全文获取类型
收费全文 | 166篇 |
免费 | 7篇 |
专业分类
公路运输 | 39篇 |
综合类 | 45篇 |
水路运输 | 47篇 |
铁路运输 | 20篇 |
综合运输 | 22篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 31篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 12篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有173条查询结果,搜索用时 15 毫秒
61.
62.
作为通信系统核心器件的功率放大器的线性度直接影响了整个系统的通信质量,而前馈线性化技术综合性能较好,一直以来都是研究的热点.论文基于自适应前馈电路的原理,引入了一种改进的LMS算法,通过计算机软件仿真,表明该算法可以很好地改善系统的线性度. 相似文献
63.
郭磊 《兰州交通大学学报》2014,(5):88-91
语言顺应论认为语言的使用即选择。语言的使用要顺应不同的交际对象和环境。本文从顺应论的四个角度,即:语言的语境顺应、语言结构顺应、动态顺应以及顺应过程的突显性,探讨了介绍语类的口译过程。在这个过程中,译员要动态地选择顺应对象和口译策略,最大限度地实现相应的语言顺应。 相似文献
64.
The first field experiment with intelligent speed adaptation (ISA) in Malaysia was held in December 2010 in the State of Penang. Eleven private cars were instrumented with an advisory system. The system used in the present study included a vocal warning message and a visual text message that is activated when the driver attempts to exceed the speed limit. When the driver decreases the speed, the warning stops; otherwise it is continuously repeated. The test drivers drove the vehicles for three months with the installed system, and the speed was continuously logged in all vehicles. The warning was however only activated in the second month of the three month period. The present study aimed to evaluate the effects of an advisory ISA on driving speed, traffic safety, and drivers' attitude, behavior, and acceptance of the system. To examine these effects, both the survey and the logged speed data were analyzed and explored. The results show a significant reduction in the mean, maximum and 85th percentile speed due to the use of the system. However, there was no long-lasting effect on the speed when the system was deactivated. In the post-trial survey, drivers declared that the system helped them well in following the speed limits and that it assisted them in driving more comfortably. Furthermore, the warning method was more accepted compared to a supportive system, such as active accelerator pedal (AAP). After the trial, most drivers were willing to keep an ISA system. 相似文献
65.
Scientific projections for climate change induced sea-level-rise highlight current and potential future consequences for low lying coastal areas. In response considerable attention has been directed toward the task of coastal adaptation planning. Experience to date indicates that adaptation planning is more complex and contested than anticipated. We argue that this is partly due to the constrained way adaptation planning is conceptualized, whereby limited attention is directed toward understanding coastal adaptation planning as a site of complex and contested knowledge dynamics. Consequently, we use a knowledge systems perspective to explore coastal adaptation planning in order to highlight some of the knowledge exchange dynamics involved. In doing so we draw on views expressed in semi-structured interviews with a diverse range of stakeholders with an interest in coastal management in Victoria, Australia. While the focus is on coastal adaptation planning in Victoria, the insights generated are intended to contribute to broadening the way in which adaptation is conceptualized. 相似文献
66.
E. G. Coombes A. P. Jones I. J. Bateman J. A. Tratalos J. A. Gill D. A. Showler 《Coastal management》2013,41(1):94-115
As tourists are sensitive to weather conditions and changes to the environments they visit, it is likely that climate change will affect coastal recreation in the future. To understand these impacts, it is first important to quantify how visitor numbers are associated with beach characteristics and weather patterns. Using the East Anglian coastline, UK, as a case study, information on the spatial distribution of visitors recorded from aircraft flights is combined with beach characteristic data in a Geographical Information System. In addition, surveys are undertaken at two beaches to assess temporal variations in visitation. The study finds a diverse range of characteristics are associated with visitor numbers. These findings are evaluated alongside the anticipated effects of climate change and management policies. Although it is predicted that warmer weather will increase visitor numbers overall, sea-level rise may reduce numbers at wide sandy beaches, which are currently most preferred by tourists. 相似文献
67.
ABSTRACTAnthropogenic climate change poses risks to transport infrastructure that include disrupted operations, reduced lifespan and increased reconstruction and maintenance costs. Efforts to decrease the vulnerability of transport networks have been largely limited to understanding projected risks through governance and administrative efforts. Where physical adaptation measures have been implemented, these have typically aligned with a traditional “engineering resilience” approach of increasing the strength and rigidity of assets to withstand the impacts of climate change and maintain a stable operating state. Such systems have limited agility and are susceptible to failure from “surprise events”. Addressing these limitations, this paper considers an alternate approach to resilience, inspired by natural ecosystems that sense conditions in real-time, embrace multi-functionality and evolve in response to changing environmental conditions. Such systems embrace and thrive on unpredictability and instability. This paper synthesises key literature in climate adaptation and socio-ecological resilience theory to propose a shift in paradigm for transport infrastructure design, construction and operation, towards engineered systems that can transform, evolve and internally manage vulnerability. The authors discuss the opportunity for biomimicry (innovation inspired by nature) as an enabling discipline for supporting resilient and regenerative infrastructure, introducing three potential tools and frameworks. The authors conclude the importance of leveraging socio-ecological resilience theory, building on the achievements in engineering resilience over the past century. These findings have immediate practical applications in redefining resilience approaches for new transport infrastructure projects and transport infrastructure renewal. 相似文献
68.
基于视觉适应性的公路隧道限速研究 总被引:1,自引:0,他引:1
通过分析隧道对驾驶员视觉、心理的影响,得出车辆通过隧道时车速的变化情况,进而确定了隧道限速段的长度。利用瞳孔面积变化速度与行车安全关系的定量分析,得出基于视觉适应能力的隧道进出口安全行车的临界速度,结合车辆在隧道限速段内的速度变化情况及隧道本身条件确定了保证行车安全的隧道限速值。 相似文献
69.
寸滩水文站是长江上游的主要控制站,分析可知,从20世纪70年代开始,由于年降水量的减少和气温的下降,年最高水位也呈逐渐下降的趋势.本文将灰色系统理论与马尔科夫链理论相结合,以1940年至2003年寸滩站年最高水位序列为研究对象,建立灰色马尔科夫预测模型.从预测结果看出,所建灰色模型大体反映了年最高水位的下降趋势,而经过马尔科夫模型对预测误差进行修正后,模型预测精度提高,计算值与实际值吻合良好.对其他站年最高水位的模拟分析表明,模型精度能满足年最高水位预报要求.说明灰色马尔科夫模型可以应用于长期预报中. 相似文献
70.