全文获取类型
收费全文 | 605篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 60篇 |
大气科学 | 39篇 |
地球物理 | 77篇 |
地质学 | 213篇 |
海洋学 | 19篇 |
天文学 | 191篇 |
综合类 | 1篇 |
自然地理 | 19篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 36篇 |
2017年 | 29篇 |
2016年 | 33篇 |
2015年 | 17篇 |
2014年 | 30篇 |
2013年 | 29篇 |
2012年 | 21篇 |
2011年 | 16篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 15篇 |
2007年 | 13篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 17篇 |
1990年 | 10篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 24篇 |
1986年 | 17篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 14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619条查询结果,搜索用时 15 毫秒
71.
Nonlinear analysis of electrostatic drift Kelvin-Helmholtz instability is performed. It is shown that the analysis leads to the propagation of the weakly nonlinear dispersive waves and the nonlinear behaviour is governed by the nonlinear Burger's equation. 相似文献
72.
The eclipsing binary AV Hya has been observed photoelectrically inU, B andV filters on 15 nights. The primary eclipse appeared to be total with a totality of 23 min duration. A modified period of 0d.6 834 062 has been obtained. Geometrical elements could only be determined for partial transit case. 相似文献
73.
The propagation of sonic discontinuity in conducting and radiating atmosphere has been discussed under the influence of magnetic field. The velocity of sonic wave and its termination into shock wave has been obtained. We have also obtained the critical time at which sonic wave terminates into shock wave. There is significant effect of magnetic field on sonic velocity and its termination into shock wave. 相似文献
74.
The photoelectric observations of the eclipsing binary XY Ceti presented by us (see Srivastava and Padalia, 1975) have been analysed by Okazaki (1978) and Ramellaet al. (1980). They presented different sets of elements from the same set of our observations. This necessitated us to obtain the elements of XY Ceti again employing recent method of determination of elements.The revised geometrical elements of the eclipsing binary XY Ceti have been obtained by the method of Fourier analysis of the light changes in the frequency-domain, which was developed by Kopal (1979). These have been compared with our earlier (Srivastava and Padalia, 1975) results obtained by employing Russell and Merrill's (1952) method. The revised absolute dimensions of XY Ceti have been obtained using the spectroscopic elements given by Popper (1971), and the newly derived geometrical elements. The Roche radii have been derived to discuss the evolution of the system. The secondary component lies reasonably near to the Main Sequence, while the primary component falls above it. The evolutionary discussion indicates that the system is a detached one. 相似文献
75.
An exact similarity solution for a spherical magnetogasdynamic shock is obtained in the case when radiation energy, radiation pressure and radiative heat flux are important. The total energy of the shock wave increase with time. We have shown that due to the magnetic field the flow variables are considerably changed. Also, due to increases in radiation pressure number the radiation flux is increased. 相似文献
76.
Photometric observations of primary minimum inU, B, andV filters have been discussed. The amplitude of variation in all the three filters is 0
m
.66. We do not find variations in the period and its revised value is 1d.0047115. 相似文献
77.
Self-similar flows of a perfect gas behind the cylindrical shock wave propagating exponentially in an atmosphere whose density varies inversely as the fourth power of shock radius are investigated. The effects of radiation flux has also been taken into consideration. The total energy of the wave is constant. 相似文献
78.
R. K. Srivastava 《Astrophysics and Space Science》1987,132(1):125-139
The colour indices and the spectrum-luminosity classification of the eclipsing binary system IZ Persei have been presented for the first time. The colour indices of the system appear reddened. Applying the interstellar reddening corrections, the spectral-luminosity classes of the primary and the secondary components of IZ Per come out to be B2.5III-V and B5III-V, respectively. The averageB-V andU-B colour excesses come out to be 0
m
.4 and 0
m
.2, respectively. The colour indices show continuous variation throughout the cycle, and indicate the presence of intrinsic variability. Tentative analysis suggests that the primary component of IZ Per is a Beta Canis Majoris-type variable. The possibility of a shell has also been discussed. 相似文献
79.
Photometric observations of CU Eridani, recently classified as non-variable, indicate it to be a variable star. 相似文献
80.
Srivastava R 《Ground water》2004,42(3):457-8; discussion 458