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71.
The Iranian Guideline for Seismic Rehabilitation of Existing Buildings (GSREB), which is currently used for vulnerability assessment of existing buildings in Iran, is evaluated in this paper. The vulnerability of sample buildings of a variety stories with special steel moment resisting frames, designed according to the Standard No.2800 requirements, is assessed by GSREB. In the vulnerability assessment, different analysis methods were used and the results, in terms of usage ratio, defined as the ratio of the strength/deformation demand to the corresponding capacity, are compared. Numerical results show that some columns of these buildings do not satisfy the life safety performance criteria in the design hazard level. Moreover, the target displacement estimated by the Displacement Coefficient Method (DCM) is larger than the maximum displacement calculated by nonlinear dynamic analysis.  相似文献   
72.
73.
This paper presents the findings of the study on treatment of domestic wastewater using a laboratory scale Hybrid Upflow Anaerobic Sludge Blanket (HUASB) reactor. The reactor with a working volume of 5.9 L and plastic cut rings as packing media was operated at varying Hydraulic Retention Time (HRT) for a period of 110 days. While the COD removal varied from 75–86%, the BOD removal was in the range of 70–91%. Methane content in the biogas was 62±3%. VFA levels fluctuating between 100 and 186 mg/L (as acetate) did not pose operational problems such as souring of the reactor. During the treatment, nutrient levels exhibited an increasing trend. HUASB system could be designed with very short HRT of 3.3 hours, which will reduce the treatment cost significantly. It appears to be a promising alternative for the treatment of domestic wastewater in developing countries like India  相似文献   
74.
Origin and chemical partitioning of heavy metals in riverbed sediments   总被引:2,自引:0,他引:2  
In the present investigation, bulk and chemical partitioning of elements in the Shefa-Rud riverbed sediments are studies. Higher concentrations of elemental concentrations have been observed in estuarine zone when compared with riverine sediments (except for AI, Fe, Pb and Mn). Manganese is mobilized under anoxic conditions prevailing in the Caspian Sea. Lithogenous materials are greatly diluted in the estuarine zone by various pollutants present in the Caspian Sea. Organic metallic bonds are not significantly present in the area of study. Geological units of the area of study have resulted in the lower concentrations of elemental concentrations of riverbed sediments when compared with published values for mean crust and world sediments ones. Though, cluster analysis has clearly shown the importance of alumina-silicates in controlling the distribution of Fe and Mn in riverbed sediments but it could not depict controlling mechanism for other studied elements. Geochemical Index (Igeo) and Enrichment Factor (EF) values are indicative of a clean environment throughout the river course. These values are in a well agreement with results of chemical partitioning data. Quantification of EF values is not logically possible and therefore Igeo values can be used more effectively.  相似文献   
75.
Arabian Journal of Geosciences - Dust storms are one of the major environmental disasters in the arid regions of Middle East, occurring in very high frequency. As a result, monitoring dust storms...  相似文献   
76.
Submarine channels act as the main conduits for the transport of sediment to deep-water basins by sediment gravity flows. The interplay between fault-related deformation and the initiation and development of the channels is poorly known. Here, we present the identification, formation and evolution of the Miocene slope-parallel channel by employing 3D seismic reflection, wireline-log and core data in the eastern slope of Yinggehai Basin, South China Sea. Based on the lengths and plan-view shapes, a total of three different types of fault-associated slope-parallel depressions have been identified. The depressions were formed in the fault zone and controlled by the reactivation of the underlying older faults. Among them, Type-1 depressions are short (<20 km) oval or circle shaped possessing only one depocenter. Type-2 depressions are elongated (25–70 km), and usually have multiple depocenters. Type-3 depressions, which are usually connected by slope-perpendicular channels in the head and middle, are longer (more than 190 km) and connect shallow and deep-water basins. The analysis of morphology, erosivity and material transport shows that Type-3 depressions are fully fledged channels. Type-1 and Type-2 depressions are channel precursors representing the initial stage of channel evolution. With this motive, a model for the initiation and evolution of slope-parallel submarine channels controlled by strike-slip-extensional faults is presented. Unlike the previous investigations which suggest that erosion takes place at the inception of submarine channel formation, the fault-controlled slope-parallel channel is mainly controlled by faulting and has no initial erosive base and does not develop levees. The depressions are extended and elongated by the continuous fault activity. It was not until the slope-parallel depression connected with large-scale slope-perpendicular channels transporting materials into the depression via erosive turbidity currents that it evolved into a channel-levee system. This study is of global importance for understanding submarine channel generation and evolution since the fault-controlled slope-parallel channels have been found in tectonic active basins worldwide.  相似文献   
77.
