全文获取类型
收费全文 | 2491篇 |
免费 | 8篇 |
专业分类
公路运输 | 828篇 |
综合类 | 99篇 |
水路运输 | 741篇 |
铁路运输 | 73篇 |
综合运输 | 758篇 |
出版年
2022年 | 14篇 |
2021年 | 17篇 |
2020年 | 20篇 |
2019年 | 14篇 |
2018年 | 64篇 |
2017年 | 84篇 |
2016年 | 179篇 |
2015年 | 25篇 |
2014年 | 42篇 |
2013年 | 308篇 |
2012年 | 134篇 |
2011年 | 207篇 |
2010年 | 181篇 |
2009年 | 101篇 |
2008年 | 167篇 |
2007年 | 95篇 |
2006年 | 42篇 |
2005年 | 50篇 |
2004年 | 39篇 |
2003年 | 38篇 |
2002年 | 29篇 |
2001年 | 37篇 |
2000年 | 26篇 |
1999年 | 25篇 |
1998年 | 53篇 |
1997年 | 32篇 |
1996年 | 32篇 |
1995年 | 40篇 |
1994年 | 19篇 |
1993年 | 22篇 |
1992年 | 18篇 |
1991年 | 21篇 |
1990年 | 10篇 |
1989年 | 19篇 |
1988年 | 24篇 |
1987年 | 21篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 10篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 24篇 |
1979年 | 20篇 |
1978年 | 13篇 |
1977年 | 22篇 |
1976年 | 15篇 |
1975年 | 21篇 |
1974年 | 15篇 |
1973年 | 15篇 |
排序方式: 共有2499条查询结果,搜索用时 109 毫秒
141.
Fuel consumption is calculated using a modelling procedure for automobiles travelling on three alternative street patterns designed for a subdivision in Kingston Township, Ontario. The modelling procedure is described. The results indicate that grid and solar superblock street patterns, compared to the existing street pattern, offer small fuel savings to a tripmaker in the portion of the work trip travelled in the subdivision. 相似文献
142.
Numerical simulations of IC engines are of high interest for automotive engineers worldwide. The simulation models should be as fast as possible, low-computational effort and predictive tool. The correct prediction of turbulence level inside the combustion chamber of spark ignition engines is the most important factor influencing to the engine working cycle. This paper presents a development of the k-ε turbulence model applied to the commercial cycle-simulation software with the high emphasis on the intake part. The validation was performed on two engine geometries with the variation of engine speed and load comparing the cycle-simulation results of the turbulent kinetic energy and in-cylinder temperature with 3-D CFD results. In order to apply the cycle-simulation turbulence model for the simulation of entire engine map, the parameterization model of turbulence constants was proposed. The parameterized turbulence model was optimized using NLPQL optimization algorithm where the single set of turbulence model parameters for each engine was found. A good agreement of the turbulent kinetic energy during the expansion was achieved when the turbulence affects the flame front propagation and combustion rate as well. 相似文献
143.
David I. A. Steel 《Maritime Policy and Management》2013,40(6):425-430
This paper discusses negotiations, relative to sea fisheries, in terms of international arrangements—arrangements between the European Economic Community (EEC) and Third Countries; and those between member states of the EEC. 相似文献
144.
145.
Richard E. Hammond 《Coastal management》2013,41(2):189-192
Onshore Planning for Offshore Oil—Lessons from Scotland by Pamela L. Baldwin and Malcolm F. Baldwin The Conservation Foundation, Washington, D.C., 1975 相似文献
146.
Alan J. Horowitz 《Transportation》2010,37(4):689-703
This paper describes a group of techniques for disaggregating origin–destination tables for travel forecasting that makes
explicit use of observed traffic on a network. Five models within the group are presented, each of which uses nonlinear least-squares
estimation to obtain row and column factors for splitting trip totals from and to larger geographical areas into smaller ones.
The techniques are philosophically similar to Fratar factoring, although the solution method is quite different. The techniques
are tested on a full-sized network for Northfield, MN and are found to work effectively. 相似文献
147.
Out-of-home activities,daily travel,and subjective well-being 总被引:1,自引:0,他引:1
Dick Ettema Tommy Gärling Lars E. Olsson Margareta Friman 《Transportation Research Part A: Policy and Practice》2010,44(9):723-732
It is argued that utility theory that underpins current cost-benefit analyses of daily travel needs to be complemented. An alternative theoretical framework is to this end proposed which applies subjective well-being (SWB) to travel behaviour analysis. It is posited in this theoretical framework that participation in goal-directed activities, facilitated or hindered by travel, contributes to SWB, that the degree of travel-related stress in participating in these activities reduces SWB, and that positive affect associated with travel in itself has an impact on SWB. 相似文献
148.
Diwakar Gupta Hao-Wei Chen Lisa A. Miller Fajarrani Surya 《Transportation Research Part A: Policy and Practice》2010,44(4):201-217
State agencies responsible for ADA-eligible paratransit services are increasingly under pressure to contain costs and maximize service quality. Many do not operate vehicles themselves; instead, they contract out the provision of services. Contractors are paid for each hour of service. They are responsible for hiring crew, forming routes, dispatching, and operating and maintaining agency-owned vehicles. In the Twin Cities of Minneapolis and Saint Paul, Metro Mobility, the agency responsible for providing paratransit services, requires contractors to use agency-approved software for booking trips dynamically and sets parameters that guide contractors’ practices. Customer trips booked in this fashion may not utilize capacity in the most efficient manner. Therefore, beginning with the daily trip schedules generated by the software, this paper proposes two approaches for improving the efficiency of paratransit operations and estimates the benefit of using these approaches via experiments that utilize Metro Mobility data. The first approach re-optimizes routes developed at the end of each day. The second approach evaluates the benefit to state agencies of selectively using non-dedicated service providers such as taxis. Both approaches are tested on actual data obtained from Metro Mobility. The study shows that a conservative estimate of savings from re-optimization would be approximately 5% of Metro Mobility’s operating costs. Savings from the use of taxis are smaller and in the range of hundreds of dollars per day. 相似文献
149.
Maarten Kroesen Eric J.E. Molin Henk M.E. Miedema Henk Vos Sabine A. Janssen Bert van Wee 《Transportation Research Part D: Transport and Environment》2010,15(3):144-153
This study assesses the effects of aircraft noise on residential satisfaction, an important indicator of subjective well-being. A structural equation model is specified that estimates the relationships between objective variables, noise annoyance variables and residential satisfaction. Secondary data-analysis is used to estimate the model. The survey was conducted in 1996/1997 among the population living within a 25-km radius of Amsterdam Schiphol, the largest airport in the Netherlands. The effect of aircraft noise annoyance is found to be relatively small. In addition, the objective level of aircraft noise exposure is found to be a better predictor of residential satisfaction than its subjective counterpart. The most important determinants of residential satisfaction are found to be road traffic noise annoyance, age and neighbor noise annoyance. 相似文献
150.