全文获取类型
收费全文 | 1240篇 |
免费 | 8篇 |
专业分类
公路运输 | 231篇 |
综合类 | 379篇 |
水路运输 | 92篇 |
铁路运输 | 98篇 |
综合运输 | 448篇 |
出版年
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 58篇 |
2017年 | 43篇 |
2016年 | 58篇 |
2015年 | 69篇 |
2014年 | 90篇 |
2013年 | 92篇 |
2012年 | 67篇 |
2011年 | 114篇 |
2010年 | 53篇 |
2009年 | 64篇 |
2008年 | 74篇 |
2007年 | 128篇 |
2006年 | 111篇 |
2005年 | 80篇 |
2004年 | 43篇 |
2003年 | 19篇 |
2002年 | 10篇 |
2001年 | 21篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 4篇 |
1991年 | 1篇 |
排序方式: 共有1248条查询结果,搜索用时 156 毫秒
221.
222.
223.
224.
225.
Traffic conflict under congested conditions is one of the main safety issues of motorcycle traffic in developing countries. Unlike cars, motorcycles often display non-lane-based movements such as swerving or oblique following of a lead vehicle when traffic becomes congested. Very few studies have quantitatively evaluated the effects of such non-lane-based movements on traffic conflict. Therefore, in this study we aim to develop an integrated model to assess the traffic conflict of motorcycles under congested conditions. The proposed model includes a concept of safety space to describe the non-lane-based movements unique to motorcycles, new features developed for traffic conflict assessment such as parameters of acceleration and deceleration, and the conditions for choosing a lead vehicle. Calibration data were extracted from video clips taken at two road segments in Ho Chi Minh City. A simulation based on the model was developed to verify the dynamic non-lane-based movements of motorcycles. Subsequently, the assessment of traffic conflict was validated by calculating the probability of sudden braking at each time interval according to the change in the density of motorcycle flow. Our findings underscore the fact that higher flow density may lead to conflicts associated with a greater probability of sudden breaking. Three types of motorcycle traffic conflicts were confirmed, and the proportions of each type were calculated and discussed. 相似文献
226.
Within the simulation-based dynamic traffic assignment (SBDTA) model, the time-dependent shortest path (TDSP) algorithm plays a crucial role in the path-set update procedure by solving for the current optimal auxiliary solution (shortest path). Common types of TDSP algorithms require temporal discretization of link/node time/cost data, and the discretization could affect the solution quality of TDSP and of the overall SBDTA as well. This article introduces two variable time-discretization strategies applicable to TDSP algorithms. The strategies are aimed at determining the optimal time discretization for time-dependent links/nodes travel time data. The first proposed strategy produces a specific discretization interval for each link. The second proposed strategy generates time-varying intervals for the same link over the analysis period. The proposed strategies are implemented in a link-based time-dependent A* algorithm in a SBDTA model DynusT and tested with two numerical experiments on two traffic networks. The results show that the proposed discretization methods achieve the research goal—to flexibly and scalably balance the memory usage and run time for SBDTA without degrading the convergence. This property is rather important when dealing with a large real-world network with a long analysis period. 相似文献
227.
Traditionally, traffic monitoring requires data from traffic cameras, loop detectors, or probe vehicles that are usually operated by dedicated employees. In efforts to reduce the capital and operational costs associated with traffic monitoring, departments of transportation have explored the feasibility of using global positioning system (GPS) data loggers on their probe vehicles that are postprocessed for analyzing the traffic patterns on desired routes. Furthermore, most cell phones are equipped with embedded assisted-GPS (AGPS) chips, and if the mode of transportation the phone is in can be anonymously identified, the phones can be treated as if they are probe vehicles that are voluntarily hovering throughout the city, at minimal additional costs. Emerging cell phones known as “smartphones” are equipped with additional sensors including an accelerometer and magnetometer. The accelerometer can directly measure the acceleration values, as opposed to having acceleration values derived from speed values in conventional GPS sensors. The magnetometer can measure mode-specific electromagnetic levels. Smartphones are subscribed with roadside Internet data plans that can provide an essential platform for real-time traffic monitoring. In this article, neural network-based artificial intelligence is used to identify the mode of transportation by detecting the patterns of distinct physical profile of each mode that consists of speed, acceleration, number of satellites in view, and electromagnetic levels. Results show that newly available values in smartphones improve the mode detection rates when compared with using conventional GPS data loggers. When smartphones are in known orientations, they can provide three-dimensional (3-D) acceleration values that can further improve mode detection accuracies. 相似文献
228.
文章结合行业发展实际,分析了当前交通试验检测机构普遍存在的问题,并从提升试验检测机构检测能力、提高服务水平和从业能力角度提出了相应的解决措施。 相似文献
229.
在城市交通出行环境日益严峻的背景下,公共交通已成为城市发展的关键要素之一,如何提高公共交通的管理质量与效能受到越来越多关注。为解决城市公共交通客流时间不均衡、高峰过度拥挤的问题,提出了时间差别定价的概念。梳理了国内外相关研究进展,从乘客出行时间、边际成本和各方利益三方面分析了时间差别定价在我国的可行性,最后研究了推动时间差别定价实施的策略建议。 相似文献
230.
成传雄 《武汉船舶职业技术学院学报》2014,(5):124-126
语境是系统功能语言学里面的一个重要概念,语境论下语言的意思表示有言内之意与言外之意两种。语境论的核心是探索有效理解原语作者真实意思的途径并为翻译服务。按照系统功能语言学对语境的分类,分别从语言的上下文语境、情景语境和文化语境等三个方面介绍了语境论之于翻译的作用,并试图寻找有效的翻译策略。 相似文献