全文获取类型
收费全文 | 72篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 5篇 |
地球物理 | 21篇 |
地质学 | 36篇 |
海洋学 | 4篇 |
天文学 | 2篇 |
综合类 | 1篇 |
自然地理 | 8篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 4篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1984年 | 1篇 |
排序方式: 共有80条查询结果,搜索用时 15 毫秒
1.
2.
Raman spectra of diopside were collected from atmospheric pressure to 71 GPa. The pressure dependences of 22 modes were determined.
Changes occurred in the spectra at three different pressures. First, at approximately 10 GPa, the two Raman modes at 356 and
875 cm−1 disappeared, while the mode at 324 cm−1 split into two modes, diverging at this pressure with significantly different pressure shifts; second, at approximately 15
GPa, a small (1 to 2 cm−1) drop in several of the frequencies was observed accompanied by changes in the pressure dependency of some of the modes;
and third, above 55 GPa, the modes characteristic of chains of tetrahedrally coordinated silicon disappeared, while those
for octahedrally coordinated silicon appeared. The first change at 10 GPa appears to be a C2/c to C2/c transition involving a change in the Ca coordination. The third change above 55 GPa appears to be a change in the silicon
coordination. At 15 GPa, it is suggested that a change in compressional mechanism takes place.
Received: 14 November 2000 / Accepted: 9 January 2002 相似文献
3.
Antonis Polatidis Anastasia Kiratzi Panagiotis Hatzidimitriou Basil Margaris 《Tectonophysics》2003,367(1-2):29-40
Qβ for shear-waves is determined for the inner part of the Hellenic arc, the back-arc area, as a function of frequency in the range 0.6–16 Hz. We used 314 digital records from 32 earthquakes with magnitudes (Mw) ranging from 3.9 to 5.1. Epicentral distances ranged from 65 to 515 km. The data were obtained in 1997 during a 6-month operation of a digital portable network in Greece. The Qβ estimates were made for five frequency bands centred at 0.8, 1.5, 3.0, 6.0 and 12.0 Hz and the Qβ values obtained were 47, 79, 143, 271 and 553, respectively. The results show that Qβ for S-waves increases with frequency taking the form Qβ=55f 0.91 (or Qβ−10.018f−0.91). The high attenuation and the strong frequency dependence found, which is close to the frequency dependence of coda Q for Greece, are characteristic of an area with high seismicity, rapid extension, and in agreement with other similar studies in Greece. 相似文献
4.
Nano-scale spatial confinement can alter chemistry at mineral–water interfaces. These nano-scale confinement effects can lead to anomalous fate and transport behavior of aqueous metal species. When a fluid resides in a nanoporous environments (pore size under 100 nm), the observed density, surface tension, and dielectric constant diverge from those measured in the bulk. To evaluate the impact of nano-scale confinement on the adsorption of copper (Cu2+), we performed batch adsorption studies using mesoporous silica. Mesoporous silica with the narrow distribution of pore diameters (SBA-15; 8, 6, and 4 nm pore diameters) was chosen since the silanol functional groups are typical to surface environments. Batch adsorption isotherms were fit with adsorption models (Langmuir, Freundlich, and Dubinin–Radushkevich) and adsorption kinetic data were fit to a pseudo-first-order reaction model. We found that with decreasing pore size, the maximum surface area-normalized uptake of Cu2+ increased. The pseudo-first-order kinetic model demonstrates that the adsorption is faster as the pore size decreases from 8 to 4 nm. We attribute these effects to the deviations in fundamental water properties as pore diameter decreases. In particular, these effects are most notable in SBA-15 with a 4-nm pore where the changes in water properties may be responsible for the enhanced Cu mobility, and therefore, faster Cu adsorption kinetics. 相似文献
5.
Komova Anastasia Melnikova Anna Namsaraev Zorigto Romanov Roman Strakhovenko Vera Ovdina Ekaterina Ermolaeva Nadezhda 《中国海洋湖沼学报》2018,36(6):1993-2001
The Baraba and Kulunda steppes are located in southwestern Siberia in an area with an arid continental climate. This paper presents results of the first study of the hypersaline Lake Krasnovishnevoye(Baraba steppe, TDS(total dissolved solids)=297 g/L, pH 7.88). The major chemical, mineralogical and biological features of the lake were studied and compared to those of Lake Malinovoe, a typical saline neutral lake of Kulunda steppe(TDS=396 g/L, pH 7.63). The phytoplankton composition and the culturable diversity of anoxygenic phototrophic bacteria from Lake Krasnovishnevoye correspond to the ones in the Kulunda lakes. Nevertheless, the peculiarities of water composition and regime of Lake Krasnovishnevoye reduce the biodiversity to prokaryotes and unicellular algae. 相似文献
6.
