全文获取类型
| 收费全文 | 106篇 |
| 免费 | 11篇 |
专业分类
| 测绘学 | 7篇 |
| 地球物理 | 31篇 |
| 地质学 | 48篇 |
| 海洋学 | 13篇 |
| 天文学 | 4篇 |
| 自然地理 | 14篇 |
出版年
| 2021年 | 3篇 |
| 2020年 | 2篇 |
| 2019年 | 2篇 |
| 2018年 | 1篇 |
| 2017年 | 6篇 |
| 2016年 | 9篇 |
| 2015年 | 6篇 |
| 2014年 | 5篇 |
| 2013年 | 6篇 |
| 2012年 | 8篇 |
| 2011年 | 9篇 |
| 2010年 | 6篇 |
| 2009年 | 10篇 |
| 2008年 | 7篇 |
| 2007年 | 3篇 |
| 2006年 | 4篇 |
| 2005年 | 6篇 |
| 2004年 | 7篇 |
| 2003年 | 1篇 |
| 2002年 | 3篇 |
| 2001年 | 1篇 |
| 2000年 | 1篇 |
| 1998年 | 1篇 |
| 1997年 | 4篇 |
| 1996年 | 1篇 |
| 1992年 | 1篇 |
| 1987年 | 1篇 |
| 1986年 | 1篇 |
| 1985年 | 1篇 |
| 1961年 | 1篇 |
排序方式： 共有117条查询结果，搜索用时 31 毫秒
101.
102.
Pilar García-Soidán Raquel Menezes Óscar Rubiños 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(5):1207-1219
Generation of replicates of the available data enables the researchers to solve different statistical problems, such as the estimation of standard errors, the inference of parameters or even the approximation of distribution functions. With this aim, Bootstrap approaches are suggested in the current work, specifically designed for their application to spatial data, as they take into account the dependence structure of the underlying random process. The key idea is to construct nonparametric distribution estimators, adapted to the spatial setting, which are distribution functions themselves, associated to discrete or continuous random variables. Then, the Bootstrap samples are obtained by drawing at random from the estimated distribution. Consistency of the suggested approaches will be proved by assuming stationarity from the random process or by relaxing the latter hypothesis to admit a deterministic trend. Numerical studies for simulated data and a real data set, obtained from environmental monitoring, are included to illustrate the application of the proposed Bootstrap methods. 相似文献
103.
New discoveries of mud volcanoes on the Moroccan Atlantic continental margin (Gulf of Cádiz): morpho-structural characterization 总被引：3，自引：3，他引：0
Ricardo León Luis Somoza Teresa Medialdea Juan Tomás Vázquez Francisco Javier González Nieves López-González David Casas María del Pilar Mata María Carmen del Fernández-Puga Carmen Julia Giménez-Moreno Víctor Díaz-del-Río 《Geo-Marine Letters》2012,32(5-6):473-488
During the MVSEIS-08 cruise of 2008, ten new mud volcanoes (MVs) were discovered on the offshore Moroccan continental margin (Gulf of Cádiz) at water depths between 750 and 1,600?m, using multibeam bathymetry, backscatter imagery, high-resolution seismic and gravity core data. Mud breccias were recovered in all cases, attesting to the nature of extrusion of these cones. The mud volcanoes are located in two fields: the MVSEIS, Moundforce, Pixie, Las Negras, Madrid, Guadix, Almanzor and El Cid MVs in the western Moroccan field, where mud volcanoes have long been suspected but to date not identified, and the Boabdil and Al Gacel MVs in the middle Moroccan field. Three main morphologies were observed: asymmetric, sub-circular and flat-topped cone-shaped types, this being the first report of asymmetric morphologies in the Gulf of Cádiz. Based on morpho-structural analysis, the features are interpreted to result from (1) repeated constructive (expulsion of fluid mud mixtures) and destructive (gravity-induced collapse and submarine landsliding) episodes and (2) interaction with bottom currents. 相似文献
104.
M. Pilar Salvador Sanchis Dino Torri Lorenzo Borselli Rorke Bryan Jean Poesen Marta S. Yañez Cati Cremer 《地球表面变化过程与地形》2009,34(15):2023-2030
Eroding channels can usually be characterized by a power relationship between channel width (W) and channel discharge (Q). This paper examines the WQ relation using a recently developed channel junction approach to extend the validity of the WQ relation and to develop a procedure for estimating the WQ exponent and proportionality coefficient. Rill and gully channel data from the literature, and new data collected in different badland areas and in a few forest mountain streams, are analysed. Analysis shows that the WQ relation for channel width collected in badlands and forests agrees with trends observed for cropland. The exponent increases with increasing channel width in a continuous fashion rather than in a step‐like way and tends to a maximum whose value ranges between 0·5 and 0·6. The proportionality coefficient can be split into two terms, one expressing the case in which an eroding channel can broaden, the other reflecting the difficulties in removing the less erodible clods or rock fragments from the channel bed. Its splitting allows the development of a more correct form of the WQ relation in agreement with modern approaches of channel geometry: one part has the dimension of a discharge and makes the power base dimensionless, while the other brings the dimension of a length, needed for the channel width, into the WQ relation. The interpretation of the two constants is supported by data collected in rainfall‐runoff simulation experiments conducted in the field. Values characterizing the two constants in some environments are also given. Nevertheless the approach is not sufficiently parameterized yet to be of practical use (e.g. in models or for estimating peak discharge in areas where rill channels have formed). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
105.
