全文获取类型
收费全文 | 564篇 |
免费 | 120篇 |
国内免费 | 120篇 |
专业分类
测绘学 | 45篇 |
大气科学 | 104篇 |
地球物理 | 199篇 |
地质学 | 227篇 |
海洋学 | 74篇 |
天文学 | 5篇 |
综合类 | 65篇 |
自然地理 | 85篇 |
出版年
2024年 | 9篇 |
2023年 | 21篇 |
2022年 | 30篇 |
2021年 | 63篇 |
2020年 | 47篇 |
2019年 | 30篇 |
2018年 | 67篇 |
2017年 | 61篇 |
2016年 | 55篇 |
2015年 | 42篇 |
2014年 | 46篇 |
2013年 | 40篇 |
2012年 | 40篇 |
2011年 | 52篇 |
2010年 | 22篇 |
2009年 | 43篇 |
2008年 | 21篇 |
2007年 | 27篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 7篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 5篇 |
1990年 | 4篇 |
1983年 | 2篇 |
排序方式: 共有804条查询结果,搜索用时 250 毫秒
791.
A key solution to urban and global sustainability is effective planning of sustainable urban development, for which geo-techniques especially cellular automata (CA) models can be very informative. However, existing CA models for simulating sustainable urban development, though increasingly refined in modeling urban growth, capture mostly the environmental aspect of sustainability. In this study, an adaptable risk-constrained CA model was developed by incorporating the social-ecological risks of urban development. A three-dimensional risk assessment framework was proposed that explicitly considers the environmental constraints on, system resilience to, and potential impacts of urban development. The risk-constrained model was then applied to a case study of Sheyang County, Jiangsu Province in the eastern China. Comparative simulations of urban development in four contrasting scenarios were conducted, namely, the environmental suitability constrained scenario, the ecological risk constrained scenario, the social risk constrained scenario, and the integrated social-ecological risk constrained scenario. The simulations suggested that considering only environmental suitability in the CA simulation of urban development overestimated the potential of sustainable urban growth, and that the urbanization mode changed from city expansion that was more constrained by social risks to town growth that was more constrained by ecological risks. Our risk-constrained CA model can better simulate sustainable urban development; additionally, we provide suggestions on the sustainable urban development in Sheyang and on future model development. 相似文献
792.
793.
794.
795.
796.
797.
798.
799.
800.
河北省地磁场变化规律研究 总被引:3,自引:3,他引:0
利用河北省地磁台1986~2005年的地磁观测资料,对该地区地磁场长期变化规律进行总结分析.这进一步认识了河北省地磁场变化规律及其特征,为地震预报提供有实用价值的第一手资料十分有意义. 相似文献