In this article we define inverse line graphs of directed graphs as a new framework for solving some classical network analysis problems. The extraction method and theories of inverse line graphs are explained in this article. It is shown that by changing the analysis space from the original directed graph to the inverse line graph, complex problems can be changed into simpler problems. We show the usefulness of the proposed framework in two particular applications: shortest path computations and the more general route planning. Considering the implementation result, we expect that this framework could be used in many more network analysis problems.  相似文献   
78.
Iran anticyclone is one of the main features of the summer circulation over the Middle East in the middle and upper troposphere. To examine the effect of the Zagros Mountains on the formation and maintenance of the Iran anticyclone, an experiment was conducted by Regional Climate Model (RegCM4) in an area between 22°?C44°N and 35°?C70°E with a 40?km horizontal grid spacing. The NCEP/NCAR re-analysis data set were used to provide the initial and lateral boundary conditions in a control run and in a simulation run by removing the Zagros Mountains. The result reveals that the Zagros Mountains have an important effect on the formation and maintenance of the low-level cyclonic circulation and mid-level anticyclonic circulation in summer. Examining the diabatic heating shows that the elimination of the Zagros Mountains causes a significant change in the heating values and its spatial distributions over the study area. Comparing the diabatic heating terms, the vertical advection term has the main contribution to the total heating. In the absence of the Zagros Mountains, the vertical advection and the mid-troposphere anticyclonic circulation are apparently weak and, therefore, the Iran subtropical anticyclone vanishes over the west of Iran. The study indicates that the Zagros Mountains as an elevated heat source have the main impact in the formation of a thermally driven circulation over the Middle East.  相似文献   
79.
Electromagnetic induction (EMI) method results are shown for vertical magnetic dipole (VMD) configuration by using the EM38 equipment. Performance in the location of metallic pipes and electrical cables is compared as a function of instrumental drift correction by linear and quadratic adjusting under controlled conditions. Metallic pipes and electrical cables are buried at the IAG/USP shallow geophysical test site in São Paulo City, Brazil. Results show that apparent electrical conductivity and magnetic susceptibility data were affected by ambient temperature variation. In order to obtain better contrast between background and metallic targets it was necessary to correct the drift. This correction was accomplished by using linear and quadratic relation between conductivity/susceptibility and temperature intending comparative studies. The correction of temperature drift by using a quadratic relation was effective, showing that all metallic targets were located as well deeper targets were also improved.  相似文献   
80.
The potential of MCM‐41 for the removal of cationic dyes from water solution was evaluated using sodium dodecyl sulfate (SDS) for the surface modification of this mesoporous material. Admicelle structures formed on the surface of the calcined MCM‐41 are capable of removing organic pollutants and cationic species from water environment. The structural, textural, and surface chemical characteristics of the prepared SDS‐modified MCM‐41 (SDS‐MCM‐41) were studied. The adsorption capacity of SDS‐MCM‐41 was evaluated for methylene blue (MB) as a target cationic dye. Equilibrium adsorption isotherm data were manipulated employing nonlinear regression analysis. The Langmuir, Freundlich, and Sips isotherm models were examined. The adsorption data were well fitted to both Langmuir and Sips isotherm models. The maximum adsorption capacity of SDS‐MCM‐41 for MB, based on Langmuir and Sips models, were 290.8 and 297.3 mg g?1, respectively. Ethanol was found to be an effective solvent for partial regeneration of the adsorbent.  相似文献   
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