全文获取类型
收费全文 | 1402篇 |
免费 | 16篇 |
专业分类
公路运输 | 261篇 |
综合类 | 304篇 |
水路运输 | 366篇 |
铁路运输 | 148篇 |
综合运输 | 339篇 |
出版年
2023年 | 11篇 |
2022年 | 38篇 |
2021年 | 25篇 |
2020年 | 15篇 |
2019年 | 17篇 |
2018年 | 41篇 |
2017年 | 26篇 |
2016年 | 40篇 |
2015年 | 26篇 |
2014年 | 33篇 |
2013年 | 162篇 |
2012年 | 82篇 |
2011年 | 110篇 |
2010年 | 80篇 |
2009年 | 97篇 |
2008年 | 77篇 |
2007年 | 82篇 |
2006年 | 84篇 |
2005年 | 68篇 |
2004年 | 17篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 19篇 |
2000年 | 20篇 |
1999年 | 11篇 |
1998年 | 24篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 21篇 |
1994年 | 5篇 |
1993年 | 12篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1973年 | 9篇 |
排序方式: 共有1418条查询结果,搜索用时 0 毫秒
101.
102.
Fuzzy-logic applied to yaw moment control for vehicle stability 总被引:6,自引:0,他引:6
B. L. Boada M. J. L. Boada V. Dí az 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2005,43(10):753-770
In this paper, we propose a new yaw moment control based on fuzzy logic to improve vehicle handling and stability. The advantages of fuzzy methods are their simplicity and their good performance in controlling non-linear systems. The developed controller generates the suitable yaw moment which is obtained from the difference of the brake forces between the front wheels so that the vehicle follows the target values of the yaw rate and the sideslip angle. The simulation results show the effectiveness of the proposed control method when the vehicle is subjected to different cornering steering manoeuvres such as change line and J-turn under different driving conditions (dry road and snow-covered). 相似文献
103.
G. Y. Zhang X. W. Zhao J. X. Qiang F. Tian L. Yang 《International Journal of Automotive Technology》2012,13(4):679-686
A novel regulation system for a vehicle generator and lead-acid battery is proposed in this paper. By integrating the regulation method, the output voltage of the generator is determined and controlled by the algorithm to save electrical energy and protect the lead-acid battery. The regulation algorithm is implemented in Matlab/Simulink, and the logic function of the system is verified using the dSPACE/AutoBox workbench. The experimental results show that the new algorithm improves the performance of the fuel economy of the vehicle and the battery state-of-health compared to the traditional control method. 相似文献
104.
105.
106.
107.
汽车动力总成三点式悬置系统的设计方法探讨 总被引:3,自引:1,他引:3
首先分析汽车动力总成一悬置系统的振动激励、质量矩阵、刚度矩阵各元素的特点及其相互关系,阐释了系统弹性解耦设计的理论基础和重要性。然后根据动力总成一悬置系统刚度矩阵各元素的解析表达式,应用V形悬置组的弹性解耦原理,论述了目前普遍应用的三点式悬置系统在弹性解耦设计方面的问题,提出了悬置布置设计匹配的有效方法。 相似文献
108.
H. -Z. Li L. Li J. Song L. -Y. Yu 《International Journal of Automotive Technology》2011,12(5):679-686
A new comprehensive driver model is presented for critical maneuvering conditions with more accurate dynamic control performance.
In order to achieve a safe maneuvering mode, a new path planning scheme to maintain stability of the vehicle was designed.
A new steering strategy, considering the errors of vehicle position and yaw angle between the real track and the planned path,
was established to obtain the steering angle. Therefore, the vehicle can be adjusted to accurately follow the desired path
with the driver model, and the stability of the vehicle and the smoothness of the steering angle input were comprehensively
considered. Simulation results were used to validate the control performance in comparison with the optimal preview driver
model proposed by Macadam. 相似文献
109.
X. D. Wu S. G. Zuo L. Lei X. W. Yang Y. Li 《International Journal of Automotive Technology》2011,12(5):671-677
The purpose of this study was to effectively identify parameters for a LuGre friction model based on experimental measures.
In earlier work related to this study (Yang et al., 2009), which was based on the characters of polygonal wear (Sueoka and Ryu, 1997), we showed a frictional vibration model
for a mass on a moving belt. This model reflected lateral vibrations caused by velocity and toe-in angle. An important aspect
of the present study is the improved friction model. A previous friction model, which divided the process into four parts,
expressed the sable excited vibration well but failed to reflect the hysteresis loop change when vehicles accelerated or decelerated
continuously. A LuGre friction model can solve this problem, but several model parameters must be obtained experimentally.
We measured contact width and length of tires as vertical pressure changed; this provided a theoretical basis for apparent
stiffness of a unit of tire tread. Based on tire data from Bakker E’s article in a SAE paper from 1987, we identified the
Stribeck exponent and Stribeck velocity in LuGre. Then, the results were implemented in a vibration system that verified the
rationality of the data. 相似文献
110.
高速公路项目因建设成本较高,贷款融资是其必要的融资方式.市场利率超预期的波动将极大地影响项目债务成本,从而影响收益.通过分析利率风险对项目债务成本的影响,根据"风险共担,收益共享"的原则,提出了包含利率补偿和成本节省共享的利率保障方法.在实物期权理论的基础上通过仿真分析了利率保障的期权价值及其影响因素.研究发现,利率保... 相似文献