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91.
Proton microprobe for chemical dating of monazite   总被引:1,自引:1,他引:0  
Although quantitative chemical analysis by proton microprobe has become an established technique, it has been rarely applied to problems in the earth sciences. The method, having lower detection limit (better than 10 ppm for U, Th and Pb) and higher spatial resolution than electron microprobe (typically 1 μm vs 3 μm), can be successfully used in geology. Here, we present a procedure for the chemical dating of monazite, (REE)PO4, by proton microprobe. The procedure is compared with electron probe microanalysis technique (EPMA).  相似文献   
92.
The paper presents the results of testing the various methods of permanent stations’ velocity residua interpolation in a regular grid, which constitutes a continuous model of the velocity field in the territory of Poland. Three packages of software were used in the research from the point of view of interpolation: GMT (The Generic Mapping Tools), Surfer and ArcGIS. The following methods were tested in the softwares: the Nearest Neighbor, Triangulation (TIN), Spline Interpolation, Surface, Inverse Distance to a Power, Minimum Curvature and Kriging. The presented research used the absolute velocities’ values expressed in the ITRF2005 reference frame and the intraplate velocities related to the NUVEL model of over 300 permanent reference stations of the EPN and ASG-EUPOS networks covering the area of Europe. Interpolation for the area of Poland was done using data from the whole area of Europe to make the results at the borders of the interpolation area reliable. As a result of this research, an optimum method of such data interpolation was developed. All the mentioned methods were tested for being local or global, for the possibility to compute errors of the interpolated values, for explicitness and fidelity of the interpolation functions or the smoothing mode. In the authors’ opinion, the best data interpolation method is Kriging with the linear semivariogram model run in the Surfer programme because it allows for the computation of errors in the interpolated values and it is a global method (it distorts the results in the least way). Alternately, it is acceptable to use the Minimum Curvature method. Empirical analysis of the interpolation results obtained by means of the two methods showed that the results are identical. The tests were conducted using the intraplate velocities of the European sites. Statistics in the form of computing the minimum, maximum and mean values of the interpolated North and East components of the velocity residuum were prepared for all the tested methods, and each of the resulting continuous velocity fields was visualized by means of the GMT programme. The interpolated components of the velocities and their residua are presented in the form of tables and bar diagrams.  相似文献   
93.
The rate and extent of the heterogeneous reaction that takes place between dissolved sodium sulphide and synthetic tenorite is studied for a wide range of sodium sulphide to copper oxide ratios. Besides the sulphidization with the formation of a copper-sulphide layer, a substantial oxidation of sulphide ions takes place at the surface of the solid. The extent of both types of reactions is quantitized by combining specific analytical methods.The results are discussed in terms of possible mechanisms and of their implications in the sulphidization process applied in the flotation of oxidized copper ores.  相似文献   
94.
Measurement results of PM10 (particulate matter with diameters below 10 μm) concentrations performed at four stations in central Poland (2007–2010) were analyzed in terms of levels and distributions of concentrations, the number of exceedances of the limit values and the causes of these exceedances. PM10 levels were similar at suburban and rural stations, except of one station located in the vicinity of a busy street. The median of PM10 concentration ranged from 26 μg/m3 at suburban station to 44 μg/m3 at Warsaw Kerb station. Seasonal variability analysis of PM10 concentration revealed an additional maximum beyond the usual autumn-winter one. This maximum occurred in April at all stations, and corresponded to seasonal wildfires activity and dust activation in Eastern Europe. Cluster analysis of back-trajectories revealed that PM10 concentrations depend on the direction of advection of the incoming air; the highest values are registered for air of regional and southern origins, while the lowest are for the airmasses coming from the north and northwest direction.  相似文献   
95.
The quantity and quality of lignin phenols (Σ8, Λ, S/V, C/V and (Ad/Al)v) in the sediments of three small Lobelia lakes with neither inlets nor outlets were investigated and compared with palynological data and lithology of the profiles. The method of alkaline CuO oxidation was used. Substantial differences with respect to sedimentary lignin concentration and provenance recorded along the profiles and among the sites are in good agreement with pollen data describing the dominant type of vegetation and with indices of soil erosion in the lakes’ catchments. This relation shows that the compositions of lignin degradation products in these lakes are closely related to the local environmental conditions. In all the lakes gymnosperm wood is the main source of lignin products; however, each lake is characterized by different S/V index values. Especially good correlations were obtained between pine pollen proportions in sediments and the S/V index. The correlation between the C/V and (Ad/Al)v indices indicates a higher degradation of organic matter when non-woody tissue is more abundant. This pilot study illustrates the usefulness and potential for a wider application of lignin oxidation products in palaeoecological reconstructions. This kind of data would be of special importance when investigating local presence/absence of woody plants and the role of angiosperms/gymnosperms in local vegetation. Estimates of lignin biodegradation levels, as well as the data on diagenetic processes, may afford supplementary information on possible disturbances in sedimentation.  相似文献   
96.
<正>Whalfera wiszniewskii sp.nov.is described from the Late Eocene Baltic amber.The genus Whalfera is considered as the only fossil genus confidently assigned to the Rhachlberothinae.Others previously placed in this subfamily belong to Paraberothinae(except perhaps for Oisea).The Late Eocene/present Rhachiberothinae and the Cretaceous Paraberothinae are considered to be the subfamilies of Berothidae.  相似文献   
97.
The rate of consumption of sulphide in the sulphidizing reactions of malachite and chrysocolla has been measured. The oxidation of sulphide ions at the surface of sulphidized chrysocolla was shown to take place. The influence of thiosulphate anions on the xanthate flotation of sulphidized malachite and chrysocolla was investigated and it was shown to depress the flotation of chrysocolla strongly.The result suggest, that the presence of thiosulphate as a product of simultaneous oxidation can be one of the reasons for the more difficult flotation of sulphidized chrysocolla.  相似文献   
98.
The site of Moravany-Žakovska in western Slovakia is situated in a loessic terrain and is dated to the end of the Late Glacial Maximum. This article shows the importance of analyzing the 0.01-0.1 mm fraction to interpret the sedimentological environment and a number of measured anthropogenic indices, such as burnt quartz grains, charcoal, radiolarite chips, microflakes, and microfragments of bone. Analysis of the profile of the site through time reveals the relationship between occupational levels and phases of slope wash that occurred during wetter climatic episodes; these are separated by phases of aeolian sedimentation. At the same time, analysis of anthropogenic indices in this size fraction permitted the identification of occupational levels, including those not recorded by macrofinds. Analysis of anthropogenic indices in horizontal exposures enabled the identification of latent settlement structures such as hearths, areas of radiolarite processing, zones where mineral dyes were prepared, and other structures not recorded by macrofinds.  相似文献   
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