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31.
Motoyoshi Ikeda 《Journal of Oceanography》1979,35(2):100-109
Characteristics of stationary Rossby-waves are investigated by use of equations expressing conservation of potential vorticity for a quasi-geostrophic two-layer flow of an incompressible inviscid fluid on a beta-plane. A two-dimensional problem is discussed; the basic flow is directing eastward without horizontal shear, and the stationary Rossby-waves are produced by a two-dimensional bump extending in the north-south direction which is located on a sloping bottom with a constant north-south gradient.When the slope is steep, stream-lines are scarcely displaced being influenced by the bump. When the bottom has no north-south inclination, however, there is a case where group velocity of Rossby-waves produced by the bump directs westward and the stream-lines meander sinusoidally at the west of the bump. This phenomenon is called upstream influence. These two special cases have a possibility to explain two different mean paths for the Kuroshio namely, the path along the continental slope and the path with a stationary meander at the west of the Izu-Ogasawara Ridge. 相似文献
32.
Margaret A. LeMone Robert L. Grossman Robert T. Mcmillen Kuo-Nan Liou S.C. Ou Stuart Mckeen Wayne Angevine Kyoko Ikeda Fei Chen 《Boundary-Layer Meteorology》2002,104(1):1-52
Aircraft, radiosonde, surface-flux, and boundary-layer windprofiler data from the Cooperative Atmosphere Surface Exchange Study's 1997 field project, CASES-97, are combined with synoptic data to study the evolution of the vertically-averaged mixed-layerpotential temperature []and mixing-ratio [Q] onthree nearly-cloudless days from 1000 CST to 1200CST (local noon is approximately 1230 CST). This was achieved through examination of the terms in the time-tendency (`budget')equations for []and [Q]. We estimate three of the terms –local time rate of change, vertical flux divergence, andhorizontal advection. For the [Q]-budget, vertical flux divergence usually dominates, buthorizontal advection is significant on one of the three days. The [Q]-budget balances for two of the three days to within the large experimental error. For the -budget,vertical flux divergence accounts for most of the morningwarming, with horizontal advection of secondary importance.The residual in the -budget has the same sign for all three days, indicating that not all the heating is accounted for. We can balance the []-budgets to within experimental error on two of the three days by correcting the vertical-flux divergence for apparent low biases in the flux measurements of one of the aircraft and in the surface fluxes, and accounting for direct heating of the mixed layer by radiative flux divergence allowing for the effects of carbonaceous aerosols. The [];-budget with these corrections also balances on the third day if horizontal gradients from synoptic maps are used to estimate the horizontal advection. However, the corrected budget for this day does not balance if the horizontal gradient in the advection term is estimated using CASES-97aircraft and radiosondes; we suggest that persistent mesoscale circulations led to an overestimate of the horizontal gradient andhence horizontal advection. 相似文献
33.
The 1995 Hyogoken–Nambu earthquake caused severe liquefaction over wide areas of reclaimed land. Furthermore, the liquefaction induced large ground displacement in horizontal directions, which caused serious damage to foundations of structures. However, few analyses of steel pipe piles based on field investigation have so far been conducted to identify the causes and process of such damage. The authors conducted a soil–pile-structure interaction analysis by applying a multi-lumped-mass-spring model to a steel pipe pile foundation structure to evaluate the causes and process of its damage. The damage process analyzed in the time domain corresponded well with the results of detailed field investigation. It was found that a large bending moment beyond the ultimate plastic moment of the pile foundation structure was induced mainly by the large ground displacement caused by liquefaction before lateral spreading of the ground and that the displacement appeared during the accumulating process of the excess pore water pressure. 相似文献
34.
Trace Metal Solid State Speciation in Aerosols of the Northern Levantine Basin,East Mediterranean 总被引:3,自引:0,他引:3
Mustafa Koçak Nilgun Kubilay Barak Herut Malcolm Nimmo 《Journal of Atmospheric Chemistry》2007,56(3):239-257
An established three stage sequential leach scheme was applied to a series of selected high volume aerosol samples (n = 35) collected from the Turkish Eastern Mediterranean coastline (Erdemli). Samples were selected according to their air
mass back trajectory history to reflect the contrasting mixtures of aerosol material present in the Eastern Mediterranean
marine aerosol. Two populations were adopted, those samples which were classed as “anthropogenic” and those which were “Saharan”
dominated aerosol populations. Applying the three stage leach it was possible to define the proportion for each of the considered
metals (Al, Fe, Cu, Pb, Cd, Zn and Mn) present in the (a) “exchangeable” (b) “carbonate / oxide” and (c) “refractory” phases,
representing novel solid state aerosol speciation data for this marine system. Clear trends were established, conforming with
data from previous studies with mainly crustal derived metals (Al and Fe) being present in the refractory phases (Al > 88%;
Fe > 84%) and those influenced by anthropogenic sources being dominating in the exchangeable phase, although for these metals
the variability was comparatively high (12–64%; 19–85%; 40–100% for Zn, Pb and Cd, respectively). For the majority, greater
exchangeable fractions were present the lower the crustal source contribution to the aerosol population, whereas the “refractory”
fraction exhibited contrasting behaviour. This was illustrated by the novel application of the mixing diagram, presenting
each of the three speciation stages against the corresponding percent anthropogenic contribution to each collected sample.
Zn, Pb and Cd all illustrated progressive decrease in the percent exchangeable with increasing crustal contribution to the
aerosol population. The percent exchangeable was discussed in terms of its use to represent the upper limit of the bioavailable
fraction of metal associated with the aerosol, post deposition. The mixing diagram approach enabled the prediction of the
residual fractions for Cd, Pb and Zn (41 ± 4%; 62 ± 4% and 82 ± 5%, respectively,) in Saharan end-member material. 相似文献
35.
