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981.
982.
对某大型内河沉管隧道基础灌砂足尺模型试验进行详细阐述,应用冲击映像法、全波场无损检测法相结合的方式对试验模型中不同工况下灌砂前、灌砂过程中以及灌砂后的效果进行测试,对模型试验中不同工况下各项测试数据及结果进行系统分析,对沉管隧道基础灌砂工艺与灌砂效果进行评价。此外,介绍该大型内河沉管隧道基础灌砂效果现场监测内容及具体实施方法,基于先期施工各管段基础灌砂现场监测、潜水探摸及管段后续沉降监测结果,对大型内河沉管隧道基础灌砂效果现场检测及处理技术进行系统的研究。主要研究结论如下: 1)冲击映像法可以监测砂积盘的生成及发展过程,可以较准确地判断灌砂填充状况和快速检测混凝土底板下部灌砂填充状态,是沉管隧道基础灌砂效果评价的有力手段,是动态把握灌砂过程、实时追踪施工过程的砂液变化的有力手段。2)已施工管段现场沉降量观测结果显示,沉管隧道E1-E6各管段已灌砂基础的承载力均满足设计要求,证明冲击映像法可以作为沉管隧道基础灌砂检测评定方法。 相似文献
983.
Increased speed variation on urban arterials is associated with reductions in both operational performance and safety. Traffic flow, mean speed, traffic control parameters and geometric design features are known to affect speed variation. An exploratory study of the relationships among these variables could provide a foundation for improving the operational and safety performance of urban arterials, however, such a study has been hampered by problems in measuring speeds. The measurement of speed has traditionally been accomplished using spot speed collection methods such as radar, laser and loop detectors. These methods can cover only limited locations, and consequently are not able to capture speed distributions along an entire network, or even throughout any single road segment. In Shanghai, it is possible to acquire the speed distribution of any roadway segment, over any period of interest, by capturing data from Shanghai’s 50,000+ taxis equipped with Global Positional Systems (GPS). These data, hereafter called Floating Car Data, were used to calculate mean speed and speed variation on 234 road segments from eight urban arterials in downtown Shanghai. Hierarchical models with random variables were developed to account for spatial correlations among segments within each arterial and heterogeneities among arterials. Considering that traffic demand changes throughout the day, AM peak, Noon off-peak, and PM peak hours were studied separately. Results showed that increases in number of lanes and number of access points, the presence of bus stops and increases in mean speed were all associated with increased speed variation, and that increases in traffic volume and traffic signal green times were associated with reduced speed variation. These findings can be used by engineers to minimize speed differences during the road network planning stage and continuing through the traffic management phase. 相似文献
984.
In this research, a Bayesian network (BN) approach is proposed to model the car use behavior of drivers by time of day and to analyze its relationship with driver and car characteristics. The proposed BN model can be categorized as a tree-augmented naive (TAN) Bayesian network. A latent class variable is included in this model to describe the unobserved heterogeneity of drivers. Both the structure and the parameters are learned from the dataset, which is extracted from GPS data collected in Toyota City, Japan. Based on inferences and evidence sensitivity analysis using the estimated TAN model, the effects of each single observed characteristic on car use measures are tested and found to be significant. The features of each category of the latent class are also analyzed. By testing the effect of each car use measure on every other measure, it is found that the correlations between car use measures are significant and should be considered in modeling car use behavior. 相似文献
985.
986.
给出广州本田雅阁轿车空调系统在车上的布置情况及控制电路图,具体介绍其电动机的检修、继电器的检测、功率晶体管与电子控制器的检修及空调系统的故障自诊断,并围绕这4部分内容分别展开探讨。 相似文献
987.
988.
989.
990.
以大型客车为研究对象,在长沙市的不同道路工况下进行了车载排放测试,借助道路测试得到的数据,利用BP神经网络,以逐秒的速度、加速度、比功率和油耗数据为输入,建立CO2、CO和NOx的排放预测模型,并用部分试验数据进行了验证.结果表明,CO2、CO和NOx预测结果的总体相关系数R为0.9167,线性高度相关,在整体误差水平... 相似文献