全文获取类型
收费全文 | 122篇 |
免费 | 6篇 |
专业分类
公路运输 | 18篇 |
综合类 | 57篇 |
水路运输 | 30篇 |
铁路运输 | 6篇 |
综合运输 | 17篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 11篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2001年 | 2篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有128条查询结果,搜索用时 0 毫秒
41.
42.
We explore the complexity issue relevant to a logistics service process characterized by unpredictable service stages and service sequences in the context of chemical tankers’ call in the Port of Houston. The operational dimensions of uncertainty and conflict surrounding process complexity are examined through a mixed-methods approach using both qualitative and quantitative data collected from the Port of Houston. We propose a taxonomy to classify several uncertainty and conflict factors emerged from our qualitative analysis, including structural conflict, structural uncertainty, infrastructural conflict, and infrastructural uncertainty. The case study findings are validated and triangulated by a quantitative analysis which quantifies the time and cost impacts of unproductive chemical tanker movement on port-call service performance. We contribute to the complexity theory by introducing four dimensions of process complexity to the stream of process-oriented logistics service research. These four complexity dimensions can be used by managers to untangle their process complexity. Our pseudo-service-stage based mapping technique will also be valuable for managers to visualize their service processes with unpredictable service sequences. Finally, we call for future research on synchronization across operational processes between service stages. 相似文献
43.
44.
45.
46.
47.
讨论在搜索雷达分扇区录取目标点迹的前提下,完成目标航迹建立的问题。通过延迟半个扇区处理的方法,有效避免了目标因跨扇区飞行所产生的航迹重新建立问题。在航迹处理过程中,将航迹分类处理,有效地解决了航路交叉问题,同时又利于计算机程序的实现。 相似文献
48.
提出了层次网格化的一体化站点布局方法,建立了基于风险、安全状况和工作量等3个指标的综合评判体系和评判模型。以长江海事局管辖长江干线内河水域116个一体化站点为对象,运用该方法对站点进行了3个层次的等级划分。 相似文献
49.
����������������н�ͨϵͳ���������������о� 总被引:18,自引:0,他引:18
首先综述了当今关于小世界网络、无标度网络以及复杂加权网络的最新研究成果,并从城市交通系统的角度出发,指出了综合利用复杂网络理论、动态系统理论、现代控制理论及交通科学和工程等多学科的理论与方法,在探索城市交通网络的时空复杂性及其演化机理,揭示交通流的演化过程,缓解和预防交通拥堵,指导交通实践等方面,都具有重大的科学理论意义与实际应用价值,是值得深入研究与探讨的大问题。并进一步指出了一些今后关于城市交通网络复杂性问题的研究主题。 相似文献
50.
Objective To detect the change of brain activity under different depth of anesthesia (DOA) noninvasively. A,fethods The Lempel-Ziv complexity C(n) was used to analyze EEG and its four components (delta, theta, alpha, beta), which was recorded from SD rats under different DOA. The relationship between C(n) and DOA was studied. Results The C(n) of EEG will decrease while the depth of anesthesia increasing and vice versa. It can be used to detect the change of DOA sensitively. Compared with power spectrum, the change of C(n) is opposite to that of power spectrum. Only the C (n) of delta rhythm has obvious variations induced by the change of DOA, and the variations of delta is as similar as the EEG's. Conclusion The study shows that the desynchronized EEG is replaced by the synchronized EEG when rat goes into anesthesia state from awake, that is just the reason why complexity and power spectrum appear corresponding changes under different DOA. C(n) of delta rhythm dynamic change leads to the change of EEG, and the delta rhythm is the dominant rhythm during anesthesia for rats. 相似文献