全文获取类型
收费全文 | 1129篇 |
免费 | 49篇 |
专业分类
公路运输 | 598篇 |
综合类 | 216篇 |
水路运输 | 236篇 |
铁路运输 | 113篇 |
综合运输 | 15篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 43篇 |
2020年 | 31篇 |
2019年 | 25篇 |
2018年 | 23篇 |
2017年 | 26篇 |
2016年 | 24篇 |
2015年 | 28篇 |
2014年 | 77篇 |
2013年 | 53篇 |
2012年 | 156篇 |
2011年 | 86篇 |
2010年 | 78篇 |
2009年 | 80篇 |
2008年 | 64篇 |
2007年 | 96篇 |
2006年 | 82篇 |
2005年 | 57篇 |
2004年 | 35篇 |
2003年 | 27篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有1178条查询结果,搜索用时 297 毫秒
71.
Márton Kuslits Dieter Bestle 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2019,57(4):520-542
This paper presents a new steer-by-wire concept using an all-wheel drive vehicle layout with in-wheel motors while completely omitting the application of any dedicated steering device. Steering is based on the so-called differential steering principle which generates the necessary steering moment about the kingpins by a traction force difference between left and right sides of the vehicle. In order to investigate the behaviour of the vehicle and to design the underlying control algorithms, a planar vehicle model is presented, where the vehicle is described as constrained non-holonomic system requiring a special treatment. A state feedback linear controller for controlling of the lateral dynamics of the vehicle at higher speeds and a simple PI angle controller for low-speed manoeuvring are developed. The resulting behaviour of the system is investigated by various simulation experiments demonstrating a comparable steering performance of the new steering concept as that of conventional passenger cars. 相似文献
72.
为解决二次衬砌脱空的问题,实现在浇筑过程中对衬砌脱空的主动监测,结合隧道二次衬砌衬背脱空的成因,研发基于分布式压密传感器的隧道衬砌脱空主动监测系统。该系统由分布式压密传感带、延长线、直显终端及工业电脑组成,具有原理简单、安装便捷等优点。通过在衬砌层间预埋分布式压密传感器,对浇筑过程进行主动监测,结合带模注浆技术,实现对衬砌脱空的精准注浆与快速处治,有效解决隧道衬砌脱空问题。在验证试验中,系统在浇筑过程中共发现2处拱顶空洞,证明该系统对脱空监测的有效性。同时,该系统在国内部分重点铁路线已经取得应用,现场应用情况表明,该系统对二次衬砌拱顶脱空的识别准确率可达到95.5%。 相似文献
73.
74.
75.
电动助力转向系统滑模变控制技术研究 总被引:1,自引:0,他引:1
以电动助力转向系统中直流助力电机的控制器为研究对象,依据助力电机的数学模型,应用带观测器补偿的滑模变结构控制方法,设计了滑模变控制器,通过调节助力电机的电压,获得预期的输出电流。仿真结果表明,所设计的滑模变控制器使助力电机具有很好的动态性能,系统基本无抖动现象,实现了助力电机输出电流对目标电流的跟踪特性。 相似文献
76.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(8):1225-1244
This paper presents a method to design a rollover prevention controller for vehicle systems. The vehicle rollover can be prevented by a controller that minimises the lateral acceleration and the roll angle. Rollover prevention capability can be enhanced if the controlled vehicle system is robust to the variation of the height of the centre of gravity and the speed of the vehicle. For this purpose, a robust controller is designed with linear matrix inequality-based trajectory sensitivity minimisation. Differential braking and active suspension are adopted as actuators that generate yaw and roll moments, respectively. The newly proposed method is shown to be effective in preventing rollover by the simulation on a non-linear multibody dynamic simulation software, CarSim®. 相似文献
77.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1563-1584
A virtual test rig is presented using a three-dimensional model of the elasto-kinematic behaviour of a vehicle. A general approach is put forward to determine the three-dimensional position of the body and the main parameters which influence the handling of the vehicle. For the design process, the variable input data are the longitudinal and lateral acceleration and the curve radius, which are defined by the user as a design goal. For the optimisation process, once the vehicle has been built, the variable input data are the travel of the four struts and the steering wheel angle, which is obtained through monitoring the vehicle. The virtual test rig has been applied to a standard vehicle and the validity of the results has been proven. 相似文献
78.
本文在对斯太尔重型汽车的双轴转向传动机构进行分析的基础上建立了数学模型,研究了各部分的传动过程,并采用MATLAB语言编写了转向传动机构分析程序,对转向轴内外轮之间,前后轮间的转角匹配,以及最小转弯半径的匹配关系进行了优化。 相似文献
79.
转向前桥在汽车上一个非常重要的功能就是实现汽车转向,而转向角是决定转向前桥性能的一个非常重要的参数,本文解决了在桥总成装配线快速调整某转向前桥转向角问题。 相似文献
80.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):527-559
The paper addresses the need for improved mathematical models of human steering control. A multiple-model structure for a driver's internal model of a nonlinear vehicle is proposed. The multiple-model structure potentially offers a straightforward way to represent a range of driver expertise. The internal model is combined with a model predictive steering controller. The controller generates a steering command through the minimisation of a cost function involving vehicle path error. A study of the controller performance during an aggressive, nonlinear steering manoeuvre is provided. Analysis of the controller performance reveals a reduction in the closed-loop controller bandwidth with increasing tyre saturation and fixed controller gains. A parameter study demonstrates that increasing the multiple-model density, increasing the weights on the path error, and increasing the controller knowledge range all improved the path following accuracy of the controller. 相似文献