全文获取类型
收费全文 | 109篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 6篇 |
大气科学 | 5篇 |
地球物理 | 18篇 |
地质学 | 39篇 |
海洋学 | 11篇 |
天文学 | 31篇 |
自然地理 | 3篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有113条查询结果,搜索用时 296 毫秒
71.
Francesco Demartin Italo Campostrini Carlo Castellano Massimo Russo 《Physics and Chemistry of Minerals》2014,41(6):403-407
The new mineral parascandolaite, isotypic to cubic perovskites, space group Pm \(\overline{3}\) m (no. 221) is the natural analog of the synthetic fluoride KMgF3 and is related to neighborite, NaMgF3. It was found as a volcanic sublimate at Vesuvius volcano on 1944 eruption lava scoria, associated with opal, cerussite, mimetite, phoenicochroite and coulsellite. It occurs as transparent colorless to white cubic crystals up to 0.5 mm in length with vitreous luster. The density measured by flotation in a diiodomethane–toluene mixture is 3.11(1) g/cm3; that calculated from the empirical formula and single-crystal X-ray data is 3.123 g/cm3. The mineral is isotropic with n = 1.395(5) (580 nm). The six strongest reflections in the X-ray powder diffraction pattern are: [d obs in Å(I)(h k l)] 2.001(100)(2 0 0), 2.831(83)(1 1 0), 2.311(78)(1 1 1), 1.415(56)(2 2 0), 1.633(35)(2 1 1) and 1.206(22)(3 1 1). The unit-cell parameter is a = 4.0032(9) Å. The structure was refined to a final R(F) = 0.0149 for 35 independent observed reflections [I > 2σ(I)]. The mineral is named after the Italian mineralogist Antonio Parascandola (1902–1977). 相似文献
72.
The nationalization of electoral change in a geographical perspective: the case of Italy (2006–2008)
Luana Russo 《GeoJournal》2014,79(1):73-87
This paper assesses the nationalization of electoral change in a setting of major changes at the party level. After discussing the theoretical difference between the configuration of the electorate and its movement, the Italian case is examined. In order to check whether strategic voting dynamics took place between the 2006 and 2008 Italian Parliamentary elections, the swing voters’ estimates are obtained. After having shown that the Italian electorate behaved strategically, we investigated whether the swing had a national or a territorial pattern. The findings show that the switching occurred in Italy between the 2006 and the 2008 elections can be considered national. 相似文献
73.
Claudia Mignelli Daniele Peila Stefano Lo Russo Sara Maria Ratto Massimo Broccolato 《Natural Hazards》2014,73(1):23-35
Many kilometres of roads are close to rock slopes that are prone to rockfalls. The fulfilment of safety requirements in such situations is a multidimensional design process involving public and private technicians in the assessment and management of the problem. In this paper, a rockfall risk management approach has been applied to the road infrastructure network of the Regione Autonoma Valle D’Aosta, in order to calculate the level of risk and of its reduction using rockfall protection devices. In order to better understand the methodology, a comparative analysis of road accidents in Aosta Valley has been discussed. The road risk assessment was developed taking into account the absence of rockfall protection devices, and when they are present, different levels of efficacy have been considered. 相似文献
74.
75.
Simplified formulae for the BIQUE estimation of variance components in disjunctive observation groups 总被引:7,自引:1,他引:6
General rigorous and simplified formulae are reported for the best invariant quadratic unbiased estimates of the variance–covariance
components, which can be applied to all least-squares adjustments with the general linear stochastic model. Simplified procedures
are given for two cases frequently recurring in geodetic applications: uncorrelated groups of correlated or uncorrelated observations,
with more than one variance component in each group.
Received: 19 November 1998 / Accepted: 21 March 2000 相似文献
76.
F. Barone E. Covino L. Di Fiore L. Milano G. Russo 《Astrophysics and Space Science》1991,183(1):117-127
In this third paper of the series, we analyze five more EB-type eclipsing binaries with short periods (<1 day) and suspected to be contact, or near-contact systems.We find that V747 Cen and ZZ Aur are almost contact systems, RY Ind is a semi-detached system, while AX Vir and ST Car are both detached systems. 相似文献
77.
