全文获取类型
收费全文 | 95篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 22篇 |
地球物理 | 53篇 |
地质学 | 19篇 |
天文学 | 7篇 |
自然地理 | 8篇 |
出版年
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 2篇 |
2013年 | 11篇 |
2012年 | 6篇 |
2011年 | 4篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1977年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有110条查询结果,搜索用时 515 毫秒
101.
An improvement to the volcano-scan algorithm for atmospheric correction of CRISM and OMEGA spectral data 总被引:1,自引:0,他引:1
Patrick C. McGuire Janice L. Bishop Adrian J. Brown Giuseppe A. Marzo Scott L. Murchie Mario Parente Ted L. Roush Michael D. Smith Michael J. Wolff 《Planetary and Space Science》2009,57(7):809-815
The observations of Mars by the CRISM and OMEGA hyperspectral imaging spectrometers require correction for photometric, atmospheric and thermal effects prior to the interpretation of possible mineralogical features in the spectra. Here, we report on a simple, yet non-trivial, adaptation to the commonly-used volcano-scan correction technique for atmospheric CO2, which allows for the improved detection of minerals with intrinsic absorption bands at wavelengths between 1.9 and 2.1 μm. This volcano-scan technique removes the absorption bands of CO2 by ensuring that the Lambert albedo is the same at two wavelengths: 1.890 and 2.011 μm, with the first wavelength outside the CO2 gas bands and the second wavelength deep inside the CO2 gas bands. Our adaptation to the volcano-scan technique moves the first wavelength from 1.890 μm to be instead within the gas bands at 1.980 μm, and for CRISM data, our adaptation shifts the second wavelength slightly, to 2.007 μm. We also report on our efforts to account for a slight ∼0.001 μm shift in wavelengths due to thermal effects in the CRISM instrument. 相似文献
102.
103.
104.
105.
106.
Robin K. McGuire 《地震工程与结构动力学》1977,5(3):211-234
The calculation of design spectra for building sites threatened by seismic ground motion is approached by considering the maximum responses of linearly elastic oscillators as indicators of ground motion intensity. Attenuation functions describing the distribution of response as a function of earthquake magnitude and distance are derived using 68 components of recorded ground motion as data. With a seismic hazard analysis for several hypothetical building sites, the distributions of maximum oscillator responses to earthquakes of random magnitude and location are calculated, and spectra are drawn to indicate the maximum responses associated with specified probability levels. These spectra are compared to design spectra calculated from published methods of amplifying peak ground motion parameters. The latter spectra are found to be inconsistent in terms of risk for building sites very close and very far from faults. A ground motion parameter defined to be proportional to the maximum response of a 1 Hz, 2 per cent damped linearly elastic oscillator is investigated; this parameter, in conjunction with peak ground acceleration, is found to lead to risk-consistent design spectra. Through these two parameters, a design earthquake magnitude and design hypocentral distance are defined, for a specified building site and risk level. The use of these parameters in the seismic hazard mapping of a region is illustrated. 相似文献
107.
108.
A ground motion selection procedure for enforcing hazard consistency and estimating seismic demand hazard curves
下载免费PDF全文
![点击此处可从《地震工程与结构动力学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This paper develops a procedure to select unscaled ground motions for estimating seismic demand hazard curves (SDHCs) in performance‐based earthquake engineering. Currently, SDHCs are estimated from a probabilistic seismic demand analysis, where several ensembles of ground motions are selected and scaled to a user‐specified scalar conditioning intensity measure (IM). In contrast, the procedure developed herein provides a way to select a single ensemble of unscaled ground motions for estimating the SDHC. In the context of unscaled motions, the proposed procedure requires three inputs: (i) database of unscaled ground motions, (ii) I M , the vector of IMs for selecting ground motions, and (iii) sample size, n; in the context of scaled motions, two additional inputs are needed: (i) a maximum acceptable scale factor, SFmax, and (ii) a target fraction of scaled ground motions, γ. Using a recently developed approach for evaluating ground motion selection and modification procedures, the proposed procedure is evaluated for a variety of inputs and is demonstrated to provide accurate estimates of the SDHC when the vector of IMs chosen to select ground motions is sufficient for the response quantity of interest. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
109.
The authors define a spatio-statistical response of hurricane frequency to the solar cycle. Previous research indicates reduced (increased) hurricane intensities and frequency in the western (eastern) tropical Atlantic. However, no formal quantitative relationship has been spatially established between hurricane frequency and solar activity. The authors use a Bayesian hierarchical space–time model, an increasingly popular approach due to its advantage in facilitating regression modeling of space–time phenomena in the context of large data sets. Regional hurricane frequency over the period 1866–2010 is examined in response to September sunspot number (SSN) while controlling for other relevant climate factors. The response features a 13 % reduction in probability of annual hurricane occurrence for southeastern Cuba, the southern Bahama islands, Haiti, and Jamaica when the SSN is 80 sunspots. In contrast, hurricane risk in regions of the southeastern Atlantic is predicted to increase by 73 % when the SSN is 160 sunspots. The model can be ported to explore other relationships over contiguous space. 相似文献
110.
Xenoliths of lower crustal and upper mantle rocks from the Cima volcanic field (CVF) commonly contain glass pockets, veins,
and planar trains of glass and/or fluid inclusions in primary minerals. Glass pockets occupy spaces formerly occupied by primary
minerals of the host rocks, but there is a general lack of correspondence between the composition of the glass and that of
the replaced primary minerals. The melting is considered to have been induced by infiltration of basaltic magma and differentiates
of basaltic magma from complex conduits formed by hydraulic fracturing of the mantle and crustal rocks, and to have occurred
during the episode of CVF magmatism between ∼7.5 Ma and present. Variable compositions of quenched melts resulted from mixing
of introduced melts and products of melting of primary minerals, reaction with primary minerals, partial crystallization,
and fractionation resulting from melt and volatile expulsion upon entrainment of the xenoliths. High silica melts ( >∼60%
SiO2) may result by mixing introduced melts with siliceous melts produced by reaction of orthopyroxene. Other quenched melt compositions
range from those comparable to the host basalts to those with intermediate Si compositions and elevated Al, alkalis, Ti, P,
and S; groundmass compositions of CVF basalts are consistent with infiltration of fractionates of those basalts, but near-solidus
melting may also contribute to formation of glass with intermediate silica contents with infiltration only of volatile constituents.
Received: 15 June 1995 / Accepted: 13 December 1995 相似文献