全文获取类型
收费全文 | 173篇 |
免费 | 8篇 |
专业分类
公路运输 | 11篇 |
综合类 | 5篇 |
水路运输 | 50篇 |
铁路运输 | 7篇 |
综合运输 | 108篇 |
出版年
2021年 | 2篇 |
2020年 | 3篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 33篇 |
2012年 | 3篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1972年 | 2篇 |
排序方式: 共有181条查询结果,搜索用时 15 毫秒
151.
It is well known from the literature that road lighting has significant safety benefits. The NZTA Economic Evaluation Manual (EEM) quotes a 35% reduction in crashes as the effect of upgrading or improving lighting where lighting is poor. 相似文献
152.
Allan William Young 《Coastal management》2013,41(5):527-535
AbstractMoving assets out of vulnerable areas, known as “retreat,” is a necessary but unpopular option when coastal hazards impact land. Most people prefer protection options. Governments and private land owners tend to adopt a “wait-and-see” approach for retreat. This may be because the time for retreat seems some way off, or because protection has not yet been ruled out, or to avoid unwelcome news. This policy void has allowed people to assume that government will offer to “buyout” property on generous terms after coastal hazards inevitably force the owner to relocate. The problem with that assumption is that (a) it is unaffordable as a solution for all at-risk properties and (b) it acts as an incentive to intensify development in locations vulnerable to coastal hazards. It is, in effect, a form of market distortion which promotes maladaptive behavior. We therefore need to retire that assumption by articulating a standard default arrangement for retreat. This essay suggests that government should establish a default position of renting land, rather than acquiring it, once assets are abandoned by private land owners. This provides sufficient leverage to protect the public interest and a level of financial assistance to the relocating land owner, while allowing markets to properly reflect risk and enabling coastal adaptation. 相似文献
153.
154.
车钩改进与互换的管理 总被引:1,自引:0,他引:1
在美国,车钩几乎是铁路装备中既要受美国联邦铁路管理委员会管理,又要受美国铁路协会监督的仅有部件,要求各制造商生产的车钩必须具有良好的互换性。这一要求适用于车钩的几乎每一单件,即钩舌、钩锁和钩体。机、货车的可靠连接完全取决于整个车钩的互换性。这一要求使得ABC 相似文献
155.
介绍了无间隙牵引杆和关节连接器在北美货车联运中的运用情况,比较分析了其与常规车钩缓冲装置运用上的互换性和可维修性,同时阐述了牵引杆的结构特点和性能特征。 相似文献
156.
157.
William C. Vantuono 《国外铁道车辆》2001,38(5):20-24
介绍了美国几家主要货车制造商开发的新型有盖漏斗车、双层棚车、大载重平车、铝合金煤炭漏斗车、双层汽车运输车、冷藏车和可交换车体货车等车型的主要特点和结构参数,其共同目标是延长车辆寿命、减轻车辆自重、提高有效运载能力. 相似文献
158.
THECHANGESOFBONEVOLUMEANDTURNOVERINPOSTMENOPAUSALWOMENWITHOSTEOPOROSIS:AREPORTOF293BONEBIOPSIESZhuJianmin;WilliamE.Huffer,Pat... 相似文献
159.
Abstract An essential aspect of economic analysis associated with planning efforts is identifying the composition of existing economic activity and understanding historical trends in economic change. The shift‐share model is a useful and inexpensive tool for this purpose. Shift‐share analysis evaluates changes in local economic activities relative to changes in a reference area (usually the state or nation). Economic change is separated into a reference area component, an industry mix component, and a local share component. These measure, respectively, the effect on the local economy due to changes in the reference area, factors specific to the local mix of industries, and the changing competitive position of the local area relative to the reference area. A shift‐share analysis of Florida's coastal counties reveals that all grew much faster over the 1965–1975 period than did the national economy. This rapid growth is primarily a result of a net shift of economic activity toward the study area relative to the nation. However, a few coastal counties did exhibit a mix of slow‐growing industries. Specific industry results for Florida counties at the eighty‐industry level reveal that many industries showed significant shifts toward Florida's coastal counties. The performance of individual industries in the coastal counties generally exceeded that of the same industries in noncoastal counties. 相似文献
160.