全文获取类型
收费全文 | 98篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
大气科学 | 2篇 |
地球物理 | 17篇 |
地质学 | 20篇 |
海洋学 | 8篇 |
天文学 | 15篇 |
综合类 | 1篇 |
自然地理 | 40篇 |
出版年
2021年 | 4篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 7篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1967年 | 2篇 |
排序方式: 共有103条查询结果,搜索用时 343 毫秒
61.
The thermogravimetric measurements on fayalite reported by Nakamura and Schmalzried (1983) have been reassessed using the compound-energy model and computer calculations which eliminate much mathematical manipulation and subjective choice. The calculated phase field for fayalite differs somewhat from the one obtained by Nakamura and Schmalzried (1983) but there is satisfactory agreement in the experimental range. 相似文献
62.
D. R. Barraclough T. D. G. Clark S. W. H. Cowley F. H. Hibberd R. Hide D. J. Kerridge F. J. Lowes S. R. C. Malin T. Murphy H. Rishbeth S. K. Runcorn H. C. Soffel D. N. Stewart W. F. Stuart K. A. Whaler D. E. Winch 《Surveys in Geophysics》1992,13(1):47-88
A joint Discussion Meeting of the Royal Astronomical Society and the Royal Irish Academy, held on January 11th, 1991, commemorated the establishment of some early magnetic observatories, discussed recent research using global geomagnetic data and described the present status of magnetic observatories in the United Kingdom. The observatory and instruments at the Dublin magnetic observatory; the origins of the Greenwich magnetic observatory, and why it eventually had to be resited; and the history of the Munich magnetic observatory formed the historical part of the proceedings. Current research topics discussed were the geomagnetic secular variation and deep Earth structure and dynamics; fluid flow patterns near the top of the core; the origin of the annual variation of the geomagnetic field; results of an analysis of monthly means from some British observatories; a new theory of the geomagnetic daily variation; and the interactions between ionospheric science and geomagnetism. The present-day observatory scene was described in terms of the information that can be derived from the almost 40 year series of data from Hartland magnetic observatory; of the methods used to process data from the three UK magnetic observatories, which nowadays are operated automatically and remotely; and (a look into the future) of a new project, INTERMAGNET, which aims to make available, in near real time, data from the world-wide network of magnetic observatories. 相似文献
63.
Summary An attempt is made to determine the optimum representation of the geomagnetic field in terms of spherical harmonics with regard to the number of parameters required for an adequate accuracy of fit, and considering the effect of allowing for the oblateness of the earth. A representative set of geomagnetic data was subjected to a set of analyses with from 8 to 120 coefficients for both spherical and oblate models of the earth. It is concluded that a sixth order analysis (48 coefficients) with no allowance for oblateness is the most compact representation of the field compatible with tolerable accuracy. 相似文献
64.
S.M. McLennan J.F. Bell III P.R. Christensen P.A. de Souza J. Farmer D.A. Fike A. Ghosh J.P. Grotzinger K.E. Herkenhoff J.R. Johnson B. Jolliff A.H. Knoll M.C. Malin J. Pocock L.A. Soderblom N.J. Tosca M.B. Wyatt 《Earth and Planetary Science Letters》2005,240(1):95-121
Impure reworked evaporitic sandstones, preserved on Meridiani Planum, Mars, are mixtures of roughly equal amounts of altered siliciclastic debris, of basaltic provenance (40 ± 10% by mass), and chemical constituents, dominated by evaporitic minerals (jarosite, Mg-, Ca-sulfates ± chlorides ± Fe-, Na-sulfates), hematite and possibly secondary silica (60 ± 10%). These chemical constituents and their relative abundances are not an equilibrium evaporite assemblage and to a substantial degree have been reworked by aeolian and subaqueous transport. Ultimately they formed by evaporation of acidic waters derived from interaction with olivine-bearing basalts and subsequent diagenetic alteration. The rocks experienced an extended diagenetic history, with at least two and up to four distinct episodes of cementation, including stratigraphically restricted zones of recrystallization and secondary porosity, non-randomly distributed, highly spherical millimeter-scale hematitic concretions, millimeter-scale crystal molds, interpreted to have resulted from dissolution of a highly soluble evaporite mineral, elongate to sheet-like vugs and evidence for minor synsedimentary deformation (convolute and contorted bedding, possible teepee structures or salt ridge features). Other features that may be diagenetic, but more likely are associated with relatively recent meteorite impact, are meter-scale fracture patterns, veins and polygonal fractures on rock surfaces that cut across bedding. Crystallization of minerals that originally filled the molds, early cement and sediment deformation occurred syndepositionally or during early diagenesis. All other diagenetic features are consistent with formation during later diagenesis in the phreatic (fluid saturated) zone or capillary fringe of a groundwater table under near isotropic hydrological conditions such as those expected during periodic groundwater recharge. Textural evidence suggests that rapidly formed hematitic concretions post-date the primary mineral now represented by crystal molds and early pore-filling cements but pre-date secondary moldic and vug porosity. The second generation of cements followed formation of secondary porosity. This paragenetic sequence is consistent with an extended history of syndepositional through post-depositional diagenesis in the presence of a slowly fluctuating, chemically evolving, but persistently high ionic strength groundwater system. 相似文献
65.
