全文获取类型
收费全文 | 173篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 7篇 |
地球物理 | 74篇 |
地质学 | 49篇 |
海洋学 | 20篇 |
天文学 | 12篇 |
综合类 | 2篇 |
自然地理 | 17篇 |
出版年
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 1篇 |
2011年 | 8篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 7篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有184条查询结果,搜索用时 15 毫秒
11.
Gerardo Grelle Laura Bonito Maresca Rosalba Silvia Iacurto Claudia Madiai Paola Revellino Giuseppe Sappa 《地震工程与工程振动(英文版)》2021,20(1):63-78
The estimate of seismic site effects by experimental approaches is based on different assumptions aimed at simplifying the complex actual site conditions and related uncertainties.However,the reliability of the results can increase if the experimental data is focused on quite strong seismic sequences and the on-site acquisition of a large number of signals is deemed strategic for the assessment of the expected phenomena.Based on these considerations,the ground motion at the Red Zone sector of Amatrice hill,violently struck by the 2016-2017 Central Italy seismic sequence,was analyzed via an observational approach.A large set of weak motions(moment magnitude Mw 2.5-3.9)was analyzed in this study by means of standard(SSR)and horizontal to vertical(HVSR)spectral ratio techniques.The results from the experimental analysis of the site effects by using weak motion and noise signals show a significant amplification at the top of Amatrice hill with a remarkable polarization of the motion and changes in spectral shapes according to the topographic setting of the relief. 相似文献
12.
13.
14.
15.
16.
Estimation of residual fluxes in estuarine cross sections is a very important procedure to establish, among others aspects, residence time of contaminants, circulation pattern, and sediment transport dynamics. However, the analytical procedure to obtain such values is not trivial and is presented in detail, demonstrating the importance of the grid-cell area as a weighting element in the calculation of spatial averages. The procedure is tested with four different grid designs and it is shown that grids with proportional columns and rows are the only ones that do not introduce statistical noise in the estimation of the residual fluxes. The four designs are also tested with data from a cross section of the Bahía Blanca Estuary (Argentina), results again show that the proportional columns and rows grid provide the best approach in calculating residual fluxes. 相似文献
17.
Echavarri-Erasun B Juanes JA García-Castrillo G Revilla JA 《Marine pollution bulletin》2007,54(7):941-954
An investigation on the effects of deepwater outfall discharges on the status of rocky reef communities was carried out. The sanitation system was found to be an environmentally suitable option for the protection of those habitats situated in high energy coastal environments. Sediments occurring between the predominating rocky substrates showed low values of the fine fraction (<63microm) and organic matter content. In addition, high average concentrations of Cd, Hg and Zn were found in these sediments, though these values were similar to those registered in non-affected sites, far away from the outfall. On the other hand, those assemblages typical of hard substrates that settled near the outfall showed an increase in total richness and abundance of macroinvertebrates. Moreover, the average number of species of each taxonomic group, a good indicator of the maintenance of the previous trophic structure, only varied considerably over time at the rip-rap protection. In a global context, those changes were not directly related to the discharge disturbances, but to the natural variability or the successional processes occurring within those communities. Only communities dwelling in the rip-rap protection area were affected by the proximity of the discharges. 相似文献
18.
Snakebite envenoming is an important public health problem worldwide and addressing this issue has turned into a challenge for applied science. In this sense, the study of the distributional patterns of problematic snakes is central in terms of public health. Global Climate Change is affecting the distributional ranges of snakes, so that decisions regarding treatment of ophidism (poisoning by snake venom) may also change spatially and/or temporally. Here, we assessed suitable climate spaces at present conditions and estimated potential future changes in the distributions of the five southernmost venomous snakes, responsible for almost 99 % of accidents in Argentina, by implementing an ensemble of forecasts between different algorithms and scenarios for 2030 and 2080. Present suitable climate spaces showed high concordance with known distribution of the species. Future projections show moderate “north to south” displacements of the snakes’ suitable climate spaces, implying potential increments of suitable spaces in human populated areas in Argentina. Our results suggest the necessity of considering ophidism as a dynamic problem. In this regard, the analyses implemented here are useful tools in improving the assessment of snakebite envenoming in light of global climate change. 相似文献
19.
Gerardo J. M. Luna J. L. Sokoloski Roberto D. D. Costa 《Astrophysics and Space Science》2006,304(1-4):283-285
We describe X-ray and optical observations of the symbiotic star RX Pup. From low resolution optical spectra, we obtain a reddening for RX Pup of E(B−V)=0.79. We use the neutral column density corresponding to this reddening as a lower limit for the X-ray spectra fits. The X-ray spectra can be fitted with either a two-temperarure thermal plasma model or a single-temperature plasma plus a narrow line at ≈0.55 keV, each modified by interstellar absorption. The RX Pup X-ray flux is not variable within the observation exposure time, suggesting that unlike in most CVs, an accretion disk boundary layer does not contribute significantly to the X-ray flux. Instead, the X-ray emission may come from shock-heated gas further away from the compact object. 相似文献
20.
Flood-prone areas assessment using linear binary classifiers based on flood maps obtained from 1D and 2D hydraulic models 总被引:3,自引:0,他引:3