全文获取类型
收费全文 | 536篇 |
免费 | 25篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 8篇 |
大气科学 | 53篇 |
地球物理 | 110篇 |
地质学 | 204篇 |
海洋学 | 60篇 |
天文学 | 60篇 |
综合类 | 1篇 |
自然地理 | 66篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 13篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 19篇 |
2014年 | 30篇 |
2013年 | 43篇 |
2012年 | 31篇 |
2011年 | 33篇 |
2010年 | 38篇 |
2009年 | 22篇 |
2008年 | 31篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 27篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有562条查询结果,搜索用时 0 毫秒
561.
Dissolution of jarosite [KFe3(SO4)2(OH)6] at pH 2 and 8: Insights from batch experiments and computational modelling 总被引:1,自引:0,他引:1
Adrian M.L. Smith Karen A. Hudson-Edwards William E. Dubbin 《Geochimica et cosmochimica acta》2006,70(3):608-621
Jarosite [KFe3(SO4)2(OH)6] is a mineral that is common in acidic, sulphate-rich environments, such as acid sulphate soils derived from pyrite-bearing sediments, weathering zones of sulphide ore deposits and acid mine or acid rock drainage (ARD/AMD) sites. The structure of jarosite is based on linear tetrahedral-octahedral-tetrahedral (T-O-T) sheets, made up from slightly distorted FeO6 octahedra and SO4 tetrahedra. Batch dissolution experiments carried out on synthetic jarosite at pH 2, to mimic environments affected by ARD/AMD, and at pH 8, to simulate ARD/AMD environments recently remediated with slaked lime (Ca(OH)2), suggest first order dissolution kinetics. Both dissolution reactions are incongruent, as revealed by non-ideal dissolution of the parent solids and, in the case of the pH 8 dissolution, because a secondary goethite precipitate forms on the surface of the dissolving jarosite grains. The pH 2 dissolution yields only aqueous K, Fe, and SO4. Aqueous, residual solid, and computational modelling of the jarosite structure and surfaces using the GULP and MARVIN codes, respectively, show for the first time that there is selective dissolution of the A- and T-sites, which contain K and SO4, respectively, relative to Fe, which is located deep within the T-O-T jarosite structure. These results have implications for the chemistry of ARD/AMD waters, and for understanding reaction pathways of ARD/AMD mineral dissolution. 相似文献
562.
Karen Stamatelopoulou-Seymour Don Francis John Ludden 《Contributions to Mineralogy and Petrology》1983,84(1):6-14
A sequence of ultramafic rocks in the Lac Guyer Archean greenstone belt exhibit brecciated flow tops, pillow structures, and spinifex textures testifying to their volcanic origin. Massive, spinifex-textured and differentiated flows in the sequence have the chemical characteristics of peridotitic komatiite, with MgO ranging from 19–25 wt.%. Associated pillowed flows have compositions that straddle the conventional boundary between komatiite and komatiitic basalt with MgO contents ranging from 16 to 19 wt.% MgO and are best termed pyroxenitic komatiites. Unlike other komatiitic occurrences, the peridotitic and pyroxenitic komatiites at Lac Guyer constitute a continuous chemical spectrum with no evidence of population minimum near 18 wt.% MgO. The contrasting behaviour of highly compatible elements, such as Ni and Cr, versus incompatible elements, such as Zr, indicate that this compositional spectrum was produced by a variation in the extent of partial melting (10–40%) of a garnet lherzolite source in the Archean mantle. The pyroxenitic komatiites represent liquids produced during lower (10–20%) degrees of melting during which garnet remained in the mantle residue. However, a change in slope in the distribution of Zr vs. Y between the pyroxenitic and the peridotitic komatiites indicates that garnet was completely consumed at the more extensive degrees of melting which produced the peridotitic komatiites. The Lac Guyer volcanic rocks display a population minimum at 15 wt.% MgO separating komatiitic magmas whose compositions are controlled by partial melting from basalts whose composition is controlled by crystal fractionation. The population minimum near 18 wt.% MgO which is taken as the boundary between komatiite and komatiitic basalt may have a similar origin. 相似文献