This paper presents the development and utilisation of an automated image processing algorithm for detection and analysis
of grains. Using optical polarising microscopy, a set of colored images are collected from an area on a thin section. A filtering
operation, using rotation of a morphological alternating sequence filter (based on a structuring element), is used to remove
twinning features within individual grains. Filtering is followed by the watershed segmentation technique to determine grain
boundaries. The method is used for the identification of calcite grains in marble and the subsequent analysis of morphological
anisotropy. 相似文献
36.
Occurrence frequency of unusual weather caused by anomalous synoptic patterns has its peaks in the middle latitude regions
and the subtropical regions. Height anomaly patterns at the 500 mb level for the last three decades show the expansion of
negative area in the northern hemisphere, resulting in increase of variability in space and time. 相似文献
37.
SummaryVariability and Anisotropy of Mechanical Properties of the Pittsburgh Coal Seam Results of an experimental program to determine the vertical variation of material stiffness and strength of an important coal seam are presented, with the aim of providing information for realistic modeling for purposes of analysis. The seam is divided into four zones, and data from each are evaluated statistically. It is concluded that this seam contains two zones with measurably different properties, which, however, are small compared to the observed scatter of data.
With 10 Figures 相似文献
ZusammenfassungStreubereich und Anisotropie der mechanischen Eigenschaften des Pittsburgher Kohleflözes Es werden Ergebnisse eines Versuchsprogramms zur Bestimmung der senkrechten Veränderung der Steifheit und Festigkeit des Materials in einem wichtigen amerikanischen Kohlenflöz präsentiert, um Unterlagen für realistische Modellbildung zum Zwecke der Spannungsberechnung zu liefern. Der Flöz ist in vier Zonen unterteilt, deren Daten statistisch untersucht wurden. Es ergab sich, daß dieser Flöz zwei Zonen mit meßbar unterschiedlichen Eigenschaften enthält; diese Unterschiede sind aber klein im Vergleich zur Streuung der einzelnen Daten.
RésuméVariabilité et anisotropie des propriétés mécaniques du banc de charbon de Pittsburgh On a analysé, par échantillons, la variabilité de la résistance et du module d'un banc de charbon épais, avec la profondeur. Le but de l'étude est d'obtenir des valeurs réalistes qui puissent être utilisées dans une analyse par méthodes numériques. Le banc est divisé en quatre zones, et les résultats sont analysés de façon statistique, séparément pour chaque zone. On a conclut que ce banc contient deux zones dont les propriétés mécaniques diffèrent. Cependant ces différences ne dépassent pas l'ordre de grandeur des écarts dans les observations sur chaque zone.
With 10 Figures 相似文献
38.
Seven rare-earth elements (La, Ce, Sm, Eu, Tb, Yb, Lu) and Co, Cr, Sc, Ba, Hf and Th have been determined by non-destructive neutron activation analysis on the Quaternary volcanic rocks in Hokkaido, Japan. The trace-element abundances are discussed in terms of the petrological problems, particularly the origin of calc-alkali magma. On the basis of the La/Sm ratio and the contents of K, Ba, Th and La, lateral variations in the contents of trace elements exist across the Kurile and the northern Honshū arcs. The calc-alkali rocks can be classified into three types which correspond to Kuno's three basalt-magma types. There is no essential difference in the rare-earth patterns between the basaltic rocks and the associated calc-alkali rocks in each petrographic province. This suggests that the calcalkali rocks may be derived from the basaltic magmas by fractional crystallization under certain conditions. 相似文献
39.
Summary The theory of secondary vorticity is used to explain the essence of so-called secondary or upper vorticity centres, discovered on satellite photographs. The general equation of vorticity, which is then adjusted by means of the equations of state and motion, is transformed into a specially selected intrinsic co-ordinate system. Three-component equations of vorticity are discussed for cases important meteorologically. The conclusion could be drawn that the secondary vorticity centres may be identified with centres of so-called secondary vorticity and that the theoretical facts about their origin and occurrence may be used, together with satellite photographs, to improve weather forecasts. 相似文献
40.
The behaviour of tetrahedrally coordinated and octahedrally coordinated Cr3+ ions in diopside is discussed from the study on the join CaMg-Si2O6-CaCrCrSiO6. The molecule CaCrCrSiO6 decomposes into uvarovite+eskolaite and its maximum solubility in diopside is 6.7 wt percent at 940 ° C. Crystalline phases are diopside ss (ss is abbreviation of solid solution), uvarovite ss, wollastonite ss, spinel and eskolaite. The diopside ss is blue in colour. Its optical spectra were measured in the wavelenght range of 325–2600 nm, and assigned after tetrahedral configuration Td and octahedral configuration Oh. It is estimated that octahedral Cr3+ ions are in high spin state, while tetrahedral Cr3+ ions may be probably in low spin state. The t and B are 10,300–10,370 cm–1 and 429–432 cm–1. The CFSE for tetrahedral low spin Cr3+ ions is nearly the same as that for octahedral high spin Cr3+ ions. The ionic radii of tetrahedral low spin Cr3+ ions calculated are 0.47–0.53 Å, shrinked from the radius of octahedral high spin Cr3+ ion (0.615 Å) as much as 14–24 percent. Petrologic implications of the result are also discussed.The first half of the D. Sc. dissertation of K. Ikeda presented to Hokkaido University in June, 1976 相似文献