全文获取类型
收费全文 | 3523篇 |
免费 | 13篇 |
专业分类
公路运输 | 819篇 |
综合类 | 940篇 |
水路运输 | 969篇 |
铁路运输 | 147篇 |
综合运输 | 661篇 |
出版年
2023年 | 11篇 |
2022年 | 38篇 |
2021年 | 24篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 369篇 |
2017年 | 331篇 |
2016年 | 369篇 |
2015年 | 26篇 |
2014年 | 33篇 |
2013年 | 127篇 |
2012年 | 174篇 |
2011年 | 410篇 |
2010年 | 383篇 |
2009年 | 137篇 |
2008年 | 307篇 |
2007年 | 203篇 |
2006年 | 84篇 |
2005年 | 116篇 |
2004年 | 56篇 |
2003年 | 60篇 |
2002年 | 27篇 |
2001年 | 18篇 |
2000年 | 21篇 |
1999年 | 10篇 |
1998年 | 20篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 19篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1973年 | 5篇 |
1972年 | 2篇 |
排序方式: 共有3536条查询结果,搜索用时 15 毫秒
971.
A new model system dealing with trips of length up to 100 km has recently been developed in Norway. A new way of dealing with
seasonal passes for public transport is used in the travel-to-work model. The objective was to account for the fact that a
respondent that posses a seasonal pass for public transport may behave as if public transport is free on the day they report
a travel diary. On the other hand, we can not assume that public transport is free for respondents that used other modes of
transport or that public transport is free to alternative destinations. This problem was solved by defining seasonal pass
as a separate alternative in the form of a nest that included all modes of travel. The cost of a seasonal pass is a common
cost for all modes in the nest and will thus not affect the choice within the nest. The estimation of this specification is
compared with the more common approach of assigning an average cost per day based on the cost of a monthly pass and the number
of workdays in a month. The comparison indicates that the “average cost per day” approach may produce biased estimates for
several parameters. It also turns out that the cost parameter for seasonal pass is higher than the parameter for “out of pocket”
cost, probably reflecting that there will be some uncertainty with respect to the actual use of a seasonal pass. 相似文献
972.
Nazneen Ferdous Abdul Rawoof Pinjari Chandra R. Bhat Ram M. Pendyala 《Transportation》2010,37(3):363-390
This paper proposes a multiple discrete continuous nested extreme value (MDCNEV) model to analyze household expenditures for
transportation-related items in relation to a host of other consumption categories. The model system presented in this paper
is capable of providing a comprehensive assessment of how household consumption patterns (including savings) would be impacted
by increases in fuel prices or any other household expense. The MDCNEV model presented in this paper is estimated on disaggregate
consumption data from the 2002 Consumer Expenditure Survey data of the United States. Model estimation results show that a
host of household and personal socio-economic, demographic, and location variables affect the proportion of monetary resources
that households allocate to various consumption categories. Sensitivity analysis conducted using the model demonstrates the
applicability of the model for quantifying consumption adjustment patterns in response to rising fuel prices. It is found
that households adjust their food consumption, vehicular purchases, and savings rates in the short run. In the long term,
adjustments are also made to housing choices (expenses), calling for the need to ensure that fuel price effects are adequately
reflected in integrated microsimulation models of land use and travel. 相似文献
973.
This paper proposes a new activity-based transit assignment model for investigating the scheduling (or timetabling) problem
of transit services in multi-modal transit networks. The proposed model can be used to generate the short-term and long-term
timetables of multimodal transit lines for transit operations and service planning purposes. The interaction between transit
timetables and passenger activity-travel scheduling behaviors is captured by the proposed model, as the activity and travel
choices of transit passengers are considered explicitly in terms of departure time choice, activity/trip chain choices, activity
duration choice, transit line and mode choices. A heuristic solution algorithm which combines the Hooke–Jeeves method and
an iterative supply–demand equilibrium approach is developed to solve the proposed model. Two numerical examples are presented
to illustrate the differences between the activity-based approach and the traditional trip-based method, together with comparison
on the effects of optimal timetables with even and uneven headways. It is shown that the passenger travel scheduling pattern
derived from the activity-based approach is significantly different from that obtained by the trip-based method, and that
a demand-sensitive (with uneven headway) timetable is more efficient than an even-headway timetable. 相似文献
974.
