全文获取类型
| 收费全文 | 19053篇 |
| 免费 | 4432篇 |
| 国内免费 | 8020篇 |
专业分类
| 测绘学 | 580篇 |
| 大气科学 | 680篇 |
| 地球物理 | 2132篇 |
| 地质学 | 24166篇 |
| 海洋学 | 1373篇 |
| 天文学 | 127篇 |
| 综合类 | 1448篇 |
| 自然地理 | 999篇 |
出版年
| 2024年 | 214篇 |
| 2023年 | 880篇 |
| 2022年 | 846篇 |
| 2021年 | 958篇 |
| 2020年 | 838篇 |
| 2019年 | 1004篇 |
| 2018年 | 752篇 |
| 2017年 | 826篇 |
| 2016年 | 960篇 |
| 2015年 | 1081篇 |
| 2014年 | 1487篇 |
| 2013年 | 1181篇 |
| 2012年 | 1394篇 |
| 2011年 | 1511篇 |
| 2010年 | 1294篇 |
| 2009年 | 1131篇 |
| 2008年 | 1130篇 |
| 2007年 | 1196篇 |
| 2006年 | 1187篇 |
| 2005年 | 991篇 |
| 2004年 | 998篇 |
| 2003年 | 852篇 |
| 2002年 | 756篇 |
| 2001年 | 849篇 |
| 2000年 | 743篇 |
| 1999年 | 759篇 |
| 1998年 | 810篇 |
| 1997年 | 605篇 |
| 1996年 | 591篇 |
| 1995年 | 539篇 |
| 1994年 | 476篇 |
| 1993年 | 460篇 |
| 1992年 | 604篇 |
| 1991年 | 522篇 |
| 1990年 | 458篇 |
| 1989年 | 310篇 |
| 1988年 | 76篇 |
| 1987年 | 110篇 |
| 1986年 | 33篇 |
| 1985年 | 16篇 |
| 1984年 | 9篇 |
| 1983年 | 8篇 |
| 1982年 | 7篇 |
| 1981年 | 6篇 |
| 1980年 | 7篇 |
| 1979年 | 7篇 |
| 1976年 | 3篇 |
| 1973年 | 5篇 |
| 1948年 | 4篇 |
| 1941年 | 2篇 |
排序方式： 共有10000条查询结果，搜索用时 281 毫秒
41.
42.
43.
44.
GiovanniB.Piccardo 《《幕》》2003,26(3):193-199
Mantle peridotites were early exposed at the sea-floor of the Jurassic Tethys derived from the subcontinental mantle of the Europe-Adria system. During continental rifting and oceanic spreading, these lithospheric peri-dotites were percolated via diffuse reactive porous flowby melt fractions produced by near-fractional melting of the upwelling asthenosphere. Ascending melts inter-acted with the lower lithosphere, dissolving pyroxenes and precipitating olivine, and crystallized at shallower levels in the mantle column causing melt impregnation.Subsequent focused porous flow formed replacive dunitechannels, cutting the impregnated oeridotites, which were conduits for upward migration of MORB-type liq-uids. Melt migration produced depletionlrefertilization and significant heating of the percolatedlimpregnated mantle, i.e the thermochemical erosion of the litho-sphere. Impregnated and thermally modified lithos-pheric mantle was cooled by conductive heat loss dur-ing progressive lithosphere thinning and was intrudeaby MORB magmas, which formed Mg-rich and Fe-richgabbroic dykes and bodies. Alpine-Apennine ophiolitic peridotites record the deep-seated migration of melts which changed their compositions and dynamics during the rift evolution. The thermochemical erosion of the lithospheric mantle by the ascending asthenospheric melts, which induces significant compositional and rhe-ological changes in the lower lithosphere, is a major process in the evolution of the continent-ocean transi-tion towards a slow spreading oceanic system. 相似文献
45.
46.
遥感技术在构造地质研究及成矿预测中的应用杨武年，朱章森（成都理工学院）本文应用现代化遥感技术，根据遥感多波段图像信息量大、对地质构造形迹显示的宏观性、信息连续性以及对隐伏构造具“透视”作用的特点，并据遥感横张大节理和剪切节理与宏观褶皱及断裂具有成因联... 相似文献
47.
QinChengzhi ZhouChenghu PeiTao LiQuanlin 《中国地震研究》2004,18(2):178-187
The migration of strong earthquakes is an important research topic because the migration phenomena reflect partly the seismic mechanism and involve the prediction of tendency of seismic activity. Research on migration of strong earthquakes has mostly focused on finding the phenomena. Some attempts on getting regularity were comparatively subjective. This paper suggests that there should be indices of migration in earthquake dataset and the indexes should have statistical meaning if there is regularity in the migration of strong earthquakes. In this study, three derivative attributes of migration, i.e., migration orientation, migration distance and migration time interval, were statistically analyzed. Results in the North China region show that the migration of strong earthquakes has statistical meaning. There is a dominant migration orientation (W by S to E by N), a dominant distance ( ≤ 100kin and on the confines of 300 ～ 700km), and a dominant time interval ( ≤ la and on the confines of 3 - 4a). The results also show that the migration will differ slightly with different magnitude range or earthquake activity phase. 相似文献
48.
49.
50.