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101.
The Kuwait Group consists mainly of clastic sediments overlying unconformably the Dammam Formation of Tertiary age. The Kuwait Group is generally divided into three main hydrostratigraphic units: the upper and lower aquifers separated by an aquitard. The upper aquifer is further divided into the water table aquifer, an aquitard and a semiconfined aquifer. This semiconfined unit was pumped and the drawdowns were observed in piezometers screened in various subunits of the Kuwait Group. Some pumping tests of short duration were carried out in the top water table aquifer as well. These tests showed that the subunits of the Kuwait Group are hydraulically interconnected to a varying degree.

The pumping test data were analysed using conventional analytical solutions. The semiconfined pumping test was also simulated by a quasi-three-dimensional model using a leaky multiaquifer modelling technique. The initial hydraulic parameters were improved manually in the model till best fit drawdowns were obtained.

The final parameters obtained by simulation of the pumping tests were used in designing a pilot drainage system for the control of a rising groundwater table in parts of Kuwait City.  相似文献   

102.
Organochlorine compounds (OCs) in surface and core sediments collected from Lake Maryut, Egypt, were examined to elucidate their distribution, ecological risk and historical trend. To our knowledge, this is the first study on residue levels of OCs in sediments from Lake Maryut. Concentrations of PCBs and DDTs were higher than other OCs, ranging from 3.06 to 388 and from 0.07 to 106 ng/g dry wt., respectively. The highest concentrations of OCs were found at stations near the discharge point of sewage and close to industrial areas. The distribution of DDT and its metabolites suggest no recent inputs into the lake environment. Contamination levels of sedimentary PCBs and DDTs, can be categorized moderate to high compared to other urbanized regions worldwide. Temporal trends in OCs levels were influenced by input pathways at two sites. Evaluation of ecotoxicological risks suggests that adverse biological effects are expected mainly in the main basin area.  相似文献   
103.
104.
Theoretical formulations to the problem of expansion of spherical and cylindrical cavities in a layered elastic system are presented. The medium surrounding the cavity is assumed to consist of several layers, and each is idealized as a linear elastic solid. The solutions are expressed in matrix forms and can be obtained using a programmable calculator. The developed solutions are of some importance in geomechanics. The spherical cavity solution can be used to compute the settlement of single axially loaded piles. The predicted settlement using the analysis outlined herein agrees reasonably well with one case of field measurements. The cylindrical cavity solution can be used to manifest the effect of disturbed mass at the cavity wall on the stress–strain and deformation characteristics of the intact mass.  相似文献   
105.
Natural Resources Research - Two geophysical tools were used to delineate the configuration of the Nubian sandstone aquifer in the study area. Three hundred magnetic points were measured and...  相似文献   
106.
Alkaline volcanic rocks, sometimes feldspathoid bearing, appear in variable stratigraphic positions within the Eocene of the middle part of Central Iran. No magmatic zonation and no K2O enrichment in both time and space can be found in this volcanic sequence. These facts together with other geochemical and geological features of the Iranian Eocene provinces do not agree with a volcanism related to a subduction zone model.Reversely, a rift model may be applied for the interpretation of the origin of Eocene volcanic rocks and their geodynamic situation. The emissions of alkaline magma are linked with rhythmic opening of a rift zone during Eocene.A mutual contamination between a basaltic magma and a bulky palingenetic acid magma is responsible for the few volcanic rocks with calc-alkaline trend.
Zusammenfassung Alkali-Gesteine, die manchmal Feldspatoide enthalten, treten in verschiedenen stratigraphischen Stellungen innerhalb des Eozäns des Zentral-Irans auf.In diesen Vulkaniten ist keinerlei magmatische Zonierung und insbesondere keine systematische Variation der Kaligehalte festzustellen. Diese und andere geologische und geochemische Argumente sprechen gegen eine Deutung als Paläosubduktionszone.Als Alternative bietet sich das Modell der Öffnung eines Grabens an: der Alkali-Vulkanismus steht in Zusammenhang mit den verschiedenen Phasen der Entstehung und Entwicklung eines Rifts während des Eozäns.Die seltenen Vulkanite kalk-alkalischer Zusammensetzung erklären sich durch Mischung der Magmen von Alkali-Basalten mit den bedeutenden anatektischen Magmen.

Résumé Des roches alcalines, éventuellement à feldspathoïde, existent à des niveaux et dans des secteurs variés de la séquence volcanique éocène de la partie médiane de la zone de l'Iran Central; par ailleurs, dans cette série, on n'a pu mettre en évidence ni zonation magmatique, ni enrichissement en K2O. Ces faits, joints à d'autres caractères géochimiques et géologiques des provinces éocènes de l'Iran, sont en désaccord avec un volcanisme lié à une zone de subduction.En revanche, un modèle de rift peut être appliqué pour interpréter l'origine des volcanites éocènes et leur situation géodynamique. Les émissions de magma alcalin sont en effet en relation avec l'ouverture rhythmique d'une zone de rift pendant l'Eocène.Quant aux rares roches à tendance calco-alcaline, elles résultent d'une contamination mutuelle entre un magma basaltique et un important magma acide palingénétique.

