全文获取类型
收费全文 | 346篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 43篇 |
地球物理 | 75篇 |
地质学 | 148篇 |
海洋学 | 5篇 |
天文学 | 64篇 |
综合类 | 2篇 |
自然地理 | 8篇 |
出版年
2019年 | 4篇 |
2018年 | 6篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 12篇 |
2007年 | 13篇 |
2006年 | 20篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1964年 | 3篇 |
1957年 | 3篇 |
1956年 | 3篇 |
1954年 | 3篇 |
1950年 | 4篇 |
1949年 | 2篇 |
排序方式: 共有349条查询结果,搜索用时 0 毫秒
81.
Dr. Heinz -Peter Jons 《International Journal of Earth Sciences》1986,75(2):461-493
The analysis of the martian relief leads to the conclusion that some of the most important relief elements are either concentrically or radially arranged with respect to a central structure and hence form aureoles. In this paper four different types of aureoles are identified and described:
- impact aureoles (as result of extradynamics),
- volcanic aureoeles (as result of lava flow through vents),
- tectonic aureoles (as result of isostatic adjustment and/or settlement),
- permafrost-related aureoles and mega-aureoles (as result of migration above thawing permafrost in areas with high relief).
82.
Heinz Lettau 《Boundary-Layer Meteorology》1990,50(1-4):1-9
The official report on this first comprehensive field experiment in boundary-layer meteorology was published 1957 in two volumes, edited by Lettau and Davidson (hereafter L&D). The official report is supplemented in this paper by relevant pre-history developments and a discussion of some selected post-history interpretations and follow-up experiments. 相似文献
83.
拉分盆地是一种与走滑断裂带密切相关的特殊拉张构造,因其重要的构造意义,及其与火山活动、中小地震群集、特殊的成矿作用间的伴生关系而受到研究者的高度重视。关于拉分盆地的形成演化过程,已有较多的研究成果,但是由于研究手段的限制,缺少对盆地演化中次级断裂扩展过程的研究。基于离散元的数值计算方法是研究断裂扩展方式的理想方法。本文采用基于离散元的颗粒流方法,揭示纯走滑拉分盆地发育过程中的断裂扩展和连接过程,为拉分盆地演化机理和断裂扩展提供新的研究方法。同时,根据主走滑断层与块体运动方向的夹角不同,建立不同的张扭性拉分盆地模型,系统研究张扭性盆地的断裂扩展和演化机理。将上述理论研究结果与死海盆地等经典拉分盆地实例相结合,探讨了死海盆地、土耳其Cinarcik盆地、哥伦比亚El Paraiso盆地等的形成演化机理和断裂扩展方式。 相似文献
84.
Abstract— We present a new weathering index (wi) for the metallic‐Fe‐Ni‐poor chondrite groups (CK and R) based mainly on transmitted light observations of the modal abundance of crystalline material that is stained brown in thin sections: wi‐0, <5 vol%; wi‐1, 5–25 vol%; wi‐2, 25–50 vol%; wi‐3, 50–75 vol%; wi‐4, 75–95 vol%; wi‐5, >95 vol%; wi‐6, significant replacement of mafic silicates by phyllosilicates. Brown staining reflects mobilization of oxidized iron derived mainly from terrestrial weathering of Ni‐bearing sulfide. With increasing degrees of terrestrial weathering of CK and R chondrites, the sulfide modal abundance decreases, and S, Se, and Ni become increasingly depleted. In addition, bulk Cl increases in Antarctic CK chondrites, probably due to contamination from airborne sea mist. 相似文献
85.
A list of reports of Lunar Transient Phenomena (LTP) which have been observed in 1972 and 1973 by an international group of amateur astronomers is given. From 907 monitoring observations (1972: 526, 1973: 381) 92 LTP (74 reliable, 18 possible individual sightings) have been reported (1972: 52, 1973: 40) including parallel observations of the same event. The LTP were brightenings, shadings, flashes, colours, moving clouds and brightness diminutions of stars before occultations. 45 LTP events may be expected to be real in a catalogue of criteria for the reliability of observations. Sixteen events have been reported by several independent observers. A short examination of the temporal distributions of monitoring observations and recorded LTP is given. 相似文献
86.
