全文获取类型
收费全文 | 883篇 |
免费 | 8篇 |
专业分类
公路运输 | 307篇 |
综合类 | 36篇 |
水路运输 | 289篇 |
铁路运输 | 33篇 |
综合运输 | 226篇 |
出版年
2023年 | 10篇 |
2022年 | 20篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 34篇 |
2017年 | 14篇 |
2016年 | 30篇 |
2015年 | 7篇 |
2014年 | 30篇 |
2013年 | 131篇 |
2012年 | 33篇 |
2011年 | 47篇 |
2010年 | 35篇 |
2009年 | 47篇 |
2008年 | 47篇 |
2007年 | 21篇 |
2006年 | 10篇 |
2005年 | 17篇 |
2004年 | 18篇 |
2003年 | 5篇 |
2002年 | 13篇 |
2001年 | 8篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 23篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 16篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 7篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 15篇 |
1977年 | 15篇 |
1976年 | 11篇 |
1975年 | 10篇 |
1974年 | 8篇 |
1973年 | 5篇 |
排序方式: 共有891条查询结果,搜索用时 31 毫秒
791.
D. Kahn J.L. Deneubourg A. de Palma 《Transportation Research Part B: Methodological》1983,17(1):25-43
A model is presented to describe the dynamics of transportation mode choice in which the interaction between transportation users and a public transportation authority results in self-organization. The model illustrates that a sufficient number of connections between a central city and its suburbs are required for self-organization to occur whereby public transportation use and service will grow. 相似文献
792.
793.
A. D. De Pater 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1989,18(5):275-299
In the second part of the paper applications are shown for the two-axle unsymmetric running gear and for symmetric running gears with two, three and four wheelsets. 相似文献
794.
795.
796.
As urban systems increase in size and diversity, the factors which influence spatial change increase in number and their interactions become more complex. Increasing emphasis is thus being placed by some governments and agencies on regular reviews of policies and programs, to ensure that they are consistent with and facilitate the evolving urban form. Consequently, the monitoring of urban transport and activity systems is of increasing importance, to aid the review processes. This paper considers the progress which has been made in and use of procedures for monitoring urban, transport-related spatial changes. The specification, estimation and presentation of appropriate indicators is briefly discussed. Experience with the use of spatial monitoring procedures on data for two Australian cities has revealed several possible implications for transport investment practice and the development of monitoring and modelling procedures. These are discussed and the paper then indicates the approach which is currently being taken at ARRB towards developing a monitoring system. 相似文献
797.
This paper describes the application of probabilistic risk assessment techniques to level crossing safety on JR East, the largest of the six private railroads in Japan. The risk of a level crossing accident was defined as the product of the accident rate and the expected consequences per accident. Rail traffic volume, road traffic volume, visibility of the crossing from the road, road gradient, width of the crossing and the type of safety devices at the crossing were shown to influence the accident rate and the collective risk. The mean accident rate at all crossings was 0.74 per million trains. The accident rate was 0.59 per million trains at crossings equipped with barriers, 1.25 at crossings equipped with warning bells and 0.76 at pedestrian crossings. Crossings equipped with obstacle detectors had a lower accident rate (0.12 per million trains) than crossings without detectors (0.43 per million trains). Crossings with visibility less than 20 m had a 50% higher mean accident rate than crossings with visibility greater than 20 m. As the number of tracks increased, the accident rate monotonically increased due to the increased accident exposure. Risk assessment techniques were applied to determine the efficacy of the various level crossing safety devices. In addition to upgrading the safety of crossings, the management techniques stressed the importance of education campaigns in warning the public about the dangers of illegal crossings. 相似文献
798.
王志军 《西安交通大学学报(英文版)》1995,(2)
DELAYEDREPAIROFDNADAMAGEBYIONIZINGRADIATIONINPEDIATRICSYSTEMICLUPUSERYTHEMATOSUSANDJUVENILERHEUMATOIDD.Mcurdy,L.Q.Tat,WangZhi... 相似文献
799.
A new transport model for metals (named NOSTRADAMUS) has been developed to predict concentrations and distributions of Cd, Cu, Ni, Pb and Zn in the southern North Sea. NOSTRADAMUS is comprised of components for water, inorganic and organic suspended particulate matter transport; a primary production module contributes to the latter component. Metal exchange between dissolved (water) and total suspended particulate matter (inorganic + organic) phases is driven by distribution coefficients. Transport is based on an existent 2-D vertically integrated model, incorporating a 35 × 35 km grid. NOSTRADAMUS is largely driven by data obtained during the Natural Environment Research Council North Sea Project (NERC NSP). The sensitivity of model predictions to uncertainties in the magnitudes of metal inputs has been tested. Results are reported for a winter period (January 1989) when plankton production was low. Simulated ranges in concentrations in regions influenced by the largest inflows, i.e. the NE English coast and the Southern Bight, are similar to the ranges in the errors of the concentrations estimated at the northern and southern open sea boundaries of the model. Inclusion of uncertainties with respect to atmospheric (up to ± 54%) and riverine (± 30%) inputs makes little difference to the calculated concentrations of both dissolved and particulate fractions within the southern North Sea. When all the errors associated with the inputs are included there is good agreement between computed and observed concentrations, and that for dissolved and particulate Cd, Cu and Zn, and dissolved Ni and Pb, many of the observations fall within, or are close to, the range of values generated by the model. For particulate Pb, model simulations predict concentrations of the right order, but do not reproduce the large scatter in actual concentrations, with simulated concentrations showing a bias towards lower values compared to those observed. A factor which could have contributed to observed concentrations, and which is not included in the model, is considered to be a substantial benthic input of dissolved lead during this winter period, coupled to a rapid and extensive scavenging of the dissolved lead to particles. Significant reductions in riverine and aeolian inputs of total Cd and Cu of 70% and 50%, respectively, consistent with aims of North Sea Conferences, are predicted to lead to minor decreases (~ 10%) in water column concentrations of dissolved and particulate Cd and Cu, except near river sources, where maximum reductions of ~ 30–40% may occur. 相似文献
800.