全文获取类型
收费全文 | 331篇 |
免费 | 18篇 |
专业分类
公路运输 | 112篇 |
综合类 | 90篇 |
水路运输 | 90篇 |
铁路运输 | 43篇 |
综合运输 | 14篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 13篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 25篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 27篇 |
2010年 | 19篇 |
2009年 | 23篇 |
2008年 | 32篇 |
2007年 | 31篇 |
2006年 | 36篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 1篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有349条查询结果,搜索用时 365 毫秒
91.
Kho Shahriar Iqbal Gabriele Bulian Kazuhiko Hasegawa Md. Mashud Karim Zobair Ibn Awal 《Journal of Marine Science and Technology》2008,13(3):282-290
On the basis of previous studies, a series of hazards involving the typical small inland passenger ferries operating in inland
Bangladeshi waters have been identified. In particular, stormy weather conditions, overloading, and the risk of crowding to
one side have been determined as the typical events that are likely to lead to capsizing in the intact condition. In this
article, possible hazard mitigation measures are discussed, both from the regulatory and from the design point of view, for
a small inland ferry that is very similar to one that actually capsized in the past. The addressed design options involve
ballasting and hull modification by means of additional buoyancy above the waterline. From a regulatory point of view, it
is proposed that the present weather criterion in force in Bangladesh be modified by increasing the wind speed to be accounted
for and by considering the concurrent effects of wind, rolling, and the crowding of people to one side. 相似文献
92.
In support of the development of improved fillet weld sizing criteria for lightweight shipboard structures, a comprehensive static strength test program using longitudinal and transverse shear specimens according to AWS B4.0 Standards has been conducted. This test program covers base material with strength ranging from 71 ksi (490 MPa) to 96 ksi (660 MPa) and weld size ranging from 1/8″ (3 mm) to 3/8″ (10 mm). This paper focuses on a traction stress based analysis of the test data as an effort to establish a unified shear strength definition for load-carrying fillet weld specimens regardless of shear loading conditions. The proposed shear strength definition proves to be effective in correlating the fillet weld strength test data of the longitudinal and transverse shear specimens. The results of this investigation demonstrate that existing shear strength definitions used by various weld sizing criteria such as those given by Class Societies have two major limitations: (1) it cannot be related to a critical stress state on experimentally observed failure plane in transverse shear specimens; (2) it underestimates shear stress at failure due to severe stress concentration at weld end in typical longitudinal shear specimens. These two limitations have been shown to be the major cause for having two significantly different shear strength values: one is transverse shear strength obtained from transverse shear specimens and the other is longitudinal shear strength obtained from longitudinal shear specimens. 相似文献
93.
Alfonso M. Panunzio Guillaume Puel Régis Cottereau Samuel Simon Xavier Quost 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(11):1768-1795
This paper investigates the effects of the track geometry irregularities on the wheel–rail dynamic interactions and the rail fatigue initiation through the application of the Dang Van criterion, that supposes an elastic shakedown of the structure. The irregularities are modelled, using experimental data, as a stochastic field which is representative of the considered railway network. The tracks thus generated are introduced as the input of a railway dynamics software to characterise the stochastic contact patch and the parameters on which it depends: contact forces and wheelset–rail relative position. A variance-based global sensitivity analysis is performed on quantities of interest representative of the dynamic behaviour of the system, with respect to the stochastic geometry irregularities and for different curve radius classes and operating conditions. The estimation of the internal stresses and the fatigue index being more time-consuming than the dynamical simulations, the sensitivity analysis is performed through a metamodel, whose input parameters are the wheel–rail relative position and velocity. The coefficient of variation of the number of fatigue cycles, when the simulations are performed with random geometry irregularities, varies between 0.13 and 0.28. In a large radius curve, the most influent irregularity is the horizontal curvature, while, in a tight curve, the gauge becomes more important. 相似文献
94.
研究带统一通信延迟的多UUV队形控制。根据奈奎斯特准则和代数图论,提出一种与通信拓扑和通信时延有关的队形控制算法。该算法具有分布式特点,对具有双向通信拓扑和统一通信延迟的多UUV系统,能够使所有UUV的速度和位置渐近地收敛至期望值,从而达到稳定的期望队形。数值仿真结果证实所提队形控制方法的有效性。 相似文献
95.
96.
97.
隧道衬砌背后空洞健康判据试验研究 总被引:1,自引:0,他引:1
从研究衬砌背后空洞单项指标判据出发,结合实例采用室内大比例尺模型试验,分析了衬砌背后存在不同尺寸空洞时结构的承载力大小变化、病害产生形式和变化规律等。得到了隧道衬砌背后空洞的单项指标健康判据:隧道健康状态时背后无空洞,处于亚健康时背后空洞小于100 mm,病害阶段时背后空洞介于100~550 mm之间,病危阶段时背后空洞大于550 mm。 相似文献
98.
传统的桥梁结构是一种被动结构,一经设计、制造完成后,其性能及使用状态将在很大程度上存在着不可预知性和不可控制性,这就给桥梁结构的使用和维护带来不便,鉴于此,介绍桥梁结构健康检测系统的组成、特点、设计的准则以及桥梁结构损伤评估方法等内容,极大地方便了桥梁的养护工作。 相似文献
99.
对比了大型船舶中不同锚唇设计的巨大重量差异,借助力学分析,形成了基于锚链等级与规格且简单易用的锚唇设计厚度基准表。通过对日韩锚唇设计数据比较,贴切吻合更趋安全。该表的推广使用有助于我国船舶减重降耗,从而得以降低成本提升效益。 相似文献
100.