全文获取类型
收费全文 | 170篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 12篇 |
地球物理 | 37篇 |
地质学 | 71篇 |
海洋学 | 23篇 |
天文学 | 26篇 |
综合类 | 1篇 |
自然地理 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 8篇 |
2011年 | 7篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 4篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 1篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 15 毫秒
121.
The Salt Basin is a semiarid hydrologically closed drainage basin in southern New Mexico, USA. The aquifers in the basin consist largely of Permian limestone and dolomite. Groundwater flows from the high elevations (~2,500 m) of the Sacramento Mountains south into the Salt Lakes, which are saline playas. The aquifer is ‘underfit’ in the sense that depths to groundwater are great (~300 m), implying that the aquifer could transmit much more water than it does. In this study, it is speculated that this characteristic is a result of a geologically recent reduction in recharge due to warming and drying at the end of the last glacial period. Water use is currently limited, but the basin has been proposed for large-scale groundwater extraction and export projects. Wells in the basin are of limited utility for hydraulic testing; therefore, the study focused on environmental tracers (major-ion geochemistry, stable isotopes of O, H, and C, and 14C dating) for basin analysis. The groundwater evolves from a Ca–HCO3 type water into a Ca–Mg (Na) – HCO3–Mg (Cl) water as it flows toward the center of the basin due to dedolomitization driven by gypsum dissolution. Carbon-14 ages corrected for dedolomitization ranged from less than 1,000 years in the recharge area to 19,000 years near the basin center. Stable isotopes are consistent with the presence of glacial-period recharge that is much less evaporated than modern. This supports the hypothesis that the underfit nature of the aquifer is a result of a geologically recent reduction in recharge. 相似文献
122.
123.
124.
在2001~2003年Cluster飞船通过近地磁尾期间,共探测到14次重联事件,在这些事件中同时还观测到等离子体波活动.本文把14次事件分为三大类,其中:第I类包含了8次事件,它们是在等离子体片内先于重联事件观测到波活动,并且还同时观测到Hall磁场.经过分析判断,这类事件中观测到的波是右旋偏振的哨声波.第II类包含了2次事件,这类事件也观测到了Hall磁场和右旋偏振的哨声波.第Ⅲ类也包含了2次事件,这类事件只是普通的重联事件,没有观测到Hall磁场,但是波活动明显先于重联事件.在我们观测的14次事件中,比较强烈的哨声波和Hall 磁场是一一对应的,因此哨声波可能主要是在Hall磁场的四极结构区激发的. 相似文献
125.
Abdolali Ali van der Westhuysen Andre Ma Zaizhong Mehra Avichal Roland Aron Moghimi Saeed 《Ocean Dynamics》2021,71(2):217-235
Ocean Dynamics - Various uncertainties exist in a hindcast due to the inabilities of numerical models to resolve all the complicated atmosphere-sea interactions, and the lack of certain ground... 相似文献
126.
C. Hans Nelson Andres Maldonado Francis Coumes Henri Got Andre Manaco 《Geo-Marine Letters》1983,3(2-4):125-131
The Ebro Fan System consists of en echelon channel-levee complexes, 50×20 km in area and 200-m thick. A few strong reflectors in a generally transparent seismic facies identify the sand-rich channel floors and levee crests. Numerous continuous acoustic reflectors characterize overbank turbidites and hemipelagites that blanket abandoned channel-levee complexes. The interlobe areas between channel complexes fill with homogeneous mud and sand from mass flow and overbank deposition; these exhibit a transparent seismic character. The steep continental rise and sediment “drainage” of Valencia Trough at the end of the channel-levee complexes prevent the development of distributary channels and midfan lobe deposits. 相似文献
127.
Andre Deprit 《Celestial Mechanics and Dynamical Astronomy》1976,13(2):253-263
Cartan's exterior calculus is used to refer a perturbed Keplerian motion to an ideal frame by means of either the Eulerian parameters or the Eulerian angles, in which case the equations are given a Hamiltonian form. The results are compared with the corresponding systems in the orbital and nodal frames. 相似文献
128.
Andre G. Journel 《Mathematical Geology》2004,36(8):995-1014
Subject Index
Subject Index 相似文献129.
Andre Deprit 《Celestial Mechanics and Dynamical Astronomy》1975,12(4):489-493
The geodetic latitude and the height of a satellite are obtained as power series in the ellipsoid's eccentricity, the terms being Fourier sums in the geocentric latitude with polynomials in 1/r as coefficients, with a view of determining the height to the fullest accuracy required by altimetry and geodesy from satellites. 相似文献
130.