全文获取类型
收费全文 | 322篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 31篇 |
地球物理 | 67篇 |
地质学 | 114篇 |
海洋学 | 17篇 |
天文学 | 93篇 |
自然地理 | 9篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 25篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 16篇 |
2009年 | 14篇 |
2008年 | 21篇 |
2007年 | 14篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 15篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有334条查询结果,搜索用时 15 毫秒
81.
The uptake of a suite of 19 metals from coastal seawaters upon both glass and Teflon surfaces reflected primarily the sorption of particulate matter derived from crustal rock weathering. Uptake for all elements was greater in the light than in the dark. Based upon these and earlier results, a new definition of scavenging for environmental systems is proposed. 相似文献
82.
83.
N. O. Weiss 《地球物理与天体物理流体动力学》2013,107(4):344-345
Abstract Edited by D. L. Book. Springer-Verlag, New York, 1981. 226 pp., DM 72,—, $33.60. (ISBN 0 387 104828) 相似文献
84.
85.
Craig J. Copi Dragan Huterer Dominik J. Schwarz Glenn D. Starkman 《Monthly notices of the Royal Astronomical Society》2009,399(1):295-303
We investigate the angular two-point correlation function of temperature in the Wilkinson Microwave Anisotropy Probe ( WMAP) maps. Updating and extending earlier results, we confirm the lack of correlations outside the Galaxy on angular scales greater than about 60° at a level that would occur in 0.025 per cent of realizations of the concordance model. This represents a dramatic increase in significance from the original observations by the Cosmic Background Explorer Differential Microwave Radiometer ( COBE-DMR) and a marked increase in significance from the first-year WMAP maps. Given the rest of the reported angular power spectrum C ℓ , the lack of large-angle correlations that one infers outside the plane of the Galaxy requires covariance among the C ℓ up to ℓ= 5 . Alternately, it requires both the unusually small (5 per cent of realizations) full-sky large-angle correlations and an unusual coincidence of alignment of the Galaxy with the pattern of cosmological fluctuations (less than 2 per cent of those 5 per cent). We argue that unless there is some undiscovered systematic error in their collection or reduction, the data point towards a violation of statistical isotropy. The near-vanishing of the large-angle correlations in the cut-sky maps, together with their disagreement with results inferred from full-sky maps, remains open problems, and are very difficult to understand within the concordance model. 相似文献
86.
V. Silva Aguirre M. Catelan A. Weiss A. A. R. Valcarce 《Astrophysics and Space Science》2010,328(1-2):123-127
One of the most dramatic events in the life of a low-mass star is the He flash, which takes place at the tip of the red giant branch (RGB) and is followed by a series of secondary flashes before the star settles into the zero-age horizontal branch (ZAHB). Yet, no stars have been positively identified in this key evolutionary phase, mainly for two reasons: first, this pre-ZAHB phase is very short compared to other major evolutionary phases in the life of a star; and second, these pre-ZAHB stars are expected to overlap the loci occupied by asymptotic giant branch (AGB), HB, and RGB stars observed in the color-magnitude diagram (CMD). We investigate the possibility of detecting these stars through stellar pulsations, since some of them are expected to rapidly cross the Cepheid/RR Lyrae instability strip in their route from the RGB tip to the ZAHB, thus becoming pulsating stars along the way. As a consequence of their very high evolutionary speed, some of these stars may present anomalously large period change rates. We constructed an extensive grid of stellar models and produced pre-ZAHB Monte Carlo simulations appropriate for the case of the Galactic globular cluster M3 (NGC 5272), where a number of RR Lyrae stars with high period change rates are found. Our results suggest that some—but certainly not all—of the RR Lyrae stars in M3 with large period change rates are in fact pre-ZAHB pulsators. 相似文献
87.
88.
Abstract— The potential hazard of a meteorite impact in the ocean is controversial with respect to the destructive power of generated large ocean waves (tsunamis). We used numerical modeling of hypervelocity impact to investigate the generation mechanism and the characteristics of the resulting waves up to a distance of 100–150 projectile radii. The wave signal is primarily controlled by the ratio between projectile diameter and water depth, and can be roughly classified into deep‐water and shallow‐water impacts. In the latter, the collapse of the crater rim results in a wave signal similar to solitary waves, which propagate and decay in agreement with shallow‐water wave theory. The much more likely scenario for an asteroid impact on Earth is a relatively small body (much smaller than the water depth) striking the deep sea. In this case, the collapse of the transient crater results in a significantly different and much more complex wave signal that is characterized by strong nonlinear behavior. We found that such waves decay much more rapidly than previously assumed and cannot be treated as long waves. For this reason, the shallow‐water theory is not applicable for the computation of wave propagation, and more complex models (full solution of the Boussinesq equations) are required. 相似文献
89.
90.
L.H. Chan J.M. Edmond R.F. Stallard W.S. Broecker Y.C. Chung R.F. Weiss T.L. Ku 《Earth and Planetary Science Letters》1976,32(2):258-267
226Ra and Ba show a general linear correlation in the oceanic water column within the uncertainties of the data: the slope of the line is about 4.6 nanomoles (nmoles) Ra/mole Ba, the intercept being at about 4 nmoles Ba/kg. This demonstrates the usefulness of Ba as a “chemical analogue” of Ra. Box-model calculations indicate that the average deep-water excess of Ra over Ba should be about 10% relative to the surface. This is consistent with the observations outside the deep northeast Pacific. However, the uncertainties in the data are such that the regional variation in the primary input cannot be resolved. In the deep waters of the North Pacific there is in fact a large excess of Ra relative to Ba. The one detailed profile presently available (204) can be explained consistently by a simple vertical advection-diffusion model. 相似文献