全文获取类型
收费全文 | 312篇 |
免费 | 7篇 |
专业分类
测绘学 | 6篇 |
大气科学 | 22篇 |
地球物理 | 166篇 |
地质学 | 70篇 |
海洋学 | 3篇 |
天文学 | 29篇 |
综合类 | 1篇 |
自然地理 | 22篇 |
出版年
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 11篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 6篇 |
2007年 | 10篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1987年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1968年 | 6篇 |
1967年 | 3篇 |
1966年 | 5篇 |
1965年 | 3篇 |
1963年 | 3篇 |
1960年 | 4篇 |
1959年 | 6篇 |
1958年 | 5篇 |
1957年 | 3篇 |
1956年 | 2篇 |
1954年 | 3篇 |
1948年 | 2篇 |
排序方式: 共有319条查询结果,搜索用时 15 毫秒
21.
22.
23.
Václav Bucha Josef Horáček Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1973,17(4):321-336
Summary The paper brings a brief geological asessment of the sedimentational cycles, analyses the methods of collection and investigation of samples and the representativeness of the results obtained. Problems of magnetic cleaning and the types of demagnetization curves investigated are discussed. The continuous nature of the variations of the magnetic declination, inclination and remanent magnetization, determined by palaeomagnetic investigation of Quaternary sediments, is also discussed. The conclusion contains the principal facts about the dynamics of the geomagnetic field in the Quaternary and points out the possibility of applying them to the theory of the geomagnetic field, as well as to geological correlations. 相似文献
24.
Josef Gochermann Walter F. Wargau Claus Tappert Theodor Schmidt-Kaler Robert S. Stobie Fred Marang Greg Roberts Francois G. van Wyk Peter Rucks 《Experimental Astronomy》1999,9(1):1-15
In order to decide whether the seeing conditions at SAAO/Sutherland justify the erection of a 3.5 m telescope and also to compare Sutherland with the Gamsberg/Namibia site, a seeing campaign covering 15 months has been carried out. For direct comparison with the results of the seeing campaign at Gamsberg twenty years before the same QUESTAR telescope was employed. The seeing is determined by the scattering of the star-trail exposed on a film in the focal plane of the telescope. The campaign commenced in February 1992. Up to May 1993, data for 204 nights, that is 47.3% of the total number of nights, were collected. Due to wind speeds above 30 km h-1, 25 out of the 204 nights were not considered in the final reduction. The useful 179 nights are evenly distributed over the campaign period. The median seeing value for the whole period is = 0.52. There are differences during the year: the best season gives = 0.42, the worst = 0.67. Each night was divided into three intervals, although data for each of the three intervals were not always available. Generally, there is an improvement in the seeing during the course of a night. The results are compared to the seeing values of Gamsberg/Namibia and ESO/La Silla. 相似文献
25.
Hans Josef Schober 《Icarus》1976,28(3):415-420
The minor planet 79 Eurynome was observed during the 1974 opposition for four nights in November, using a photoelectric photometer attached to the 60 cm telescope at the Observatoire de Haute Provence, France. A synodic period of Psyn = 5h 58m46s ± 6s m.e. was derived. The total amplitude of the lightcurve is only 0.05 mag. The lightcurve shows a double maximum and double minimum. Both minima appear to be at the same level. Observations were carried out in an instrumental filter system (UBV)' Results are shown only for V′, but U′ and B′ measurements supplement the conclusions concerning the rotation. The phase angle α, covered by the observations, ranges from 3 to 5°. The present results for 79 Eurynome rule out the longer period of 0d.49830 derived by F. Scaltriti and V. Zappalà in favor of their possible period of 0d.24915. 相似文献
26.
27.
Josef Bochníček Tomáš Zelinka Reviewer T. Kolbenheyer 《Studia Geophysica et Geodaetica》1981,25(4):411-412
Summary The authors prove that the solution of Laplace's equation under Neumann's boundary conditions can be transformed to an advantage into determining the field which is generated by charges, induced by the external field at surfaces of discontinuity. 相似文献
28.
Marcela Laštovičková Josef Pek Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1979,23(1):94-98
Summary A profile model of electric resistivity as a function of depth was compiled, the initial parameters being the values of the electric resistivity determined experimentally for basaltic and eclogitic rocks from the Bohemian Massif. The curves of the apparent resistivity were computed for this model and the measure of information evaluated for the various model layers. The dominant influence of the subsurface layer was proved. 相似文献
29.
¶rt;m uu nau mu m a nu a¶rt;u ¶rt; D-amu u. a¶rt; m nu u u. u¶rt;a a a mu nma u nma mu m (20 ¶rt; 150 ). 相似文献
30.
Václav Bucha Reviewer F. Rein Reviewer J. Bochníček 《Studia Geophysica et Geodaetica》1977,21(3-4):350-360
Summary As a result of investigating the relations between the variations of geomagnetic activity and meteorological factors [1, 2] a mechanism of solar-terrestrial relationships and a model of the changes of atmospheric circulation in the Northern Hemisphere are proposed; this provides an explanation of the causes of the fluctuation of the climate, of dry and cold periods and differing vegetation conditions in various years in dependence on the intensity of geomagnetic activity. 相似文献