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61.
Mass and Metallurgical Balance Forecast for a Zinc Processing Plant Using Artificial Neural Networks
Niquini Fernanda Gontijo Fernandes Costa João Felipe Coimbra Leite 《Natural Resources Research》2020,29(6):3569-3580
Natural Resources Research - The forecasting of ore concentrate and tailings mass and metallurgical recovery at a processing plant is not a simple task. It starts with data collection, which is... 相似文献
62.
Julian Augley Mark Huxham Teresa F. Fernandes Alastair R. Lyndon 《Journal of Sea Research》2008,60(4):292-296
Previous population estimates of the 0+ plaice (Pleuronectes platessa L.) in the Firth of Forth, east central Scotland, did not take account of the Forth estuary west of the Forth bridges. Previous work found plaice in the estuary grew as fast as, or faster than, the outer firth plaice. It was hypothesised that salinity may affect growth rates of early 0+ plaice. This hypothesis was tested in a laboratory experiment, by exposing juvenile plaice to three different, but naturally — experienced by the juveniles, salinities; 25, 30 and 35. Plaice fed a minimum ration did not grow in length. Mean weight decreased at all three salinities, however, the lowest weight loss was found at the lowest salinity (25) and the highest weight loss was found at the highest salinity (35). The minimum feeding ration was halted and plaice were then fed ad libitum. Consumption rates were not significantly different during the ad libitum feeding, while significant differences in mean weight change were found between the highest and lowest salinities. 相似文献
63.
A.O.M.S. Gross G.T.R. Droop C.C. Porcher L.A.D. Fernandes 《Precambrian Research》2009,170(3-4):157-174
This paper reports a study of the metamorphic evolution of pelitic, semi-pelitic migmatites and mafic granulites of the Chafalote Metamorphic Suite (CMS), Uruguay, which represents the southernmost exposures of high-grade metamorphic rocks in the Dom Feliciano Belt, Uruguain—Sul-Rio-Grandense shield, South America. This belt is one of the Brasiliano orogens that crop out along the Brazilian and Uruguayan Atlantic margin, and the CMS is one of several disconnected segments of supracrustal rock in a dominantly granitic terrain. Petrological evidence from CMS mafic granulites and semi-pelitic migmatites indicates four distinct metamorphic assemblages. The early prograde assemblage (M1) is preserved only as inclusions in porphyroblasts of the peak-metamorphic (M2) assemblage. Peak-metamorphism was followed by near-isothermal decompression (M3), which resulted in symplectites and coronitic textures in the mafic granulites and compositional zoning of Ca in garnet (decreasing rimwards) and plagioclase (increasing rimwards) in the semi-pelitic migmatites. The retrograde metamorphic assemblage (M4) is represented by hydration reaction textures replacing minerals of the M2 and M3 assemblages. Average P–T calculations using the program THERMOCALC and conventional thermobarometric methods yield peak-metamorphic (M2) P–T conditions of 7–10 kbar and 830–950 °C, near-decompressional (M3) P–T conditions of 4.8–5.5 kbar and 788–830 °C and M4 retrograde P–T conditions of 3–6 kbar and 600–750 °C. The calculated P–T path for the CMS rocks is ‘clockwise’ and incorporates a near-isothermal decompression segment followed by minor cooling, consistent with a history of crustal thickening followed by extensional collapse at ca. 650–600 Ma. The metamorphism recorded by rocks of this crustal segment may be correlated with 650 Ma metamorphism in the Coastal Terrane of the Kaoko Belt in Namibia, being the first unequivocal match between South America and Africa provided by crystalline rocks south of the Congo Craton. 相似文献
64.
Any dynamical system can be put in generalized canonical form through the introduction of a set of auxiliary ‘conjugate’ variables
or momenta and solved by perturbation theory based on Lie series. The application of Hori's method for generalized canonical
system leads to a new canonical transformation — the Mathieu transformation — defined by the solution of the Hori auxiliary
system. This new transformation simplifies the algorithm since the inversion of the solution of the Hori auxiliary system
is no longer necessary. In this paper, we wish to show some peculiarities of this technique. 相似文献
65.
66.
Miguel Bergano Francisco Fernandes Luís Cupido Domingos Barbosa Rui Fonseca Ivan Ferreira Bruce Grossan George Smoot 《Experimental Astronomy》2011,30(1):23-37
The international Galactic Emission Mapping project aims to map and characterize the polarization field of the Milky Way.
In Portugal it will map the sky polarized emission of the Northern Hemisphere in C-band and provide templates for map calibration
and foreground control of microwave space data to be provided by ESA Planck Surveyor mission and later missions. The receiver
system is equipped with a novel receiver with a full digital back-end using a low-cost Field Programmable Gate Array without
compromising its performance relation. This new digital backend comprises a base-band complex cross-correlator outputting
the four Stokes parameters of the incoming polarized radiation. In this document we describe the design and implementation
of the complex correlator using the FPGA and the dedicated digitizers at each receiver arm, detailing the method applied at
the several algorithm stages. This correlator is suitable for large sky area polarization continuum surveys. 相似文献
67.
R. R. Brooks M. Hoashi E. Fernandes de Lima M. L. dos Santos D. E. Ryan J. Holzbecher J. H. Johnston Y. Kawachi P. P. Sipiera 《Meteoritics & planetary science》1990,25(3):231-232
Abstract— The Iguaraçu meteorite, a single stone of 1200 g, fell in Paraná State, Brazil in October 1977. It is classified as an H5 ordinary chondrite with olivine of composition Fa 18.7. 相似文献
68.
69.
Adriana Valio P. Kaufmann C. G. Giménez de Castro J.-P. Raulin L. O. T. Fernandes A. Marun 《Solar physics》2013,283(2):651-665
We present a new system of two circular polarization solar radio telescopes, POEMAS, for observations of the Sun at 45 and 90 GHz. The novel characteristic of these instruments is the capability to measure circular right- and left-hand polarizations at these high frequencies. The two frequencies were chosen so as to bridge the gap at radio frequencies between 20 and 200 GHz of solar flare spectra. The telescopes, installed at CASLEO Observatory (Argentina), observe the full disk of the Sun with a half power beam width of 1.4°, a time resolution of 10 ms at both frequencies, a sensitivity of 2?–?4 K that corresponds to 4 and 20 solar flux unit (=104 Jy), considering aperture efficiencies of 50±5 % and 75±8 % at 45 and 90 GHz, respectively. The telescope system saw first light in November 2011 and is satisfactorily operating daily since then. A few flares were observed and are presented here. The millimeter spectra of some flares are seen to rise toward higher frequencies, indicating the presence of a new spectral component distinct from the microwave one. 相似文献
70.
P. Wurz D. Abplanalp M. Tulej M. Iakovleva V. A. Fernandes A. Chumikov G. G. Managadze 《Solar System Research》2012,46(6):408-422
Knowing the chemical, elemental, and isotopic composition of planetary objects allows the study of their origin and evolution within the context of our Solar System. Landed probes are critical to such an investigation. Instruments on a landed platform can answer a different set of scientific questions than can instruments in orbit or on Earth. Composition studies for elemental, isotopic, and chemical analysis are best performed with dedicated mass spectrometer systems. Mass spectrometers have been part of the early lunar missions, and have been successfully employed to investigate the atmospheres of Mars, Venus, Jupiter, Saturn, Titan, and in comet missions. Improved mass spectrometer systems are foreseen for many planetary missions currently in planning or implementation. 相似文献