全文获取类型
收费全文 | 156篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 7篇 |
大气科学 | 13篇 |
地球物理 | 43篇 |
地质学 | 74篇 |
海洋学 | 6篇 |
天文学 | 18篇 |
自然地理 | 2篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 12篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 14篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1977年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1966年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1948年 | 2篇 |
1942年 | 1篇 |
1941年 | 1篇 |
1940年 | 5篇 |
1939年 | 1篇 |
1937年 | 1篇 |
1930年 | 1篇 |
1924年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有163条查询结果,搜索用时 15 毫秒
31.
We consider an immiscible incompressible two-phase flow in a porous medium composed of two different rocks so that the capillary pressure field is discontinuous at the interface between the rocks. This leads us to apply a concept of multivalued phase pressures and a notion of weak solution for the flow which have been introduced in Cancès and Pierre (SIAM J Math Anal 44(2):966–992, 2012). We discretize the problem by means of a numerical algorithm which reduces to a standard finite volume scheme in each rock and prove the convergence of the approximate solution to a weak solution of the two-phase flow problem. The numerical experiments show in particular that this scheme permits to reproduce the oil-trapping phenomenon. 相似文献
32.
Axelle Bouiges Amir Yassin Maya Ikogou Clément Lelarge Axelle-Rolande Sikoa Stefano Mona Michel Veuille 《Comptes Rendus Geoscience》2013,345(7-8):297-305
Previous genetic studies showing evidence of past demographic changes in African drosophilids suggested that these populations had strongly responded to Quaternary climate changes. We surveyed nine species of Zaprionus, a drosophilid genus mostly present in Africa, in forests located between southern Senegal and Gabon. The mitochondrial COI gene showed contrasted levels of sequence variation across species. Populations of the only cosmopolitan species of the genus, Z. indianus, and of its closely related sibling species, Z. africanus, are highly polymorphic and appear to have undergone a continuous population expansion beginning about 130,000 years ago. Five less variable species probably underwent a population expansion beginning only about 20,000–30,000 years ago. One of them, Z. taronus, was significantly structured between forest blocks. The last two species were nearly monomorphic, probably due to infection by Wolbachia. These results are similar to those obtained in three species from the melanogaster subgroup, and may be typical of the responses of African drosophilid populations to glacial cycles. 相似文献
33.
Assimilation of carbonate country rock by the parent magma of the Panzhihua Fe-Ti-V deposit(SW China):Evidence from stable isotopes 总被引:4,自引:0,他引:4
Clement Ganino Chris Harris Nicholas T.Arndt Stephen A.Prevec Geoffrey H.Howarth 《地学前缘(英文版)》2013,4(5):547-554
The Panzhihua intrusion in southwest China is part of the Emeishan Large Igneous Province and host of a large Fe-Ti-V ore deposit.During emplacement of the main intrusion,multiple generations of mafic dykes invaded carbonate wall rocks,producing a large contact aureole.We measured the oxygen-isotope composition of the intrusions,their constituent minerals,and samples of the country rock.Magnetite and plagioclase from Panzhihua intrusion haveδ18O values that are consistent with magmatic equilibrium, and formed from magmas withδ18O values that were 1-2‰higher than expected in a mantle-derived magma.The unmetamorphosed country rock has highδ18O values,ranging from 13.2‰(sandstone) to 24.6-28.6‰(dolomite).The skarns and marbles from the aureole have lowerδ18O andδ13C values than their protolith suggesting interaction with fluids that were in exchange equilibrium with the adjacent mafic magmas and especially the numerous mafic dykes that intruded the aureole.This would explain the alteration ofδ18O of the dykes which have significantly higher values than expected for a mantle-derived magma.Depending on the exactδ18O values assumed for the magma and contaminant, the amount of assimilation required to produce the elevatedδ18O value of the Panzhihua intrusion was between 8 and 13.7 wt.%,assuming simple mixing.The exact mechanism of contamination is unclear but may involve a combination of assimilation of bulk country rock,mixing with a melt of the country rock and exchange with CO2-rich fluid derived from decarbonation of the marls and dolomites.These mechanisms,particularly the latter,were probably involved in the formation of the Fe-Ti-V ores. 相似文献
34.
35.
36.
H. Cl. 《International Journal of Earth Sciences》1937,28(3-4):357-357
Ohne Zusammenfassung 相似文献
37.
Jan Erik H. Weber Kai H. Christensen Cléa Denamiel 《Continental Shelf Research》2009,29(11-12):1448-1453
A new theoretical approach for the wave-induced setup over a sloping beach is presented that takes into consideration the explicit variations of the surface waves due to bottom slope and viscosity. In this way, the wave forcing of the mean Lagrangian volume fluxes is calculated without assuming that the local depth is constant. The analysis is valid in the region outside the surf zone and is based on the shallow-water assumption. A novel approach for separating the viscous damping of the waves from the frictional damping of the mean flow is introduced, where the mean Eulerian velocity is applied in the bottom stress for the mean fluxes. In the case where the onshore Lagrangian mean transport is zero, a new formula is derived for the Eulerian mean free surface slope, in which the effects of bottom slope, viscous wave damping and frictional bottom drag on the mean flow are clearly identified. The analysis suggests that viscous damping of the waves and frictional dissipation of the Eulerian near-bed return flow could lead to setup outside the surf zone. 相似文献
38.
H. Cl 《International Journal of Earth Sciences》1939,30(7-8):810-813
Ohne Zusammenfassung 相似文献
39.
H. Cl 《International Journal of Earth Sciences》1940,31(3-4):305-307
Ohne Zusammenfassung 相似文献
40.
Vadlamudi Brahmananda Rao Emanuel Giarolla Clóvis Monteiro do Espírito Santo Sergio Henrique Franchito 《Journal of Oceanography》2008,64(4):551-560
A comparison of monthly wind stress derived from winds of NCEP/NCAR (National Centers for Environmental Prediction/National
Center for Atmospheric Research) reanalysis and UWM/COADS (The University of Wisconsin-Milwaukee/Comprehensive Ocean-Atmosphere
Data Set) dataset (1950–1993), and of NCEP/NCAR reanalysis and satellite-based QuikSCAT dataset (2000–2006), is made over
the South Atlantic (10°N–40°S). On a mean seasonal scale, the comparison shows that these three wind stress datasets have
qualitatively similar patterns. Quantitatively, in general, from about the equator to 20°S in the mid-Atlantic the wind stress
values are stronger in NCEP/NCAR data than those in UWM/COADS data. On the other hand, in the Intertropical Convergence Zone
(ITCZ) area the wind stress values in NCEP/NCAR data are slightly weaker than those in UWM/COADS data. In the South Atlantic,
between 20° S–40°S, the QuikSCAT dataset presents complex circulation structures which are not present in NCEP/NCAR and UWM/COADS
data. The wind stress is used in a numerical ocean model to simulate ocean currents, which are compared to a drifting-buoy
observed climatology. The modeled South Equatorial Current agrees better with observations between March–May and June–August.
Between December–February, the South Equatorial Current from UWM/COADS and QuikSCAT experiments is stronger and more developed
than that from NCEP/NCAR experiment. The Brazil Current, in turn, is better represented in the QuikSCAT experiment. Comparison
of the annual migration of ITCZ at 20° and 30°W in UWM/COADS and NCEP/NCAR data sources show that the southernmost position
of ITCZ at 30°W in February, March and April coincides with the rainy season in NE Brazil, while the northernmost position
of ITCZ at 20°W in August coincides with the maximum rainfall of Northwest Africa. 相似文献