全文获取类型
收费全文 | 2087篇 |
免费 | 105篇 |
专业分类
公路运输 | 684篇 |
综合类 | 556篇 |
水路运输 | 499篇 |
铁路运输 | 379篇 |
综合运输 | 74篇 |
出版年
2024年 | 9篇 |
2023年 | 18篇 |
2022年 | 47篇 |
2021年 | 85篇 |
2020年 | 86篇 |
2019年 | 41篇 |
2018年 | 46篇 |
2017年 | 60篇 |
2016年 | 48篇 |
2015年 | 86篇 |
2014年 | 167篇 |
2013年 | 86篇 |
2012年 | 188篇 |
2011年 | 173篇 |
2010年 | 136篇 |
2009年 | 133篇 |
2008年 | 145篇 |
2007年 | 171篇 |
2006年 | 156篇 |
2005年 | 62篇 |
2004年 | 56篇 |
2003年 | 33篇 |
2002年 | 26篇 |
2001年 | 25篇 |
2000年 | 12篇 |
1999年 | 12篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 5篇 |
1994年 | 12篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 7篇 |
排序方式: 共有2192条查询结果,搜索用时 15 毫秒
81.
82.
Life events, such as the birth of a child, disrupt habitual travel behaviour and provide a valuable opportunity to influence the adoption of sustainable transport practices. However, in order for sustainable travel practices to be adopted, an understanding is required of the factors that influence travel mode choice among families with young children. Research in this field is particularly timely given many in the millennial generation, a comparably large cohort, are approaching this life stage. This comprehensive literature review develops a framework of factors influencing travel mode choice among families with young children. The findings reveal a multitude of factors influence decisions about mode choice, and, in particular, encourage travel by car, when travelling with young children. The paper concludes with an agenda for future research about travel among families with young children, a largely overlooked group of transport users. 相似文献
83.
84.
Yukinobu Nagata Koji Gotoh Masahiro Toyosada 《Journal of Marine Science and Technology》2009,14(1):104-114
Many accidents are caused by fatigue in welded built-up steel structures, and so it is important to estimate the fatigue lives
of such structures quantitatively for safety reasons. By assuming that fatigue cracks cannot grow without an accumulation
of alternating tensile/compressional plastic strain, one of the authors identified an improved effective stress intensity
factor range ΔK
RPG based on the re-tensile plastic zone generating (RPG) load, which represents the driving force for fatigue cracks, and suggested
that ΔK
RPG should be used as the parameter to describe fatigue crack growth behavior. The “FLARP” numerical simulation code in which
ΔK
RPG is implemented as the fatigue crack growth parameter, was developed in order to predict fatigue crack initiation and propagation
behavior. In this paper, it is demonstrated that FLARP gives accurate estimates for fatigue life by comparing the estimated
fatigue crack growth curves and S–N curves with the experimental results for in-plane gusset welded joints, which are used in many welded steel structures. Moreover,
the effect of induced bending moment due to the linear misalignment in the out of plane direction on the fatigue strength
of in-plane gusset welded joints is investigated through numerical simulations. 相似文献
85.
86.
87.
硅烷浸渍混凝土耐酸雨性能的研究 总被引:4,自引:0,他引:4
采用酸雨模拟试验方法,研究了两种硅烷对不同配合比的混凝土耐酸雨性能的影响,重点研究了硅烷浸渍混凝土的外观、体积、质量、强度及吸水率与碳化深度等性能,并建立了硅烷浸渍混凝土的服役寿命预测模型。试验结果表明,无论是否浸渍硅烷,掺磨细高炉矿渣粉的混凝土耐酸雨性能明显优于不掺矿渣粉的混凝土。两种硅烷可有效提高混凝土耐酸雨性能,有效延长混凝土在酸雨环境下的服役寿命。6689硅烷浸渍混凝土的各项耐酸雨性能指标略优于6403硅烷。 相似文献
88.
防风网结构风振疲劳特性研究 总被引:1,自引:0,他引:1
针对某港实际工程.采用有限元方法对防风网结构在脉动风荷载作用下的动力响应进行分析,并根据瞬态动力分析的结果,找出防风网结构应力疲劳最危险的单元。结合疲劳分析的基本理论,应用雨流法统计最危险单元的应力时程,得到应力循环次数及应力幅大小,根据Miner线性累积损伤准则编写ANSYS的风振疲劳程序.计算得到防风网结构的疲劳寿命。根据实际工程,验证设计风速为26.8m/s持续作用下防风网结构的疲劳寿命。 相似文献
89.
90.