全文获取类型
| 收费全文 | 3473篇 |
| 免费 | 297篇 |
| 国内免费 | 498篇 |
专业分类
| 测绘学 | 73篇 |
| 大气科学 | 156篇 |
| 地球物理 | 460篇 |
| 地质学 | 1106篇 |
| 海洋学 | 729篇 |
| 天文学 | 1430篇 |
| 综合类 | 91篇 |
| 自然地理 | 223篇 |
出版年
| 2024年 | 15篇 |
| 2023年 | 42篇 |
| 2022年 | 72篇 |
| 2021年 | 87篇 |
| 2020年 | 86篇 |
| 2019年 | 91篇 |
| 2018年 | 84篇 |
| 2017年 | 100篇 |
| 2016年 | 82篇 |
| 2015年 | 109篇 |
| 2014年 | 123篇 |
| 2013年 | 113篇 |
| 2012年 | 114篇 |
| 2011年 | 161篇 |
| 2010年 | 134篇 |
| 2009年 | 277篇 |
| 2008年 | 261篇 |
| 2007年 | 275篇 |
| 2006年 | 287篇 |
| 2005年 | 220篇 |
| 2004年 | 221篇 |
| 2003年 | 185篇 |
| 2002年 | 173篇 |
| 2001年 | 170篇 |
| 2000年 | 156篇 |
| 1999年 | 139篇 |
| 1998年 | 149篇 |
| 1997年 | 49篇 |
| 1996年 | 51篇 |
| 1995年 | 49篇 |
| 1994年 | 39篇 |
| 1993年 | 19篇 |
| 1992年 | 18篇 |
| 1991年 | 16篇 |
| 1990年 | 15篇 |
| 1989年 | 8篇 |
| 1988年 | 6篇 |
| 1987年 | 6篇 |
| 1986年 | 10篇 |
| 1985年 | 19篇 |
| 1984年 | 15篇 |
| 1983年 | 6篇 |
| 1982年 | 5篇 |
| 1981年 | 8篇 |
| 1978年 | 2篇 |
| 1954年 | 1篇 |
排序方式： 共有4268条查询结果，搜索用时 31 毫秒
41.
42.
Fabio Fontanot Pierluigi Monaco Stefano Borgani 《Monthly notices of the Royal Astronomical Society》2003,341(2):692-706
We apply the ztrace algorithm to the optical NOG and infrared PSC z galaxy catalogues to reconstruct the pattern of primordial fluctuations that have generated our local Universe. We check that the density fields traced by the two catalogues are well correlated, and consistent with a linear relation [either in δ or in log (1 +δ) ] with relative bias (of NOG with respect to PSC z ) b rel = 1.1 ± 0.1 . The relative bias relation is used to fill the optical zone of avoidance at | b | < 20° using the PSC z galaxy density field.
We perform extensive testing on simulated galaxy catalogues to optimize the reconstruction. The quality of the reconstruction is predicted to be good at large scales, up to a limiting wavenumber klim ≃ 0.4 h Mpc−1 beyond which all information is lost. We find that the improvement arising from the denser sampling of the optical catalogue is compensated by the uncertainties connected to the larger zone of avoidance.
The initial conditions reconstructed from the NOG catalogue are found (analogously to those from the PSC z ) to be consistent with a Gaussian paradigm. We use the reconstructions to produce sets of initial conditions ready to be used for constrained simulations of our local Universe. 相似文献
We perform extensive testing on simulated galaxy catalogues to optimize the reconstruction. The quality of the reconstruction is predicted to be good at large scales, up to a limiting wavenumber k
The initial conditions reconstructed from the NOG catalogue are found (analogously to those from the PSC z ) to be consistent with a Gaussian paradigm. We use the reconstructions to produce sets of initial conditions ready to be used for constrained simulations of our local Universe. 相似文献
43.
W.W. Zeilinger S. De Rijcke H. Dejonghe G.K.T. Hau 《Astrophysics and Space Science》2003,284(2):607-610
Deep imaging and long-slit spectroscopy was obtained for a sample of dwarf ellipticals in the Fornax cluster, NGC 5044 and
NGC 5898 groups using the ESO VLT. The observational data extend out to typically 1.5–2 effective radii and indicate a kinematic
dichotomy in the family of ellipticals. The observed stellar kinematics indicate a luminosity–velocity dispersion relation
largely supporting Supernova-driven stellar mass loss scenarios for the formation of dwarf ellipticals. Stellar dynamical
models favour dark matter halos with typical mass-to-light ratios in the range of 3 to 9 solar units.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
44.
Ramona Núñez-López Anton Lipovka Vladimir Avila-Reese 《Monthly notices of the Royal Astronomical Society》2006,369(4):2005-2012
Possible detection of signatures of structure formation at the end of the 'dark age' epoch ( z ∼ 40–20) is examined. We discuss the spectral–spatial fluctuations in the cosmic microwave background radiation (CMBR) temperature produced by elastic resonant scattering of CMBR photons on deuterated hydrogen (HD) molecules located in protostructures moving with peculiar velocity. Detailed chemical kinematic evolution of HD molecules in the expanding homogeneous medium is calculated. Then, the HD abundances are linked to protostructures at their maximum expansion, whose properties are estimated by using the top-hat spherical approach and the Λ cold dark matter (ΛCDM) cosmology. We find that the optical depths in the HD three lowest pure rotational lines for high-peak protohaloes at their maximum expansion are much higher than those in LiH molecule. The corresponding spectral–spatial fluctuation amplitudes, however, are probably too weak to be detected by current and forthcoming millimetre telescope facilities. We extend our estimates of spectral–spatial fluctuations to gas clouds inside collapsed CDM haloes by using results from a crude model of HD production in these clouds. The fluctuations for the highest peak CDM haloes at redshifts ∼20–30 could be detected in the future. Observations will be important to test model predictions of early structure formation in the Universe. 相似文献
45.
46.
47.
48.
49.
50.