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271.
Michael J. Sobey 《Maritime Policy and Management》1993,20(1):3-29
On 19 October 1989, the International Maritime Organization adopted a joint uslliberian resolution meant to advance international cooperation in maritime casualty investigations. This resolution reflected an international determination to achieve greater cooperation between different states in investigative matters, in a manner consistent with international law. This paper examines how the IMO resolution addresses some of the inherent problems in such a multi-national industry. It also examines the question of whether us lawmakers may, or should, impose stricter controls and restrictions unilaterally on foreign-flag ships which call on us ports. 相似文献
272.
Traditionally, researchers studying transportation choice have used data either acquired from household surveys or broad,
region-wide aggregates. At the disaggregate level, researchers usually do not have access to important variables or observations.
This study investigates the potential usefulness of a proxy approach to modeling discrete choice vehicle ownership: substituting
narrow area-based aggregate proxies for missing micro-level explanatory variables by accessing large, publicly maintained
datasets. We use data from the 2000 Bay Area Travel Survey (BATS) and the contemporaneous U.S. Census file to compare three
models of vehicle ownership, drawing area-wide proxies from increasing levels of aggregation. The models with proxies are
compared with a parallel model that uses only survey data. The results indicate that the proxy models are preferred in terms
of model selection criteria, and predict vehicle ownership as well or better than the survey model. Parameter values produced
by the proxy method effectively approximate those returned by household survey models in terms of coefficient sign and significance,
particularly when the aggregate variables are representative of their household-level counterparts. The proxy model with the
narrowest level of aggregation achieved the best fit, coefficient precision, and percentage of correct prediction.
相似文献
Jeffrey WilliamsEmail: |
273.
Albert Lutz Bernhard Schick Henning Holzmann Michael Kochem Harald Meyer-Tuve Olav Lange 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(10):1432-1497
ABSTRACTVehicle simulation has a long tradition in the automotive industry as a powerful supplement to physical vehicle testing. In the field of Electronic Stability Control (ESC) system, the simulation process has been well established to support the ESC development and application by suppliers and Original Equipment Manufacturers (OEMs). The latest regulation of the United Nations Economic Commission for Europe UN/ECE-R 13 allows also for simulation-based homologation. This extends the usage of simulation from ESC development to homologation. This paper gives an overview of simulation methods, as well as processes and tools used for the homologation of ESC in vehicle variants. The paper first describes the generic homologation process according to the European Regulation (UN/ECE-R 13H, UN/ECE-R 13/11) and U.S. Federal Motor Vehicle Safety Standard (FMVSS 126). Subsequently the ESC system is explained as well as the generic application and release process at the supplier and OEM side. Coming up with the simulation methods, the ESC development and application process needs to be adapted for the virtual vehicles. The simulation environment, consisting of vehicle model, ESC model and simulation platform, is explained in detail with some exemplary use-cases. In the final section, examples of simulation-based ESC homologation in vehicle variants are shown for passenger cars, light trucks, heavy trucks and trailers. This paper is targeted to give a state-of-the-art account of the simulation methods supporting the homologation of ESC systems in vehicle variants. However, the described approach and the lessons learned can be used as reference in future for an extended usage of simulation-supported releases of the ESC system up to the development and release of driver assistance systems.Abbreviations: ABS: Anti-lock braking system; ADR: Australian design rules; ALB: Automatic load-dependent brake force controller; AMEVSC: Alternative method to assess the electronic vehicle stability control system; APP: Application; BSC: Brake slip controller; CAE: Computer-aided engineering; CAN: Controller area network; CAT: Category; CoG: Centre of gravity; DIN: Deutsches Institut für Normung (German Institute for Standards); EB+: Trademark of Haldex; EBD: Electronic brake force distribution; EBS: Electronic brake system; ECU: Electronic control unit; ESC: Electronic stability control; ECVWTA: European Community Whole Vehicle Type Approval; FMVSS: Federal motor vehicle safety standards; GPS: Global positioning system; GRRF: Groupe de travail en matiere de roulement et de freinage (Working Party on Braking and Running Gear); HiL: Hardware-in-the-Loop; HSRI: Highway Safety Research Institute; K&C: Kinematic and compliant (KnC); MBS: Multibody systems; MPV: Multipurpose vehicle; NHTSA: National Highway Traffic Safety Administration; OEM: Original equipment manufacturer; SiL: Software-in-the-Loop; ST: Summer tyres; STM: Single track model; StVO: Straßenverkehrsordnung (Government Highway Regulations); SUV: Sports utility vehicle; SW: Software; SwD: Sine with dwell manoeuvre; TC: Threshold consumption value; TCS: Traction control system; TRIAS: Test Requirements and Instructions for Automobile Standards; UN/ECE: United Nations Economic Commission for Europe; VAF: Value-added function; VDC: Vehicle dynamics controller; VTC: Vehicle test catalogue; WT: Winter tyres 相似文献
274.
