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   60篇
  免费   3篇
公路运输   11篇
综合类   8篇
水路运输   34篇
铁路运输   7篇
综合运输   3篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   2篇
  2014年   6篇
  2013年   5篇
  2012年   5篇
  2011年   1篇
  2010年   5篇
  2009年   11篇
  2008年   1篇
  2007年   9篇
  2006年   2篇
  2005年   2篇
  2003年   1篇
  1998年   1篇
  1994年   1篇
排序方式: 共有63条查询结果,搜索用时 31 毫秒
21.
该文根据南京市经济社会发展要求,遵循"人水和谐"理念,从分洪和调水需求出发,对秦淮东河的工程规模、功能定位、线路走向、实施难度等进行了深入研究,为工程的顺利实施提供了一定技术基础。  相似文献   
22.
In metropolitan areas of developing and emerging economies in Asia, a remarkable phenomenon of motorization with rapid economic growth is accelerating a continuous formation of auto-dependent urban structures. The delayed timing of urban railway introduction could contribute to a negative spiral of motorization, which could provoke a severe increase in CO2 emissions from transportation sector. In this paper, we attempt to evaluate the timing of urban railway station development based on the level of automobile share and an analysis of the CO2 emissions in the catchment areas of newly introduced urban railway stations in Asian metropolitan areas; Japan, Malaysia and Indonesia. The result quantitatively reveals that the earlier development of the stations in comparison to the progress of motorization tended to result in a statistically significant reduction of CO2 emissions from transportation year-by-year in the catchment areas. In addition, this study demonstrates statistically that urban development harmonized with urban railway systems with a higher service frequency should be a key factor on the strategic realization of low-carbon urban forms along public transportation corridors.  相似文献   
23.
A response of the circulation in the Japan/East Sea (JES) to different kinds of wind forcing is studied, with the emphasis on the warm season, using a primitive equation oceanic model. Wind forcing is based on typical patterns obtained from complex empirical orthogonal functions of 1°-gridded NCEP/NCAR 6 h winds for 1998–2005. These patterns are distinguished by a prevailing wind direction. Northwestern wind and strong cyclonic (C) curl prevail in winter, while a variety of patterns occur in the warm season, differing in the wind direction and curl. Three model runs are performed to examine the circulation in response to a prevailing C wind stress curl or an alternating C and anticyclonic (AC) curl or a strong C curl in the warm season. The simulated features are consistent with the observational evidence, in particular with thermal fronts and frequent eddy locations derived from multi-year infrared satellite imagery. The simulated C circulation intensifies and the subarctic region extends southward with the strengthening of a summer C wind stress curl over the JES. Variability of Subarctic Front (SF) in the western JES (between 130°E and 133°E) is strongly affected by summer wind stress curl. Forcing by an AC curl tends to shift SF northward, while SF shifts to the south under the forcing by a C curl, reaching the southern Ulleung Basin in the case of the strong C curl. In the northwestern JES (off Peter the Great Bay, Russia, and North Korea), the SF northwestern branch (NWSF) is simulated. It is a known feature in autumn and early winter and can also occur in the warm season. The simulation results suggest an AC wind stress curl as the forcing of the formation of the NWSF in the warm season. The Siberia Seamount and sharply bending coastline near Peter the Great Bay facilitate partial separation of the Primorye (Liman) Current from the coast. The wind stress curl can be an additional forcing of the Tsushima Warm Current (TWC) branching off the Korea Strait to the East Korea Warm Current (EKWC) and the offshore branch (OB). In the warm season, the simulated TWC bifurcation occurs farther north, the EKWC is strong, and the OB is weak under the forcing of the AC wind stress curl. The EKWC is weak and the OB is strong under the forcing of the strong C wind stress curl.  相似文献   
24.
Recent observations of hydrography, currents and volume transports in the straits of the East/Japan Sea are reviewed. It is newly found that bottom cold water in the Korea/Tsushima Strait originating from the northern region of the East/Japan Sea appears not only in summer and autumn but also in winter. Intensive observations in the Korea/Tsushima Strait revealed two distinct cores of northeastward currents in the upper layer of the western and eastern channels. Mean volume transport through the Korea/Tsushima Strait is calculated as 2.5 ± 0.5 Sv from four-year direct and indirect measurements. As continuous monitoring has started in the Tsugaru and Soya Straits, understanding of temporal variability of currents and volume transports through the straits is in progress. For the first time, simultaneous time series of volume transports are available in the Korea/Tsushima and Tsugaru Straits during the winter of 1999–2000. Ouflow through the Tsugaru Strait accounts for about 70% of inflow through the Korea/Tsushima Strait for this period.  相似文献   
25.
