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191.
There is growing interest amongst both practitioners and researchers in the correlates of young adults’ driving-licence-acquisition. One aspect of the ongoing scholarly debate is whether taking part in online (i.e. virtual) activities may be associated with young adults feeling less need to drive and hence to acquire a driving licence. This paper addresses this issue by drawing on analysis of two distinct datasets. Both contain rich pseudo-diary instruments in which people indicate detailed characteristics of their unique online-activity profile. This includes both indicators of the types of online activities in which respondents participate, and a separate metric of internet-use intensity. The latter is defined in one dataset as the amount of time/week spent online, and in the other dataset the frequency of their internet use. On the basis of a set of multivariate regression analyses, a positive (i.e. complementary) cross-sectional relationship between young adults’ online activity and licence-holding was found. We find that young adults who use the internet are, net of confounding effects, more likely to hold a driving licence than otherwise identical young adults who do not use the internet. Both datasets show this type of effect, and it is robust across a range of model specifications, including multi-stage estimations to address cross-correlation between indicators of internet usage. In addition to the positive net statistical association, we also report several other noteworthy effects. Of the six effects associated with online-activity types that are directly comparable between the two datasets, we find that the correlation in the parameter estimates across the two datasets is 0.63. This suggests similar types of relationships across the two datasets. Also, in several (but not all) of our analyses we found an inverted ‘U’ shaped ceteris paribus relationship between intensity-of-internet-use and licence-holding. The positive net statistical association between internet use and licence-holding is a different relationship than previously reported in the literature, and therefore further research is needed to reconcile the differences (which are likely due at least in part to different methodological approaches and data resources). Further research is also needed to continue to resolve between the relative saliency of other hypothesised determinants of licence-holding (e.g. economic and socio-demographic explanators, as well as licence-acquisition regimes that vary by time and place). 相似文献
192.
With rare exception, actual tollroad traffic in many countries has failed to reproduce forecast traffic levels, regardless of whether the assessment is made after an initial year of operation or as long as 10 years after opening. Pundits have offered many reasons for this divergence, including optimism bias, strategic misrepresentation, the promise to equity investors of early returns on investment, errors in land use forecasts, and specific assumptions underlying the traffic assignment models used to develop traffic forecasts. One such assumption is the selection of a behaviourally meaningful value of travel time savings (VTTS) for use in a generalised cost or generalised time user benefit expression that is the main behavioural feature of the traffic assignment (route choice) model. Numerous empirical studies using stated choice experiments have designed choice sets of alternatives as if users choose a tolled route or a free route under the (implied) assumption that the tolled route is tolled for the entire trip. Reality is often very different, with a high incidence of use of a non-tolled road leading into and connecting out of a tolled link. In this paper we recognise this feature of route choice and redesign the stated choice experiment to account for it. Furthermore, this study is a follow up to a previous study undertaken before a new toll road was in place, and it benefits from real exposure to the new toll road. We find that the VTTS is noticeably reduced, and if the VTTS is a significant contributing influence on errors on traffic forecasts, then the lower estimates make sense behaviourally. 相似文献
193.
In this paper the effects on the economic output, income and employment relating to Shetland are considered using an input—output model. The results are presented on the basis of an individual industry and appropriate multipliers are derived. 相似文献
194.
Britain's national rail system was ‘privatised’ as a result of the 1993 Railways Act, with most of the organisational and ownership changes implemented by 1997. This paper examines the long term impacts of these changes. A key issue when examining long term changes is that of the counterfactual – what would have happened if the changes had not occurred? A simple econometric model of the demand for passenger rail services was developed and used in conjunction with extrapolative methods for key variables such as fares and train km to determine demand-side counterfactuals. Extrapolative methods were also used to determine counterfactual infrastructure and train operation costs. Although our results are sensitive to the assumptions we have made concerning the counterfactual they suggest a number of impacts. Since privatisation, rail demand has grown strongly but our analysis indicates that transitional disruptions suppressed demand by around 9% over a prolonged period (1992/3 to 2005/6), whilst the Hatfield accident reduced demand by about 5%, albeit over a shorter period (2000/1 to 2006/7). A welfare analysis suggests that although consumers seem to have gained as a result of privatisation, for most years this has been offset by increases in costs. An exception is provided by the two years immediately before the Hatfield accident. Overall the loss in welfare since the reforms were introduced far exceeds the net receipts from the sale of rail businesses. Thus although the reforms have had advantages in terms of lower fares and better service levels than otherwise would have been the case, this appears to have been offset by increased infrastructure and train operations costs. The source of these high costs remains an area of speculation but appear to be related to aspects of both market and regulatory failure. 相似文献
195.
