全文获取类型
收费全文 | 260篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 11篇 |
大气科学 | 30篇 |
地球物理 | 40篇 |
地质学 | 136篇 |
海洋学 | 10篇 |
天文学 | 22篇 |
综合类 | 6篇 |
自然地理 | 12篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1969年 | 2篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1957年 | 3篇 |
1956年 | 4篇 |
1955年 | 2篇 |
1953年 | 2篇 |
1951年 | 3篇 |
1948年 | 5篇 |
1936年 | 1篇 |
1934年 | 1篇 |
1930年 | 1篇 |
1928年 | 2篇 |
1916年 | 1篇 |
1912年 | 1篇 |
排序方式: 共有267条查询结果,搜索用时 15 毫秒
231.
Hermann Harder 《Chemical Geology》1976,18(3):169-180
The low-temperature synthesis of clay minerals is possible through the aging of freshly prepared hydroxide—silica precipitates. The rapid synthesis of nontronite is only possible at surface temperatures under reducing conditions. Under oxidizing conditions, pure Fe(III)- or pure Al-smectite minerals could not be synthesized at low temperatures. It is only from Fe(II)-containing solutions that nontronite and lembergite, the di-[Fe(III)] and tri-[Fe(II)] octahedral three-layer silicates, are built up in several days at low temperatures. The presence of Fe(II) enables an octahedral layer of the brucite—gibbsite type to be formed. These are necessary for the bidimensional orientation of SiO4 tetrahedrons, leading to clay-mineral formation. The Fe2+ and/or Mg2+ ions are necessary for the formation of the Al3+- and Fe3+-containing three-layer silicate minerals.Under reducing diagenetic conditions, the Fe contents in recent sediments are sufficient to build up Al-rich three-layer minerals under both fresh-water and salt-water conditions. 相似文献
232.
Hermann Albert J.; Hinckley Sarah; Megrey Bernard A.; Napp Jeffrey M. 《ICES Journal of Marine Science》2001,58(5):1030-1041
233.
234.
This is based on a concept worked out by EUROSOLAR, an Association for the Solar Energy Age, of which Hermann Scheer is chairman and Wilfrid Bach is a member of the board. 相似文献
235.
236.
237.
Kochan Hermann W. Huebner Walter F. Sears Derek W. G. 《Earth, Moon, and Planets》1998,80(1-3):369-411
Comet simulation experiments are discussed, in the context of physical models and the results in cometary physics, gathered
especially from the GIOTTO space mission to comet P'Halley. The “status of the today knowledge” about comets, the experiments
could start from, is briefly reviewed. The setup of the KOSI (German = Kometen Simulation) - experiments and the techniques
to produce cometary analogous material, on the basis of that knowledge are described in general, as for the different KOSI
experiments. The limitations of the simulation of physical processes at the surface of real comets in an earth-bound laboratory
are discussed, and the possibilities to receive common insights in cometary physics are shown. Methods and procedures are
described, and the major results reviewed. As with attempting to reproduce any natural phenomenon in the laboratory, there
are short-comings to these experiments, but there are possibly major new insights to be gained. Physical laws only have the
same consequences under same experimental or environmental conditions. A number of small-scale comet simulation experiments
have been performed, since the early 60ties in many laboratories, but the largest and most ambitious series of comet simulation
experiments to date were performed between 1987 and 1993 using the German space agency's (DLR) space hardware testing facilities
in Cologne. These experiments were triggered by the scientific community after the comet P'Halley's recurrence in 1986 and
the many data gathered by the space missions in this year. Simulation experiments have proved valuable in developing methods
for making cometary analogues, and for exploring specific properties of such materials in detail. These experiments provided
new insights into the morphology and physical behavior of aggregates formed out of silicate- /water-ice -grains likely to
exist in comets. The formation of a dust mantle on the surface, and a system of ice layers below the mantle from the different
admixed materials, have been detected after the insolation of the artificial comet. The mechanisms for heat transfer between
the comet's surface and its interior, compositional, structural, and isotopic changes that occur near the comet's surface,
were described by modeling in accordance with the experimental results. The mechanisms of the ejection of dust and ice grains
from the surface, and the importance of gas-drag in propelling grains were investigated by close-up video cameras.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
238.
Ehrenfreund Pascale Krafft Catherine Kochan Hermann Pirronello Valerio 《Earth, Moon, and Planets》1998,80(1-3):1-1
Earth, Moon, and Planets - 相似文献
239.
N. Bulian A. Daum G. Hermann M. Heß W. Hofmann H. Lampeitl G. Pühlhofer C. Köhler M. Panter M. Stein G. Börst G. Rauterberg M. Samorski C. Sauerland W. Stamm 《Astroparticle Physics》1998,8(4):223-233
The HEGRA-collaboration is operating a system of imaging atmospheric Cherenkov telescopes to search for sources of TeV-γ-rays. Air showers are observed in stereoscopic mode with several telescopes simultaneously. To trigger the telescope system a versatile two-level trigger scheme has been implemented, which allows a significant reduction of the energy threshold with respect to single telescopes. The technical implementation of this trigger scheme and the performance of the trigger system are described. Results include the dependence of single- and multi-telescope trigger rates on the trigger thresholds, on the orientation of the telescopes, and on the type of the primary particle. 相似文献
240.
Evidence for Late Carboniferous subduction-type magmatism in mafic-ultramafic cumulates of the SW Tauern window (Eastern Alps) 总被引:1,自引:0,他引:1
B. Cesare D. Rubatto J. Hermann L. Barzi 《Contributions to Mineralogy and Petrology》2002,142(4):449-464
Hectometric bodies of fresh mafic-ultramafic cumulates have been discovered within the Central Gneiss of the Zillertal massif, SW Tauern window (eastern Alps, Italy). The cumulates, intruded by the Central Gneiss granitoids, are amphibole-bearing harzburgites and norites made of cumulitic olivine (Fo73-80), spinels, sulphides and plagioclase (An79-87), included in orthopyroxene (En76-83) and Ti-pargasite (Mg#=0.73-0.81). Major and trace element geochemistry indicates that these rocks represent olivine + spinel - plagioclase cumulates, in which interstitial melt crystallized as orthopyroxene + Ti-pargasite. The parental melt has trace element patterns typical of subduction zone magmas. The crystallization sequence, mineral compositions, and modes indicate that cumulates formed from a H2O-rich basaltic andesite, which intruded at low-pressure (~2 kbar) and temperatures of 1,050-1,100 °C. SHRIMP U-Pb dating of zircons from ultramafic cumulates and adjacent metagranodiorite yielded ages of 309LJ and 295Dž Ma, respectively. In agreement with field relationships, these results show that the mafic-ultramafic cumulates represent a co-genetic, early product of the Late Carboniferous plutonic activity in the western Tauern window, which started in the Westphalian, earlier than previously thought. Our data on the most primitive rocks in the Zillertal massif permit, for the first time, insight into the parental magma and thus into the origin of this Late Carboniferous calc-alkaline magmatism, which was most likely related to slab break off during the Late Variscan convergence. 相似文献