全文获取类型
收费全文 | 12517篇 |
免费 | 555篇 |
专业分类
公路运输 | 3425篇 |
综合类 | 3550篇 |
水路运输 | 3331篇 |
铁路运输 | 2284篇 |
综合运输 | 482篇 |
出版年
2024年 | 31篇 |
2023年 | 56篇 |
2022年 | 346篇 |
2021年 | 546篇 |
2020年 | 370篇 |
2019年 | 164篇 |
2018年 | 192篇 |
2017年 | 178篇 |
2016年 | 251篇 |
2015年 | 418篇 |
2014年 | 599篇 |
2013年 | 770篇 |
2012年 | 856篇 |
2011年 | 981篇 |
2010年 | 1003篇 |
2009年 | 1061篇 |
2008年 | 957篇 |
2007年 | 1108篇 |
2006年 | 1088篇 |
2005年 | 704篇 |
2004年 | 244篇 |
2003年 | 186篇 |
2002年 | 129篇 |
2001年 | 196篇 |
2000年 | 165篇 |
1999年 | 83篇 |
1998年 | 69篇 |
1997年 | 48篇 |
1996年 | 64篇 |
1995年 | 52篇 |
1994年 | 45篇 |
1993年 | 23篇 |
1992年 | 22篇 |
1991年 | 22篇 |
1990年 | 15篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 661 毫秒
551.
The core is a vital concept in cooperative game theory and has been widely used in analyzing alliance’s stability. It is especially interesting to apply core theory in liner shipping market due to the latter’s exceptional characteristic of non-homogeneous cost curves as well as divisible and fluctuant demand. Having observed some new phenomena and trends in the industry, this paper studies the economic performance and stability of liner shipping alliance by applying core theory where business cooperation is partly realized by delivering joint-service with mega container ships. To demonstrate the core situation in liner shipping alliance, a cost function is first identified on the basis of two assumptions regarding cooperation: 1) sharing or pooling vessels and 2) deploying mega container ships if needed. Taking cost functions as basis, two conditions of approaching core may be groomed, i.e., collective rationality and individual rationality. The first condition is discussed from the perspective of market, while the second condition is studied within the alliance. Stability of liner shipping alliance is then observed based on these two conditions. An illustrative case study is conducted in order to show some implications and explicitly clarify the theory. 相似文献
552.
Yang Peiju 《中国船检》2011,(7)
Authorized by the competent authority, CCS is the sole professional organization to carry out classification and statutory survey and notarial certification of ships and offshore oil and gas projects. CCS' rule and standard system for offshore installations has experienced 30 years, from none to possessing rules, from statutory and classification survey to competing for notarial certification, and from offshore to deep sea. In recent years, with the quickening of Chinese offshore oil and gas resources exploration, the rule and standard system of CCS has been strengthened and improved continuously. 相似文献
553.
554.
555.
Taking the MK7-3 of USA hydraulic buffer arresting device as the research subject, the dynamical model for the shipboard aircraft arresting system is established, and the magneto-rheological (MR) damper is applied to pulley shock absorbers for shipboard aircraft block system. Due to the effect of the MR damper has not been known completely and so far MR damper model has not been defined, we use a set of characteristic test of the MR damper, through the process of parameters identification, to establish the dynamical model for the MR damper based on the Bingham plastic model. Then, the fuzzy control rules are designed, the buffer control for the pulley buffer of shipboard aircrafts is completed in touchdown moment based on MR technology. Compared with blocking device of hydraulic pulley buffer in the same condition, the simulations results show that the proposed MR pulley buffer can effectively recognize the impact energy for shipboard block system and reduce the pull peak of arresting cable. It improves significantly safety during landing of the air vehicles and lowers the risk of accidents. 相似文献
556.
分析了现阶段公路工程建设造价投资控制现状及存在的问题,结合国外先进投资理念,针对决策阶段、建设阶段、运营阶段造价控制提出对策。根据国家交通运输"十二五"发展规划,提出了全寿命成本理念及交通建设节约资源、有效利用土地资源的新理念。 相似文献
557.
简述了海上平台发电机房通风设计方案中使用噪音分析研究的流程,介绍了建立几何模型、输入数据得到噪音预报,得出分析结果,最终完成设计方案优化,为海上平台发电机房通风设计提供了参考. 相似文献
558.
目前在电磁流量计的干标定研究中,为方便公式推导,通常将实际的圆电极简化为方电极模型.这种简化在电极尺寸较大时,会引入不必要的计算误差,影响流量计的标定精度.本文从圆电极模型出发,论述了其对应权重函数的计算过程.并针对大尺寸圆电极模型进行理想化计算,得到其点电极模型,并运用此模型进行了仿真研究. 相似文献
559.
李涛 《铁道标准设计通讯》2012,(10)
介绍宿淮铁路2座特大桥结构体系设计创新特点。理论计算分析表明:采用主跨132 m连续梁-拱组合体系单线桥可有效降低梁高,节省造价,施工和运营状态下,结构的强度、刚度、横向稳定、行车舒适度性等指标均满足规范要求;主跨108 m连续梁采用双向减隔震体系后,正常使用状态及多遇地震下结构正常工作。当设计地震及罕遇地震发生时,减隔震体系显著降低地震反应,避免了重要部位破坏,保证了桥梁结构的安全性,具有明显的经济效果。 相似文献
560.