全文获取类型
收费全文 | 5324篇 |
免费 | 863篇 |
国内免费 | 1423篇 |
专业分类
测绘学 | 997篇 |
大气科学 | 23篇 |
地球物理 | 1625篇 |
地质学 | 3640篇 |
海洋学 | 161篇 |
天文学 | 17篇 |
综合类 | 796篇 |
自然地理 | 351篇 |
出版年
2024年 | 9篇 |
2023年 | 64篇 |
2022年 | 149篇 |
2021年 | 178篇 |
2020年 | 213篇 |
2019年 | 235篇 |
2018年 | 215篇 |
2017年 | 258篇 |
2016年 | 273篇 |
2015年 | 298篇 |
2014年 | 331篇 |
2013年 | 313篇 |
2012年 | 335篇 |
2011年 | 381篇 |
2010年 | 280篇 |
2009年 | 392篇 |
2008年 | 351篇 |
2007年 | 360篇 |
2006年 | 348篇 |
2005年 | 285篇 |
2004年 | 311篇 |
2003年 | 286篇 |
2002年 | 232篇 |
2001年 | 185篇 |
2000年 | 179篇 |
1999年 | 165篇 |
1998年 | 142篇 |
1997年 | 151篇 |
1996年 | 136篇 |
1995年 | 111篇 |
1994年 | 102篇 |
1993年 | 89篇 |
1992年 | 72篇 |
1991年 | 42篇 |
1990年 | 38篇 |
1989年 | 27篇 |
1988年 | 26篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1979年 | 3篇 |
1975年 | 1篇 |
1954年 | 3篇 |
排序方式: 共有7610条查询结果,搜索用时 15 毫秒
91.
92.
93.
本文以中国西部大地形变监测与地震预测实践为基础, 简要总结回顾了利用大地形变进行强震预测研究的工作思路、方法和一些进展; 进而结合2001年昆仑山口西8.1级、 2008年四川汶川8.0级特大地震前区域地壳运动变形背景和已有的研究结果, 分析和探讨了基于大地形变监测、 并考虑地震构造的差异性来进一步提高大震预测的有效性... 相似文献
94.
Recognition of natural deformation during the excavation of ancient remains and tombs is important for tracing or enriching historic and prehistoric deformation records. Recently, the earthquake agencies,in cooperation with the cultural relics and archaeological institutions, conducted a special excavation investigation to the Gaixia remains archaeological scene in Guzhen,Anhui Province. Faults and fissures were discovered there, which,as demonstrated by the preliminary study,are the traces of two stratum d... 相似文献
95.
96.
Based on detailed field investigations,this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west,short parts of which strike near east to west,dipping north,and extends over a length of 70km. It is a major geological and geomorphological margin,controlling the neotectonic movement in this region. On the south side of the Zhangjiakou fault are the Late Quaternary unconsolidated deposits,forming basins; while on the other side are Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks, forming lower mountains and hills. The Zhangjiakou fault consists mainly of high-angle inverse strike-slip fault and partially of normal strike-slip fault. Among these,the north-dipping NW-NWW-trending secondary faults,constituting the main fracture of the fault,have inverse characteristics; those near the EW-trending secondary faults are links of the former faults,with a smaller length and normal faulting characteristics. Thus,the Zhangjiakou fault is a north-dipping inverse and partially south-dipping normal strike-slip fault. The Zhangjiakou fault has been continuously active since the Quaternary. With the exception of the western end extension,which has been active since the late Pleistocene, the main part of the fault has been active since the Holocene. The central main segment of the Zhangjiakou fault is more active. Since the mid-late period of the late Pleistocene,the average vertical slip rate of a single fault has been over 0. 07mm /a ~ 0. 30mm /a. The Zhangjiakou fault has multi-slip surfaces,and the total vertical slip rate reaches 1. 33mm /a,estimated from the Qingshuihe river terraces and the relevant drilling data. 相似文献
97.
98.
99.
100.