Lars Finner Gero Poetsch Bernhard Sarnes Michael Kolbe 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(3):305-313
DB Systemtechnik is a high-performing, customer-driven service provider that, as well as authoritatively serving the Deutsche Bahn Group by dint of its specialist knowledge is also increasingly active on the global railway market. Development and testing of pantograph models and catenary systems have been part of the company's essential activity fields from the beginning. Therefore, an efficient and high-performing simulation tool is indispensable. That is why DB Systemtechnik spent high efforts to develop the program PrOSA in cooperation with the Heinz–Nixdorf–Institut (HNI) of the university Paderborn to simulate the interaction of pantograph and catenary. This article gives an overview of the most relevant properties of PrOSA. Furthermore, it is described how the benchmark requirements were implemented and processed. 相似文献
275.
It is well known from the literature that road lighting has significant safety benefits. The NZTA Economic Evaluation Manual (EEM) quotes a 35% reduction in crashes as the effect of upgrading or improving lighting where lighting is poor. 相似文献
276.
Elizabeth McLeod Russell Moffitt Axel Timmermann Rodney Salm Laurie Menviel Michael J. Palmer 《Coastal management》2013,41(5):518-539
The highest diversity coral reefs in the world, located in the Coral Triangle, are threatened by a variety of local stresses including pollution, overfishing, and destructive fishing in addition to climate change impacts, such as increasing sea surface temperatures (SSTs), and ocean acidification. As climate change impacts increase, coral reef vulnerability at the ecoregional scale will have an increasingly important influence on conservation management decisions. This project provides the first detailed assessment of past and future climatic stress, thermal variability, and anthropogenic impacts in the Coral Triangle at the ecoregional level, thus incorporating both local (e.g., pollution, development, and overfishing) and global threats (increasing SSTs). The development of marine protected area (MPA) networks across the Coral Triangle is critical for the region to address these threats. Specific management recommendations are defined for MPA networks based on the levels of vulnerability to thermal and local stress. For example, coral reef regions with potentially low vulnerability to thermal stress may be priorities for establishment of MPA networks, whereas high vulnerability regions may require selection and design principles aimed at building resilience to climate change. The identification of climate and other human threats to coral reef systems and ecoregions can help conservation practitioners prioritize management responses to address these threats and identify gaps in MPA networks or other management mechanisms (e.g., integrated coastal management). 相似文献
277.
Freeway merging sections are critical segments that can recurrently activate peak-hour traffic congestion. This article proposes a novel vehicular gap control method as a new Active Traffic Management (ATM) strategy to be added to the existing Intelligent Transportation System (ITS) toolboxes for freeway merge control. The proposed strategy, “Gap Metering,” can be considered a non-stopping mainline version of ramp metering. It utilizes signals advising mainline through vehicles to yield sufficient gaps for merging vehicles. Detailed system design and control methods are proposed and implemented in VISSIM (please spell out the abbreviation of VISSIM for this first instance), a microsimulation software package. Different driver behavior sets with different standstill headway values are created to allow switching between gap-metered vehicles and regular vehicles. We evaluate the proposed system through two VISSIM models built and calibrated, respectively, for both the I-894 corridor in Milwaukee, WI, and the Riverside Drive segment on I-35 northbound in Austin, TX. Both corridors experience severe morning peak-hour congestion. We use the I-894 corridor for testing the system design parameters and use the I-35 corridor to conduct a comparison with the ramp metering strategies. The I-894 results indicate an average of 10–20% network delay reduction among all scenarios. We then tested the scenario on the I-35 corridor and compared with the ALINEAR ramp metering. Gap metering strategies alone or combined with ramp metering can, respectively, reduce 17% and 27% more total delay than ramp metering only control at 20% compliance rate. 相似文献
278.
