全文获取类型
收费全文 | 334篇 |
免费 | 17篇 |
专业分类
公路运输 | 48篇 |
综合类 | 58篇 |
水路运输 | 159篇 |
铁路运输 | 79篇 |
综合运输 | 7篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 17篇 |
2021年 | 23篇 |
2020年 | 22篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 24篇 |
2013年 | 19篇 |
2012年 | 26篇 |
2011年 | 25篇 |
2010年 | 17篇 |
2009年 | 15篇 |
2008年 | 17篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 15篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有351条查询结果,搜索用时 920 毫秒
151.
随着人们环保意识的增强,船舶压载水对海洋环境的污染越来越受到关注,国际海事组织(IMO)要求船舶在深海进行压载水更换。为了确保更换压载水时船舶的安全,设计船舶时必须对船舶压载舱压力损失进行计算。提供了一种计算船舶压载舱压力损失的方法,为船舶设计或选用更换压载水的压载泵提供参考。 相似文献
152.
Flying ballast is a significant safety concern for high-speed train operations on ballasted tracks. It is the phenomenon of a ballast particle displaced from the track, due to the aerodynamic force induced by a passing train traveling above a certain speed. Flying ballast can potentially damage tracks and rolling stock, thereby posing a risk to high-speed rail operations. This paper develops a Probabilistic Risk Analysis (PRA) model based on the information available from the field and the literature. The model enables a quantitative assessment of the probability of ballast particle displacement at a particular position on the track, as well as the probabilistic distribution of the total number of ballast particles that are expected to move. The model accounts for various risk factors, such as train speed, ballast gradation, and track position. The model application is illustrated using a ballasted track on the Yellow River Bridge on the Beijing-Shanghai high-speed rail line in China. The analysis finds that flying ballast probability increases when train speed increases, in particular, the problem of flying ballast becomes more pronounced when train speed exceeds 350 km per hour (217 miles per hour). Flying ballast probability might be reduced when the ballast profile is lower, given all else being equal. In addition, flying ballast probability is expected to be higher at the center of the track than in other positions. The proposed risk model can be further developed and ultimately be used to evaluate route-specific flying ballast risk, enabling the identification, assessment, and comparison of risk mitigation strategies in order to support emerging high-speed rail operations. 相似文献
153.
DANG Kun SUN Pei-ting XIAO Jing-kun SONG Yong-xin 《船舶与海洋工程学报》2006,5(4):58-61
In order to verify the effectiveness of electrolytic treatment on ships' ballast water, experiments are carried out by a pilot system in laboratory. The raw seawater and seawater with different concentrations of different algae are simulated as ships' ballast water. The algae in the raw seawater can be killed if it is treated by electrolysis with an initial residual chlorine concentration of 5 mg/L. If the seawater with one kind of algae (Nitzschia closterum, Dicrateria spp., or Pyramidomonnas sp.105cells/mL) is treated by electrolysis with an initial residual chlorine concentration of 5 mg/L the alga can be sterilized, If the seawater with one kind of algae (Dunaliella sp., Platymonas or Chlorella spp.) is directly treated by electrolyzing with an initial residual chlorine concentration of 4 mg/L, the instant mortality changes with the concentration of different algae. However, after 72 hours, in all treated samples, there are no live algal cells found. 相似文献
154.
155.
156.
概述了船舶压载监控系统的工作原理,详细分析了船舶压载监控系统的设计与应用,并对系统组成和功能进行了说明。该系统由上位计算机、下位机、触摸屏、远程I/O模块和通信以太网等组成。下位机采用可编程逻辑控制器(PLC),用于设备的开关控制、压力、流量、液位等过程量的监视和控制。上位机装有Wincc监控组态软件,可集中监控系统模拟量和开关量。 相似文献
157.
158.
159.
160.
考虑到目前国内外还没有经过广泛认可的、统一的针对PSPC涂层性能新标准的具体操作指南或指引,相关条款还存在争议,结合PSPC涂层新标准的具体内容和船企实践,对PSPC适用对象、涂层系统的要求、压载舱的涂装施工程序及检验等进行阐述,以期为船舶企业实施PSPC提供参考,为原油轮货油舱新标准COTPSPC的执行提供借鉴。 相似文献