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61.
Optimum configuration of groynes for stabilization of alluvial rivers with fine sediments 总被引:1,自引:0,他引:1
Severe bank erosion at lowland rivers in Bangladesh devours vast tract of lands and renders thousands of people homeless at high flood; also,rapid deposition changes bed topographies and seriously redu... 相似文献
62.
63.
Thomas Hobiger Tadahiro Gotoh Jun Amagai Yasuhiro Koyama Tetsuro Kondo 《GPS Solutions》2010,14(2):207-216
Off-the-shelf graphics processing units provide low-cost massive parallel computing performance, which can be utilized for
the implementation of a GPS software receiver. In order to realize a real-time capable system the crucial stages of the receiver
should be optimized to suit the requirements of a parallel processor. Moreover, the receiver should be capable to provide
wider correlation functions and provide easy access to the spectral domain of the signals. Thus, the most suitable correlation
algorithm, which forms the core part of each receivers should be chosen and implemented on the graphics processor. Since the
sampling rate of the received signal limits the real-time capabilities of the software radio it is necessary to determine
an optimum value, considering that the precision of the observable varies with sampling bandwidth. We are going to discuss
details and present our single frequency multi-channel implementation, which is capable of operating in real-time mode. Our
implementation differs from other solutions by the wideness of the correlation function and allows simple handling of data
in the spectral domain. Comparison with output from a commercial hardware receiver, which shares the antenna with the software
radio, confirms the consistency and accuracy of our development. 相似文献
64.
XIEMo-wen ZHOUGuo-yun ESAKITetsuro 《中国地理科学(英文版)》2003,13(1):66-72
In this paper ,based on a new Geographic Information System(GIS) grid-based three-dimensional (3D) deterministic model and taken the slope unit as the study object ,the landslide hazard is mapped by the index of the 3D safety factor ,Compared with the one-dimensional(1D) model of infinite slope,which is now widely used for deterministic model based landslide hazard assessment in GIS,the GIS grid-based 3D model is more acceptable and is more adapt-able for three-dimensional landslide.Assuming the initial slip as the lower part of an ellipsoid ,the 3D critical slip surface in the 3D slper stability analysis is obtained by means of a minimization of the 3D safety factor using the Monte Carlo random simulation.Using a hydraulic model tool for the watershed analysis in GIS,an automatic process has been devel-oped for identifying the slope unit from digital elevation model(DEM)data,Compared with the grid-based landslide hazard mapping method ,the slope unit possesses clear topograhical meaning,so its results are more credible,All the calcula-tions are implemented by a computational program,3DSlopeGIS,in which a GIS component s used for fulfilling the GIS spatial analysis function.and all the data for the 3D slope safety factor calculation are in the from of GIS data (the vector and the grid layers).Because of all these merits of the GIS-based 3D landslide hazard mapping method,the complex algo-rithms and iteration procedures of the 3D problem can also be perfectly implemented. 相似文献
65.
Tetsuro Hirono Masumi Sakaguchi Kenshiro Otsuki Hiroki Sone Koichiro Fujimoto Toshiaki Mishima Weiren Lin Wataru Tanikawa Masaharu Tanimizu Wonn Soh En-Chao Yeh Sheng-Rong Song 《Tectonophysics》2008,449(1-4):63-84
To characterize the fault-related rocks within the Chelungpu fault, we performed X-ray computed tomography (CT) image analyses and microstructural observations of Hole B core samples from the Taiwan Chelungpu-fault Drilling Project. We identified the slip zone associated with the 1999 Chi-Chi earthquake, within the black gouge zone in the shallowest major fault zone, by comparison with previous reports. The slip zone was characterized by low CT number, cataclastic (or ultracataclastic) texture, and high possibility to have experienced a mechanically fluidized state. Taking these characteristics and previous reports of frictional heating in the slip zone into consideration, we suggested that thermal pressurization was the most likely dynamic weakening mechanism during the earthquake. 相似文献
66.
Numerical Investigations of Mean Winds Within Canopies of Regularly Arrayed Cubical Buildings Under Neutral Stability Conditions 总被引:2,自引:2,他引:0
Recently, several attempts have been made to model the wind velocity in an urban canopy in order to accurately predict the
mixing and transport of momentum, heat, and pollutants within and above the canopy on an urban scale. For this purpose, unverified
assumptions made by Macdonald (Boundary-Layer Meteorol 97:25–45, 2000) to develop a model for the profile of the mean wind
velocity within an urban canopy have been used. In the present study, in order to provide foundations for improving the urban
canopy models, the properties of the spatially-averaged mean quantities used to make these assumptions have been investigated
by performing large-eddy simulations (LES) of the airflow around square and staggered arrays of cubical blocks with the following
plan area densities: λ
p
= 0.05, 0.11, 0.16, 0.20, 0.25, and 0.33. The LES results confirm that the discrepancy between the spatial average of wind
velocity and Macdonald’s five-point average of wind velocity can be large in both types of arrays for large λ
p
. It is also confirmed that Prandtl’s mixing length varies significantly with height within the canopy, contrary to Macdonald’s
assumption for both types of arrays and for both small and large λ
p
. On the other hand, in accordance with Macdonald’s assumption, the sectional drag coefficient is found to be almost constant
with height except in the case of staggered arrays with high λ
p
. 相似文献
67.
H. Kurokawa T. Kitahara Y. Nakai Y. Funakoshi K. Ichimoto 《Astrophysics and Space Science》1986,118(1-2):149-152
We studied the evolutional characteristics of fine structures in H flare emitting regions and their relation to X-ray and microwave emissions for selected events observed with the 60 cm Domeless Solar Telescope at Hida Observatory, University of Kyoto. The principal conclusions of this investigation are: (1) H kernel consists of some finer bright points or Hflare points whose individual size is less than 1 arc sec. (2) Impulsive brightnenings of H flare points occurred simultaneously with the spikes of the hard X-ray and microwave bursts within the time resolution of our H observations which varied from 1 to 10 s. (3) It is concluded that fast electron beams must be the principal mechanism of heating H flares during the impulsive phase of a flare.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. Contributions from the Kwasan and Hida Observatories, University of Kyoto, No. 265. 相似文献
68.
69.
Hydrogen isotope composition of deep-seated water 总被引:3,自引:0,他引:3
Yoshimasu Kuroda Tetsuro Suzuoki Sadao Matsuo 《Contributions to Mineralogy and Petrology》1977,60(3):311-315
D/H ratios of phlogopites and amphiboles from rocks of possible mantle origin and also those of water from (glass?) inclusions in olivines of the olivine nodule and peridotites have been determined. The mantle water seems to have aδD value of —85±10‰ on the basis of results of inclusions in the nodule-olivine. 相似文献
70.
Yoshimasu Kuroda Tetsuro Suzuoki Sadao Matsuo Haruo Shirozu 《Contributions to Mineralogy and Petrology》1976,57(2):223-225
Chemistry dependence of D of chlorites is inferred from data for natural chlorites. D of water equilibrated with those chlorites is estimated to be –2–8. 相似文献