Schistous rock can be considered—in a first approximation—as cross‐anisotropic linear elastic material. The determination of the corresponding material constants on the basis of the laboratory investigation of rock samples often fails, as the extraction of appropriate cores proves to be unfeasible (the cores disintegrate if the schistosity is pronounced). In this paper a new method is presented to determine the material constants of a linear elastic cross‐anisotropic rock on the basis of cavity expansion field tests, e.g. with a radial jack. To this purpose, an analytic approximation for the deformation of a hydrostatically loaded cylindrical cavity in cross‐anisotropic rock is derived which serves to the inverse analysis of the material parameters. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
7.
Zafeiria Roumelioti Anastasia Kiratzi Christoforos Benetatos 《Journal of Geodynamics》2011,51(2-3):179-189
We present a catalog of moment tensor (MT) solutions and moment magnitudes, Mw, for 119 shallow (h ≤ 40 km) earthquakes in Greece and its surrounding lands (34°N–42°N, 19°E–30°E) for the years 2006 and 2007, computed with the 1D Time-Domain Moment Tensor inversion method (TDMT_INV code of Dreger, 2003). Magnitudes range from 3.2 ≤ Mw ≤ 5.7. Green's functions (GF) have been pre-computed to build a library, for a number of velocity profiles applicable to the broader Aegean Sea region, to be used in the inversion of observed broad band waveforms (10–50 s). All MT solutions are the outcome of a long series of tests of different reported source locations and hypocenter depths. Quality factors have been assigned to each MT solution based on the number of stations used in the inversion and the goodness of fit between observed and synthetic waveforms. In general, the focal mechanisms are compatible with previous knowledge on the seismotectonics of the Aegean area. The new data provide evidence for strike-slip faulting along NW–SE trending structures at the lower part of Axios basin, close to the heavily industrialized, and presently subsiding, region of the city of Thessaloniki. Normal faulting along E–W trending planes is observed at the Strimon basin, and in Orfanou Gulf in northern Greece. A sequence of events in the east Aegean Sea close to the coastline with western Anatolia sheds light on an active structure bounding the north coastline of Psara–Chios Islands about 20–25 km in length exhibiting right lateral strike-slip faulting. 相似文献
8.
The Kouris catchment is located in the south of the Troodos massif in Cyprus. The hydrology is driven by a Mediterranean climate, a mountainous topography, and a complex distribution of hydrogeological properties resulting from complex geology. To quantify the regional water balance further, a simple method using continuous streamflow records in the River Limnatis (Kouris catchment) was applied to calculate the actual evapotranspiration rate in the dry seasons. It was found that daily cycles of streamflow, recorded by automatic pressure logger, were caused by direct evaporation from the groundwater table and by transpiration of riparian forest. The daily amounts of ‘missing’ streamflow were calculated for the period 30 October–4 November 2001 and were extrapolated to the entire dry season and to the whole Kouris catchment. The actual evapotranspiration rate from the alluvial aquifer of the region is 2·4 ± 0·5 Mm3 for April–September 2001. The validity of the assumptions and the uncertainties in the estimates used in the method are discussed. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
9.
Raman spectra of γ-Mg2SiO4 taken to 200 kbar were used to calculate entropy and heat capacity at various P-T conditions. These new thermodynamic data on γ-MgSiO4, similar data on MgSiO3 perovskite (pv), previous data on β-MgSiO4 and MgO (mw), and previous volumetric data of all phases were used to calculate the phase boundaries in the Mg2SiO4 phase diagram. Our resulting slope for the β→γ transition (50±4 bar K-1) is in excellent agreement with recent multi-anvil studies. The slopes for the β→pv+MgO and γ→pv+MgO are-7±3 and -25±4 bar K-1, respectively, and are consistent with our CO2 laser heated diamond anvil studies. These slopes result in a β-γ-MgO+pv triple point at approximately 229 kbar and 2260 K for the iron free system. 相似文献
10.