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91.
Albert Casas Pietro L. Cosentino Gianluca Fiandaca Mahjoub Himi Josep M. Macias Raffaele Martorana Andreu Muñoz Lluís Rivero Roger Sala Imma Teixell 《Surveys in Geophysics》2018,39(6):1107-1124
An integrated geophysical survey has been conducted at the Tarragona’s Cathedral (Catalonia, NE Spain) with the aim to confirm the potential occurrence of archaeological remains of the Roman Temple dedicated to the Emperor Augustus. Many hypotheses have been proposed about its possible location, the last ones regarding the inner part of the Cathedral, which is one of the most renowned temples of Spain (twelfth century) evolving from Romanesque to Gothic styles. A geophysical project including electrical resistivity tomography (ERT) and ground probing radar (GPR) was planned over 1 year considering the administrative and logistic difficulties of such a project inside a cathedral of religious veneration. Finally, both ERT and GPR have been conducted during a week of intensive overnight surveys that provided detailed information on subsurface existing structures. The ERT method has been applied using different techniques and arrays, ranging from standard Wenner–Schlumberger 2D sections to full 3D electrical imaging with the advanced Maximum Yield Grid array. Electrical resistivity data were recorded extensively, making available many thousands of apparent resistivity data to obtain a complete 3D image after a full inversion. In conclusion, some significant buried structures have been revealed providing conclusive information for archaeologists. GPR results provided additional information about shallowest structures. The geophysical results were clear enough to persuade religious authorities and archaeologists to conduct selected excavations in the most promising areas that confirmed the interpretation of geophysical data. In conclusion, the significant buried structures revealed by geophysical methods under the cathedral were confirmed by archaeological digging as the basement of the impressive Roman Temple that headed the Provincial Forum of Tarraco, seat of the Concilium of Hispania Citerior Province. 相似文献
92.
Luca Olmi Pietro Bolli Luca Cresci Francesco D’Agostino Massimo Migliozzi Daniela Mugnai Enzo Natale Renzo Nesti Dario Panella Lorenzo Stefani 《Experimental Astronomy》2017,43(3):285-309
The concept of super-resolution refers to various methods for improving the angular resolution of an optical imaging system beyond the classical diffraction limit. Although several techniques to narrow the central lobe of the illumination Point Spread Function have been developed in optical microscopy, most of these methods cannot be implemented on astronomical telescopes. A possible exception is represented by the variable transmittance filters, also known as “Toraldo Pupils” (TPs) since they were introduced for the first time by G. Toraldo di Francia in 1952 (Toraldo di Francia, Il Nuovo Cimento (Suppl.) 9, 426, 1952). In the microwave range, the first successful laboratory test of TPs was performed in 2003 (Mugnai et al. Phys. Lett. A 311, 77–81, 2003). These first results suggested that TPs could represent a viable approach to achieve super-resolution in Radio Astronomy. We have therefore started a project devoted to a more exhaustive analysis of TPs, in order to assess their potential usefulness to achieve super-resolution on a radio telescope, as well as to determine their drawbacks. In the present work we report on the results of extensive microwave measurements, using TPs with different geometrical shapes, which confirm the correctness of the first experiments in 2003. We have also extended the original investigation to carry out full-wave electromagnetic numerical simulations and also to perform planar scanning of the near-field and transform the results into the far-field. 相似文献
93.
Pietro Vittorio Curzi Enrico Dinelli Marianna Ricci Lucchi Stefano Claudio Vaiani 《Geological Journal》2006,41(5):591-612
Accumulation of continental, deltaic and shallow‐marine sediments in the Po River coastal plain preserves a record of the Late Quaternary sea‐level changes and shoreline migrations. The palaeoenvironmental evolution of this area and the changes in composition and provenance of sediments have been investigated through integrated sedimentological, micropalaeontological (mainly foraminifers) and geochemical analyses of core S1, from the southern part of the Po River delta, within a chronological framework supported by radiocarbon dating and correlations with adjacent core sequences. Eleven lithofacies, grouped into five facies associations, and four palaeontological assemblages provide the basis to define the palaeoenvironmental reconstruction of this succession consisting, from the base to the top, of: (i) continental sediments accumulated during the Late Pleistocene; (ii) back‐barrier sediments marking the onset of Holocene sea‐level rise; (iii) transgressive sands deposited during the rapid landward migration of a barrier‐lagoon system; (iv) shallow‐marine and prodelta sediments with faunal associations indicating a gradual approach to the Po River mouth; and (v) sub‐recent delta front sands that form a considerable portion of the present coastal plain. Bulk chemical composition of sediments shows remarkable relationships with palaeoenvironments and locally improves facies characterizations. For example, they reveal carbonate leaching that emphasizes the occurrence of palaeosols in continental deposits or record enrichments in loss on ignition, S and Br, diagnostic of organic‐rich layers in back‐shore sediments. Selected geochemical elements (e.g. Mg and Ni) are particularly effective for the recognition of sediment provenances from the three main source areas observed in the subsurface deposits of the Po River coastal plain (e.g. Apenninic rivers, North Adriatic rivers and Po River). An Apenninic provenance is observed in continental and back‐barrier sediments. A North Adriatic provenance characterizes the transgressive sands and the shallow‐marine deposits; a significant Po River provenance is recorded in sediments related to the onset of the prodelta environment, confirmed by foraminiferal assemblages indicating remarkable increase in fluvial influxes. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
94.
