全文获取类型
收费全文 | 619篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 15篇 |
大气科学 | 49篇 |
地球物理 | 91篇 |
地质学 | 106篇 |
海洋学 | 31篇 |
天文学 | 308篇 |
综合类 | 3篇 |
自然地理 | 37篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 11篇 |
2020年 | 9篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 17篇 |
2016年 | 11篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 13篇 |
2012年 | 18篇 |
2011年 | 17篇 |
2010年 | 12篇 |
2009年 | 40篇 |
2008年 | 31篇 |
2007年 | 28篇 |
2006年 | 42篇 |
2005年 | 39篇 |
2004年 | 48篇 |
2003年 | 36篇 |
2002年 | 37篇 |
2001年 | 29篇 |
2000年 | 26篇 |
1999年 | 21篇 |
1998年 | 26篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1970年 | 3篇 |
1967年 | 1篇 |
排序方式: 共有640条查询结果,搜索用时 15 毫秒
71.
J. Crummy A. C. Fabian L. Gallo R. R. Ross 《Monthly notices of the Royal Astronomical Society》2006,365(4):1067-1081
We present a large sample of type 1 active galactic nuclei (AGN) spectra taken with XMM–Newton , and fit them with both the conventional model (a power law and blackbody) and the relativistically blurred photoionized disc reflection model of Ross & Fabian. We find that the disc reflection model is a better fit. The disc reflection model successfully reproduces the continuum shape, including the soft excess, of all the sources. The model also reproduces many features that would conventionally be interpreted as absorption edges. We are able to use the model to infer the properties of the sources, specifically that the majority of black holes in the sample are strongly rotating, and that there is a deficit in sources with an inclination >70°. We conclude that the disc reflection model is an important tool in the study of AGN X-ray spectra. 相似文献
72.
73.
74.
A. C. Fabian 《Astrophysics and Space Science》2005,300(1-3):97-105
Several AGN and black hole X-ray binaries show a clear very broad iron line, which is strong evidence that the black holes
are rapidly spinning. Detailed analysis of these objects shows that the emission line is not significantly affected by absorption
and that the source variability is principally due to variation in amplitude of a power-law. Underlying this is a much less
variable, relativistically-smeared, reflection-dominated, component which carries the imprint of strong gravity at a few gravitational
radii. The strong gravitational light bending in these regions then explains the power-law variability as due to changes in
height of the primary X-ray source above the disc. The reflection component, in particular its variability and the profile
of the iron line, enables us to study the innermost regions around an accreting, spinning, black hole. 相似文献
75.
76.
77.
A. C. Fabian C. S. Reynolds G. B. Taylor R. J. H. Dunn 《Monthly notices of the Royal Astronomical Society》2005,363(3):891-896
Recent X-ray and optical observations of the Perseus cluster indicate that a combination of weak shocks at small radii (≳20 kpc) and viscous and conductive dissipation of sound waves at larger radii is responsible for heating the intracluster medium and can balance radiative cooling of cluster cores. We discuss this mechanism more generally and show how the specific heating and cooling rates vary with temperature and radius. It appears that this heating mechanism is most effective above 107 K , which allows for radiative cooling to proceed within normal galaxy formation but stifles the growth of very massive galaxies. The scaling of the wavelength of sound waves with cluster temperature and feedback in the system are investigated. 相似文献
78.
On the X-ray spectra of luminous, inhomogeneous accretion flows 总被引:1,自引:0,他引:1
A. Merloni J. Malzac A. C. Fabian R. R. Ross 《Monthly notices of the Royal Astronomical Society》2006,370(4):1699-1712
79.
80.