To improve understanding of DOC dynamics in seasonal Mediterranean environments, rainfall, soil water, groundwater and stream water samples were taken during a 27-month period in the Can Vila catchment (northeast Spain). Using these data, we characterized DOC dynamics in the different hydrological compartments and analysed the factors affecting them. We also analysed DOC dynamics during storm events and the factors that control DOC delivery to the stream. The results show some seasonality in rainwater and soil water DOC concentrations, while no clear seasonality was observed in stream water and groundwater, where DOC dynamics were strongly related to discharge and water table variations. For storm events with several discharge peaks, the slope of the discharge–DOC concentration relationship was higher for the first peak. The rather similar dynamics of stream water DOC concentration in all floods contrast with the observed diversity of hydrological processes. This raises the question of the origin of the observed rapid DOC increase.
EDITOR M.C. AcremanASSOCIATE EDITOR K. Heal 相似文献
106.
Asuncion Beamonte Pilar Gargallo Manuel Salvador 《Journal of Geographical Systems》2010,12(2):227-240
In this paper, we extend the Bayesian methodology introduced by Beamonte et al. (Stat Modelling 8:285–311, 2008) for the estimation and comparison of spatio-temporal autoregressive models (STAR) with neighbourhood effects, providing
a more general treatment that uses larger and denser nets for the number of spatial and temporal influential neighbours and
continuous distributions for their smoothing weights. This new treatment also reduces the computational time and the RAM necessities
of the estimation algorithm in Beamonte et al. (Stat Modelling 8:285–311, 2008). The procedure is illustrated by an application to the Zaragoza (Spain) real estate market, improving the goodness of fit
and the outsampling behaviour of the model thanks to a more flexible estimation of the neighbourhood parameters. 相似文献
107.
Israel Gómez M. Pilar Martín 《International Journal of Applied Earth Observation and Geoinformation》2011
Each year thousands of ha of forest land are affected by forest fires in Southern European countries such as Spain. Burned area maps are a valuable instrument for designing prevention and recovery policies. Remote sensing has increasingly become the most widely used tool for this purpose on regional and global scales, where a large variety of techniques and data has been applied. This paper proposes a semiautomatic method for burned area mapping on a regional scale in Mediterranean areas (the Iberian Peninsula has been used as a study case). A Multi-layer Perceptron Network (MLPN) has been designed and applied to MODIS/Terra Surface Reflectance Daily L2G Global 500m SIN Grid multitemporal composite monthly images. The compositing criterion was based on maximum surface temperature. The research covered a six year period (2001–2006) from June to September, when most of the forest fires occur. The resulting burned area maps have been validated using official fire perimeters and compared with MODIS Collection 5 Burned Area Product (MCD45A1). The MLPN shown as an effective method, with a commission error of 29.1%, in the classification of the burned areas, while the omission error was of 14.9%. The results were compared with the MCD45A1 product, which had a slightly higher commission error (30.2%) and a considerably higher omission error (26.2%), indicating a high underestimation of the burned area. 相似文献
108.
Fernando Bea Ali Mazhari Pilar Montero Sadraldin Amini Jalil Ghalamghash 《Journal of Asian Earth Sciences》2011,40(1):172-179
The Khalifan pluton of the Sanandaj-Sirjan Zone is composed of A-type peraluminous leucogranites with Nd model ages around 1.2 Ga. It intrudes an unfossiliferous sedimentary sequence previously considered as Cretaceous by analogy with neighboring areas. However, zircon U–Pb SHRIMP and Pb–Pb sequential evaporation dating have revealed that Khalifan granites are Carboniferous, with a precise age of 315 ± 2 Ma. This is the first reliable Variscan age obtained so far in this area, but there are geological indicators that other small plutonic bodies might also be Variscan. The existence of Carboniferous granite rocks in the Sanandaj-Sirjan Zone casts doubts on whether it was a part of the Cimmerian superterrane detached from east Gondwanide terranes because these characteristically lack Variscan magmatism. The age, chemical features and Nd isotopes of Khalifan granites are similar to those of the southernmost Urals and Tien Shan, so that we tentatively suggest that this area bears a Middle Asian instead of Cimmerian linkage. 相似文献
109.
Jose Antonio de‐la‐Ossa‐Carretero Yoana Del‐Pilar‐Ruso Francisca Giménez‐Casalduero José Luis Sánchez‐Lizaso 《Marine Ecology》2016,37(3):503-517
The distribution and composition of Amphipoda assemblages were analysed off the coasts of Alicante (Spain, Western Mediterranean), a disturbed area affected by several co‐occurring anthropogenic impacts. Although differences among sampled stations were mainly related to natural parameters, anthropogenic activities were linked with changes in amphipod assemblages. Expansion of the Port of Alicante, a sewage outfall and a high salinity brine discharge could be causing the disappearance of amphipods at stations closer to these disturbances. However, the completion of port enlargement works and mitigatory dilution of the brine discharge has led to the recovery of the amphipod assemblage. Among the natural parameters, depth determines the distribution of some of the species. While Siphonoecetes sabatieri was abundant at shallow stations, Ampelisca spp., Photis longipes, Pseudolirius kroyeri, Apherusa chiereghinii and Phtisica marina were more abundant at deeper stations. Grain size and percentage of organic matter also influenced amphipod distribution, resulting in changes in species composition and in the relative percentages of different trophic groups. Species such as Ampelisca brevicornis, Perioculodes longimanus, Urothoe hesperiae and Urothoe elegans were more abundant at stations with a high content of fine sand. Carnivorous species, mainly of the Oedicerotidae family, were more abundant at those stations with a low organic matter content, while detritivorous species were more abundant at stations with a higher mud content. Among 62 identified species, three were reported for the first time from the Spanish Mediterranean coast, two species were recorded for the second time and a new species of Siphonoecetes was found, Siphonoecetes (Centraloecetes) bulborostrum. These results confirm the need for further data on amphipods from the Mediterranean Spanish coast. 相似文献
110.