全文获取类型
收费全文 | 26937篇 |
免费 | 342篇 |
国内免费 | 178篇 |
专业分类
测绘学 | 495篇 |
大气科学 | 1555篇 |
地球物理 | 5250篇 |
地质学 | 10515篇 |
海洋学 | 2590篇 |
天文学 | 5930篇 |
综合类 | 52篇 |
自然地理 | 1070篇 |
出版年
2022年 | 301篇 |
2021年 | 479篇 |
2020年 | 452篇 |
2019年 | 510篇 |
2018年 | 1061篇 |
2017年 | 985篇 |
2016年 | 1028篇 |
2015年 | 461篇 |
2014年 | 887篇 |
2013年 | 1482篇 |
2012年 | 1069篇 |
2011年 | 1321篇 |
2010年 | 1234篇 |
2009年 | 1452篇 |
2008年 | 1247篇 |
2007年 | 1386篇 |
2006年 | 1249篇 |
2005年 | 753篇 |
2004年 | 798篇 |
2003年 | 741篇 |
2002年 | 697篇 |
2001年 | 610篇 |
2000年 | 504篇 |
1999年 | 403篇 |
1998年 | 404篇 |
1997年 | 381篇 |
1996年 | 286篇 |
1995年 | 297篇 |
1994年 | 273篇 |
1993年 | 213篇 |
1992年 | 246篇 |
1991年 | 202篇 |
1990年 | 225篇 |
1989年 | 199篇 |
1988年 | 171篇 |
1987年 | 200篇 |
1986年 | 187篇 |
1985年 | 219篇 |
1984年 | 215篇 |
1983年 | 214篇 |
1982年 | 201篇 |
1981年 | 193篇 |
1980年 | 171篇 |
1979年 | 189篇 |
1978年 | 180篇 |
1977年 | 162篇 |
1976年 | 148篇 |
1975年 | 151篇 |
1974年 | 141篇 |
1973年 | 179篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
113.
114.
115.
116.
Churyumov K. I. Klesachonok V. V. Mussaev F. A. Bikmaev I. F. Galazutdinov G. H. 《Earth, Moon, and Planets》1997,78(1-3):105-110
We present the results of the preliminary study of the comet Hale-Bopp spectrum obtained April 17, 1997 by K. Churyumov and F. Mussayev with the help of the 1-meter Zeiss reflector and the echelle spectrometer (spectral resolutionλ/Δ λ ≈ 50000), CCD and the long slit, oriented along the radius-vector(“Sun-comet direction”). Energy distributions for three selected regions including the C3, C2 (0-0) and CN(Δ ν = 0) molecules emissions of the comet Hale-Bopp spectrum were built. The rotational lines of the CN(Δ ν = 0) band were identified. The nature of the high emission peak near λ 4020 Å in the C3 band is discussed. The presence of the cometary continuum of the nonsolar origin is assumed. 相似文献
117.
V. I. Ferronsky S. A. Denisik S. V. Ferronsky 《Celestial Mechanics and Dynamical Astronomy》1996,64(3):167-183
The physical meaning of the terms of the potential and kinetic energy expressions, expanded by means of the density variation function for a nonuniform self-gravitating sphere, is discussed. The terms of the expansions represent the energy and the moment of inertia of the uniform sphere, the energy and the moment of inertia of the nonuniformities interacting with the uniform sphere, and the energy of the nonuniformities interacting with each other. It follows from the physical meaning of the above components of the energy structure, and also from the observational fact of the expansion of the Universe that the phase transition, notably, fusion of particles and nuclei and condensation of liquid and solid phases of the expanded matter accompanied by release of energy, must be the physical cause of initial thermal and gravitational instability of the matter. The released kinetic energy being constrained by the general motion of the expansion, develops regional and local turbulent (cyclonic) motion of the matter, which should be the second physical effect responsible for the creation of celestial bodies and their rotation. 相似文献
118.
119.
120.
L. I. Onuora 《Astrophysics and Space Science》1987,136(1):11-15
The inflationary unvierse model predicts the density parameter 0 to be 1.0 with the cosmological constant 0 usually taken to be zero, whereas observational estimates give 00.2 and 010-57 cm–2. It was found, however, that the observed variation of angular diameter with redshift for extragalactic radio sources could be interpreted in terms of a low density universe with linear size evolution of the sources for either an inflationary model with 0 or an open model with =0. 相似文献