全文获取类型
收费全文 | 630篇 |
免费 | 23篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 16篇 |
大气科学 | 26篇 |
地球物理 | 255篇 |
地质学 | 136篇 |
海洋学 | 3篇 |
天文学 | 199篇 |
自然地理 | 19篇 |
出版年
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 33篇 |
2015年 | 22篇 |
2014年 | 37篇 |
2013年 | 36篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 11篇 |
2009年 | 14篇 |
2008年 | 9篇 |
2007年 | 7篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2002年 | 6篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 9篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 17篇 |
1988年 | 9篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1973年 | 11篇 |
1972年 | 7篇 |
1971年 | 11篇 |
1969年 | 6篇 |
1968年 | 10篇 |
1967年 | 9篇 |
1963年 | 7篇 |
排序方式: 共有654条查询结果,搜索用时 125 毫秒
41.
Summary The hypothesis of an expanding Earth is discussed on the basis of lunar laser ranging It is provcd that the given data do not indicate a secular increase in the principal moment of the Earth's inertia which would have to occur if the Earth were really expanding.
¶rt;amunma au u mu u ammuu a¶rt;u u ¶rt;a n a auu . aam, m n mu ¶rt;a m umamu amaua ma uuu u, m ¶rt; nmmam auu, u n¶rt; u m.相似文献
42.
aamuam uu am a (m u naamuu n) u u (a) uu a uu mu uu. mam (19), (28) naam, m amua am mau u m ¶rt; am amu: a) na ¶rt;um am, n n a uu am u uu a uu; ) ma ¶rt;um am, m aam uu a uu. 相似文献
43.
The paper considers a puff diffusion in its inertial stage when particle separation obeys the laws of the inertial subrange and depends only on eddy energy dissipation rate . The can be determined in the surface layer by the turbulent kinetic energy equation. Similarity equations connect with diffusion measure .A simple analytical model has been deduced to estimate pollutants diffusion during calms. 相似文献
44.
Summary Tests on the vertical vibrating table in the frequency range of70–110 Hz indicate that quartz gravity meters are10–100 times more sensitive at some frequencies than under low-frequency excitation. At high frequencies, the reading beam is at rest and deflected from the correct position. Slow fluctuations of amplitude and frequency near resonance could cause slow irregular motion of the beam with absence of low-frequency ground motion of sufficient intensity.
unmauaum a mua um¶rt; ¶rt;uana amm 70–110u mam, m a m ammaaum 10–100 a mum nu uamm au. u amm au u a¶rt;um n m mu m nu. ¶rt; auauu anum¶rt; u amm au uu aa m am uamm u ua ¶rt;a mmmm uamm au n ¶rt;mam umumu.相似文献
45.
M. štemprok 《International Journal of Earth Sciences》1987,76(1):169-175
Greisenisation is a postmagmatic process associated with the origin of leucocratic high silica granites. In its course feldspars and Fe-micas are decomposed. The changes caused by greisenisation in various rock types are discussed and the data on the nature of greisenising fluids are summarized.
Zusammenfassung Vergreisung ist ein postmagmatischer Vorgang, der mit der Entstehung leukokrater SiO2-reicher Granite verbunden ist. In seinem Verlauf sind Feldspäte und Fe-Glimmer zersetzt. Die Auswirkung von Vergreisung auf verschiedene Gesteinstypen sowie der Charakter der vergreisenden Fluide wird diskutiert.
Résumé La greisénisation est un processus postmagmatique associé à la formation des leucogranites riches en silice. Au cours de ce processus, les feldspaths et les micas ferreux sont décomposés. La note discute les modifications apportées par la greisénisation dans les roches de diverses natures; elle résume les données relatives à la nature des fluides responsables du phénomène.
, , . . , .相似文献
46.
Summary The routine nulling procedure is modified on the basis of the theoretical decay of transient motion of the gravity meter beam and the time needed for its stabilizing. 相似文献
47.
The eruptive prominence observed on 27 May 1999 in H at Ondejov Observatory is analyzed using image-processing techniques. To understand the physical processes behind the prominence eruption, heated structures inside the cold H prominence material are sought. Two local minima of intensity (holes), the first above and the second below the erupting H prominence, have been found in the processed H images. A comparison of H images with the SOHO/EIT and Yohkoh/SXT images showed: (a) the cold H prominence is visible as a dark feature in the EIT images, (b) the upper local minimum of intensity in the H image corresponds to a hot structure seen in EIT, (c) the lower minimum corresponds to a hot loop observed by SXT. The physical significance of the H intensity minima and their relation to the hot structures observed by EIT and SXT is discussed. The time sequence of observed processes is in favor of the prominence eruption model with the destabilization of the loop spanning the prominence. For comparison with other events the velocities of selected parts of the eruptive prominence are determined. 相似文献
48.
The Velenje area (almost 200 km2 with over 31,000 inhabitants) is based on the Šalek Valley, which became a leading area of industrialisation and urbanisation
after the Second World War, with consequent pollution problems. Various industrial plants polluted the river Paka while more
serious hazards arose through the coal mine which is a still causing landscape subsidence and the thermal power station in
the neighbourhood of Šoštanj which is a major source of sulphur dioxide and nitrogen oxide pollution. In 1987 there was an
ecological protest which marked the beginning of a sustainable development strategy for the community. During the past decade
programmes have dealt with the degradation of air, soil and water to achieve cleaner air, a transformation in landuse and
enhancement the river's formerly weak self-purifying capabilities. This article examines the changes in the valley since the
attention of the authorities was drawn to the deterioration of living conditions. Despite the pressures of transition which
have seen unemployment rising to over ten percent, significant environmental improvements have been made and the area stands
as a model for the rest of the country.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
49.
Miroslav Kocifaj 《Studia Geophysica et Geodaetica》1992,36(4):376-391
Summary The vertical profile of the aerosol attenuation coefficient can be calculated from the measurements of the spectral flux density of direct solar radiation and spectral radiance in a clear sky in a certain sun aureola by using the theory applied in this article. The process of solar radiation scattering is solved up to third order. 相似文献
50.