Pietro Bolli Luca Cresci Frederick Huang Sergio Mariotti Dario Panella 《Experimental Astronomy》2018,45(2):165-176
A High Temperature Superconductor filter operating in the C-band between 4200 and 5600 MHz has been developed for one of the radio astronomical receivers of the Sardinia Radio Telescope. The motivation was to attenuate an interference from a weather radar at 5640 MHz, whose power level exceeds the linear region of the first active stages of the receiver. A very sharp transition after the nominal maximum passband frequency is reached by combining a 6th order band-pass filter with a 6th order stop-band. This solution is competitive with an alternative layout based on a cascaded triplet filter. Three units of the filter have been measured with two different calibration approaches to investigate pros and cons of each, and data repeatability. The final performance figures of the filters are: ohmic losses of the order of 0.15–0.25 dB, matching better than ?15 dB, and ?30 dB attenuation at 5640 MHz. Finally, a more accurate model of the connection between external connector and microstrip shows a better agreement between simulations and experimental data. 相似文献
95.
Capacity and economic efficiency in small-scale fisheries: Evidence from the Mediterranean Sea 总被引:4,自引:0,他引:4
To design an effective capacity management plan for small-scale fisheries one must understand what one is measuring and define its capacity. As recognized by some authors, overcapacity is a problem that generally affects small-scale fisheries just as much as it does other types of fishing. This study aims to estimate fishing capacity, technical efficiency, scale efficiency and capacity utilization in a particular small-scale fishery in the Mediterranean, i.e., the Northwest Sardinian fleet in Italy. A non-parametric approach using a data envelopment analysis (DEA) model was applied to a sample of trawls in order to estimate their economic capacity, and related measurements were taken. The capacity and efficiency with reference to two different alternative scenarios were also calculated. 相似文献
96.
97.
Roberto Ambrosini Pietro Bolli Claudio Bortolotti Francesco Gaudiomonte Filippo Messina Mauro Roma 《Experimental Astronomy》2010,27(3):121-130
Apart from externally generated Radio Frequency Interference (RFI), the occurrence of self-interference is a major concern
at any modern radio telescope site. Antenna servo motor controllers, data acquisition processors, and fast computing capabilities
operate very close to extremely sensitive and wideband radio astronomical receivers. In this paper, we present a set of measurements
of the RFI level generated by a cluster of computers that will be installed at the site of the Sardinia Radio Telescope (SRT).
The measured levels are compared to Recommendation ITU-R RA.769-2, which gives the threshold levels for interference detrimental
to radio astronomy observations. Our analysis shows that, with proper shielding of the noisiest devices, it will be possible
to preserve the present excellent RFI conditions of the SRT site. 相似文献
98.
Hydrogeology Journal - This study aims to determine the groundwater flow in a large area of the Venice (northeast Italy) lagoon that is under great anthropogenic pressure, which is influencing the... 相似文献
99.
Early Jurassic syn‐sedimentary extensional tectonics in the central Southern Alps controlled patterns of deposition within the Calcari Grigi carbonate platform. We used variogram maps to gather model‐independent information on the spatial distribution of thicknesses of selected platform units and investigated whether major syn‐sedimentary faults outlined subsiding domains during platform growth. Thicknesses display a spatial organization that suggests that large fault belts, often coincident with exposed Jurassic extensional structures, transected large parts of the platform. The network of four fault systems (trending NNW–SSE and NE–SW) displays orthorhombic symmetry, suggesting non‐Andersonian faulting and a true triaxial strain field with N100°E maximum extension or transfer shear zones connecting major NNW–SSE‐trending extensional faults. In both cases, inherited structures of Permian to Triassic age may have played a primary role in Jurassic faulting. If confirmed throughout the South‐Alpine domain, this arrangement could shed new light on Early Jurassic rifting mechanisms in the Southern Alps. 相似文献
100.
Pietro?Carveni Giuliana?MeleEmail author Santo?Benfatto Sebastiano?Imposa Maria?Salleo Puntillo 《Bulletin of Volcanology》2011,73(6):633-638
Unique volcanic structures, known in the literature as “lava trees” and “tree molds”, have formed at several sites on Mt.
Etna volcano (northeastern Sicily, Italy). They form when a fluid lava flow runs over a tree, wraps around it and, while the
wood burns off, solidifies forming a hollow cast of the tree. The inhabitants of the Etna area call these formations “pietre
cannone” (“cannon stones”) because of their cylindrical shape. The first documentation of lava trees is from Hawaii, but the
first eye-witnessed accounts of their formation are, to our knowledge, from Etna’s 1865 eruption. Although many of the literature
examples of lava trees and tree molds formed in pahoehoe, many of those reported in this work formed in a’a. The sites where
we have found the lava tree molds are located within the territory of the Etna Regional Park; most occur next to walking trails
and have a high potential for geotourism. 相似文献