. The frequency response of the active suspension is determined for comparison with some suspension systems found in literature
An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently. 相似文献
An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently. 相似文献
206.
207.
R. Van Der Valk H.B. Pacejka 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1993,22(2):97-121
A dynamical model is presented to analyse the stability of motion of the two-wheeled 'Fokker F.28-like' landing gear including tyres. The model is equally applicable to similar landing gears. The influence of the introduction of a specially designed torsional damper on the dynamical behaviour of the landing gear-tyre combination is investigated. Results of the stability calculations are supported by test results. 相似文献
208.
Werner Jacobs Dirk Dubois Eva Floren Diane Aerts Jan Goris Anna Buczynska René Van Grieken 《WMU Journal of Maritime Affairs》2011,10(1):117-126
Maritime transport of benzene is regulated by the International Maritime Organisation (IMO). Two important guidelines for a ship’s crew in this matter are IMO circulars 1095 and 1220. The first one describes the minimum safety standards for ships carrying liquids in bulk containing benzene while circular 1220 deals with structural guidelines for new ships carrying liquids in bulk containing benzene, but also technical developments could help in improving safety and health protection on board chemical tankers carrying benzene in bulk. The aim of the present paper is to determine the benzene concentration in the working and living environment on board a modern chemical tanker carrying benzene in bulk, where all safety, technical and operational procedures described by IMO in the above-mentioned circulars are followed. During specific cargo operations, we measured the benzene concentrations on different locations on board by means of Radiello® passive diffusive samplers. Despite all measures taken, we found an important difference in benzene concentration between operations with a benzene cargo compared to operations without benzene on board, as well as inside and outside the accommodation. Moreover, even during discharge operations, where the emission is theoretically zero, we found an important increase in the benzene concentration. In addition, we found less favourable results for the engine room. 相似文献
209.
Studies that model the effects of land use on commuting generally use a trip-based approach or a more aggregated individual-based
approach: i.e. commuting is conceptualized in terms of modal choice, distance and time per single trip, or in terms of daily
commuting distance or time. However, people try to schedule activities in a daily pattern and, thus, consider tours instead
of trips. Data from the 2000 to 2001 Travel Behaviour Survey in Ghent (Belgium) illustrate that car use and commuting times
significantly differ between commuting trips within work-only tours and more complex tours. Therefore, this paper considers
trip-related decisions simultaneously with tour-related decisions. A multiple group structural equation model (SEM) confirmed
that the relationship between land use and commuting differs between work-only tours and more complex tours. Trips should
be considered within tours in order to correctly understand the effect of land use scenarios such as densifying on commuting.
Moreover, the use of multiple group SEM enabled us to address the issue of the complex nature of commuting. Due to interactions
between various explanatory variables, land use patterns do not always have the presumed effect on commuting. Land use policy
can successfully influence commuting, but only if it simultaneously accounts for the effects on car availability, car use,
commuting distance and commuting time. 相似文献
210.
Manivannan Kandasamy Seng Keat Ooi Pablo Carrica Frederick Stern Emilio F. Campana Daniele Peri Philip Osborne Jessica Cote Neil Macdonald Nic de Waal 《Journal of Marine Science and Technology》2011,16(2):157-167
This paper details the CFD validation studies carried out as a prerequisite for multi-fidelity CFD-based design optimization
of high-speed passenger-only ferries aimed at reducing far-field wake energy that causes beach erosion. A potential flow program
(WARP) and a URANS program (CFDSHIP) were validated using full-scale measurements of resistance, sinkage, trim, and far-field
wake train obtained over a wide range of speeds for two high-speed semi-planing foil-assisted catamarans: Spirit (LOA-22 m)
and 1060 (LOA-17 m). This study posed a unique combination of challenges for CFD modeling: the foil appended geometry required
complicated surface overset grids, the effect of the waterjet and wind resistance had to be modeled, and a method had to be
devised to extrapolate the calculated near-field elevation to get the far-field wake train using Havelock sources. A more
concentrated effort was applied to the URANS verification and validation which forms the focus of this paper. The results
show that URANS is able to accurately predict the resistance and motions for both vessels when coupled with models that account
for the propulsors and air resistance. The overall accuracy of URANS for the performance analysis of the foil-assisted, semi-planing
catamarans was adequate to warrant its use as a tool for subsequent design and optimization of a new vessel with significantly
reduced wakes. 相似文献