全文获取类型
收费全文 | 3937篇 |
免费 | 711篇 |
国内免费 | 460篇 |
专业分类
测绘学 | 684篇 |
大气科学 | 268篇 |
地球物理 | 1051篇 |
地质学 | 1205篇 |
海洋学 | 453篇 |
天文学 | 161篇 |
综合类 | 657篇 |
自然地理 | 629篇 |
出版年
2024年 | 11篇 |
2023年 | 41篇 |
2022年 | 79篇 |
2021年 | 117篇 |
2020年 | 132篇 |
2019年 | 162篇 |
2018年 | 134篇 |
2017年 | 148篇 |
2016年 | 164篇 |
2015年 | 213篇 |
2014年 | 213篇 |
2013年 | 246篇 |
2012年 | 247篇 |
2011年 | 211篇 |
2010年 | 158篇 |
2009年 | 202篇 |
2008年 | 240篇 |
2007年 | 265篇 |
2006年 | 236篇 |
2005年 | 203篇 |
2004年 | 173篇 |
2003年 | 163篇 |
2002年 | 114篇 |
2001年 | 129篇 |
2000年 | 143篇 |
1999年 | 132篇 |
1998年 | 121篇 |
1997年 | 96篇 |
1996年 | 102篇 |
1995年 | 78篇 |
1994年 | 90篇 |
1993年 | 66篇 |
1992年 | 50篇 |
1991年 | 49篇 |
1990年 | 33篇 |
1989年 | 45篇 |
1988年 | 24篇 |
1987年 | 17篇 |
1986年 | 21篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1954年 | 4篇 |
排序方式: 共有5108条查询结果,搜索用时 15 毫秒
81.
B. Tapley J. Ries S. Bettadpur D. Chambers M. Cheng F. Condi B. Gunter Z. Kang P. Nagel R. Pastor T. Pekker S. Poole F. Wang 《Journal of Geodesy》2005,79(8):467-478
A new generation of Earth gravity field models called GGM02 are derived using approximately 14 months of data spanning from
April 2002 to December 2003 from the Gravity Recovery And Climate Experiment (GRACE). Relative to the preceding generation,
GGM01, there have been improvements to the data products, the gravity estimation methods and the background models. Based
on the calibrated covariances, GGM02 (both the GRACE-only model GGM02S and the combination model GGM02C) represents an improvement
greater than a factor of two over the previous GGM01 models. Error estimates indicate a cumulative error less than 1 cm geoid
height to spherical harmonic degree 70, which can be said to have met the GRACE minimum mission goals.
Electronic Supplementary Material Supplementary material is available in the online version of this article at 相似文献
82.
In space-borne gravitational field determination, two challenges are inherent. First, the continuation of the data down to
the surface of the Earth is an ill-posed problem, requiring therefore regularization techniques. Second huge data sets result
requiring efficient numerical methods. In this paper, we show how locally supported wavelets on the sphere can be developed
by means of a spherical version of the so-called up function. By construction, the corresponding scaling functions and wavelets
are infinitely smooth, so that they can be used for regularization purposes. In particular, we show how the ill-posed pseudo-differential
equations coming from satellite missions can be regularized by efficient numerical schemes using locally supported wavelets.
These methods seem in particular to be interesting for regional gravity field modelling. 相似文献
83.
Introduction The tidal variation signals of the solid Earth recorded with the modern measuring techniques can be used to provide effectively the means to cognize the Earths motion, deformation and structure character, especially to monitor the material motion in the Earths interior. In the recent 20 years, the distribution character of the global gravity field has made great progress since the continuous and deep theoretical studies in geophysics and geodesy domains. The successful manufactur… 相似文献
84.
Paleolatitudes of the Kerguelen hotspot: new paleomagnetic results and dynamic modeling 总被引:1,自引:0,他引:1
The Kerguelen Plateau, a Large Igneous Province in the southern Indian Ocean, was formed as a product of the Kerguelen hotspot in several eruptive phases during the last 120 Myr. We obtained new paleolatitudes for the central and northern Kerguelen Plateau from paleomagnetic investigations on basalts, which were drilled during ODP Leg 183 to the Kerguelen Plateau-Broken Ridge. The paleolatitudes coincide with paleolatitudes from previous investigations at the Kerguelen Plateau and Ninetyeast Ridge (the track of the Kerguelen hotspot) and indicate a difference between paleolatitudes and present position at 49°S of the Kerguelen hotspot. We show that true polar wander, the global motion between the mantle and the rotation axis, cannot explain this difference in latitudes. We present numerical model results of plume conduit motion in a large-scale mantle flow and the resulting surface hotspot motion. A large number of models all predict southward motion between 3° and 10° for the Kerguelen hotspot during the last 100 Myr, which is consistent with our paleomagnetic results. 相似文献
85.
86.
87.
88.
89.
90.
Daily geomagnetic variations on the Iberian Peninsula 总被引:2,自引:0,他引:2