全文获取类型
收费全文 | 127篇 |
免费 | 9篇 |
专业分类
公路运输 | 19篇 |
综合类 | 37篇 |
水路运输 | 54篇 |
铁路运输 | 24篇 |
综合运输 | 2篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 16篇 |
2011年 | 9篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 16篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有136条查询结果,搜索用时 31 毫秒
71.
72.
73.
This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user's public key. The advantage of an identity-based public key system is that it can avoid public key certificates and certificate management. Our identity-based encryption scheme enjoys short ciphertexts and provable security against chosen-ciphertext attack (CCA). 相似文献
74.
This paper proposes an adaptively secure solution to certificateless distributed key encapsulation mechanism from pairings by using Canetti's adaptive secure key generation scheme based on discrete logarithm. The proposed scheme can withstand adaptive attackers that can choose players for corruption at any time during the run of the protocol, and this kind of attack is powerful and realistic. In contrast, all previously presented threshold certificateless public key cryptosystems are proven secure against the more idealized static adversaries only. They choose and fix the subset of target players before running the protocol. We also prove security of this scheme in the random oracle model. 相似文献
75.
为提高无人水下航行器的操纵性和运动控制算法的高效性,对航行器水的动力特性进行分析尤为重要。基于黏性流体理论,采用高效的计算域分区法提高航行器变攻角网格的生成效率,开展不同攻角和航速下的航行器水动力数值预报与分析,定量给出航行器的升阻力、升阻比和俯仰力矩系数随攻角的变化规律,得到航行器上浮和下潜时对应的最优攻角和动压力中心点偏移量,为航行器的运动的姿态控制提供设计和指导依据。分析攻角对航行器压力场、速度场和涡量场的影响规律,为后续优化航行器构型、提高航行器的水动力性能奠定基础。 相似文献
76.
77.
78.
联合作战复杂信息远程火力打击战法-应用 总被引:2,自引:1,他引:1
借助仿真、概率统计以及博弈分析的混合方法,通过对与复杂信息环境有关的不完全信息进行统计分析,构建了在复杂信息环境下全局最优的远程火力打击战法设计的理论模型,对该模型的初步研究表明:全局最优的远程火力打击战法比局部最优的远程火力打击战法更能满足复杂多变的战场需求,取得更好的战果。 相似文献
79.
远程火力打击的信息欺骗定量分析方法-原理 总被引:1,自引:1,他引:0
文章针对定量分析信息欺骗对远程火力打击影响的难题,采用贝叶斯统计推测、博弈均衡分析和序分析方法得出了由基本概率矩阵元素构成的偏序关系决定是否存在信息欺骗机会的结论,不仅提供了解决此难题的可行方法,而且提供了科学运用远程火力打击战法的依据。 相似文献
80.
Angle of attack and lateral force are two important parameters influencing wheel-rail wear. This paper deals with the question of influences of the angle of attack and the lateral force on the wear of rail. A series of experiments are conducted on 1/4 JD-1 Wheel/Rail Tribology Simulation Facility. The angles of attack selected in the tests are 0°16′30″, 0°37′40″ and 1°0′0″ respectively. The lateral forces selected in the tests are 0.694 kN, 1.250 kN and 2.083 kN, respectively corresponding to the lateral forces of 25 kN, 45 kN and 75 kN measured in the field, with the aim of keeping the same ratio of L/V between laboratory and field conditions. It is found that the larger the angle of attack is, the more serious the wear of rail is. The relation of rail wear rate versus angle of attack is non-linear, and the relation of rail wear rate versus lateral force is approximately linear. The influence of angle of attack is more serious than that of lateral force. For the tractive wheelset, the wear index involving linear and quadratic function terms of angle of attack has good agreement with the limited experimental data. Some conclusions are given. 相似文献