全文获取类型
收费全文 | 3549篇 |
免费 | 559篇 |
国内免费 | 831篇 |
专业分类
测绘学 | 180篇 |
大气科学 | 333篇 |
地球物理 | 797篇 |
地质学 | 2265篇 |
海洋学 | 396篇 |
天文学 | 229篇 |
综合类 | 182篇 |
自然地理 | 557篇 |
出版年
2024年 | 18篇 |
2023年 | 55篇 |
2022年 | 107篇 |
2021年 | 146篇 |
2020年 | 154篇 |
2019年 | 165篇 |
2018年 | 120篇 |
2017年 | 122篇 |
2016年 | 153篇 |
2015年 | 158篇 |
2014年 | 192篇 |
2013年 | 265篇 |
2012年 | 173篇 |
2011年 | 185篇 |
2010年 | 152篇 |
2009年 | 238篇 |
2008年 | 221篇 |
2007年 | 224篇 |
2006年 | 229篇 |
2005年 | 226篇 |
2004年 | 183篇 |
2003年 | 145篇 |
2002年 | 171篇 |
2001年 | 133篇 |
2000年 | 154篇 |
1999年 | 119篇 |
1998年 | 118篇 |
1997年 | 88篇 |
1996年 | 91篇 |
1995年 | 68篇 |
1994年 | 67篇 |
1993年 | 49篇 |
1992年 | 49篇 |
1991年 | 47篇 |
1990年 | 35篇 |
1989年 | 37篇 |
1988年 | 22篇 |
1987年 | 11篇 |
1986年 | 14篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1978年 | 2篇 |
1973年 | 1篇 |
1963年 | 2篇 |
排序方式: 共有4939条查询结果,搜索用时 31 毫秒
111.
Paul Claval 《GeoJournal》2004,60(4):321-328
The way that space is thought of is at the heart of the cultural approach in geography. The passing down of all the components
of a culture depends upon the way data is aquired and processed, the results memorized or broadcast. Communication shapes
the experience and the knowledge of space and time. It gives to everyone the idea that the real world is doubled by a beyond
which plays a central role in social life, since it is upon such a beyond that normative thinking relies and that a significance
is given to individual and social life. The spheres of lived-in and known space and time, as well as that of the beyond, vary
according to available technologies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
112.
Deformation History of the Kunavaram Complex, Eastern Ghats Belt, India: Implications for Alkaline Magmatism Along the Indo-Antarctica Suture 总被引:1,自引:0,他引:1
The Kunavaram alkaline complex is a NE-SW trending elongate body located along a major lineament, the Sileru Shear Zone (SSZ) that is regarded as a Proterozoic suture related to Indo-Antarctica collision. The complex is hosted within migmatitic quartzofeldspathic gneisses, mafic granulites retrogressed to amphibolites, and quartzites. The structural evolution of the country rocks and the alkaline complex are similar. The first phase of deformation, D1, produces a pervasive segregation banding (S1) in all rock units within and outside the complex. A second deformation phase D2 isoclinally folded S1 along subvertical axial planes with shallow plunging axes. F2 isoclinal folds are ubiquitous in the country rocks and the eastern extremity of the complex. In the interior of the alkaline body, D2 strain decreases and S1 is commonly subhorizontal. While amphibolite to granulite facies conditions prevailed during deformation, post-D2 annealing textures testify to persisting high grade conditions. In the west, a NNE-SSW trending dextral shear zone with strike-slip sense (D3) truncates the complex. Within this shear zone, quartzofeldspathic country rocks are plastically deformed, while hornblende-K-feldspar assemblages of the complex are retrogressed to biotite and plagioclase. Warping related to D3 shears also resulted in fold interference patterns on the subhorizontal S1 foliation in low D2 strain domains. Based on its steep dip, north-easterly trend, and non-coaxial nature with dextral strike-slip sense, the D3 shear zone can be correlated with the SSZ. Since this shear zone, i.e., the SSZ, is not associated with primary igneous fabrics and resulted in solid state deformation of the complex, it cannot be considered as a conduit for alkaline magmatism, but is probably responsible for the post-tectonic disposition of the pluton. 相似文献
113.
114.
115.
116.
WILLIAM A. KOELSCH 《Geographical review》2004,94(4):502-518
ABSTRACT. Strabo of Amasia (ca. 64 B.c.‐ca. A.D. 23) wrote the first comprehensive geography of the world known to the Greeks and Romans. Interest in Strabo and his Geography, which survives nearly intact in seventeen books, has fluctuated over the centuries among both classicists and historians of geography. After some historical background on Strabo and his reception, this essay considers the contribution of two significant recent English‐language treatments, as well as Strabo's Geography itself, and suggests ways in which the Strabonic model may have renewed relevance to the geographer's task of interpreting the oikoumene in the contemporary world. 相似文献
117.
118.
119.
Heavy metal concentrations were investigated in overbank sediments of the Mala Panew River, southern Poland. Samples were collected from seven vertical profiles located within channel infills of a 20th century floodplain at three sites, each up to 50 m wide. In each profile, 15–24 samples were collected and analysed for Ba, Cd, Cu, Pb, and Zn. Sequential extraction of these elements was carried out in the 0.063-mm fraction of selected samples. Additionally, the age of the oldest trees growing close to the profiles has been used to estimate the initiation of sediment accumulation there. Ba, Cu, and Pb, which occur mostly in less mobile, moderately reducible, and residual fractions, were used for sediment dating. Zn and Cd, which in 50–75% occur in the mobile exchangeable fraction, were not suitable for dating. Correlation of Ba, Cu, and Pb concentrations in vertical profiles with changes in the load of effluents discharged to the river showed abrupt changes in the thickness of the strongly polluted sediments across the floodplains. A comparison of the relative changes between heavy metal peaks in sediments of similar age in the different profiles suggests a variable rate of downward metal migration. In general, none of the heavy metals investigated seems to have been mobilised within the stratigraphic layers above the water table. In layers located at stratigraphically lower levels, the Zn and Cd peaks seem to migrate several centimetres to several decimetres down in the profile. In profiles inundated for several weeks every year, Zn and Cd, as well as the relatively less mobile Ba, Cu, and Pb, have migrated downward by several decimetres. The investigation shows that frequent fluctuations of the water table have blurred the original depositional metal patterns of metal concentrations within a period of less than 40 years. 相似文献
120.
Introduction The velocity field of surface plate motion can be split into a poloidal and a toroidal parts.At the Earth′s surface,the toroidal component is manifested by the existence of transform faults,and the poloidal component by the presence of convergence and divergence,i.e.spreading and subduc-tion zones.They have coupled each other and completely depicted the characteristics of plate tec-tonic motions.The mechanism of poloidal field has been studied fairly clearly which is related to … 相似文献