全文获取类型
收费全文 | 579篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 58篇 |
大气科学 | 34篇 |
地球物理 | 70篇 |
地质学 | 208篇 |
海洋学 | 17篇 |
天文学 | 186篇 |
综合类 | 1篇 |
自然地理 | 19篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 35篇 |
2017年 | 25篇 |
2016年 | 33篇 |
2015年 | 17篇 |
2014年 | 29篇 |
2013年 | 27篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 23篇 |
2009年 | 21篇 |
2008年 | 13篇 |
2007年 | 13篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 15篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 9篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 5篇 |
排序方式: 共有593条查询结果,搜索用时 0 毫秒
191.
R. K. Srivastava 《Astrophysics and Space Science》1987,134(1):177-180
The period study of the eclipsing binary system GH Pegasi has been presented for the first time. A new period (P=2d.556135) of GH Peg, based on all available times of minima, has been given. O–C diagrams of the system have also been presented for the first time, and the period changes present in the system have been analysed. The period shows changes around the year 1972 and 1981. The total period change in different portions of the O–C diagram, based on the corrected period, ranges from 5.2×10–6 d to 7.0×10–5 d. The photoelectric minima show sufficiently large scatter in the system. 相似文献
192.
Scanner observations of the coma of periodic comet Encke (P/Encke) are presented for four nights in March 1984 during its post-perihelion period. The strong emission features of CN and C2 molecules have been identified and the abundances of CN and C2 are estimated. The production rates of these molecules have also been derived from their band luminosities. No trace of sodium emission has been found in this comet. 相似文献
193.
In this paper, similarity solutions for the propagation of strong-plane shock waves in optically-thin grey atmospheres are obtained in the presence of a magnetic field. Density and magnetic field are constant in the undisturbed gaseous medium in front of the shock. Planck's diffusion approximation has been taken into account in this problem and a comparative study has been made between the results of ordinary gasdynamics and magnetogasdynamics. 相似文献
194.
Plane-symmetric solutions of Einstein's field equations in vacuum, in the presence of electromagnetic fields and with cosmological constant are explored in null coordinates. The gravitational field of an infinite plane (uncharged and charged both) is thus obtained in a simple and systematic way. The method adopted for these solutions has possibilities of generalization. 相似文献
195.
R. C. Srivastava 《Astrophysics and Space Science》1983,92(2):359-364
The propagation of a magnetogasdynamic shock wave originating in a stellar interior, is ocnsidered when it approaches the surfaces of the star. The flow behind the shock wave is assumed isothermal rather than adiabatic to stimulate the conditions of large radiative transfer near the stellar surface. The product solution of McVittie has been used to obtain exact solution of the problem. It has been obtained that velocity, density, pressure and magnetic field increases as we move from shock surface towards the nucleus of the star. 相似文献
196.
This paper studies sonic waves in an optically thick medium under the influence of a magnetic field. The conductivity of the medium has been taken to be infinite. The effects of radiation, radiation energy density, radiative heat transfer and magnetic field have been taken into account. It has been obtained that the magnetic field has significant effect on sonic velocity. The fundamental differential equations governing the growth and decay of sonic waves are determined and solved. 相似文献
197.
In the present work the reflection of a plane shock wave is studied in order to achieve a high pressure and temperature state by a reflected shock wave. We consider the plane geometry and solve the one-dimensional, time-dependent system of hyperbolic equations by Rusanov's method. 相似文献
198.
R. K. Srivastava 《Astrophysics and Space Science》1983,92(1):149-159
UBV photometry of the eclipsing binary system XX Cas has been presented. Primary eclipse appears to be a total occultation rather than a partial transit (Pierce, 1938). A slightly improved period of 3d.0671708 has been obtained, and the colour of the system discussed. 相似文献
199.
We underline the importance of Alfvén wave dissipation in the magnetic funnels through the viscous and resistive plasma. Our
results show that Alfvén waves are one of the primary energy sources in the innermost part of coronal holes where the solar
wind outflow starts. 相似文献
200.