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51.
We present the results of spectroscopy of 39 H II regions in the spiral galaxy NGC 6946. The spectral observations were carried out at the 6-m BTA telescope of the SAO RAS with the SCORPIO focal reducer in the multi-slit mode with the dispersion of 2.1 Å/px and spectral resolution of 10 Å. The absorption estimates for 39 H II regions were obtained. Using the “strong line” method (NS-calibration) we determined the electron temperature, and the abundances of oxygen and nitrogen for 30 H II regions. The radial gradients of O/H and N/H were constructed. 相似文献
52.
53.
A.S. Astakhov E.A. Gusev A.N. Kolesnik R.B. Shakirov 《Russian Geology and Geophysics》2013,54(9):1056-1070
The chemical composition of bottom sediments in the Chukchi and, partly, East Siberian Seas was studied. In the south and west of the Chukchi Sea, a zone has been detected with the accumulation of sediments rich in organic carbon, an increased background content and anomalies of sulfophile metals (Mo, Zn, Hg, Ag, Au), iron-group metals (V, Ni, Co), and some PGE (Ru, Pt). This zone is confined to the neotectonic active system of rift troughs extending from the Bering Strait and eastern Chukchi Peninsula to the continental slope, where it is bounded by the Cenozoic Charlie rift basin of the Canadian hollow. The geochemical features of the carbon-enriched sediments evidence that they formed under oxygen-deficient conditions and, sometimes, in suboxic and anoxic environments near endogenic water and gas sources. The high carbon and metal contents suggest that the very fine-grained sediments in the rift troughs of the Chukchi Sea are a possible analog of some types of ancient highly carbonaceous sediments belonging to black shales. 相似文献
54.
N. A. Dianskii A. V. Gusev V. V. Fomin 《Izvestiya Atmospheric and Oceanic Physics》2012,48(2):222-240
We present two calculations of pollutant dispersal in the Pacific Ocean: (1) during possible ship-wrecks in the process of
spent nuclear fuel transportation from Petropavlovsk-Kamchatsky and (2) pollutant spread from the Japanese coast after the
Fukushima-1 nuclear disaster on March 11, 2011. The circulation was calculated using a σ model of ocean hydrothermodynamics
developed at the Institute of Numerical Mathematics (INM), Russian Academy of Sciences (RAS); it is adapted to cover the Pacific
Ocean basin from the equator to the Bering Strait with a high (1/8)° spatial resolution and it is capable of reproducing the
mesoscale ocean variations. The pollutant dispersal in the case of possible shipwrecks was estimated for currents characteristic
for a statistically average year with atmospheric forcing in accordance with the so-called normal CORE year data. The pollution
spread from the Fukushima-1 nuclear power plant (NPP) was estimated by calculating the circulation with the real atmospheric
forcing in accordance with the NCEP analysis data obtained from the Hydrometeorological Centre of Russia. It is noteworthy
that a simplified assimilation of the observed sea surface temperature (SST) was performed. In both cases the currents were
calculated simultaneously with the transport calculation of the pollutant as a passive admixture, which corresponds to a real-time
calculation of pollutant transport. A map analysis of pollution dispersal shows that the horizontal transport is substantially
more intense in the upper ocean layers than in deep ones. Therefore, like in the North branch of Kuroshio, pollutants can
be delivered to the deep layers not through deep-water horizontal transport, but rather as a result of vertical downwelling
from the already contaminated upper layers. However, the complex three-dimensional structure of the horizontal and vertical
transport may lead to reverse situations. A calculation of pollution transport from the Fukushima-1 NPP showed that radioactive
pollution would propagate eastward and not present the danger for Russian territory. Moreover, even for an exaggerated scenario
of pollution emission, the background pollution level will be exceeded only in a narrow region within 50 km of the Japanese
coast. 相似文献
55.
A 3D eco-hydrodynamical model of high resolution (0.25° × 0.25°, 27 σ-levels) is used to simulate the seasonal variability of the ocean circulation and marine ecosystem in the Central-Eastern Basin of the North Atlantic including the Canary upwelling system. According to the model results, in the winter period, the “patches” of maximal phytoplankton and zooplankton biomass are often located in upwelling zones in the open ocean on the periphery of cyclonic eddies rather than in the coastal upwelling zones. In the summer period, when the phytoplankton biomass reaches maximal (in the annual cycle) values, the maxima of the phytoplankton are located in the coastal upwelling zones. As shown, there is no simple relationship between the nitrate distributions, on the one hand, and the phytoplankton and zooplankton ones, on the other hand. 相似文献
56.