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107.
Summary Lead-zinc mineralization occurs in Miocene sediments along the Egyptian Red Sea Coast in several localities. Galena samples were collected from some of these localities for isotopic and trace elements studies. The isotopic ratios206Pb/204Pb,207Pb/204Pb,209Pb/204Pb for these samples indicate that they are contaminated with radiogenic lead (J-type anomalous lead) with different degrees. The variation in the degree of contamination is significant and indicates a non-uniform source of uranium and thorium from which radiogenic lead was deriven. The highst contaminations were observed in samples collected from sediments overlying or close to acidic basement rocks. The trace element content indicates that galenas were formed at low temperature from solutions that circulated the underlying basement picking several trace elements in addition to radiogenic lead.  相似文献   
108.
Groundwater contamination is one of the most significant problems in arid countries. Al-Quwiy’yia region is an example of an area where the groundwater is contaminated as a result of infiltration of waste water in low-lying areas adjacent to inhabited zones. Such contamination poses significant environmental threats for the surrounding environment and groundwater. Surface observations and spatial distribution of contamination observed in the shallow aquifer indicate that the main contamination sources were from sewage as well as from waste water dumping. However, the main source of water supply for the whole area is groundwater abstracted from the relatively shallow aquifer. Therefore, the transient electromagnetic method (TEM) and 2D electrical resistivity tomography (2D ERT) have been applied close to the waste water dump site to characterize the response of pollution plumes. Both of these geoelectrical techniques are sensitive to electrical conductivity as well as to other physical properties, which are greatly influenced by the polluted groundwater. Therefore, it is possible to profile the contamination plumes, both vertically and horizontally, in the vicinity of the measured stations. The ERT profiles gave detailed information about the lateral distribution of the contaminated groundwater, whereas the TEM demonstrated the vertical extensions.  相似文献   
109.
The present study aims to explain some hydrogeological problems that are related to geological setting in two wadis: El Kallabiyyah and As Sabil East Esna. For this purpose, land magnetic, vertical electrical soundings, and two-dimensional electrical resistivity imaging profiles were measured. The lithological succession comprises Upper Cretaceous to Quaternary deposits that rest on a Precambrian basement rock. The results of the interpretation of the land magnetic measurements in wadi El Kallabiyyah represent the depth to the basement rock which ranges from 260 to 660 m and increases towards the northeast trend, but in wadi As Sabil, there is a large basin at the center of the wadi with the recorded depth to the basement reaching 1,300 m due to the effect of two normal faults (F1 and F2). The results of the interpretation of the vertical electrical sounding and two-dimensional imaging confirmed the presence of these faults in wadi As Sabil. The results of the geoelectrical measurements in wadi El Kallabiyyah represented the water-bearing layer at the third unit that consists of sands, gravels, boulders, and clays. The presence of clay will affect the potentiality of a drilled well. For wadi As Sabil, the results of geoelectrical measurements led to the lower part of the second unit which acts as a water-bearing layer that consists of sands, boulders, gravels, and clays. It can be concluded that the best site for drilling wells in wadi El Kallabiyyah is at vertical electrical sounding no.5 with a total depth of not less than 230 m. In wadi As Sabil, the drilled wells must be concentrated at the center and the downstream.  相似文献   
110.
The bottom of the magnetized crust determined from the spectral analysis of magnetic anomaly is interpreted as a level of the Curie point isotherm. A spectral analysis technique was used to estimate the depth of the magnetic anomalies sources (Curie point depth analysis) of the eastern shore of the Gulf of Suez, Egypt. The depth to the tops and centers of the magnetic anomalies are calculated by azimuthally averaged power spectrum method for the whole area. The results obtained suggests from this study showed that the average depth to the top of the crustal block ranges between 1.15 and 1.9 km, whereas the average depth to the center of the deepest crustal block ranges between 9.1 and 12.7 km. Curie point depths in the study area range between 14.5 km in the northwestern part of the study area and 26 km in the southeastern part of the study area. The results imply a high geothermal gradient (34.7 °C/km) and corresponding high heat flow value (72.87 mW/m2) in the northwestern part of the study area. The southeastern part of the study area displays a low geothermal gradient (24.26 °C/km) and low heat flow value (50.9 mW/m2). These results are consistent with the existence of the possible promising geothermal reservoir in the eastern shore of the Gulf of Suez especially at Hammam Faraun area.  相似文献   
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