Florian Heinz Ralf Hartmut Güting 《International journal of geographical information science》2018,32(9):1737-1769
Moving object databases are designed to store and process spatial and temporal object data. An especially useful moving object type is a moving region, which consists of one or more moving polygons suitable for modeling the spread of forest fires, the movement of clouds, spread of diseases and many other real-world phenomena. Previous implementations usually allow a changing shape of the region during the movement; however, the necessary restrictions on this model result in an inaccurate interpolation of rotating objects. In this paper, we present an alternative approach for moving and rotating regions of fixed shape, called Fixed Moving Regions, which provide a significantly better model for a wide range of applications like modeling the movement of oil tankers, icebergs and other rigid structures. Furthermore, we describe and implement several useful operations on this new object type to enable a database system to solve many real-world problems, as for example collision tests, projections and intersections, much more accurate than with other models. Based on this research, we also implemented a library for easy integration into moving objects database systems, as for example the DBMS Secondo (1) (2) developed at the FernUniversität in Hagen. 相似文献
87.
88.
89.
Heinz Bottke 《Mineralium Deposita》1969,4(4):355-367
Zusammenfassung Die Eisenmanganerze der Grube Dr. Geier bei Bingen am Rhein/Westdeutschland gehören zu den Verwitterungslagerstätten des Mangans. Sie sind an mitteldevonische Dolomite einer isoklinalen Mulde gebunden, die von marinen Sanden des Oligozäns überlagert werden. Ihre Bildungsräume sind Dolinen des Dolomitkarstes. Die Anlage der Dolinen ist gebunden an die Verbreitungsbereiche massiger Dolomite sowie an Zonen starker tektonischer Beanspruchung, in denen sie sich durch Mischungskorrosion gebildet haben. Ihre Füllungen bestehen bis zu 50% aus unvererzten tertiären Feinsanden und Tonen. Die Eisenmanganerze mit einem durchschnittlichen Fe/Mn-Verhältnis von 2:1 entstanden aus deszendenten Verwitterungslösungen durch eine gegenseitige Ausfällung von Hydroxidsolen des Fe und Mn. Mineralogisch bestehen sie aus Muskovit (10–50%), Goethit (30–50%), röntgenamorphen Mn-Oxiden (20–30%) sowie Hartmanganerzkonkretionen (0–22%) aus Manganit und Polianit/Pyrolusit. Die Herkunft der Mn-führenden Verwitterungslösungen wird sowohl aus den benachbarten Tonschiefern als auch aus den Dolomiten angenommen.
Tertiary manganese-ores of the Dr. Geier-Mine, near Bingen on the Rhine, were mined since 1840, and are genetically connected with the karst of middle Devonian dolomites. They show relations between the karst topography and their petrofacies and tectonic structures. Cavities, caverns, sinkholes and dolines depend on fractures, joint-sets (ac, okl, hol, hkl) and bedding planes of an isoclinal trough. These structures in the massive dolomites have been the waterways formed through-mixed corrosion during an uplift-period and under a warm climate in the Eocene and the Lower Oligocene. Clays, sands, brecciated slides and the ores are the fillings of dolines, which posess their greatest extension near strike-faults of the syncline. The ores are mixed iron-manganese ores with a proportion of Fe: Mn of 2:1. The clayish ore types contain variable amounts of muscovite (10–50%), goethite (30–50%), amorphous Mn-oxides (20–30%) and hard concretions of manganite and pyrolusite (0–22%). The genesis of the ores is explicable as a mixture of colloidal solutions of Fe- and Mn-hydroxides under oxidizing conditions of the karst-hydrography.相似文献
90.