In this paper we review freight forecasting models and current advances and needs with respect to data and model development.
We then present a case study to suggest which models should be developed for the State of California in the US. We suggest
several alternatives including an aggregate commodity flow model, a disaggregate regional logistics model and a hybrid regional
logistics model with a truck touring model. We point out however, that the data requirements for the latter model would be
extensive. In addition, the development of hybrid models, for example progress in the integration of regional logistics models
with urban truck touring models, will introduce new problems such as reconciling the outputs of multiple models for consistency. 相似文献
975.
Smart card systems have become the predominant method of collecting public transport fares in Japan. Transaction data obtained
through smart cards have resulted in a large amount of archived information on how passengers use public transportation. The
data have the potential to be used for modeling passenger behavior and demand for public transportation. This study focused
on train choices made by railway passengers. If each passenger’s train choice can be identified over a long period of time,
this information would be useful for improving the customer relationship management of the railway company and for improving
train timetables. The aim of this study was to develop a methodology for estimating which train is boarded by each smart card
holder. This paper presents a methodology and an algorithm for estimation using long-term transaction data. To validate the
computation time and accuracy of the estimation, an empirical analysis is carried out using actual transaction data provided
by a railway company in Japan. The results show that the proposed method is capable of estimating passenger usage patterns
from smart card transaction data collected over a long time period. 相似文献
976.
977.
The paper reports a modelling system to simulate goods movements at an urban scale. It allows joint analysis of choices made
by end-consumers (assumed to be families) and retailers. These movements are examined at two levels: analysis of commodity
flows, in terms of quantity, generated by the consumption of commodities; analysis of commodity flows, in terms of vehicles,
due to restocking. The first level allows us to calculate the goods quantity flows due to consumption and restocking; the
second level allows us to determine the service, vehicles used and target time, as well as the route chosen for restocking
sales outlets in order to estimate vehicle flows on the urban/metropolitan transportation network. The modelling system is
a multi-step model and considers a disaggregated approach for each decisional level. 相似文献
978.
Jiechao Liu Paramsothy Jayakumar Jeffrey L. Stein 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2019,57(6):874-913
Previous work by the authors focused on obstacle avoidance in large, high-speed autonomous ground vehicles within unknown and unstructured environments. This work resulted in a nonlinear model predictive control based algorithm that simultaneously optimises both the speed and steering commands. The algorithm can exploit the dynamic limits of the vehicle to navigate it to a target position as quickly as possible without compromising safety. In the algorithm, a model of the vehicle is used explicitly to predict and optimise future actions, but in practice the model parameter values are not known exactly. Thus, in this paper, the robustness of the algorithm to parametric uncertainty is evaluated. It is first demonstrated that using nominal parameter values in the algorithm leads to safety issues in 24% of the evaluated scenarios with the considered parametric uncertainty distributions. To improve the algorithm's robustness, a novel double-worst-case formulation is developed that simultaneously accounts for the robust satisfaction of the two safety requirements of high-speed obstacle avoidance: collision-free and no-wheel-lift-off. Results from simulations with stratified random scenarios and worst-case scenarios show that the double-worst-case formulation renders the algorithm robust to all uncertainty realisations tested. The trade-off between robustness and the task completion performance is also quantified. 相似文献
979.
980.
Xuyu Hu 《WMU Journal of Maritime Affairs》2018,17(3):347-375
Mandatory rules exist in contracts for international liner shipping primarily because of imbalances and non-equity in the allocation of contract responsibilities. The superior bargaining position owned by the carriers depends largely upon liner market monopoly levels, the supply and demand balance between the shipper and carrier, and the cargo volume size of the shippers. With the development of shipping technologies, mode of transport, and shipping competition policy, the unequal comparison of bargaining forces between shippers and carriers changes. When the existing mandatory rule was deemed no longer necessary due to changing circumstances, legislation requirements to restore freedom to contract became apparent. When both sides have equal bargaining power, adoption of the principle of freedom of contract for their business relationships is suitable. The Rotterdam Rules concerning freedom of volume contract construction is based on equal bargaining powers between both sides and responds to the evolving situation of the industry. The Rules represent the development trend of today’s theory of contracts for international liner shipping and the demand for legal and institutional changes. 相似文献