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41.
A mixture containing equal amounts of forsterite and grossularite by weight (Fo50Gr50) has been studied at temperatures between 750 and 1400°C under pressures ranging from 6 to 25 kbar in presence of excess water. The assemblages noted under low pressure (<8 kbar) are as follows: Diopsidess+forsteritess+monticellitess+vapor and Diopsidess+forsteritess+monticellitess+liquid+vapor. (ss denotes solid solution) Under intermediate pressures between 8 and 24 kbar following assemblages were noted in the order of increasing temperature: Diopsidess+forsteritess+spinel+vapor, Diopsidess+forsteritess+spinel+liquid+vapor, Diopsidess+forsteritess+liquid+vapor, and Forsteritess+liquid+vapor. At pressures above 24 kbar the assemblages are as follows: Diopsidess+forsteritess+garnet+vapor, Diopsidess+forsteritess+garnet+liquid+vapor, Diopsidess+forsteritess+liquid+vapor, and Forsteritess+liquid+vapor. Electron microprobe analyses of diopside and forsterite crystallized at 1050°C and 23 kbar, show that the former contains 6 to 6.5 wt % of Al2O3 as solid solution whereas the latter incorporates 1.3 wt % of monticellite in solid solution. The monticellite content of forsterite increases at low pressures at a given temperature to about 6 wt % at 1050°C and 6 kbar. The study indicates that forsteritic olivine does not coexist with pure grossularite in the studied temperature and pressure ranges, although the former is in equilibrium with pyrope-rich garnet, containing 23 mole % grossularite. The study supports the conclusion ofWerner andLuth (1973) that the solubility of monticellite in forsterite decreases with increasing pressure at a given temperature. The results of the investigation are also in agreement with the findings ofKushiro andYoder (1966), who noted that spinel peridotites found in folded belts and in alkalic basalts are produced under intermediate pressures, whereas garnet peridotite xenoliths found in kimberlite and in orogenic belts are formed at high pressures. 相似文献
42.
43.
The textures and chemical compositions of the constituent minerals of the fine-grained aggregates (FGA's) of L3 chondrites were studied by the backscattered electron image technique, electron probe microanalysis, and transmission electron microscopy. Plagioclase and glass in the interstices between fine grains of olivine and pyroxene indicate that the FGA's once partly melted. Compositional zoning and decomposition texture of pyroxenes are similar to those observed in chondrules, indicating a common cooling history of the FGA's and chondrules. Therefore, the mechanism that caused melting of the FGA's is considered to be the same as for chondrules. Bulk compositions of the FGA's are within the range of those of chondrules, so some chondrules probably were produced by complete melting of the same precursor materials as those of the FGA's. The precursor materials must have included fine olivine and other grains that probably are condensates. 相似文献
44.
Yuichiro Nakai Tomoki Sakamoto Tomomi Terajima Kenzo Kitamura Tomoki Shirai 《水文研究》1999,13(4):515-529
To evaluate the interactive effects of snow and forest on turbulent fluxes between the forest surface and the atmosphere, the surface energy balance above a forest was measured by the eddy correlation method during the winter of 1995–1996. The forest was a young coniferous plantation comprised of spruce and fir. The study site, in Sapporo, northern Japan, had heavy and frequent snowfalls and the canopy was frequently covered with snow during the study period. A comparison of the observed energy balance above the forest for periods with and without a snow‐covered canopy and an analysis using a single‐source model gave the following results: during daytime when the canopy was covered with snow, the upward latent heat flux was large, about 80% of the net radiation, and the sensible heat flux was positive but small. On the other hand, during daytime when the canopy was dry and free from snow, the sensible heat flux was dominant and the latent heat flux was minor, about 10% of the net radiation. To explain this difference of energy partition between snow‐covered and snow‐free conditions, not only differences in temperature but also differences in the bulk transfer coefficients for latent heat flux were necessary in the model. Therefore, the high evaporation rate from the snow‐covered canopy can be attributed largely to the high moisture availability of the canopy surface. Evaporation from the forest during a 60‐day period in midwinter was estimated on a daily basis as net radiation minus sensible heat flux. The overall average evaporation during the 60‐day period was 0·6 mm day−1, which is larger than that from open snow fields. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
45.
