首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   435篇
  免费   22篇
公路运输   77篇
综合类   154篇
水路运输   168篇
铁路运输   42篇
综合运输   16篇
  2024年   2篇
  2023年   3篇
  2022年   1篇
  2021年   6篇
  2020年   11篇
  2019年   10篇
  2018年   8篇
  2017年   12篇
  2016年   11篇
  2015年   15篇
  2014年   30篇
  2013年   45篇
  2012年   44篇
  2011年   36篇
  2010年   25篇
  2009年   28篇
  2008年   29篇
  2007年   28篇
  2006年   38篇
  2005年   24篇
  2004年   12篇
  2003年   7篇
  2002年   9篇
  2001年   8篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1996年   2篇
  1994年   2篇
  1993年   2篇
  1991年   2篇
  1988年   1篇
排序方式: 共有457条查询结果,搜索用时 15 毫秒
151.
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   
152.
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   
153.
利用三峡水库成库初期实测资料分析长江典型弯曲型河段龙王沱以及牛屎碛河段的泥沙淤积特性。结果表明:龙王沱河段呈现累积性淤积态势,龙王沱累积性淤积了67.8万m3,牛屎碛河段从2007年开始淤积,主要淤积在深槽。2008年持续淤积,到2010年5月,牛屎碛河段共淤积了20.8万m3。从长远来看,随着水库水位的进一步抬高,弯曲型河段的泥沙淤积将进一步加重,对可能出现的航道碍航问题应引起足够的重视。  相似文献   
154.
潍坊港地处莱州湾底部的粉砂质海岸,岸滩宽浅、泥沙运动活跃,在极端恶劣天气条件下,岸滩泥沙会大量悬浮,容易在航道内形成骤淤。中港区3.5万t级航道不仅需在现有1.0万t级航道基础上加宽、浚深和延长,其向外海延伸的航段已超出现有防波挡沙堤的掩护范围,防波挡沙堤需相应延伸以缓解大风天的航道泥沙骤淤,同时要辅以疏浚维护才能保持航道足够的通航水深。  相似文献   
155.
文章总结了黄骅港航道淤积特点和防沙减淤整治经验,分析了粉沙质海岸上各港区扩建航道的可行性和合理性。根据黄骅港的发展历程,目前黄骅港建设的起步阶段已经完成,粉沙质海岸建港优势逐渐体现。黄骅港航道整治成功不仅保证黄骅港健康发展,也为其他粉沙质海岸建港提供有益的参考。  相似文献   
156.
ABSTRACT

Anthropogenic 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   
157.
交通事故黑点是由好多种因素综合到一起而形成的。利用粗集理论及遗传算法对冗余的黑点成因进行删减,得到主要的黑点成因,从而进行有针对性的治理,以达到减少交通事故的目的。  相似文献   
158.
第16届亚运会是亚运史上竞赛项目、参会人数、场馆数量最多的一届,带来了大量突发、集中且具有冲击性的交通需求,在城市日常交通趋于饱和的情况下,亚运交通与日常交通存在资源博弈现象.针对广州市日常交通出行需求和交通运作状况,从客流规模、服务对象、规格要求、时间分布和空间分布等方面系统地分析了亚运交通需求特性,并集约、高效地采取了“集中交通资源保障亚运交通服务质量和降低交通干扰体现亚运交通和谐”两个方面的交通组织对策,确保了亚运会的交通安全顺畅、高效有序,为城市开展大型活动的交通运行保障工作提供了借鉴.  相似文献   
159.
立交型式选择是立交建设中重要的前期工作,立交型式不同,将使整个立交的交通功能、投资、景观及社会和经济效益等方面受到影响。本文采用粗糙集理论,通过对相同道路条件下不同立体交叉口设计方案进行粗糙集评价,建立了对已有的立交桥设计方案的评价模型,针对具体问题对冗余指标进行筛选,再根据数据自身特点赋予其权重,这种方法可以有效避免传统的主观评价和层次分析法主观确定各个指标隶属度的弊端。  相似文献   
160.
白云隧道地下风机房穿越煤系地层,施工中所有平巷均存在瓦斯。介绍了白云隧道通风斜井地下风机房洞室在瓦斯地层中施工所采取的综合治理措施:超前预注浆防护、加强初支、改进通风、实施瓦斯监测等。采用上述措施最终安全、顺利地通过了瓦斯出露段,施工经验可供同类工程建设者参考。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号