全文获取类型
收费全文 | 200篇 |
免费 | 10篇 |
国内免费 | 17篇 |
专业分类
测绘学 | 16篇 |
大气科学 | 5篇 |
地球物理 | 14篇 |
地质学 | 133篇 |
综合类 | 7篇 |
自然地理 | 52篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 14篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 18篇 |
2006年 | 16篇 |
2005年 | 22篇 |
2004年 | 12篇 |
2003年 | 17篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有227条查询结果,搜索用时 296 毫秒
111.
112.
113.
基于遥感技术的都汶公路地震次生山地灾害分布规律分析 总被引:3,自引:0,他引:3
选择汶川县境内的都汶公路(漩口-汶川路段)作为调查研究对象,利用遥感技术提取公路沿线的各类地震次生山地灾害的分布信息,将灾害点分布与海拔高度、坡度和坡向等要素进行叠加分析,获得了次生山地灾害的分布规律,其特点为:①地震次生山地灾害集中分布在映秀-北川断裂与汶川-茂汶断裂之间;②次生山地灾害主要发生在海拔高度1 000~2 000 m的地带;③次生山地灾害主要分布在30~60°的边坡;④地震及余震期间以崩塌、滑坡、滚石为主,后期以泥石流、滑坡为主;⑤次生山地灾害具有沿岷江河谷发育且在河流左右两岸呈不对称分布等特点. 相似文献
114.
115.
116.
Land use and landscape pattern change: a linkage to the construction of the Qinghai-Xizang Highway 总被引:1,自引:0,他引:1
Based on digital land use data from 1995 to 2000 and road data, the land use and landscape changes of Golmud, Qumaleb and Zhidoi are studied on a macro-scale. Land use and landscape changes in highway buffer zones and city expansion are special subjects. A new formula is used to define the exact degree of dynamic land use. To adequately define land use and landscape pattern changes, the buffer zones, illustrating the changes at different distances from the road, are recognized with ArcGIS 8.1 software. Prominent changes took place in land use and landscape patterns from 1995 to 2000, and the area of built-up land increased by 323.8%. The comprehensive degree of dynamic land use is 2.25, and the degree of dynamic land use of built-up land is the highest, followed by cultivated land. Woodland has the lowest value. The used degree index of land resources declined by 38.8 from 1995 to 2000. Landscape changed dramatically which influenced ecological processes immensely. Different from the corridor effect of other traffic routes, the corridor effect of this section of road is not obvious and its "point" radiation effect can be easily seen. The expanding range of Golmud City is confined to a 3 km buffer, while for Wudaoliang, it is 1 km. No land use change happened in the Nanshankou buffer. 相似文献
117.
118.
119.
120.
With lots of indoor and outdoor experiments, several key technical issues in construc-tion of the Desert Highway have been solved satisfactorily, on the basis of great achievements ofthe studies in respects of dry compaction on sand base, design parameters, structure combinationof subgrade and pavement, stabilization analysis of sand base strengthened with geotextile and acomplete set of construction techniques. It is the first time the achievements of the study weresuccessfully applied in the Taklimakan Desert where the natural condition is extremely harsh. Ithas been proved that it is economic and reasonable with reliable techniques and simple construc-tion methods. The Desert Highway constructed with the achievements is the first-grade highwayrunning through huge migratory desert for long distance in the world. 相似文献