V. N. Chebrov A. A. Gusev V. K. Gusyakov V. N. Mishatkin A. A. Poplavskii 《Seismic Instruments》2010,46(3):275-285
The initial information and requirements for developing a seismologic observation system and data-processing and transfer
tools for a tsunami warning system and its functions and tasks are considered. The structure of the seismologic observation
system for the tsunami warning service (TWS) in the Russian Far East is proposed. A study of general technical and methodological
problems is carried out to increase the efficiency for urgent tsunami prediction from continuous seismic monitoring data of
territories of the Russian Far East and the world. Special attention is paid to the problem of tsunami prediction from seismologic
data on strong earthquakes in near zone of a protected territory (up to 200 km). 相似文献
57.
58.
A method is developed for the reconstruction of a non-uniform distribution of scattering properties in the upper layers of the Earth using data on broadening of an incoherent body-wave group or pulse along a number of rays. The theoretical basis for this reconstruction is a linear integral formula after Bocharov (1985, 1988), which is employed to design a linear inversion procedure. The inversion is performed in terms of a single scalar parameter of effective turbidity. This parameter presents an adequate generalization of the common turbidity parameter used in the isotropic scattering case; it describes, simultaneously, scattering attenuation, pulse broadening and backscattering or coda formation. As a preliminary step, necessary conditions of applicability of the transport equation approach for the analysis of regional high-frequency seismic waves are verified. A new compact derivation of Bocharov's formula is then presented. A linear least-squares inversion procedure for recovering a layered turbidity structure is proposed and tested on synthetic data of onset-to-peak delays of incoherent body-wave pulses. A few practical aspects of the application of the general approach to seismological data are analysed, including the correctness of the low-angle approximation, the use of peak delay observations instead of pulse centroid, the effects of a realistic spatial spectrum of inhomogeneity field, the potential bias produced by intrinsic loss, and the distortions produced by a non-spherical (double dipole) source radiation pattern. The latter point is considered as critically important, as one can expect significant data contamination by nodal arrivals. An efficient robust estimation procedure is designed and tested that is capable of suppressing distortions from nodal and near-nodal data. 相似文献
59.
N. V. Yagova V. A. Pilipenko E. N. Fedorov A. D. Lhamdondog Yu. P. Gusev 《Izvestiya Physics of the Solid Earth》2018,54(5):749-763
The problem of estimating the time derivatives of the horizontal components of the geomagnetic field and forecasting the probability of the occurrence of perturbations that exceed a given threshold level (the over-threshold perturbations) arises in the applications concerned with the geomagnetically induced currents (GICs). In this work, we consider the temporal and spatial structure of the Pi3 pulsations with quasi-periods of 102 to 103 s during which the auroral and subauroral stations of the IMAGE network record over-threshold values in the derivatives of the meridional (along the longitudinal circle) BX component and latitudinal (along the latitudinal circle) BY component. The extreme |dBX/dt| values mainly develop against the background of the Pi3 pulsations with a complex frequency content, whereas the extreme |dBY/dt| values appear when the buildup (decay) phases of the bay-like disturbance associated with the evolution of a substorm coincide with the respective phases of the field of pulsations. The conditions under which the derivatives |dBX/dt| and |dBY/dt| reach their over-threshold values are studied for subauroral latitudes by the technique of superposed epoch analysis. The extreme values of the derivatives most frequently occur during the main phase of moderate magnetic storms or beyond the storm—during high substorm activity under the conditions of a negative vertical component of the interplanetary magnetic field. The probability of the occurrence of over-threshold values increases at high amplitudes of the Pi3 pulsations and depends on their spectral content. The problem of analyzing and forecasting the over-threshold |dBY/dt| perturbations is complicated by the fact that the scale of the perturbations is small along the lines of latitude and large along the meridians. This can result in GIC excitation in the North–South oriented electric power lines by the geomagnetic perturbations localized within a narrow band in longitude which can be missed during the measurements. 相似文献
60.
The modified scale M s(20R) is developed for the magnitude classification of the earthquakes of Russia’s Far East based on the surface wave amplitudes at regional distances. It extends the applicability of the classical Gutenberg scale M s(20) towards small epicentral distances (0.7°–20°). The magnitude is determined from the amplitude of the signal that is preliminarily bandpassed to extract the components with periods close to 20 s. The amplitude is measured either for the surface waves or, at fairly short distances of 0.7°–3°, for the inseparable wave group of the surface and shear waves. The main difference of the M s(20R) scale with the traditional M s(BB) Soloviev–Vanek scale is its firm spectral anchoring. This approach practically eliminated the problem of the significant (up to–0.5) regional and station anomalies characteristic of the M s(BB) scale in the conditions of the Far East. The absence of significant station and regional anomalies, as well as the strict spectral anchoring, make the M s(20R) scale advantageous when used for prompt decision making in tsunami warnings for the coasts of Russia’s Far East. 相似文献