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961.
This paper presents an innovative approach to analyzing road vehicle freight traffic that uses a dynamic panel data specification derived from a gravity model. This dynamic approach, which has recently been employed in international goods trade models in lieu of the traditional static specification, is applied to the case of Spain using data for the countrys 15 NUTS-3 regions between 1999 and 2009. Using the system general method of moments approach, we obtained significant evidence that the flow of vehicles carrying commodities by road has a strong persistence effect when controlling for unobserved heterogeneity. We also found that the quality of road transport infrastructure has a significant impact on vehicle trips. According to our findings, we suggest that this type of specification be employed in distribution models in which fixed effects and lags of the dependent variable are included to account for unobserved heterogeneity and persistence effects, respectively. 相似文献
962.
S. J. Lee 《International Journal of Automotive Technology》2010,11(4):471-479
The analytical model of an air spring can be effectively used for the design of air spring equipped vehicles to provide better
ride and handling characteristics along with various functions for passenger convenience. However, establishing a general
model of an air spring poses particular difficulties due to the severe nonlinearities in the stiffness and the hysteresis
effects, which are hardly observed in conventional coil springs. The purpose of this study is to develop a general analytic
model of an air spring — one which represents the main characteristics of stiffness and hysteresis and which can be connected
to a model of pneumatic systems desigined to control air spring height. To this end, the mathematical model was established
on the basis of thermodynamics with the assumptions that the thermodynamic parameters do not vary with the position inside
the air spring, that the air has the ideal gas property, and that the kinetic and potential energies of the air are negligible.
The analysis of the model has revealed that the stiffness is affected by the volume variation, the heat transfer, and the
variation of the air mass and the effective area. However, the hysteresis is mainly affected by the heat transfer and the
variation of the effective area. In particular, it was revealed that the increase of the volume due to the cross-sectional
area increases the stiffness, while the increase of the volume due to the other reason decreases it. In addition, the model
was used to develop the sufficient stability condition, and the stability of the model was analyzed. The paper also presents
the comparison between the simulation and experimental results to validate the established model and demonstrates the potential
of the model to be usefully employed for the development of the air spring and its algorithm for use in a pneumatic system. 相似文献
963.
In this article, we use the unrestricted two-regime autoregressive threshold model to test both nonlinearity and stationarity of China’s real exchange rate against its Hong Kong and Macau special administrative regions (SARs). Our main finding is that China’s real exchange rate is neither linear nor stationary, indicating that the purchasing power parity does not hold between China Mainland and its two SARs, which implies, to certain extent, the three economies may not meet the condition of constituting an optimal currency area. 相似文献
964.
In this study, correlation between vehicle fuel efficiency and total fuel energy consumption is analyzed to support the energy consumption and greenhouse gas (GHG) emissions reduction master plan in Korea. The background and highlights of recently amended fuel economy regulations and fuel efficiency labeling standards in Korea are also introduced. 18 representative vehicle groups, classified by class, type, size, and fuel, are selected by investigating vehicle distribution statistics based on market penetration and registration data sets in order to reflect and predict total fuel energy consumption in the overall ground transportation sector in Korea. Validity of the vehicle survival patterns modeled and vehicle classification rules are confirmed by comparing national fuel energy consumption statistics to the total amount of fuel consumed by each selected representative vehicle group. The latter figures are approximated from representative number of registrations, weighted average fuel economy, and average annual distance traveled. 相似文献
965.
The purpose of the paper is to analyze effectiveness before and after implementation of the bus rapid transit operation. The paper includes a speed analysis based on the Downs–Thomson paradox, and a reliability analysis based on variance analysis of arrival time. According to the speed analysis, some road sections are now under phase 2 in the Downs–Thomson paradox, which is a state in which the bus speeds are greater than the auto speeds. In the future, it is predicted that autos and buses will reach an equilibrium speed which is in phase 3 of the multi‐modal equilibrium theory. According to the reliability analysis of arrival time at each bus stop, in roads of median arterial bus lanes, the variance of arrival time is generally smaller than after the scheme implemented in 8 months later. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
966.
The marine shipping industry faces challenges to reduce engine exhaust emissions and greenhouse gases (GHGs) from ships, and in particular, carbon dioxide. International regulatory bodies such as the International Maritime Organization and National Environmental Agencies of many countries have issued rules and regulations to drastically reduce GHG and emissions emanating from marine sources. This study investigates the possibility of using natural gas and hydrogen as alternative fuels to diesel oil for marine gas turbines and uses a mathematical model to assess the effect of these alternative fuels on gas turbine thermodynamic performance. Results show that since natural gas is categorized as a hydrocarbon fuel, the thermodynamic performance of the gas turbine cycle using natural gas was close to that of the diesel case. However, the gas turbine thermal efficiency was found to be slightly lower for natural gas and hydrogen fuels compared to diesel fuel. 相似文献
967.
Supply chain finance (SCF) is concerned because of its service efficiency for the real economy. Beside the bank, some enterprises have provided the SCF service. E-commerce platform firms develop small and micro loan system in China. A given small enterprise can apply for a loan through its platform. Based on the latest SCF developments and the relevant literature, this study focuses on the coordination mechanism of SCF. We construct a game theory model including supplier, retailer and financial service provider to analyze the decision making of them. We find the optimal solution to the supplier, retailer and financial service provider. 相似文献
968.
Christian Bueger 《WMU Journal of Maritime Affairs》2012,11(1):15-31
That piracy needs to be addressed onshore is a widely shared assumption. While the majority of counter-piracy measures focus
on the sea, a number of onshore counter-piracy initiatives have been launched. We can observe the seeds of an alternative
land-based policy approach. One set of land-based programs aims at strengthening the legal and security state apparatus to
better deter and punish pirates. The other set of programs aims at addressing local populations on regional, clan or village
levels. Such projects aim at increasing surveillance, sensitizing populations for the consequences of piracy, and providing
rehabilitation or alternative livelihood opportunities. In this article, I review the latter type of projects and discuss
the promises and difficulties of addressing piracy by such measures. I discuss five major problems: knowledge problems, implementation
problems, counterintuitive consequences, tensions towards other parts of counter-piracy strategy, and the securitization of
aid. 相似文献
969.
Costas Lambrou 《WMU Journal of Maritime Affairs》2012,11(1):129-141
A prominent feature of modern day piracy is the ransom that is demanded for the safe release of the ship, cargo and crew.
The recent upsurge of this type of piracy, in areas of the world that are of strategic importance to the shipping industry,
has created many challenges for shipowners, underwriters and the law relating to marine insurance. The aim of this paper is
to examine how the marine insurance market is being affected by the threat of modern day piracy, and seeks to identify the
options that are available for the recovery of a ransom payment by the shipowner. Moreover, this study aims to identify the
legal issues that might prevent a shipowner from recovering a ransom payment under an insurance policy or from the other interests
in a common adventure. The study establishes that a reasonably made ransom payment by the shipowner will amount to an extraordinary
expense that is taken to minimise or avert a loss. Such an act can generally be recovered under the insurance policy as a
sue and labour expense or from other interests in the common adventure as a general average expense. However, illegality,
unseaworthiness and exemption clauses in a marine policy are identified as being legal issues that may prevent a shipowner
from recovering the ransom payment. Some of these problems may be overcome if clauses are carefully drafted to specifically
cater for modern day piracy in a marine insurance policy. Several inconsistencies may also be resolved by transferring the
piracy peril to war risks cover. The shipowner’s duty is to respond to the changing circumstances, by ensuring that his vessel
is sufficiently equipped and the crew is properly trained to resist a hijacking. 相似文献
970.