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   44篇
  免费   1篇
公路运输   2篇
综合类   2篇
水路运输   23篇
铁路运输   2篇
综合运输   16篇
  2018年   1篇
  2017年   2篇
  2015年   2篇
  2013年   9篇
  2012年   3篇
  2009年   2篇
  2008年   5篇
  2007年   2篇
  2005年   1篇
  2000年   1篇
  1999年   1篇
  1996年   4篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1981年   1篇
排序方式: 共有45条查询结果,搜索用时 15 毫秒
21.
Truck emissions at a port may have a severe impact on neighbors, resulting in a politically sensitive sustainability issue for the port management. Strict emissions controls may adversely affect throughput whereas the lack of strict controls will be unacceptable to local citizens and environmental interests. We develop an economic model minimizing cost of truck emissions control and collateral production changes and apply it to decision making for a port seeking to meet a throughput goal while also attempting to satisfy an emissions constraint. Outcomes predicted by the model allow informed decisions about the impact of controls.  相似文献   
22.
更具环保性,成本更高,是国际海事组织新标准要求船舶经营人放弃船舶传统燃料而采用蒸馏燃料的两个结果.此外,全球统一的船舶传统燃料环保标准也是放弃船舶燃料而采用蒸馏燃料的必然结果.  相似文献   
23.
The issue of quality assurance in higher education is at the top of the agenda of universities throughout the world. For the World Maritime University, an institution with highly international staff and student bodies, a complex base of voluntary funding and isolated from any national or European system of education, the problem of defining quality and instituting a quality management system has been a particularly complex and vital task. Our quality standards are the key to our survival.  相似文献   
24.
A new study by the U.S. Advisory Commission on Intergovernmental Relations focuses on the adaptions in transit services, finances, institutions, and policy processes occasioned by current financial stress at all levels of government and by the devolution of national responsibilities to the state and local governments. This study found, in part, that (1) most metropolitan transportation planning organizations now are locally governed and staffed. (2) their planning is becoming increasingly isolated, less comprehensive, and shorter range. (3) some such organizations are experiencing strong pressure to decentralize or subregionalize, and (4) the desire for these organizations to exercise more effective areawide leadership is not matched with local approval of greater powers for them. The study concludes that informal coordination techniques or new powers granted by state legislatures are the two most likely facilitators of improved metropolitan transportation leadership in the 1980s.  相似文献   
25.
本文检视影响连续壁槽沟开挖稳定因子,并以案例介绍采择「调高稳定液之质量与浓度」、「缩小连续壁单元长度、连续壁单元间钢筋不搭接等缩短开挖时间」、「提高稳定液与地下水位之液面差」、「灌浆地盘改良」等兼顾安全与经济性之设计、施工处理对策.  相似文献   
26.
27.
In probe-based traffic monitoring systems, traffic conditions can be inferred based on the position data of a set of periodically polled probe vehicles. In such systems, the two consecutive polled positions do not necessarily correspond to the end points of individual links. Obtaining estimates of travel time at the individual link level requires the total traversal time (which is equal to the polling interval duration) be decomposed. This paper presents an algorithm for solving the problem of decomposing the traversal time to times taken to traverse individual road segments on the route. The proposed algorithm assumes minimal information about the network, namely network topography (i.e. links and nodes) and the free flow speed of each link. Unlike existing deterministic methods, the proposed solution algorithm defines a likelihood function that is maximized to solve for the most likely travel time for each road segment on the traversed route. The proposed scheme is evaluated using simulated data and compared to a benchmark deterministic method. The evaluation results suggest that the proposed method outperforms the bench mark method and on average improves the accuracy of the estimated link travel times by up to 90%.  相似文献   
28.
Treaties on Trial: The Continuing Controversy Over Northwest Indian Fishing Rights by Fay G. Cohen (Seattle: University of Washington Press, 1986), 229 pages.  相似文献   
29.
Abstract

Designing environmental monitoring programs to deal with widespread, subtle, and/or cumulative impacts on a regional basis is challenging. It requires a shift away from focusing primarily on individual point sources to a more regional perspective. It also necessitates involving scientists and managers together in a cooperative effort to establish priorities and articulate clear objectives. In our view, this objective‐setting task is neither a strictly scientific nor a strictly management activity. It depends on effective communication between scientists and managers but is confounded by differing perspectives, value systems, and behaviors. We present a conceptual framework to assist managers and scientists in this process. This is intended to structure such communication by helping to create a context that permits fruitful give‐and‐take between the two groups. We then describe a six‐part model for specifying the key elements of regional monitoring objectives.  相似文献   
30.
Coral reef areas are threatened worldwide by growing populations, tourism development, and use of poison and dynamite in fishing in areas adjacent to the reefs. The designation of marine protected areas is one strategy for addressing these problems. Wakatobi National Park, established in Eastern Indonesia in 1996, contains approximately 50,000 ha of coral reefs and a resident population of Sama-Bajo people whose traditions and current livelihoods tie them closely to the sea. The present research, using participatory rural appraisal methods, focused upon the impact of the designation of the Marine Park on their lives and investigated the potential for public participation in park planning and management. The Wakatobi Park Management Plan does not address the needs and interests of local people. Priority should be placed on adaptation of park zoning and protection regulations to accommodate the livelihood requirements of indigenous communities.  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