John Dinwoodie 《Maritime Policy and Management》2000,27(1):17-30
In recent years, external pressures on maritime businesses have increased their need to employ high calibre personnel, educated to respond effectively to these pressures. Set against this requirement, the onus of acquiring a university education has shifted to the individual, as state subsidies to individuals seeking to undertake higher education in British universities have declined, and many corporate training programmes have been aimed at meeting the needs of an organization rather than the individuals within them. If the future supply of graduates is to match ongoing industrial requirements, one needs to understand why students enrol on particular courses, and how importantly they perceive employment considerations to be when making their decisions. This paper reports on a survey of why students at several British universities chose to enrol on undergraduate courses in Maritime Business, and considers the implications of its findings for ensuring that an adequate supply of suitably educated graduates will continue to be available to meet industrial needs. 相似文献
196.
The workshop considered system development as a key element of improving the performance of public transport. The main theme was the governance of decision making, design and development of public transport projects. A first main finding is that governance should be improved to keep focus on the original values for which the projects are started. Many projects lose sight of their original aims through the long and often problematic process from inception to operation. A second main finding is that the technological choice, mainly between rubber on tarmac and steel on rails, can be postponed, as both technologies start to overlap in their capacities. A stronger focus on functional needs in the earlier phases of the projects could help. Finally, as the different technologies provide similar options and can be used interchangeably, communicating the service they provide in other ways then through vehicle and infrastructure technology becomes more important. 相似文献
197.
Sara Y. Kenno Sreekanta Das John B. Kennedy Ronald B. Rogge Michael Gharghouri 《Marine Structures》2010,23(3):263-273
This paper provides an in-depth study of residual stress distributions found in stiffened steel plate structures, such as those typically used in ship hulls. The effect of stiffener spacing on the distribution of residual stress components was studied. The welding heat input was also varied between high and moderate to study the effect of heat input level on residual stress distributions. Four specimens, resembling typical stiffened steel plate structures used in ship hulls were built and tested. Steel plates of 9.5 mm thickness were stiffened by welding L127 × 76 × 9.5 steel angles. The test was completed using the neutron diffraction method. The three normal components of residual stress were obtained in this study. It was found that a lower heat input results in higher tensile residual stress and that there exists a critical stiffener spacing somewhere beyond 250 mm that creates a maximum tensile residual stress value near the welded connection. 相似文献
198.
Mark Lijesen Willemijn van der Straaten Jasper Dekkers Roel van Elk John Blokdijk 《Transportation Research Part D: Transport and Environment》2010,15(1):51-59
Airport noise nuisance is a negative externality especially when it occurring near urban areas. Like all externalities, noise nuisance may be a reason for government intervention. When intervening, governments should set quantitative policy targets with care. In practice, this issue is generally neglected. This line of research sets the first step towards determining optimal policy targets in the case of noise nuisance near airports, more specifically in the case of Amsterdam Airport. We use hedonic pricing to establish the benefits of noise reduction. Furthermore, we develop a bottom-up cost function to analyze the costs of reducing noise for airlines. We then equate marginal costs and benefits to establish the optimal level of noise reduction, which appears to be 3 dB in the case of Amsterdam Airport. Welfare increasing measures include alternative approach procedures, regional substitution of planes within existing fleets and early depreciation of noisy planes increase welfare. Reducing the number of flights has a negative effect on net welfare. 相似文献
199.
ABSTRACTThe advent of road transport automation is suggested to be one of four key technological transitions that could amount to a major transformation in mobility practices. Specifically, fully Automated Vehicles (AVs) might replace the current private car owner user model with fleets of on-demand synchronously-shared automated taxis. However, significant barriers to this vision becoming the norm remain. This paper examines two critical user-acceptance aspects of the transition: willingness to adopt AVs, and willingness to share an AV with others, particularly strangers. Our novel survey (n?=?899) included a choice experiment featuring four future full automation transport services (private, synchronously/asynchronously shared, and public). Cluster analysis examined respondents' preferences and their demographic and psycho-social characteristics. We uncover significant uncertainty about willingness to adopt automation and sharing, and important differences between clusters within our sample. For example, under 50% of participants report willingness to use an AV over their normal mode, or would prefer an automated option to a current human-driven option. Our findings raise critical questions for policymakers and transport authorities. Not least, how can AV technologies help realise the environmental and social benefits of widespread vehicle sharing in a context of a travelling public that still prefers its privacy on-the-move? 相似文献
200.
John K. Stanley David A. Hensher 《Transportation Research Part A: Policy and Practice》2011,45(10):1020-1030
Transport is Australia’s third largest and second fastest growing source of greenhouse gas (GHG) emissions. The road transport sector makes up 88% of total transport emissions and the projected emissions increase from 1990 to 2020 is 64%. Achieving prospective emission reduction targets will pose major challenges for the road transport sector. This paper investigates two targets for reducing Australian road transport greenhouse gas emissions, and what they might mean for the sector: emissions in 2020 being 20% below 2000 levels; and emissions in 2050 being 80% below 2000 levels. Six ways in which emissions might be reduced to achieve these targets are considered. The analysis suggests that major behavioural and technological changes will be required to deliver significant emission reductions, with very substantial reductions in vehicle emission intensity being absolutely vital to making major inroads in road transport GHG emissions. 相似文献