Surface flow and suspended sediment discharge from the head hollow of the Jozankei Experimental Watershed in Hokkaido, northern Japan, were measured to clarify the implications of subsurface hydrology for soil movement. Subsurface discharges during the extremely large storms of 1993 to 1994 were measured in a V-notch weir installed at a natural spring near the bottom of the head hollow, and shallow groundwater levels were observed in the wells excavated in the hollow. Sediment samples whose particle size range from 0·001 to 0·1 mm were manually and automatically collected at 15 to 60 min intervals, by use of 1 or 21 polyethylene bottles. Maximum concentration and flux of suspended sediment during the storms preceded the peak discharge of subsurface flow by several hours. Neither the changes in concentration (mg l−1) nor flux (mg s−1) of suspended sediment coincided with those in subsurface discharge (l s−1). Furthermore, sediment concentration was poorly correlated with the rate of change in subsurface discharge (l s−2) during the rising limb of the hydrograph. Suspended sediment flux during the acceleratory limb, however, was closely correlated with the rate of change in subsurface discharge. The relationship between suspended sediment flux and rate of change in subsurface discharge were in inverse proportion to initial subsurface discharge before the storm runoff and they represented rare seasonal variation. Subsurface hydraulic erosion and transport of suspended sediment resulting from changes in rate of change in subsurface discharge actively occur during the acceleratory rising limb of the hydrograph. Accordingly, subsurface hydraulic erosion during the acceleratory rising limb of the hydrograph can be physically understood by analysing suspended sediment flux associated with rate of change in subsurface discharge and initial subsurface discharge. © 1997 John Wiley & Sons, Ltd. 相似文献
46.
T. Kitamura M. Matsuoka S. Miyamoto M. Nakagawa M. Oda Y. Ogawa K. Takagishi U. R. Rao E. V. Chitnis U. B. Jayanthi A. S. Prakasa-Rao S. M. Bhandari 《Astrophysics and Space Science》1971,12(2):378-393
Results of rocket observations of SCO X-1 over the spectral range of 220 keV are presented. The observations have been performed partly in India and partly in Japan under the collaboration of the three groups. The present results are compared with results of similar observations carried out by the LRL (Lawrence Radiation Laboratory) group. Some of these X-ray observations were accompanied by simultaneous optical observations. Relationships between the hardness of the X-ray spectrum and the X-ray intensity and between the hardness and the optical luminosity are compiled. The relationships among the parameters (temperature, density and size) which characterize the postulated isothermal cloud model of SCO X-1 are given. They indicate that SCO X-1 is characterized by a temperature of about 107–108K, a density of about 1016–1017 cm–3 and a radius of about 108–109 cm respectively. We further show that the temperature is inversely correlated with the size of the source; an increase in temperature corresponds to a decrease in the radius and an increase in density. 相似文献
47.
Masatoshi Kitamura 《Astrophysics and Space Science》1969,3(1):163-174
Variation of the residual intensities of metallic and hydrogen lines of R CMa with phase is presented from measurement of its spectrograms obtained with dispersions of 10.3 Å/mm and 4.1 Å/mm at the Okayama Astrophysical Observatory. It is found from variation of the residual intensities of these lines, with the exception of the Ca–K line, that the duration of the eclipse is longer than expected from the photometric elements. The fractional loss of light of the eclipsed component at mid-eclipse has been derived from the ratio between residual intensities of the lines at mid-minimum and outside eclipse. The value so deduced is found to be larger than expected from the light-curve analysis. The behaviour of the residual intensities of the K line around the mid-minimum provides some evidence of emission at the line center. The possible existence of gaseous matter surrounding the components is discussed.Presented at the Trieste Colloquium on Mass Loss from Stars, September 12–16, 1968. 相似文献
48.
Masatoshi Kitamura 《Astrophysics and Space Science》1974,28(1):L17-L23
From a discussion of narrow-band observations of Zeta Aurigae in the 1963–64 eclipse, the duration of totality has been precisely found to be 36.901 days, which is appreciably smaller than the value 37.48 days currently used. The present result reveals that a hypothesis of gradual expansion of the K-type supergiant component could not be tenable. 相似文献
49.
Kenzo Takano 《Journal of Oceanography》1975,31(2):105-108
The finite difference analog of the linear vorticity equation for the mass transport in the ocean does not hold good unless the grid size is smaller than a certain number.I thank Profs. YaleMintz, AkioArakawa and TaroMatsuno for their valuable suggestions. 相似文献
50.
The present paper deals with the dynamic steady-state force-displacement relationships (complex stiffness) for rectangular rigid foundations resting on a semi-infinite medium, consisting of homogenous, isotropic, linear elastic materials. The foundations are considered to be excited under harmonic vertical and rocking vibration. This gives mixed boundary value problems which cannot be easily solved by analytical approaches. Therefore, a numerical method is proposed here. The method is based on quite, simple equations, and is straightforward in computation, compared with other methods. Although the proposed method gives just approximate solutions, it is satisfactory for engineering practices, and the soluations become highly accurate for a small value of ωB/Vs. The results obtained by the proposed method are compared with those of other methods to evaluate the accuracy of the results. The effects of length/width ratio and the area of the contact plane of the foundations are also discussed. 相似文献