全文获取类型
收费全文 | 2236篇 |
免费 | 38篇 |
专业分类
公路运输 | 343篇 |
综合类 | 551篇 |
水路运输 | 978篇 |
铁路运输 | 131篇 |
综合运输 | 271篇 |
出版年
2024年 | 4篇 |
2023年 | 10篇 |
2022年 | 31篇 |
2021年 | 59篇 |
2020年 | 66篇 |
2019年 | 31篇 |
2018年 | 41篇 |
2017年 | 50篇 |
2016年 | 42篇 |
2015年 | 60篇 |
2014年 | 151篇 |
2013年 | 147篇 |
2012年 | 148篇 |
2011年 | 187篇 |
2010年 | 150篇 |
2009年 | 112篇 |
2008年 | 141篇 |
2007年 | 179篇 |
2006年 | 227篇 |
2005年 | 109篇 |
2004年 | 75篇 |
2003年 | 60篇 |
2002年 | 40篇 |
2001年 | 62篇 |
2000年 | 20篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 4篇 |
排序方式: 共有2274条查询结果,搜索用时 312 毫秒
81.
82.
针对输油管弯头以及管壁上的缺陷,用有限元法对其进行了分析计算,找出了输油管弯头的危险部位,给出了管壁危险部位腐蚀缺陷处的应力分布规律以及危险点,并研究了缺陷的长度、宽度和剩余壁厚对应力的影响;同时拟合了缺陷处应力的计算公式,为工程技术人员的设计计算和现场管道安全运营动态管理提供了依据. 相似文献
83.
84.
85.
孙化栋 《青岛远洋船员学院学报》2012,(3):26-29
本文首先介绍了IMO NOx排放规则,指出SCR技术是目前最有效的应对措施。在介绍SCR系统基本组成及工作原理的基础上,讨论了目前此领域的两个研究热点:在重质燃油的使用条件下和二冲程柴油机使用条件下的SCR系统所面临的问题。 相似文献
86.
黄晶 《南通航运职业技术学院学报》2014,13(1):126-128
文章在分析目前国际航运业务管理专业实践教学体系现状的基础上,通过调研就业企业和岗位的素质要求,提出了一套基于就业导向的立体化实践教学体系,以实现就业的无缝对接。 相似文献
87.
为了简化集油工艺、降低工程投资,对于外围油田的低产、油气比高以及原油凝固点较低的油井,通常应用树状电加热集油工艺,其中电加热保温管道是该工艺的关键部件和设施。传统的电加热管道存在着接头数量多、过热烧损等问题,影响正常运行。文中设计一种可更换电伴热体的新型伴热保温管道结构,使电热体接头数量显著减少,实现了不开挖更换和修复伴热体,延长了管道整体寿命,增强了电加热系统的稳定性和可靠性,取得了良好效果。 相似文献
88.
ABSTRACTThe container shipping industry is receiving growing attention in driving the performance of global supply chains. This phenomenon has accelerated supply chain integration (SCI) within the industry. Although SCI could offer numerous benefits, it is often quoted to be implemented easier in theory than in practice. The high failure rate that is associated with SCI is often not addressed in the literature. Grounded on resource-based view (RBV) theory, this paper is aimed at identifying the critical success factors (CSFs) and examining their influence on SCI and supply chain performance (SCP). Survey questionnaires were administered on 164 container shipping firms. The constructs were validated empirically using confirmatory factor analysis and were subsequently analysed using structural equation modelling. The proposed CSFs in this study are found to be positively corelated with SCI, which, in turn, is positively correlated with SCP. This paper has contributed to both theory and practice by applying RBV theory to identify the key resources and capabilities that are necessary for SCI in the container shipping industry. 相似文献
89.
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
90.
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