全文获取类型
收费全文 | 2608篇 |
免费 | 134篇 |
专业分类
公路运输 | 489篇 |
综合类 | 613篇 |
水路运输 | 1018篇 |
铁路运输 | 389篇 |
综合运输 | 233篇 |
出版年
2024年 | 9篇 |
2023年 | 21篇 |
2022年 | 54篇 |
2021年 | 80篇 |
2020年 | 86篇 |
2019年 | 51篇 |
2018年 | 33篇 |
2017年 | 70篇 |
2016年 | 80篇 |
2015年 | 106篇 |
2014年 | 206篇 |
2013年 | 163篇 |
2012年 | 200篇 |
2011年 | 285篇 |
2010年 | 173篇 |
2009年 | 138篇 |
2008年 | 169篇 |
2007年 | 220篇 |
2006年 | 214篇 |
2005年 | 107篇 |
2004年 | 62篇 |
2003年 | 49篇 |
2002年 | 30篇 |
2001年 | 35篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 4篇 |
排序方式: 共有2742条查询结果,搜索用时 46 毫秒
161.
R. Fortunier J.B. Leblond J.M Bergheau . ENSM-SE centre SMS cours Fauriel - St-Etienne cedex France . LMM UMR /CNRS/Université Paris VI Tour case place Jussieu Paris cedex France . LTDS UMIR CNRS/E 《上海交通大学学报(英文版)》2000,(1)
IntroductionltiswellknownthatmetallmpicalstrUcforeofsteelsandheattransferarefullycouPled.PhasechangesdependontemPertheeevoluton,whereastemPertheeisinfluencedbycontrastsofmaterialcharacteristicsbetWeenphasesandlatenheateffects.AlotofworkhasbeenpefformedonthssubeCt,andclassicalmodelsarenowwidelyimPlementedintofiniteelementcomPutercodes[l][2][31[4][5][61.Thesemodelsaregenerallybasedonf.AVramityPekinetics[7][8]l9]Whnthephasechangeisgovernedbydiffusion,.TheKoistinen-Marburgerlaw[l0]fOrmfornsi… 相似文献
162.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1183-1204
The aim of this study is to investigate the ability of an essentially nonlinear vibration absorber to mitigate the large accelerations transmitted to a passenger compartment of a vehicle which is subjected to shock-type transient loading at the chassis. For such problems, the induced vibration typically attains its maximum value shortly after the application of the loading; thus, it may be impossible to dissipate a major portion of the input energy prior to the occurrence of the peak response. Here, a class of absorbers possessing a form of discontinuous essential stiffness nonlinearity is employed to achieve the desired mitigation. In this paper, we apply a single vibro-impact (VI) absorber to the chassis and examine whether the resulting energy transfer mechanism is an effective way to reduce the peak value of the inertial force measured at the passenger compartment. The influence of the absorber parameters is first studied based on a practical impulsive force, and the optimal design of the absorber is then obtained. Next, an asymmetric clearance arrangement of the absorber is suggested to facilitate the mitigation. Finally, an impulsive acceleration excitation is applied to the system to examine the robustness and efficacy of the optimised absorber. Results of numerical simulations demonstrate that a properly designed VI absorber can significantly decrease the maximum inertial force at the passenger compartment, generated by external impulsive excitations. 相似文献
163.
针对液态硫磺的物理特性及运输条件,使用热煤油加热系统对液态硫磺进行保温、加热.对液态硫磺船加热系统中的硫磺罐保温层、热煤油加热系统做了分析,提出硫磺热煤油加热系统的可行性设计方法、经济保温层的计算公式,阐述了硫磺罐加热盘管设计应注意的问题. 相似文献
164.
台北都会区大众捷运系统为顺利取得捷运系统用地充分土地利用,以捷运土地开发方式提供民众在征收以外之一项选择,从而减少政府财政负担,增加财务效益。并导入以大众运输为导向发之土地开发(Transit Oriented Development TOD)规划理念,同时强化土地开发使用的强度增加使用诱因;规划健全捷运转乘需求,以达到运具整合之功能,并纳入公共元素,进行整体开发。为了捷运土地开发能更顺利、公平、效率的推动,藉本文将施行成效及与相关捷运场、站共同开发之案例进行检讨,提供其他类似开发案参考。 相似文献
165.
液压油过滤技术在工程机械中的应用 总被引:1,自引:0,他引:1
针对工程机械液压油污染等级问题,探讨了液压油过滤技术根据液压油过滤工艺设计了一种具有三级滤芯的过滤机和管路组成的过滤系统,使用快换接头将过滤系统与工程机械液压油箱连接,能满足大批量工程机械液压油过滤作业的需要。用检测仪检测证明:该过滤系统过滤后的液压油污染等级优于行业要求标准 相似文献
166.
167.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(12):1874-1896
ABSTRACTThe effect of centre-of-gravity heights on the high-speed performance measures of long combination vehicles including truck with double centre-axle trailers, Nordic, and A-double combination vehicles is investigated. The high fidelity three-dimensional models, used in this research, are validated against physical test data. These models are often accurate in terms of the actual dynamic behaviours of the vehicle. On the other hand, the simple yaw-plane single-track models with linear tires require less number of vehicle parameters. In this paper, it is investigated how accurate the estimations of performance measures are at high forward speeds by such single-track linear (STL) models. The influence of load height is especially studied. The high-speed performance-based standard or PBS measures considered are rearward amplifications of both lateral acceleration and yaw velocity; lateral load transfer; yaw damping and high-speed transient offtracking. The results show that tire relaxation has a large effect and it is rather easy to add to an STL model, so it is assumed to be modelled in STL. With realistically high payload and a required accuracy of PBS measures of approximately 10%, only the accuracy of rearward amplification of yaw velocity calculated by the frequency response is fulfilled by the STL. With low payload, the same statement is valid, but with around 5% in required accuracy. The roll dynamics effects are more important than the tire non-linearities. 相似文献
168.
船上船污应急计划的编制和实施,对减轻海洋环境污染起了积极作用,尽管目前大量船舶都编制了该计划,经调查发现许多船舶在应用中还存在不少问题,为进一步提高各类船舶对所发生的油污应急反应能力,必须加强演练,定期评估、检查和修改已制定的计划。 相似文献
169.
170.
为加强轮机人员对电力系统知识的掌握,根据现代大型集装箱船电力系统的特点,详细介绍了船舶应急电系统受控的逻辑关系,特别指出联络开关的意义和作用,可为船舶电站设计、轮机设备维护管理及故障分析提供指导。 相似文献