全文获取类型
收费全文 | 3619篇 |
免费 | 109篇 |
专业分类
公路运输 | 962篇 |
综合类 | 915篇 |
水路运输 | 995篇 |
铁路运输 | 524篇 |
综合运输 | 332篇 |
出版年
2024年 | 6篇 |
2023年 | 27篇 |
2022年 | 72篇 |
2021年 | 78篇 |
2020年 | 57篇 |
2019年 | 45篇 |
2018年 | 57篇 |
2017年 | 63篇 |
2016年 | 75篇 |
2015年 | 100篇 |
2014年 | 153篇 |
2013年 | 248篇 |
2012年 | 194篇 |
2011年 | 277篇 |
2010年 | 266篇 |
2009年 | 263篇 |
2008年 | 292篇 |
2007年 | 278篇 |
2006年 | 253篇 |
2005年 | 215篇 |
2004年 | 100篇 |
2003年 | 87篇 |
2002年 | 111篇 |
2001年 | 88篇 |
2000年 | 73篇 |
1999年 | 40篇 |
1998年 | 19篇 |
1997年 | 26篇 |
1996年 | 15篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1972年 | 4篇 |
排序方式: 共有3728条查询结果,搜索用时 359 毫秒
61.
In this introduction to the special issue on habitual travel choice, we provide a brief account of the role of habit in travel behaviour, discuss more generally what habitual choice is, and briefly review the issues addressed in the solicited papers. These issues include how habitual travel behaviour should be measured, how to model the learning process that makes travel choice habitual, and how to break and replace car-use habits. 相似文献
62.
63.
Habitual travel behaviour: Evidence from a six-week travel diary 总被引:1,自引:0,他引:1
This paper introduces different methods to measure similarity of travel behaviour addressing the question of how repetitious travel behaviour actually is. It compares empirical results of the different methods based on the data from a six-week travel diary. In general, the results show that the day-to-day behaviour is more variable if measured with trip-based methods instead of methods based on time budgets. Furthermore, it is confirmed that the similarity declines if the method captures more of the complexity of the travel pattern. It is also shown that travel behaviour is neither totally repetitious nor totally variable. Even for the whole observation period, it is demonstrated that two days always have some common elements. Additionally, it is found that the different methods yield the same pattern of variability for different types of day. Travel behaviour is clearly more stable on work days. Similar results for all methods are also obtained concerning the question of how long the minimum period of observation should be. All measures show that the period should not be less than two weeks if one aims at measuring variability. 相似文献
64.
A. Eichberger W. Rulka 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2004,41(5):401-413
Applying a non-linear model reduction method to the tire suspension system of road vehicles enables an automatic transfer of complex offline simulation vehicle models to a mathematical model, which fits the real time simulation requirements. The basic assumption, that high frequent inner suspension dynamics are not relevant to handling manoeuvres, converts the differential algebraic equation system (DAE) of suspensions with kinematical closed loops into pure elasto-kinematical linkage equations. The equations of motions can be represented as an ordinary differential equation system (ODE) and considerable simulation time reductions are obtained for the off-line simulation and real time simulation is enabled. This so-called macro joint approach is an alternative modelling method to the well-known look-up table representation of suspension kinematics but it keeps the parameterisation of the original suspension model and is suitable to parameterised real time MBS models. With a second step the dynamics, caused by compliance in the suspension bushings, are reduced to their quasi-static behaviour. The consideration of these quasi-elasticity has nearly no influence on the necessary simulation time. This contribution shows the theoretical background and demonstrates the advantage of the macro joint model reduction approach on a typical vehicle example. 相似文献
65.
针对既有桥梁结构的特点,建立了考虑荷载历史的可靠度分析模型,并讨论了其计算方法。应用所研究的方法,对一座实际钢筋混凝土桥梁的承载能力可靠度进行了分析和评估;结果表明,荷载历史对该桥可靠度提高的影响不容忽视。 相似文献
66.
Claudio Mazzoleni Hans Moosmüller Hampden D. Kuhns Robert E. Keislar Peter W. Barber Djordje Nikolic Nicholas J. Nussbaum John G. Watson 《Transportation Research Part D: Transport and Environment》2004,9(6):477-496
Carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO) emission factors (EFs) are measured with a commercial vehicle emissions remote sensing system (VERSS) during a large-scale vehicle exhaust emissions study in Las Vegas. Particulate matter (PM) EFs are simultaneously measured for individual vehicles with a newly developed PM-VERSS based on ultraviolet backscatter light detection and ranging (Lidar). The effectiveness of CO and HC EFs as proxy for NO and PM EFs for spark-ignition vehicles is evaluated. Poor correlations were found between EFs for pollutants on an individual vehicle basis indicating that high EFs for one or more pollutants cannot be used as a predictor of high EFs for other pollutants. Stronger functional relationships became evident after averaging the EF data in bins based on rank-order of a single pollutant EF. Low overlap between the highest 10% emitters for CO, HC, NO, and PM was found. These results imply that for an effective reduction of the four pollutants, inspection and maintenance (I/M) programs, including clean screening, should measure all four pollutants individually. Fleet average CO and HC concentrations determined by gaseous VERSS were compared with fleet average CO and HC concentrations measured at low-idle and at high-idle during local I/M tests for spark-ignition vehicles. The fleet average CO concentrations measured by I/M tests at either idle were about half of those measured by remote sensing. The fleet average high-idle HC concentration measured by I/M tests was about half of that measured by VERSS while low-idle I/M and VERSS HC average concentrations were in better agreement. For a typical vehicle trip, most of the fuel is burned during non-idle conditions. I/M measurements collected during idling conditions may not be a good indicator of a vehicle’s potential to be a high emitter. VERSS measurements, when the vehicle is under a load, should more effectively identify high emitting vehicles that have a large contribution to the mobile emissions inventory. 相似文献
67.
68.
69.
简要说明了客车全承载车身技术的重要性和全承载车身的优越性;阐述了全承载车身的发展历程和在我国的应用现状,最后详细说明了全承载车身结构的特点及优点,使我们对于全承载车身结构技术有了一个更全面的认识。 相似文献
70.
Dongzi Zhu Hampden D. Kuhns John A. Gillies Vicken Etyemezian Scott Brown Alan W. Gertler 《Transportation Research Part D: Transport and Environment》2012,17(4):332-340
The effectiveness of control measures to reduce road dust emissions is analyzed using a year’s data of road dust emissions collected with a mobile sampling platform and a survey of road maintenance practices in the Lake Tahoe Basin of Nevada and California US. Attributes such as sweeping practices, anti-icing, shoulder improvement, pavement condition, trackout, and abrasive material from road segments were analyzed with a feature subset selection algorithm. Street sweeping was found to be an effective means of controlling dust emissions from roads. Road dust from dirty tertiary roads served as a continuous source of suspendable material for adjacent high-speed roads in the winter time. To be most effective, emission control strategies require that not only primary roads, but all roads be swept after snow storms to recover applied abrasive material. 相似文献