66.
67.
68.
A. Wilkinson J.-L. Prieur R. Lemoine D. Carter D. Malin W. B. Sparks 《Monthly notices of the Royal Astronomical Society》2000,319(4):977-990
A morphological and two-colour charge-coupled device photometry study of the shell galaxy 0422−476, one of the richest known azimuthally distributed shell galaxies, is presented. Taking this galaxy as a prototype, a general method for reducing observational data of these objects is defined and quantitative parameters for use in further theoretical studies are derived.
According to some recent models (e.g. that of Thomson and Wright in 1990), the shells in such a galaxy could be density waves induced in a thick disc population of dynamically cold stars by a weak interaction with another galaxy. In 0422−476 there is no evidence of either a conventional exponential disc or a thick disc. Although it is not possible to rule out the weak interaction model, the observations continue to favour the merger model (e.g. that of Quinn from 1984). 相似文献
According to some recent models (e.g. that of Thomson and Wright in 1990), the shells in such a galaxy could be density waves induced in a thick disc population of dynamically cold stars by a weak interaction with another galaxy. In 0422−476 there is no evidence of either a conventional exponential disc or a thick disc. Although it is not possible to rule out the weak interaction model, the observations continue to favour the merger model (e.g. that of Quinn from 1984). 相似文献
69.
S. R. C. Malin O. Özcan S. B. Tank M. K. Tunçer & O. Yazc-Çakn 《Geophysical Journal International》2000,140(3):F13-F16
The magnetic north ( H ), magnetic east ( D ) and vertically downward ( Z ) components of the geomagnetic field were monitored at Elazıgˇ, Turkey, with a three-component fluxgate magnetometer during the 1999 August 11 total eclipse of the Sun. The results were compared with those obtained with an identical instrument at Kandilli magnetic observatory, which is at a similar latitude to Elazıgˇ, but clear of the band of totality. An increase of D is found during the eclipse, rising to a maximum close to the time of maximum eclipse. The reality of this effect is confirmed by noting a similar feature, also centred on the time of eclipse, at a number of European observatories. 相似文献
70.
Rosie Chance Alex R. Baker Frithjof C. Küpper Claire Hughes Bernard Kloareg Gill Malin 《Estuarine, Coastal and Shelf Science》2009
A number of field and laboratory studies on the impact of marine macroalgae on dissolved inorganic iodine speciation are presented. Within tidally isolated rock pools, the brown macroalga Fucus serratus was found to both release stored iodide and to facilitate the reduction of iodate to iodide. In contrast, no discernible changes in iodine speciation were observed in rock pools containing green macroalgae of the genus Ulva. Incubation experiments confirmed that the macroalgae Laminaria digitata, F. serratus and Kallymenia antarctica release iodide, though the rate of release varied between species and between specimens of the same species. Application of oxidative stress by treatment with cell wall derived oligoguluronate elicitors increased the efflux of iodide by L. digitata approximately 20-fold. The release of iodide by macroalgae may impact upon the formation of volatile iodine species (molecular iodine and iodocarbons) that are of importance in the coastal atmosphere. 相似文献