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821.
Werner Kündig F. Zehender D. Elber E. Ammann Erik Mittelholzev J. Ruchti Prof. Dr. K. Wuhrmann A. v. Hirschheydt P. Duerst R. Gächter 《Aquatic Sciences - Research Across Boundaries》1970,32(1):345-351
Ohne Zusammenfassung 相似文献
822.
823.
Profiles of electrical conductivity in the troposphere and stratosphere were measured by balloon-borne conductivity sondes at Garmisch-Partenkirchen, West Germany, from January to May, 1980, when volcanic activity was low. The aerosol concentration has been deduced from the relative decrease of conductivity from surrounding values by assuming the effective attachment coefficient of ions to aerosols. A prominent decrease of the conductivity near the tropopause is usually observed indicating high concentrations of Aitken particles (500–1000 cm–3). A decrease of conductivity, well above the tropopause, is sometimes observed, probably due to the transport of tropospheric Aitken particles with high concentration (200–400 cm–3) into the stratosphere. 相似文献
824.
L. Schultz H. Palme B. Spettel H.W. Weber H. Wänke M. Christophe Michel-Levy J.C. Lorin 《Earth and Planetary Science Letters》1982,61(1):23-31
Allan Hills (ALHA) 77081 is achondritic in texture while the mineral composition and the chemistry are chondritic with the exception of a few elements. An assignment to one specific group of ordinary chondrites is therefore difficult. In many respects this meteorite is similar to the unusual stone meteorite Acapulco. The REE pattern of ALHA 77081 is essentially flat and the distribution ratios of siderophile elements between metal and silicates are high compared to ordinary chondrites.Gas retention ages are 3.5±0.5 AE for U, Th-He and 4.50±0.15 AE for K-Ar. In spite of the high degree of recrystallisation the meteorite contains trapped noble gases in amounts comparable to type 4 chondrites.Cosmic ray tracks and spallogenic noble gases indicate a small preatmospheric radius of about 2–3 cm. Spallogenic nuclides produced by solar cosmic rays or stopped solar flare ions may be present. 相似文献
825.
Experimental high-pressure results on phase stability, electrical conductivity and compression behavior up to 5 and 21 GPa respectively are used to calculate an isothermal equation of state for a monosulfid solid solution (MSS-composition) in the FeNiS system. The high-pressure relations in the range 1–8 GPa are very complex. A continuous electrical transition, from semiconducting to metallic, takes place at high pressures and temperatures and results in anomalous compression behavior at pressures in this region. No polymorphic transition from the NiAs-structure to another type could be observed; however, density increases by as much as 8.8%. Using compression values for pressure greater than 10 GPa, the bulk modulus, a zero-pressure density and a core density were calculated. Extrapolation for the conditions of the outer core yields a difference in the density of up to 20%, relative to seismological models.In a composition model with (Fe, Ni)+MSS, a MSS-content must be assumed to be in the range of 30–35 wt% at the core-mantle boundary (CMB) and 13–17 wt% at the inner-core boundary (ICB). That corresponds to a sulfur content of 10.8–13.3 wt% (CMB) and 4.9–6.5 wt% (ICB), respectively, the values increasing with increasing Ni content of the MSS-phase. 相似文献
826.
For the following problems - estimating the statistical parameters of the precise levelling, - adjusting the primary levelling networks and - estimating vertical crustal movements mathematical models are being sketched out. Results obtained in evaluating primary relevellings in the G.D.R. are reported. 相似文献
827.
R.J. Floran Martin Prinz P.F. Hlava Klaus Keil B. Spettel H. Wänke 《Geochimica et cosmochimica acta》1981,45(12):2385-2391
The Johnstown meteorite is a brecciated orthopyroxenite (diogenite) containing coarsegrained centimeter-sized clasts of cumulate origin that have undergone subsolidus recrystallization. The brecciated portion is dominated by subangular fragments of orthopyroxene (Wo2–3En72–74Fs23–25) in a variably comminuted matrix of the same material. Minor and accessory phases include plagioclase (An82–90Ab10–18Or0–1), diopside (Wo44–45En46–47Fs9–10), olivine (Fo71–72), tridymite, troilite, metallic Ni-Fe (~3% Ni), and chromite (Cm71–80Hc1–8Sp11–19Mt2–4Uv1–3).The clastic component is parental to the brecciated matrix which contains no foreign lithic or mineralogic components. Siderophile trace element studies, however, reveal the presence of meteoritic (chondritic) contamination in the brecciated portion using unbrecciated clasts for indigenous values. Rare earth element abundances show a wide range of values for the light REE in different samples, although all samples exhibit a strong negative Eu anomaly, indicative of earlier plagioclase fractionation. Two pairs of adjacent brecciated and unbrecciated samples from different portions of the meteorite show, respectively, the most enriched and the most depleted light REE patterns. The variability in La content is over a factor of 100. However, in each case the REE pattern for the brecciated portion is very similar to that of the unbrecciated portion. These differences are attributed to sampling of variable amounts of residual, REE-enriched, trapped liquid. The most representative REE pattern for the bulk meteorite has an intermediate composition and was obtained from the largest sample. The data presented here indicate that Johnstown is a monomict breccia, in contrast to several other diogenites which may be considered to be polymict on the basis of their mineral compositions and/or clast populations. 相似文献
828.
Lotova N.A. Obridko V.N. Vladimirskii K.V. Bird M.K. Pätzold M. Sieber W. Güsten R. Korelov O.A. 《Solar physics》1999,189(2):387-398
Long-term scintillation measurements of the solar wind formation zone at solar elongations ranging from 1°–8° (Sun impact parameters: 4–30 R
) were recorded using the water maser source IRC-20431 at the wavelength =1.35 cm during its annual solar occultations in December 1981–1998. Dramatic changes in the spatial dependence of the scintillation index were recorded over the course of the 11-year solar cycle. Markedly diminished scattering, attributed to a pronounced heliolatitude effect, was observed at the closest solar approach distances in the years around solar activity minimum. From parallel investigations of the solar magnetic field structure it was determined that the field strength at the source of the solar wind streamlines is the governing factor for the solar wind acceleration process. Particularly apparent in the scintillation data during solar activity minimum is the increasing role of the polar coronal holes with their associated open magnetic field structure. The dependence of the solar scattering intensity on heliolatitude fades in the years of high solar activity as the level of scintillations increases at polar latitudes. 相似文献
829.
Elie Eichenberger F. Klötzli Kerry R. Kelts H. R. Bürgi F. Stössel H. Jäckli 《Aquatic Sciences - Research Across Boundaries》1976,38(2):247-250
Ohne Zusammenfassung 相似文献
830.
Dr. René Gächter 《Aquatic Sciences - Research Across Boundaries》1976,38(1):1-28
This study shows that it is possible to restore a highly eutrophic lake by the mean of bottom water siphoning. The main effects
of the hypolimnion drainage, such as, erosion of the hypolimnion and increase of the nutrient export out of the lake are discussed.
From mass balance calculations it is deduced that in eutrophic shallow lakes the nutrient supply to the trophogenic layer
by the sediments can exceed temporarily the external loading by more than a hundredfold. The process of a lakes selfmaintaining
auteutrophication is described. An extended summary in English is given at the end of the paper.
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