全文获取类型
收费全文 | 288篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 14篇 |
地球物理 | 81篇 |
地质学 | 110篇 |
海洋学 | 29篇 |
天文学 | 29篇 |
综合类 | 2篇 |
自然地理 | 31篇 |
出版年
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 18篇 |
2009年 | 15篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 14篇 |
2005年 | 9篇 |
2004年 | 15篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有298条查询结果,搜索用时 15 毫秒
291.
Eiji Ohtani Naohisa Hirao Tadashi Kondo Masayoshi Ito Takumi Kikegawa 《Physics and Chemistry of Minerals》2005,32(1):77-82
We observed a direct reaction of metallic iron with water to form iron hydride and iron oxide, 3Fe + H2O–>2FeHx + FeO, at pressures from 6 GPa to 84 GPa and temperatures above 1,000 K in diamond anvil cell (DAC). Iron hydride is dhcpFeHx or -FeHx, and iron oxide has the rhombohedral or B1 structure at pressures at least up to 37 GPa. The formation of an assembly composed of dhcpFeHx and FeO with the B8 structure was observed at 84 GPa. In primordial Earth, water formed by dehydration of the low temperature primitive materials reacts with metallic iron in the high temperature component to form iron hydride FeHx and iron oxide FeO. The former would be incorporated in the iron forming the core. Thus hydrogen could be an important element of the Earths core. This reaction would be essential for transport of hydrogen into the core in the accretion stage of the Earth. 相似文献
292.
293.
The intensity ratios of Niii, Oiii, Oiv, and Ov lines observed by the HCO experiment on Skylab are compared with the results of recent multilevel calculations. It is found that solar transition-region spectra require Lyman continuum absorption. The equivalent optical thickness of the absorbers causing the weakening is found to be 1.6–1.7 for a quiet area, 1.4–1.9 for a coronal hole, and 2.4–2.5 for active regions. These values are consistent with previous estimates from different methods. 相似文献
294.
295.
296.
Tomohiro?OhuchiEmail author Xinglin?Lei Yuji?Higo Yoshinori?Tange Takeshi?Sakai Kiyoshi?Fujino 《Contributions to Mineralogy and Petrology》2018,173(10):88
The role of aqueous fluid in fracturing in subducting slabs was investigated through a series of deformation experiments on dunite that was undersaturated (i.e., fluid-free) or saturated with water (i.e., aqueous-fluid bearing) at pressures of 1.0–1.8 GPa and temperatures of 670–1250 K, corresponding to the conditions of the shallower regions of the double seismic zone in slabs. In situ X-ray diffraction, radiography, and acoustic emissions (AEs) monitoring demonstrated that semi-brittle flow associated with AEs was dominant and the creep/failure strength of dunite was insensitive to the dissolved water content in olivine. In contrast, aqueous fluid drastically decreased the creep/failure strength of dunite (up to ~?1 GPa of weakening) over a wide range of temperatures in the semi-brittle regime. Weakening of the dunite by the aqueous fluid resulted in the reduction of the number of AE events (i.e., suppression of microcracking) and shortening of time to failure. The AE hypocenters were located at the margin of the deforming sample while the interior of the faulted sample was aseismic (i.e., aseismic semi-brittle flow) under water-saturated conditions. A faulting (slip rate of ~?10?3 to 10?4 s?1) associated with a large drop of stress (Δσ?~?0.5 to 1 GPa) and/or pressure (ΔP?~?0.5 GPa) was dominant in fluid-free dunite, while a slow faulting (slip rate?<?8?×?10?5 s?1) without any stress/pressure drop was common in water-saturated dunite. Aseismic semi-brittle flow may mimic silent ductile flow under water-saturated conditions in subducting slabs. 相似文献
297.
298.
A numerical study which takes into account wave dispersion effects has been carried out in the Indian Ocean to reproduce the initial stage of wave propagation of the tsunami event that occurred on December 26, 2004. Three different numerical models have been used: the nonlinear shallow water (nondispersive), the nonlinear Boussinesq, and the full Navier-Stokes aided by the volume of fluid method to track the free surface. Numerical model results are compared against each other. General features of the wave propagation agreed very well in all numerical studies. However some important differences are observed in the wave patterns, i.e., the development in time of the wave front is shown to be strongly connected to the dispersion effects. Discussions and conclusions are made about the spatial and temporal distribution of the free surface reaffirming that the dispersion mechanism is important for tsunami hazard mitigation. 相似文献