全文获取类型
收费全文 | 942篇 |
免费 | 44篇 |
国内免费 | 46篇 |
专业分类
测绘学 | 19篇 |
大气科学 | 25篇 |
地球物理 | 85篇 |
地质学 | 96篇 |
海洋学 | 41篇 |
天文学 | 749篇 |
综合类 | 13篇 |
自然地理 | 4篇 |
出版年
2024年 | 6篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 7篇 |
2017年 | 10篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 21篇 |
2013年 | 15篇 |
2012年 | 23篇 |
2011年 | 21篇 |
2010年 | 31篇 |
2009年 | 84篇 |
2008年 | 69篇 |
2007年 | 102篇 |
2006年 | 72篇 |
2005年 | 88篇 |
2004年 | 69篇 |
2003年 | 66篇 |
2002年 | 57篇 |
2001年 | 52篇 |
2000年 | 32篇 |
1999年 | 35篇 |
1998年 | 46篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有1032条查询结果,搜索用时 62 毫秒
61.
62.
On the origins of part-time radio pulsars 总被引:1,自引:0,他引:1
Bing Zhang Janusz Gil Jaroslaw Dyks 《Monthly notices of the Royal Astronomical Society》2007,374(3):1103-1107
63.
Mark Cropper Silvia Zane Roberto Turolla Luca Zampieri Matteo Chieregato Jeremy Drake Aldo Treves 《Astrophysics and Space Science》2007,308(1-4):161-166
We report XMM-Newton observations of the isolated neutron star RBS1774 and confirm its membership as an XDINS. The X-ray spectrum is best fit
with an absorbed blackbody with temperature kT=101 eV and absorption edge at 0.7 keV. No power law component is required. An absorption feature in the RGS data at 0.4 keV
is not evident in the EPIC data, but it is not possible to resolve this inconsistency. The star is not seen in the UV OM data
to m
AB
∼21. There is a sinusoidal variation in the X-ray flux at a period of 9.437 s with an amplitude of 4%. The age as determined
from cooling and magnetic field decay arguments is 105–106 yr for a neutron star mass of 1.35–1.5 M⊙.
相似文献
64.
65.
I. Zh. Stefanov 《Astronomische Nachrichten》2016,337(3):246-253
The observation of a pair of simultaneous twin kHz QPOs in the power density spectrum of a neutron star or a black hole allows its mass‐angular‐momentum relation to be constrained. Situations in which the observed simultaneous pairs are more than one allow the different models of the kHz QPOs to be falsified. Discrepancy between the estimates coming from the different pairs would call the used model into question. In the current paper, the relativistic precession model is applied to the twin kHz QPOs that appear in the light curves of three groups of observations of the accreting millisecond X‐ray pulsar IGR J17511–3057. It was found that the predictions of one of the groups are practically in conflict with the other two. Another interesting result is that the region in which the kHz QPOs have been born is rather broad and extends quite far from the ISCO. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
66.
Y.‐C. Wei C.‐M. Zhang Y.‐H. Zhao Q.‐H. Peng X.‐J. Wu J. Wang Y.‐Y. Pan H.‐X. Yin Y. Yan T.‐S. Yan H.‐J. Tian A. Esamdin A.L. Luo Y. Cai A. Taani 《Astronomische Nachrichten》2010,331(8):817-831
Under the two initial 1‐D one parameter velocity distribution forms (one is normal, the other is exponential), the z direction scale height evolution of normal neutron stars in the Galaxy is studied by numerical simulation. We do statistics for the cases at different time segments, also do statistics for the cumulative cases made of each time segment. The results show in the cumulative cases the evolution curves of the scale heights are smoother than in the each time segment, i.e., the cumulation improve the signal‐to‐noise ratio. Certainly the evolution cases are different at different Galactic disk locations, which also have very large difference from the average cases in the whole disk. In the initial stages of z evolution of normal neutron stars, after the beginning transient states, the cumulative scale heights increase linearly with time, and the cumulative scale height increasing rates have linear relationship with the initial velocity distribution parameters, which have larger fluctuation in the vicinity of the Sun than in the whole disk. We utilize the linear relationship of the cumulative scale height increasing rates vs. the initial velocity distribution parameters in the vicinity of the Sun to make comparison with the observation near the Sun. The results show if there is no magnetic decay, then the deserved initial velocity parameters are obvious lower than the present well known results from some authors; whereas if introducing magnetic decay, for the 1‐D normal case we can make consistence among concerning results using magnetic decay time values which are supported by some authors, while for the 1‐D exponential case the results show the lackness of young pulsar samples in the larger z in the vicinity of the Sun (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
67.
68.
69.
70.
Hydrodynamically stationary, spherically symmetric accretion onto a neutron star is examined taking the reverse effect of radiation into account. It is assumed that the plasma flow is adiabatic and that radiation is generated in a thin surface layer of the neutron star, where incoming particles are slowed down. It is shown that for stationary accretion, neither a stop, nor a substantial slowing down of the accretion flux is possible for any physically allowed conditions far from the neutron star. 相似文献