We describe observations of the class 3+ flare of August 28, 1966, made at the Mount Wilson Observatory. This great proton flare followed the sequence: (1) Precursor flare; (2) Filament eruption; (3) Beginning in penumbra of large spot; (4) Rapid elongation in two strands; (5) Great spray and surface wave; (6) Rapid separation of two strands to maximum brightness; and (7) Slow spread of brightness and decay.The soft X-ray burst coincides with stages 3–6, decaying through stage 7; the hard (> 80 keV) burst coincides, but decays more rapidly.Considering a demi-cylinder of emitting material, the soft X-rays are explained by a 4-million-degree plasma, or at least a large flux of electrons with that amount of energy. Given this flux, the microwave burst is explained by synchrotron emission with the low frequency cut-off due to coronal absorption.The class-2 flare of August 30, 1966, is also discussed.This research was supported by the Advanced Research Projects Agency under the Office of Naval Research Grant N00014-67-C-0140 and the National Aeronautics and Space Administration under Grant NGR 05 002 034.NASA International University Fellow at the California Institute of Technology, 1967–1968, now at Arcetri Astrophysical Observatory. 相似文献
78.
Fabio Russo Federico Lombardo Eugenio Gorgucci 《Physics and Chemistry of the Earth》2006,31(18):1252-1261
Rainfall fields estimation over a catchment area is an important stage in many hydrological applications. In this context, weather radars have several advantages because a single-site can scan a vast area with very high temporal and spatial resolution. The construction of weather radar systems with dual polarization capability allowed progress on radar rainfall estimation and its hydro-meteorological applications. For these applications of radar data it is necessary to remove the ground clutter contamination with an algorithm based on the backscattering signal variance of the differential reflectivity. The calibration of the GDSTM model (Gaussian Displacements Spatial-Temporal Model), a cluster stochastic generation model in continuous space and time, is herewith presented. In this model, storms arrive in a Poisson process in time with cells occurring in each storm that cluster in space and time. The model is calibrated, using data collected by the weather radar Polar 55C located in Rome, inside a square area of 132 × 132 km2, with the radar at the centre. The GDSTM is fitted to sequences of radar images with a time interval between the PPIs scans of 5 min. A generalized method of moment procedure is used for parameter estimation. For the validation of the ability of the model to reproduce internal structure of rain event, a geo-morphological rainfall-runoff model, based on width function (WFIUH), was calibrated using simulated and observed data. Several rainfall fields are generated with the stochastic model and later they are used as input of the WFIUH model so that the forecast discharges can be compared to the observed ones. 相似文献
79.
Geomorphology and landslide susceptibility assessment using GIS and bivariate statistics: a case study in southern Italy 总被引:3,自引:2,他引:1
In this article, the results of a study aimed to assess the landslide susceptibility in the Calaggio Torrent basin (Campanian
Apennines, southern Italy) are presented. The landslide susceptibility has been assessed using two bivariate-statistics-based
methods in a GIS environment. In the first method, widely used in the existing literature, weighting values (Wi) have been calculated for each class of the selected causal factors (lithology, land-use, slope angle and aspect) taking
into account the landslide density (detachment zones + landslide body) within each class. In the second method, which is a
modification of the first method, only the landslide detachment zone (LDZ) density has been taken into account to calculate
the weighting values. This latter method is probably characterized by a major geomorphological coherence. In fact, differently
from the landslide bodies, LDZ must necessarily occur in geoenvironmental classes prone to failure. Thus, the calculated Wi seem to be more reliable in estimating the propensity of a given class to generate failure. The thematic maps have been reclassified
on the basis of the calculated Wi and then overlaid, with the purpose to produce landslide susceptibility maps. The used methods converge both in indicating
that most part of the study area is characterized by a high–very high landslide susceptibility and in the location and extent
of the low-susceptible areas. However, an increase of both the high–very high and moderate–high susceptible areas occurs in
using the second method. Both the produced susceptibility maps have been compared with the geomorphological map, highlighting
an excellent coherence which is higher using method-2. In both methods, the percentage of each susceptibility class affected
by landslides increases with the degree of susceptibility, as expected. However, the percentage at issue in the lowest susceptibility
class obtained using method-2, even if low, is higher than that obtained using method-1. This suggests that method-2, notwithstanding
its major geomorphological coherence, probably still needs further refinements. 相似文献
80.
