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181.
Andrea Dini Gianfranco Di Vincenzo Giovanni Ruggieri Jeffrey Rayner Pierfranco Lattanzi 《Mineralium Deposita》2005,40(3):337-346
The Monte Ollasteddu deposit represents a major gold discovery in the Variscan basement of southeastern Sardinia. Gold occurs
in late-Variscan extensional brittle structures hosted by meta-volcanic, and subordinately meta-sedimentary, rocks. The vein
mineralogy is dominated by quartz; arsenopyrite is the main sulphide. Reconnaissance 40Ar–39Ar dating gives ages around ∼260 Ma on K-feldspar from mineralized veins, whereas metamorphic white mica from the host rock
gives ages clustering at ∼307 Ma. The best age estimate for biotite from a nearby leucogranite body is 286.3±2.2 Ma. The Pb
isotope signature of ore and gangue minerals is entirely consistent with literature data for Variscan deposits of Sardinia,
and for European Variscan gold deposits. Fluid inclusion data point to the presence of both CO2-bearing and CO2-free fluids, with homogenization temperatures ranging from 220 to 415°C, with low-to-moderate salinities (0.4–6.2 wt% NaCl
equivalent). Monte Ollasteddu shows several features similar to European Variscan gold deposits; however, the age of mineralization
might post-date granitoid intrusion by as much as 30 Ma, being instead coeval with very late calc-alkaline basaltic dykes,
marking the transition to a post-orogenic, pre-Tethyan geodynamic setting.
Electronic Supplementary Material Supplementary material is available for this article at 相似文献
182.
Vincenzo Minganti Renzo Capelli Giuliana Drava Rodolfo De Pellegrini Giorgio Brunialti Paolo Giordani Paolo Modenesi 《Journal of Atmospheric Chemistry》2003,45(3):219-229
The concentrations of Cd, Cu, Mn, Ni, Pb, V, and Zn were measured in four different species of lichens (Parmelia caperata, P. pastillifera, P. saxatilis, P. sulcata) sampled in North-West Italy, in order to obtain maps showing metal distribution and the degree of deviation from background (natural) conditions. Significant differences among the species were found for Zn, Mn, Pb and V, suggesting that the combined use of mixed species in biomonitoring surveys can affect the interpretation of results. Results obtained for Parmelia caperata samples have been compared with background (natural) levels, and maps showing the distribution of each metal expressed as deviation from background levels have been obtained. Overall such maps show a medium to high alteration degree in the study area. 相似文献
183.
Luciano Telesca Vincenzo CuomoVincenzo Lapenna Maria Macchiato 《Physics of the Earth and Planetary Interiors》2002,131(1):47-62
We investigate the time dynamics of worldwide volcanic activity in order to find the presence of time correlation structures, by applying the Fano factor (FF) method. The analysis, performed on 35 time-occurrence volcanic eruptive sequences with volcanic explosivity index (VEI≥0) has revealed fractal behaviors in the most of the data sets considered, with fractal exponent α ranging from ∼0.2 to 0.9. 相似文献
184.
We present the photoelectric observations of the asteroids 26 Proserpina, 194 Prokne, 287 Nephthys, and 554 Peraga, performed in the years 1977–1978 at the Astronomical Observatory of Torino. The resulting synodic rotation periods are, for Proserpina, 13h13; Prokne, 15h67; and Peraga, 13h63. The period of Nephthys is possibly ~7h or the double. A tentative value for the phase coefficient of Peraga was found: 0.043 mag/degree. 相似文献
185.
The paper deals with the proposal and the experimental validation of a novel dissipative bracing system for the seismic protection of structures; compared with other similar systems, it is characterized by smaller size and weight, which makes it easier to move and to install, as well as particularly suitable to be inserted in light‐framed structures (e.g. steel structures of industrial plants). The proposed system consists of an articulated quadrilateral with steel dissipaters inserted, to be connected by tendons to frame joints; the prototypes have been designed and realized for the seismic protection of a two‐storey, large‐scale, steel frame, specially designed for shaking‐table tests. The paper, after an illustration of the system, and of its design and behaviour, presents the shaking‐table tests carried out. The experimental results have fully validated the proposed system, showing its good performance in controlling the seismic response of framed structures. A numerical non‐linear model, set up and validated on the basis of the physical tests, has been used to help interpreting the experimental results, but also to perform parametrical studies for investigating the influence of the design parameters on the performance of the control system. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
186.
