全文获取类型
收费全文 | 1426篇 |
免费 | 22篇 |
专业分类
公路运输 | 568篇 |
综合类 | 45篇 |
水路运输 | 372篇 |
铁路运输 | 48篇 |
综合运输 | 415篇 |
出版年
2023年 | 14篇 |
2022年 | 38篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 29篇 |
2017年 | 38篇 |
2016年 | 64篇 |
2015年 | 21篇 |
2014年 | 72篇 |
2013年 | 193篇 |
2012年 | 78篇 |
2011年 | 75篇 |
2010年 | 82篇 |
2009年 | 98篇 |
2008年 | 72篇 |
2007年 | 41篇 |
2006年 | 32篇 |
2005年 | 35篇 |
2004年 | 24篇 |
2003年 | 23篇 |
2002年 | 26篇 |
2001年 | 20篇 |
2000年 | 21篇 |
1999年 | 19篇 |
1998年 | 14篇 |
1997年 | 17篇 |
1996年 | 20篇 |
1995年 | 25篇 |
1994年 | 12篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 15篇 |
1980年 | 9篇 |
1979年 | 13篇 |
1978年 | 5篇 |
1977年 | 12篇 |
1976年 | 15篇 |
1975年 | 18篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1972年 | 4篇 |
排序方式: 共有1448条查询结果,搜索用时 156 毫秒
61.
This paper proposes the adoption of an integrated inventory and transportation system (IITS) to minimize the total costs of inventory and transportation. A non-linear programing is developed by analyzing transportation and inventory costs with one supplier and many retailers in the distribution environment. The paper compares the proposed model with the traditional approach in computing total costs with numerical data. The results indicate that the total costs can be optimized by adopting integrated programing rather than the traditional approach, along with achieving improved customer service levels. In particular, sensitivity analysis is applied to determine the performance of the IITS under various transportation costs, holding costs and shortage costs. It shows that the transportation cost per unit is most sensitive in the proposed model. In this situation, the IITS is more effective for cost saving when set-up cost, holding and shortage costs are high, but is less effective for situations involving high per-unit transportation costs. 相似文献
62.
Rutherford H. Platt 《Coastal management》2013,41(3):265-284
The ocean and Great Lakes coasts of the United States are experiencing widespread economic and environmental damage from coastal flooding and erosion. During this century, public response to such coastal hazards has evolved haphazardly in response to particular disasters. Over time, however, the range of response has broadened as research has helped to refine public understanding of physical coastal processes, and specific disasters have been studied before longer term forms of institutional response have been formulated. Earlier reliance on engineered shoreline protection has been supplemented by beach nourishment, flood insurance, building and land use regulations, coastal zone planning, and other approaches. This article interprets the evolution of such public policy innovations in terms of a model that depicts the interaction of spatially differentiated systems of physical, legal, and cultural phenomena in the coastal context. 相似文献
63.
John H. Mott 《先进运输杂志》2013,47(5):498-511
A method for modeling air carrier departure delays at commercial‐service airports as autoregressive random processes is presented. This method employs the correlation of a priori demand data to significantly reduce prediction error in the optimal least‐squares estimator for additive white noise. The reduction factor of the prediction error is demonstrated to be on the order of 102 over that of the unbiased estimator. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
64.
Peter J. Wilcoxen 《Coastal management》2013,41(3):173-191
Abstract One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside Sewer Transport. Results obtained show that erosion produced by accelerated sea level rise could cause substantial damage to the structure. Large expenditures on beach nourishment will be required to protect the transport and the recreational value of the beach. 相似文献
65.
William H.K. Lam 《运输规划与技术》2013,36(4):245-258
This paper investigates the role of transport pricing in network design and describes two facts about flow pattern in a transportation system. The first, illustrated by an example of Braess paradox, is that adding a new link to the network does not necessarily minimize the total travel time. The second is that introducing of appropriate toll pricing may reduce not only the total network time but also the travel time for each individual traveller. It follows with the investigations of different system objectives and different pricing policies (only toll pricing and distance‐based pricing are considered), and shows how they affect the system performance and flow pattern. Lastly, a systematic optimization process is proposed for integrated planning of transport network and pricing policies. 相似文献
66.
Darcy L. Gray Rosaline R. Canessa Rick B. Rollins Philip Dearden C. Peter Keller 《Coastal management》2013,41(6):575-597
Although the success of marine protected areas (MPAs) and associated zoning schemes is largely dependent on stakeholder acceptance and support, there have been relatively few studies examining the response of recreational stakeholders to MPA proposals. This study investigates the response of recreational boaters to a proposed MPA in British Columbia, Canada. Using a structured questionnaire (n = 543) and a focus group (n = 6), the research examines the level of support for the concept of marine zoning and identifies key factors influencing support or opposition. Results indicate that a small majority of recreational boaters support the concept of marine zoning, but that there are areas of concern that ought to be addressed as MPA implementation proceeds. Support for zoning was strongly related to perceived benefits, particularly environmental benefits. Furthermore, perceived benefits overall were found to outweigh concerns as determinants of recreational boater support for zoning. Major dimensions of opposition included perceptions of over-regulation, loss of access for boating, and mistrust of the government. A suggestion is that such concerns may be mitigated through focused communication and meaningful involvement of boaters in the zoning process. 相似文献
67.
Peter Th. Oppenheim 《运输规划与技术》2013,36(3):179-186
One of the great dilemmas facing major airports is the problem of capacity and seasonal surges of activity. This paper suggests a system of small, inexpensive Airport Terminal Modules, which together with a new type of Mobile Lounge, could make available a considerable degree of flexibility. The ATM's are designed to allow maximum variations of aircraft type and passenger load as well as high ground utilization. This concept would allow major airports to be extended with a minimum of inconvenience as demand becomes apparent, thereby allowing financial expenditure to be carefully controlled and more evenly spread. 相似文献
68.
Luciana V. R. de Messano Barbara L. Ignacio Maria H. C. B. Neves Ricardo Coutinho 《船舶与海洋工程学报》2014,13(3):346-353
In the presence of biofilms, stainless steels (SS) exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential (Eco,) behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor (an anthropogenically disturbed area) was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms (especially Navicula sp.) on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island (an undisturbed area). The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge. 相似文献
69.
Peter Mueller Mark Griffiths 《经济导报》2007,(2):82-87
尽管癌症治疗在过去的十多年取得了显著进展,但肿瘤学仍属于目前最不能满足临床需要的学科领域。在过去十多年里,临床药理学的进步和研发活动方面的巨大投资使得“癌症治疗”发展为“治疗过程研究”的数量急剧增加。但事实上,癌症和其他慢性疾病一样,治疗效果都很差,由此很多大型医药公司和生物制药公司都比以往更大力度的投入资金,用于肿瘤学和其他强效候选药物的研发上。[第一段] 相似文献
70.
Damper Models for Heavy Vehicle Ride Dynamics 总被引:18,自引:0,他引:18
F. H. Besinger D. Cebon D. J. Cole 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(1):35-64
A laboratory rig for testing hydraulic dampers using the 'hardware-in-the-loop' method is described, and the accuracy of the test method is investigated. A mathematical model of a hydraulic shock absorber is then developed. The model is suitable for vehicle simulations and has seven parameters which can be determined by simple dynamic measurements on a test damper. The shock absorber model is validated under realistic operating conditions using the test rig, and the relative importance of various features of the model on the accuracy of vehicle simulations is investigated. 相似文献