全文获取类型
收费全文 | 893篇 |
免费 | 30篇 |
专业分类
公路运输 | 415篇 |
综合类 | 34篇 |
水路运输 | 64篇 |
铁路运输 | 239篇 |
综合运输 | 171篇 |
出版年
2025年 | 3篇 |
2024年 | 30篇 |
2023年 | 18篇 |
2022年 | 47篇 |
2021年 | 36篇 |
2020年 | 70篇 |
2019年 | 12篇 |
2018年 | 50篇 |
2017年 | 32篇 |
2016年 | 39篇 |
2015年 | 40篇 |
2014年 | 63篇 |
2013年 | 24篇 |
2012年 | 47篇 |
2011年 | 54篇 |
2010年 | 39篇 |
2009年 | 36篇 |
2008年 | 23篇 |
2007年 | 43篇 |
2006年 | 39篇 |
2005年 | 39篇 |
2004年 | 28篇 |
2003年 | 32篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 12篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 1篇 |
排序方式: 共有923条查询结果,搜索用时 0 毫秒
41.
42.
解放牌CA1111P1K2L7型柴油载货汽车起动系统电路中增设了DK238型电源总开关和断油电磁铁,该装置具有电源电路和起动电路的保护作用,介绍了该起动系统电路的结构及工作原理,以及该电路的常见故障与诊断。 相似文献
43.
滑模摊铺机施工混凝土路面工艺原理及设备选型 总被引:1,自引:0,他引:1
傅智 《筑路机械与施工机械化》1997,14(2):25-30
从滑模摊铺水泥混凝土路面施工应用的角度,以不配备布料机,单台滑模摊铺机施工时的工艺理论及机构设计上,对如何适应和满足中国高等级公路水泥混凝土路面施工的需要,提出了滑模摊铺机施工工艺原理以及各施工单位在选择滑模摊铺机械时应该注意的工艺技术细节和随机附件的选配要求。 相似文献
44.
Sashank Musti 《Transportation Research Part A: Policy and Practice》2011,45(8):707-720
In today’s world of volatile fuel prices and climate concerns, there is little study on the relationship between vehicle ownership patterns and attitudes toward vehicle cost (including fuel prices and feebates) and vehicle technologies. This work provides new data on ownership decisions and owner preferences under various scenarios, coupled with calibrated models to microsimulate Austin’s personal-fleet evolution.Opinion survey results suggest that most Austinites (63%, population-corrected share) support a feebate policy to favor more fuel efficient vehicles. Top purchase criteria are price, type/class, and fuel economy. Most (56%) respondents also indicated that they would consider purchasing a Plug-in Hybrid Electric Vehicle (PHEV) if it were to cost $6000 more than its conventional, gasoline-powered counterpart. And many respond strongly to signals on the external (health and climate) costs of a vehicle’s emissions, more strongly than they respond to information on fuel cost savings.Twenty five-year simulations of Austin’s household vehicle fleet suggest that, under all scenarios modeled, Austin’s vehicle usage levels (measured in total vehicle miles traveled or VMT) are predicted to increase overall, along with average vehicle ownership levels (both per household and per capita). Under a feebate, HEVs, PHEVs and Smart Cars are estimated to represent 25% of the fleet’s VMT by simulation year 25; this scenario is predicted to raise total regional VMT slightly (just 2.32%, by simulation year 25), relative to the trend scenario, while reducing CO2 emissions only slightly (by 5.62%, relative to trend). Doubling the trend-case gas price to $5/gallon is simulated to reduce the year-25 vehicle use levels by 24% and CO2 emissions by 30% (relative to trend).Two- and three-vehicle households are simulated to be the highest adopters of HEVs and PHEVs across all scenarios. The combined share of vans, pickup trucks, sport utility vehicles (SUVs), and cross-over utility vehicles (CUVs) is lowest under the feebate scenario, at 35% (versus 47% in Austin’s current household fleet). Feebate-policy receipts are forecasted to exceed rebates in each simulation year.In the longer term, gas price dynamics, tax incentives, feebates and purchase prices along with new technologies, government-industry partnerships, and more accurate information on range and recharging times (which increase customer confidence in EV technologies) should have added effects on energy dependence and greenhouse gas emissions. 相似文献
45.
Vehicle electrification is a promising approach towards attaining green transportation. However, the absence of charging stations limits the penetration of electric vehicles. Current approaches for optimizing the locations of charging stations suffer from challenges associated with spatial–temporal dynamic travel demands and the lengthy period required for the charging process. The present article uses the electric taxi (ET) as an example to develop a spatial–temporal demand coverage approach for optimizing the placement of ET charging stations in the space–time context. To this end, public taxi demands with spatial and temporal attributes are extracted from massive taxi GPS data. The cyclical interactions between taxi demands, ETs, and charging stations are modeled with a spatial–temporal path tool. A location model is developed to maximize the level of ET service on the road network and the level of charging service at the stations under spatial and temporal constraints such as the ET range, the charging time, and the capacity of charging stations. The reduced carbon emission generated by used ETs with located charging stations is also evaluated. An experiment conducted in Shenzhen, China demonstrates that the proposed approach not only exhibits good performance in determining ET charging station locations by considering temporal attributes, but also achieves a high quality trade-off between the levels of ET service and charging service. The proposed approach and obtained results help the decision-making of urban ET charging station siting. 相似文献
46.
Electric vehicles (EVs), specifically Battery EVs (BEVs), can offer significant energy and emission savings over internal combustion engine vehicles. Norway has a long history of research and government incentives for BEVs. The BEV market in Norway allows us to fully examine consumers’ BEV choices influenced by car specifications, prices and government incentives (public bus lanes access, toll waiver and charging stations). The Random-Coefficient Discrete Choice Model (referred to as the BLP model) is applied to understand the choices of heterogeneous personal consumers and business buyers. Our study is instantiated on the entire EV sales data in Norway from 2011 to 2013, as well as a set of demographics at the municipality level. The results suggest significant positive effects of BEV technology improvement, space, toll waiver and charging station density on EV demand for both personal consumers and business buyers. However, the effects on business buyers may be generally less pronounced than on personal consumers. Interestingly, bus lanes access demonstrates a negative impact for personal consumers, possibly due to consumers’ concern regarding bus lane congestion. In addition, preferences on the BEV price can vary statistically among consumers with different income levels. Compared to the BEV technology development, demographical features and municipal incentives may have generally less impacts on market shares within the BEV market. 相似文献
47.
48.
工程机械底盘液压驱动装置性能分析(1) 总被引:3,自引:1,他引:2
姚怀新 《筑路机械与施工机械化》2003,20(6):60-62
液压驱动装置的结构形式与性能是工程机械底盘液压驱动与控制的两大重要组成部分之一。分析讨论了各类结构形式的液压驱动装置及其与行走机构组成不同形式的液压车辆底盘时的性能与特点。对车辆工作所需要的特殊功能,如液压同步、限速、制动以及补油回路等也进行了讨论,有助于工程车辆的理论研究与产品设计。 相似文献
49.
50.