Robert A. Ayuso Antonia Messina Benedetto De Vivo Selma Russo Laurel G. Woodruff John F. Sutter Harvey E. Belkin 《Contributions to Mineralogy and Petrology》1994,117(1):87-109
The Sila batholith is the largest granitic massif in the Calabria-Peloritan Arc of southern Italy, consisting of syn to post-tectonic, calc-alkaline and metaluminous tonalite to granodiorite, and post-tectonic, peraluminous and strongly peraluminous, two-mica±cordierite±Al silicate granodiorite to leucomonzogranite. Mineral 40Ar/39Ar thermochronologic analyses document Variscan emplacement and cooling of the intrusives (293–289 Ma). SiO2 content in the granitic rocks ranges from 57 to 77 wt%; cumulate gabbro enclaves have SiO2 as low as 42%. Variations in absolute abundances and ratios involving Hf, Ta, Th, Rb, and the REE, among others, identify genetically linked groups of granitic rocks in the batholith: (1) syn-tectonic biotite±amphibole-bearing tonalites to granodiorites, (2) post-tectonic two-mica±Al-silicate-bearing granodiorites to leucomonzogranites, and (3) post-tectonic biotite±hornblende tonalites to granodiorites. Chondrite-normalized REE patterns display variable values of Ce/Yb (up to 300) and generally small negative Eu anomalies. Degree of REE fractionation depends on whether the intrusives are syn- or post-tectonic, and on their mineralogy. High and variable values of Rb/Y (0.40–4.5), Th/Sm (0.1–3.6), Th/Ta (0–70), Ba/Nb (1–150), and Ba/Ta (50–2100), as well as low values of Nb/U (2–28) and La/Th (1–10) are consistent with a predominant and heterogeneous crustal contribution to the batholith. Whole rock 18O ranges from +8.2 to +11.7; the mafic cumulate enclaves have the lowest 18O values and the two-mica granites have the highest values. 18O values for biotite±honblende tonalitic and granodioritic rocks (9.1 to 10.8) overlap the values of the mafic enclaves and two-mica granodiorites and leucogranites (10.7 to 11.7). The initial Pb isotopic range of the granitic rocks (206Pb/204Pb 18.17–18.45, 207Pb/204Pb 15.58–15.77, 208Pb/204Pb 38.20–38.76) also indicates the predominance of a crustal source. Although the granitic groups cannot be uniquely distinguished on the basis of their Pb isotope compositions most of the post-tectonic tonalites to granodiorites as well as two-mica granites are somewhat less radiogenic than the syn-tetonic tonalites and granodiorites. Only a few of the mafic enclaves overlap the Pb isotope field of the granitic rocks and are consistent with a cogenetic origin. The Sila batholith was generated by mixing of material derived from at least two sources, mantle-derived and crustal, during the closing stages of plate collision and post-collision. The batholith ultimately owes its origin to the evolution of earlier, more mafic parental magmas, and to complex intractions of the fractionating mafic magmas with the crust. Hybrid rocks produced by mixing evolved primarily by crystal fractionation although a simple fractionation model cannot link all the granitic rocks, or explain the entire spectrum of compositions within each group of granites. Petrographic and geochemical features characterizing the Sila batholith have direct counterparts in all other granitic massifs in the Calabrian-Peloritan Arc. This implies that magmatic events in the Calabrian-Peloritan Arc produced a similar spectrum of granitic compositions and resulted in a distinctive type of granite magmatism consisting of coeval, mixed, strongly peraluminous and metaluminous granitic magmas. 相似文献