全文获取类型
收费全文 | 81篇 |
免费 | 0篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 10篇 |
地球物理 | 16篇 |
地质学 | 17篇 |
海洋学 | 2篇 |
天文学 | 28篇 |
自然地理 | 5篇 |
出版年
2018年 | 1篇 |
2015年 | 2篇 |
2013年 | 2篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2001年 | 1篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1962年 | 1篇 |
1959年 | 1篇 |
1946年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有81条查询结果,搜索用时 15 毫秒
21.
22.
An Aerobee 150 was launched into the umbra from Wallops Island at 18:36:15 UT 7 March, 1970, carrying two intensity calibrated EUV Wadsworth grating spectrographs. The experiment was a collaborative venture between groups from A.R.U. Culham, H.C.O., Imperial College and York University, Toronto. This was the first attempt to record stigmatic spectra of the chromosphere and corona in the EUV, analogous to the visible eclipse Flash Spectrum.A wealth of new observational data has demonstrated the importance of a new instrumental and experimental technique for recording the ultraviolet flash spectrum. Lyman- limb spectroheliograms reveal complex activity extending high into the corona in contrast to the modest level of activity observed in H. Preliminary intensity reduction shows that Lyman- dominates as the principle radiation loss for these features. 相似文献
23.
24.
MATTHIAS F. COMERFORD ROBERT H. MC CORKELL SAMUEL W. TISHLER 《Meteoritics & planetary science》1968,4(1):7-21
Abstract Examination of an iron meteorite found in South Africa discloses it to be a coarse octahedrite containing 6.90 weight-percent nickel. The meteorite body contains several inclusions of troilite, or troilite plus graphite, and at least one of pure graphite veined with kamacite. Kamacite, cohenite, and phosphides are the other major constituents of the structure. 相似文献
25.
Cross-sections of the Hartley-Huggins bands of 03 at the temperature 195 K have been obtained from photoabsorption measurements at column densities in the range 2 × 1017?1 × 1021 cm?2 throughout the wavelength region 240–350 nm with a 6.65 m photoelectric scanning spectrometer equipped with a 2400 lines mm?1 grating and operated at an instrumental width (FWHM) of 0.003 nm. The assumptions made in putting the measured relative cross-sections on an absolute basis are discussed. Fine structure in the cross-section observed in the Huggins bands is illustrated in the region 323–327 nm where shallow features of width 0.01–0.02 nm occur superposed on a stronger apparent continuum exhibiting broader wavy structure. 相似文献
26.
We present a detailed study of the distribution of key deuterated species (viz., atomic D and HD) and the associated deuterium Lyman-α airglow in the jovian thermosphere. The reactions that appear to govern the abundances of these deuterated species are used in conjunction with C2-chemistry in a 1-D photochemical-diffusion model. While the D abundance is mainly sensitive to H densities and the vibrational temperature profile, the D vertical distribution also depends on other parameters such as eddy mixing and the uncertain values of some of the reaction rate constants. We consider different scenarios by varying several parameters controlling the D distribution in the thermosphere. A radiative transfer model with coupling of the H and D Lyman-α lines is employed to obtain line profiles and total intensities at disk center for these scenarios. This allows a comparison of the impact of various parameters on the jovian D Lyman-α emission. A consequence of these chemical processes in the jovian thermosphere is the formation of CH2D, CH3D, and C2H5D, and other deuterated species. We also discuss the source of these deuterated hydrocarbons and their abundance. We find that HD vibrational chemistry impacts D in the thermosphere, CH3D and C2H5D are vibrationally enhanced in the thermosphere, and variations in abundance of CH3D and C2H5D in the thermosphere may reflect dynamical activity (i.e., Kh) in the jovian upper atmosphere. An observing program dedicated to providing such measurements of these testable phenomena would provide further insight into the synergistic coupling between chemistry, energetics and airglow in the jovian upper atmosphere. 相似文献
27.
Hannah Parkinson Shaun Cole John Helly 《Monthly notices of the Royal Astronomical Society》2008,383(2):557-564
We present a new Monte Carlo algorithm to generate merger trees describing the formation history of dark matter haloes. The algorithm is a modification of the algorithm of Cole et al. used in the galform semi-analytic galaxy formation model. As such, it is based on the Extended Press–Schechter theory and so should be applicable to hierarchical models with a wide range of power spectra and cosmological models. It is tuned to be in accurate agreement with the conditional mass functions found in the analysis of merger trees extracted from the Λ cold dark matter Millennium N -body simulation. We present a comparison of its predictions not only with these conditional mass functions, but also with additional statistics of the Millennium Simulation halo merger histories. In all cases, we find it to be in good agreement with the Millennium Simulation and thus it should prove to be a very useful tool for semi-analytic models of galaxy formation and for modelling hierarchical structure formation in general. We have made our merger tree generation code and code to navigate the trees available at http://star-www.dur.ac.uk/~cole/merger_trees . 相似文献
28.
Extreme ultraviolet observations of a quiet region of the Sun on August 18, 1969, with the Harvard spectroheliometer on OSO 6 indicate that the chromospheric network can be observed in lines of the chromosphere and transition region (T = 8.4 × 105 K) with almost identical structure. At coronal heights, the network changes but some residual structure can still be discerned in Mgx and perhaps Sixii (T = 2.3 × 106 K), although there is little or no evidence remaining in Fexvi (T = = 3.5 × 106 K). 相似文献
29.
The Influence of Continents and Oceans on Geomagnetic Variations 总被引:2,自引:0,他引:2
W. D. Parkinson 《Geophysical Journal International》1962,6(4):441-449
30.
中国铂矿资源严重不足,主要分布在中国西部,根据原生矿床特征可划分为4类:①硫化物型;②铬铁矿型;③辉石岩型;④层控型。寻找铂矿新类型和富铂(岩石)资源,应成为解决中国铂矿资源紧缺的重要任务。铂矿找矿方向:地台与地槽接合部位,特别是围绕着基性、超基性岩内外接触带,铂的预富集岩带与层控型铂矿带,另外还有砂铂型铂矿发育区有望扩大找铂前景。 相似文献