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   1207篇
  免费   26篇
公路运输   374篇
综合类   44篇
水路运输   388篇
铁路运输   33篇
综合运输   394篇
  2023年   4篇
  2022年   27篇
  2021年   8篇
  2020年   7篇
  2019年   11篇
  2018年   38篇
  2017年   36篇
  2016年   36篇
  2015年   11篇
  2014年   57篇
  2013年   197篇
  2012年   64篇
  2011年   73篇
  2010年   61篇
  2009年   50篇
  2008年   56篇
  2007年   34篇
  2006年   30篇
  2005年   31篇
  2004年   15篇
  2003年   26篇
  2002年   24篇
  2001年   22篇
  2000年   14篇
  1999年   17篇
  1998年   25篇
  1997年   23篇
  1996年   26篇
  1995年   16篇
  1994年   9篇
  1993年   11篇
  1992年   16篇
  1991年   13篇
  1990年   11篇
  1989年   7篇
  1988年   5篇
  1987年   4篇
  1986年   5篇
  1985年   7篇
  1984年   9篇
  1982年   6篇
  1981年   12篇
  1980年   13篇
  1979年   10篇
  1978年   8篇
  1977年   8篇
  1976年   8篇
  1975年   14篇
  1973年   8篇
  1972年   4篇
排序方式: 共有1233条查询结果,搜索用时 78 毫秒
591.
592.

Development of awareness and capacity is a central component to the delivery of ICM and spans from local communities to national-level politicians. Education and training activities associated with ICM must be extremely varied to match both the existing capacity and role that the stakeholders play within the process of ICM. Consequently, there cannot be considered any effective “generic” ICM training; training must be tailored to match the requirements of target groups. The transfer and uptake of good-practice thus becomes an important aspect of quality enhancement in ICM capacity development. Six case studies from the Asia-Pacific region are presented that show diverse and innovative examples of good practice. A comparative analysis of these case studies is carried out in terms of institutional level of impact. In addition a generic systems-based evaluation framework is used to determine the extent to which the training impacts upon ICM implementation indicators. It is concluded that the exchange, transfer, and translation to local conditions of appropriate good practice in ICM capacity development can be an important element in enhancing the impact of ICM programs on the coastal environments and societies. Furthermore, there appears to be a positive link between the involvement of national/state/regional stakeholders in capacity-building initiatives and impacting a wider variety of indicators of ICM delivery.  相似文献   
593.
Using data collected from May 1978 to November 1996, this article assesses the effects of fluctuating water levels on the beach and shoreline at the Northeast Beach, Point Pelee, Lake Erie, Canada. To compare the serial dynamics of lake levels with net shoreline positional changes and beach net sediment flux, the data are transformed to standard scores to deal with the differences in the units and in the scale associated with each variable. The results demonstrate that over the 18-year period, fluctuating lake levels are associated with shifts in shoreline position and the development of various aggradational and degradational states at the beach. A sustained rapid rise in lake levels will initiate an erosional sequence which will persist even with declining water levels. With a persistent decline in water levels the beach and shoreline will adjust very gradually from unstable, erosional states to an aggradational state. Other results emphasize that those beach sectors directly governed by artificial structures suffered disproportionately higher erosion during high-water levels. Coastal managers must, therefore, be cognizant of the fact that shore protection devices must be carefully designed in order to be effective against the influence of fluctuating lake levels.  相似文献   
594.
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   
595.
Abstract

Competent administration of the Coastal Zone Management Act of 1972 (CZMA) must proceed on an informed understanding of the organization styles and capacities of agencies presently dealing with similar problems. One such agency, the San Francisco Bay Conservation and Development Commission (BCDC), the forerunner of the California model of coastal management, is analyzed here to shed light on where we are headed and what we can expect administratively as the CZMA becomes an operation reality.

The major administrative insights offered fall into the areas of: (1) effectiveness assessment‐the BCDC's success is systematically defined and measured, and a discussion of what effectiveness evaluation implies in the area of coastal resource management is undertaken; (2) understanding organizational success—the BCDC's administrative style is analyzed in terms of the synergy which has been created between its organizational structure and decision‐making process; and (3) implications of agency success—which of the BCDC's lessons are most valuable and how these can be applied to other situations are shown.  相似文献   
596.
The signalling system affects the type of service that can be provided on any particular railway line. The aims set when it comes to designing these systems to operate a railway line are: to ensure safety of operation and to ensure flexible and efficient running. When building a line capacity optimisation algorithm, it must reach a compromise solution between two parameters: minimise the interval between trains and keep journey time as low as possible. This paper aims to describe the algorithm developed between METRO DE MADRID and CITEF (Railway Technology Research Centre of the Universidad Politécnica de Madrid – UPM) that allows the capacity of an underground line equipped with ATP Distance To Go systems to be studied and optimised. This algorithm facilitates the tasks of signalling design and optimisation. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
597.
This study presents a means of determining a historic (generalised cost based) price index for cycling in the UK for the period 1949–2006 using annual demand data. By specifying demand as a function of generalised price and income and then applying a structural time-series model to elucidate the unobserved component of prices (while controlling for observed income levels), it is illustrated that the role of prices in influencing demand is non-trivial. Over the sample period price responses generally influence demand for cycling to a greater extent than income effects.  相似文献   
598.
This study aims at evaluating the customer expectations in a public sector passenger transport company, a crucial sector in developing countries like India. A questionnaire containing 18 quality characteristics was administered to various customers of three bus depots of one division of a state road transport undertaking in South India. Attribute‐based perceptual mapping using discriminant analysis was done to position the three depots and to identify their strengths and weaknesses. The findings would help prioritize different parameters and also provide guidelines for managers to focus on and to improve. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
599.
This paper presents the results of a parametric study of probabilistic modelling of the ultimate strength of ship plates with non-uniform corrosion represented by random fields. The load-shortening behaviour of the plates with non-uniform reduction of thickness due to corrosion under longitudinal compression is obtained using a general-purpose nonlinear finite element analysis program. A nonlinear time-dependent corrosion model is used to define the probabilistic characteristics of the random fields based on corrosion data measured in plate elements at different locations of bulk carriers. Based on the probabilistic models derived by Monte Carlo simulation, equations to predict the mean and the 5 % characteristic value of the ultimate strength of plates with non-uniform corrosion are developed. Finally a regression equation is proposed to take into account the effect of non-uniform corrosion patterns in the predictions of the ultimate strength of plates with uniform corrosion.  相似文献   
600.
The establishment and implementation of a training programme requires a training needs assessment (TNA). Without this approach, more often than not, training programmes have failed to succeed and to make such an assessment the instructional designer, i.e. the person in charge for this work, needs to follow a methodology. Unlike the other industries, the port industry has neglected the use of these methodologies, which is shown by the lack of research work published in academic journals. With a view to fill the existing gap, the paper proposes a five-step TNA methodology to be used in the port industry and applies its first three steps to investigate the port training situation in the new European Union member states. To achieve this objective, the paper is structured in the following way: Section 1 puts the research work into context; section 2 addresses the role of ports; section 3. presents a port TNA methodology; section 4. explains research methodology; section 5 addresses port training issues in the new European-member states; and section 6 presents conclusions and further comments.  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