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941.
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The electrogenerative removal of cobalt is conducted in a batch reactor equipped with three‐dimensional electrodes: Reticulated vitreous carbon (RVC) and porous graphite (PG‐25) as cathode materials. In this process, a chemical reaction takes place spontaneously in a divided cell where cobalt is reduced at the cathode and zinc is oxidized to produce electrical energy without an external supply of energy. The results obtained show that RVC serves as a more suitable cathode material than PG‐25 in this system. At optimum conditions, more than 99% of cobalt were removed and recovered in its metallic state after 10 h of operation with an initial 200 mg L?1 Co(II) solution at pH 4 in 0.2 M Na2SO4 and 0.4 M boric acid. Scanning electron microscopy and X‐ray diffraction analyses are performed to study the morphology and crystallographic patterns of cobalt deposits on the cathodes, respectively. 相似文献
946.
This paper presents the results of an experimental investigation on the rocking behavior of rigid blocks. Two types of test specimens have been tested, namely M and C types. Nine blocks of the M type and two blocks of the C type with different aspect ratios were tested with varying initial rotational amplitudes and with different materials at the contact interface, namely concrete, timber, steel, and rubber. The results showed that the interface material has significant influence on the free rocking performance of the blocks. Blocks tested on rubber had the fastest energy dissipation followed by concrete and timber bases, respectively. Analysis of the test results has shown that the energy dissipation in the case of tests on a rubber base is a continuous mechanism whereas in the case of tests on rigid bases, i.e. timber and concrete, energy dissipation is a discrete function. Finally, the rocking characteristics of the blocks were calculated using piecewise equations of motion and numerical analysis. It was possible to predict the correct free rocking amplitude response when a reliable value for the coefficient of restitution was used. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
947.
Mohamed Sobaih 《Geotechnical and Geological Engineering》2011,29(3):249-258
Population increase and development plans in Egypt require the establishment of many new cities near Cairo. One of these cities
is the 15th of May City located about 30 km south of Cairo. The site of this city is very near from two quarries belonging
to two cement companies. The inhabitants used to complain from the blastings in these quarries. At a certain stage some buildings
have suffered different levels of damage. Upon the request of official authorities a study program has been performed to identify
the causes and the safety of five chosen buildings. The program included experimental testing to measure the vibration of
the chosen buildings during blasting operations. Three-dimensional structural analysis has been also performed. Results have
showed that the damage was due to Dahshour Earthquake of Oct. 12th, 1992 and not due to quarry blastings. Many other useful
conclusions have been obtained. 相似文献
948.
Abdel Monem Mohamed Soltan Wolf A. Kahl Mahmoud M. Hazem Mechael Wendschuh Reinhard X. Fischer 《Mineralogy and Petrology》2011,103(1-4):9-17
The microstructure of grainstone, grain-supported limestone, samples representing different geographic and stratigraphic intervals in Egypt were examined before and after calcination at 950°C for 0.25, 0.5, 1 and 2?h. The examination utilized are X-ray diffraction (XRD), X-ray fluorescence (XRF), transmitted light microscopy (TLM), scanning electron microscopy (SEM) and X-ray micro tomography (??-CT). Both the free lime content and reactivity of the produced quicklime were measured. The quicklime produced at 950°C for 0.25 and 0.5?h is un-reactive (RDIN < 10) due to its low content of free lime. However, quicklime produced at 1 and 2?h conditions is highly reactive (RDIN > 30) with variable reactivity due to the differences in the lime microfabric. The grainstones enriched in nummulites resulted in quicklime of higher reactivity than those dominated by foraminifera, peloids and miliolids. This is mainly attributed to the preservation of the intraparticle pores of the original limestone and the development of pinhole and fracture micropores. The shape of pores and not their amount is the main controlling variable in the quicklime reactivity. The grainstones enriched in fracture pores showed more reactive lime, whereas those with compact structures are less reactive post calcination. 相似文献
949.
The monthly geochemical study of Bizerte lagoon principal affluent water consists in characterizing the water geochemical facies and their inorganic pollution degree by nutrients. The major elements analysis shows calcium sulfate to chloride calcium balanced facies. The geochemical analysis of water nutritive salts shows generally a good to excellent quality. Wadi Guenniche is considered more polluted as we recorded the highest nutrients contents. The principal component analysis of the connections between the physicochemical and geochemical parameters of Bizerte lagoon affluent water show that the low salinities, the turbidity, and the low contents of major sodium, chloride ions, and nutritive elements are the major factors of the environment controlling the good quality of this fresh water. 相似文献
950.
This paper discusses the practical use of filtering and inversion in VLF-EM data processing and interpretation. The advantages and disadvantages of both mentioned techniques were outlined to avoid the misleading interpretation of such data in some case studies. Much concern is taken to show the interval distance effect upon the correct depth identification of the anomalous body by either inversion or filtering. The methodology of the study is going through proposing an initial model, generating the synthetic VLF-EM data of the model by means of forward modeling, filtering (Karous–Hjelt filter) and inversion (Inv2DVLF software) of the synthetic data and comparing between the results of both methods and the initial model. The study reached to (1) Karous–Hjelt filter provides misleading depths for his limited depth of resolution and cannot provide estimates of deep targets if the profile is too small, whereas inversion provides exact results, particularly in case of shallow anomalous target; (2) crossover between in-phase and out-of-phase data could resulted from a small shallow conductive target or a large deep one; (3) selection of a reasonable environmental resistivity has an important impact on the inversion process; and (4) the numerical reflection resulted during VLF-EM data inversion could lead to an erroneous interpretation. 相似文献