This research aims to estimate potential inter-regional passenger flows for air transport in the Middle East under open skies polices, once deregulation agreements are reached between neighboring countries. To arrive at reasonable demand estimates, Western and Eastern European demand data was analyzed as a first step, since it is assumed that current Middle Eastern demand is distorted as a direct result of regional political instability. The major factors affecting demand, based on the European dataset, included population size, gross domestic product (GDP) per capita, absolute difference in GDP per capita between two countries, great circle distance and membership of the European Union and World Trade Organization. Subsequently, a 21 country database was estimated for passenger flow in the Middle East region on an average peak season day. The demand estimations became input for a hub location model (p-hub median formulation) in order to achieve the second major aim of this research, objective identification of potential regional gateways. The results proved robust to both single and multiple allocation model assumptions, with Cairo and Tehran consistently achieving hub status, along with Istanbul and Riyadh, as the number of potential hubs increased. Finally, this research shows that under conditions of peace, given existing socio-economic indicators, inter-regional passenger demand flow could increase by upwards of 51% and regulatory authorities ought to consider the necessary infrastructure and demand management policies to enable the conservative regional demand growth estimated.  相似文献   
26.
Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues.  相似文献   
27.
The seasonal dynamics of phytoplankton blooms in the central Japan/East Sea (JES) show pronounced year-to-year variability based on Sea-viewing Wide Field-of-view Sensor (SeaWiFS; 19972003) and Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra (20002003) observations. Wind seems to strongly influence this variability. To study the relationship between wind and bloom initiation, we analyzed daily, remotely sensed wind stress data (Active Microwave Instrument–wind [AMI–wind], NASA Scatterometer [NSCAT], and Quick Scatterometer [QuickSCAT]: 19972003) and daily chlorophyll concentrations based on ocean color data (SeaWiFS and MODIS). The results agreed well with the hypotheses; in spring, blooms began 615 days after wind stress weakened. Fall blooms started 39 days after wind strengthened. We also simulated seasonal changes using a simple light–nutrient model using two values for the respiration ratio: 10% and 20%. The use of 20% seemed to reproduce the timing of the spring bloom quite well but underestimated the absolute level of chlorophyll concentration. On the other hand, using 10% produced a better estimation of the chlorophyll concentration but failed to match the timing. Neither of the model runs reproduced the timing of the fall bloom well.  相似文献   
28.
高又兵 《交通标准化》2010,(23):140-142
车辆的外廓尺寸是公路几何设计中的重要控制因素。《公路工程技术标准》明确规定了设计车辆的种类及其外廓尺寸,作为确定道路交叉布置和道路几何形状的基本依据。而实际上因某些特殊需要,公路上经常出现外廓尺寸超出设计车辆最大尺寸范围的超长车辆,现行路线规范中平曲线加宽值不能满足其转弯要求。结合水东服务区设计实例,对超长车辆转弯时平曲线半径加宽值验算进行详细论述,具有一定的实际意义。  相似文献   
29.
阳明路东延伸一期工程是解决南昌市旧城区"南北不畅,东西不通"交通状况的重要项目,工程总体设计牵涉面广,难度大。该文介绍了工程总体设计的思路,可供道路专业人员参考。  相似文献   
30.

The ultimate goal of integrated coastal management (ICM) is to improve the quality of life of coastal inhabitants through achieving the sustainable development objectives. Achieving this goal, however, is often hindered by policy and financial and capacity barriers. This article discusses the role of the interaction between the dynamic forces and essential elements of ICM to address the environmental and management issues at the local level. The experience of Xiamen Municipality, People's Republic of China, is highlighted to showcase how it transformed from an environmentally degraded municipality into a modern, urban garden city in a span of just more than a decade. The socioeconomic and ecological benefits of ICM in Xiamen are obvious, measurable, and well-appreciated by both the government and the citizenry. Useful lessons have also been drawn from several ICM initiatives in East Asia in relation to strengthening coastal management. The key ones are briefly discussed.  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