Luigi Vincenzo Patella 《Pure and Applied Geophysics》1958,40(1):85-96
Riassunto L'A. espone un nuovo metodo electtrico dimisura di potenziali elettrocinetici (P.S.), ricordando dapprima i precedenti, per il rapidoritrovamento sperimentale dei paleo-alvei fluviali, e per l'interpretazione delle relative elettrodiagrafie P.S. così ottenute. — L'A. esemplifica per ora i risultati pratici conseguiti altrove, sopratutto in Russia dove l'argomento è stato posto per la prima volta in forma teorica rigorosa, e in una prossima nota completando l'attuale testo esporrà i risultati ottenuti personalmente.
Relazione presentata il 10 Aprile 1958 alla Sesta Assemblea Generale della Società Italiana di Geofisica e Meteorologia (Genova: 10–12 Aprile 1958). 相似文献
Summary The A. expounds a new electrical method for measuring electrokinetic potentials (Spontaneous Potentials), touching first upon the previous works, in view of easily refinding experimentally the palaeo river-beds, and interpreting the relating electro-graphics, obtained by these measures. — The A. exemplifies, for the present, the practical results realized elsewhere, particularly in Russia, where the problem has been set down for the first time in a rigorously theoretical way; in a next paper the A., perfecting the present work, will expound the personally attained results.
Relazione presentata il 10 Aprile 1958 alla Sesta Assemblea Generale della Società Italiana di Geofisica e Meteorologia (Genova: 10–12 Aprile 1958). 相似文献
187.
Gaetano Guida Vincenzo Palmeri Luca Settanni Raimondo Gaglio Marco Tolone Vito Ferro 《国际泥沙研究》2022,37(4):493-504
Calanchi(plural of calanco) are typical Italian badlands created by a combination of morphogenetic processes(rill and interrill erosion, gullying, piping, and mass movements) mainly originated by the effect of water. Calanchi are characterized by the sparse and patchy distribution of vegetation, and, in interplant areas, the soil surface is colonized by an association of organisms known as biological soil crust(BSC). A morphometric analysis of 45 basins in the studied calanchi area, based on a h... 相似文献
188.
Vincenzo Pane Diego Bellavita Manuela Cecconi Alessia Vecchietti 《Geotechnical and Geological Engineering》2017,35(2):765-780
The paper presents a methodology aimed at reducing—or even avoiding—the risk of heave and uplift failures of reinforced concrete diaphragm walls. The method is based on the simple concept of increasing the drainage capacity of the embedded portion of the retaining walls. The behaviour of a strutted excavation in a cohesionless soil below groundwater is examined by means of two distinct series of numerical analyses, respectively focused on the hydraulic and mechanical behaviour of the retaining system. It is shown that, for some frequent cases, such methodology is capable to improve the safety of the retaining system with respect to both hydraulic and geotechnical limit states. 相似文献
189.
Kafeel Ahmad Zafar Iqbal Khan Asma Ashfaq Muhammad Ashraf Nudrat Aisha Akram Muhammad Sher Hazoor Ahmad Shad Vincenzo Tufarelli Antonio Lonigro Mariano Fracchiolla Eugenio Cazzato 《Environmental Earth Sciences》2017,76(8):322
Bio-concentration of elements such as Mo, As, Se, Fe, Cu, Zn, Ni and Pb was analyzed in spring onion (Allium fistulosum L.) in three different locations of central Punjab, Pakistan. At location GW, relatively low level of hazardous elements was found in spring onion, suggesting that groundwater is a safe source of water for irrigating food crops. The pH of soil at wastewater irrigation was found less acidic (pH 7.4) than the other sites. The range of concentration in the different samples of spring onion was as follows: 6.15–8.16 mg kg?1 for Mo, 2.77–4.28 mg kg?1 for As, 0.395–0.705 mg kg?1 for Se, 36.73–48.17 mg kg?1 for Fe, 10.58–16.26 mg kg?1 for Cu, 28.87–39.79 mg kg?1 for Zn, 6.66–8.75 mg kg?1 for Ni and 4.33–6.09 mg kg?1 for Pb, respectively. High bio-concentration of Zn (15.37) from soil to spring onion was found at canal water irrigated location. The estimated daily intake of metal for spring onion was less, but the health risk index was higher than 1 for Mo, As, Cu, Pb and Ni, respectively. This was due to higher proportion of spring onion in diet, which consequently increased the health risk index for metals. Therefore, it is recommended to avoid growing vegetables in untreated urban and rural wastewater containing elevated amounts of metals. 相似文献