Dynamic message signs (DMS) have been widely used by transportation agencies to disseminate traffic information (referred to in this article as “public traffic information”) for decades. Unfortunately, their effectiveness is limited, based on the following reasons: they are costly, can only present a limited amount of information, and typically only display information in one language. The wide availability of smart devices and the development of connected vehicles offer the possibility to create “virtual” DMS (VDMS), utilizing geofencing and audible messages to convey public traffic information. This research compares the ability of VDMS to convey public traffic information with existing DMS. A mixed repeated-measure experiment using a driving simulator was designed that examined the impacts of driver age, information transmission mode, amount of information, and driving complexity on message comprehension. Forty-two participants were recruited and each of them was tested under different combinations of the three within-subject factors. Participant performance was measured in terms of message comprehension, distraction, and self-reported overall difficulty level in receiving messages. Results revealed that VDMS generally performs better than DMS as information content increases and driving condition complexity increases, regardless of driver age. VDMS increased message comprehension by 16% under relatively complex driving conditions, reduced driver reaction time to unexpected stimuli (as measured with a reduced time-to-brake of 0.39 s), and made the same messages easier to process and retain for drivers than DMS. Based on these results, it is recommended that transportation agencies give careful consideration to VDMS as a future strategy for delivering public traffic information in a connected vehicle environment. 相似文献
279.
Zeqi?Lu Tiejun?YangEmail author Michael?J.?Brennan Xinhui?Li Zhigang?Liu 《船舶与海洋工程学报》2014,13(3):291-298
Motivated by the need for improving the isolation performance, many research studies have been performed on isolators with nonlinear characteristics. Based on the shape of their phase portrait, such devices can be configured as either a mono-or bi-stable isolator. This paper focuses on investigating the relative performance of these two classes under the same excitations. Force transmissibility is used to measure the isolation performance, which is defined in terms of the RMS of the ratio of the transmitted force to the excitation force. When the system is subjected to harmonic excitation, it is found that the maximum reduction of the force transmissibility in the isolation range using Quasi-Zero stiffness is achieved. When the system is subjected to random excitation, it has the same effect of Quasi-Zero stiffness. Further, optimum damping can be changed with stiffness and has minimum value. 相似文献
280.
New evidence on walking distances to transit stops: identifying redundancies and gaps using variable service areas 总被引:1,自引:0,他引:1
Ahmed El-Geneidy Michael Grimsrud Rania Wasfi Paul Tétreault Julien Surprenant-Legault 《Transportation》2014,41(1):193-210
The percentage of the population being served by a transit system in a metropolitan region is a key system performance measure but depends heavily on the definition of service area. Observing existing service areas can help identify transit system gaps and redundancies. In the public transit industry, buffers at 400 m (0.25 miles) around bus stops and 800 m (0.5 miles) around rail stations are commonly used to identify the area from which most transit users will access the system by foot. This study uses detailed OD survey information to generate service areas that define walking catchment areas around transit services in Montreal, Canada. The 85th percentile walking distance to bus transit service is found to be around 524 m for home-based trip origins, 1,259 m for home-based commuter rail trip origins. Yet these values are found to vary based on our analysis using two statistical models. Walking distances vary based on route and trip qualities (such as type of transit service, transfers and wait time), as well as personal, household, and neighbourhood characteristics. Accordingly, service areas around transit stations should vary based on the service offered and attributes of the people and places served. The generated service areas derived from the generalized statistical model are then used to identify gaps and redundancies at the system and route level using Montreal region as an example. This study can be of benefit to transport engineers and planners trying to maximize transit service coverage in a region while avoiding oversupply of service. 相似文献