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61.
S. V. Popov M. P. Antipov A. S. Zastrozhnov E. E. Kurina T. N. Pinchuk 《Stratigraphy and Geological Correlation》2010,18(2):200-224
Sea-level fluctuations in the terminal Eocene, Oligocene, and Neogene of the Eastern Paratethys are quantitatively assessed
on the basis of facies and old coastlines traced on the northern platform shelf, levels of river valley incisions, and the
study of seismic profiles. The first data massif allows the characterization and correlation of transgression stages in the
history of the Eastern Paratethys. The greatest transgressions fall within the first half of the Late Eocene, mid-Early Oligocene,
initial Late Oligocene, initial Early Miocene, the initial Tchokrakian, Karaganian and Sarmatian in the Middle Miocene, the
middle and late Sarmatian and early Pontian in the Late Miocene, and the Akchagylian in the Caspian basin of the Pliocene.
In contrast, the greatest incisions of northern rivers running from the platform allow us to establish the time and extent
of the main declines in the base levels of the erosion. Maximal incisions date back to the terminal Eocene-initial Oligocene,
terminal Solenovian time in the terminal Rupelian, the terminal Maikop in the Early Miocene, the terminal Sarmatian and middle
Pontian in the Late Miocene, and the Early Pliocene in the Caspian basin. Large regressions also formed unconformity surfaces,
traced on seismic profiles as erosion boundaries of several orders. The surfaces are confined to the Eocene/Oligocene boundary,
middle and late Maikop, Sarmatian/Meotian boundary, middle Pontian, and terminal Miocene-initial Pliocene, as well as being
traced even in the most deep-water basins. The synthesis of these data suggests a preliminary version for the curve of transgression-regression
cyclicity. Its correlation with the eustatic curve shows their similarity only in the lower part-prior to the initial Middle
Miocene, when Paratethys became a semi-closed basin. 相似文献
62.
N. N. Antropov A. V. Bogatyy G. A. Dyakonov N. V. Lyubinskaya G. A. Popov S. A. Semenikhin V. K. Tyutin M. M. Khrustalev V. N. Yakovlev 《Solar System Research》2012,46(7):531-541
This paper presents an overview of the works on ablative pulsed plasma thrusters (APPTs) carried out at the Research Institute of Applied Mechanics and Electrodynamics (RIAME). The main features of next generation thrusters developed at the RIAME in the 2000s are discussed together with the optimization criteria for APPTs intended for use in correction propulsion systems of small spacecraft, e.g., MKA-FKI (developed by the Lavochkin Association) and Soyuz-Sat-O (developed by Maksimov Space Systems Research Institute and the Production Corporation Polyot). 相似文献
63.
Y. -D. Park I. S. Kim O. I. Bugaenko M. I. Divlekeev V. V. Popov V. N. Dermenjiev 《Astronomy Reports》2001,45(9):729-737
A two-dimensional polarization image of the inner regions of the solar corona (R≤1.5R ?) during the total solar eclipse of August 11, 1999 is presented. This image clearly exhibits both small-and large-scale structure in the distribution of deviations of the plane of polarization from its theoretical direction for coronal emission in the near infrared (570–800 nm). An accuracy for the deviation angles of ≤1° was achieved by reducing the instrumental scattered light in the telescope, installing a continuously rotating polaroid near the image plane of the entrance pupil (i.e., the Lyot stop plane), and developing a special algorithm for constructing the polarization images based on the IDL software, in which the properties of the light are described in terms of the Stokes parameters. This algorithm was used to process 24 digitized polarization images of the corona, corresponding to one complete rotation of the polaroid. Analysis of the polarization image for angles of 0°–5° indicates the existence of significant deviations in the inner corona. The polar and equatorial coronal regions are characterized by diffuse and almost uniform structure of the deviation angles, 0.5° ± 0.5°, corresponding to Thomson scattering of the photospheric radiation by free electrons. Four large-scale structures over the NE, SE, NW, and SW limbs covering about 60° in position angle have deviations of 1°–3°. Numerous small-scale structures with dimensions up to 30″ and deviation angles of 3°–5° tracing strongly curved coronal streamers were detected in active coronal regions, especially over the NE limb. Interpretation of these deviations in terms of flows of moving electrons implies tangential velocities of up to 2.5×104 km/s, i.e., electron energies of up to 2×103 eV. 相似文献
64.
G. V. Novikov V. K. Egorov V. I. Popov L. V. Sipavina 《Physics and Chemistry of Minerals》1977,1(1):1-14
Iron-rich pyrrhotites proved to be metastable and to decompose at 70–140° C to troilite and pyrrhotite with less iron content as shown by nuclear gamma-resonance (Mössbauer) studies at high temperatures. Coherence of decomposition product lattices was established by studying powder samples textured in a magnetic field. Detailed X-ray powder diffraction and Mössbauer investigations revealed two different mechanisms of transformation in metastable associations. Kinetic phenomena are discussed in terms of a thermodynamic model of two-phase assemblage. 相似文献
65.
María Paula Iglesia Llanos Jennifer Alice Tait Viktor Popov Alexandra Abalmassova 《Earth and Planetary Science Letters》2005,240(3-4):732-747
The study area is situated along the Zolotica river in NW Russia, located within the Kola–Dvyna Rift System in the Baltic Shield that developed during Meso and Neoproterozoic times. A 9-m thick section made up of shallow marine sediments of Upper Ediacaran age was sampled in this locality. Two volcaniclastic levels from the middle part of the section yielded an age of 556 Ma. (U/Pb SHRIMP-II on zircons). Two magnetic components were successfully isolated, component A (Decl = 157.1, Incl = 68.0, 95 = 1.9°, N = 575 in situ) carried by magnetite and component B (Decl = 120.3, Incl = − 31.7, 95 = 3.9°, N = 57, bedding corrected), carried by haematite. While component A is thought to represent a younger overprint direction, the in situ direction for component B on the other hand, is dissimilar to any expected younger direction and is considered to be primary magnetisation in origin, acquired during or soon after deposition of the sediments in the Late Ediacaran. The corresponding palaeomagnetic pole for component A in situ is located at Lon = 55.4°E, Lat = 31°N, A95 = 2.7° and for component B at Lon = 110°E, Lat = 28.3°S, A95 = 3.8°, N = 57. Combined with other palaeomagnetic poles of the same tectonostratigraphic unit an alternative apparent polar wander path for the Late Proterozoic–Early Palaeozoic of Baltica is proposed. Such an alternative path shows that after the mid Cryogenian (750 Ma), the poles that were situated over South Africa (p.d.c.) moved to the east until they reached Australia during the Late Ediacaran (555 Ma) where they remained approximately stationary until the beginning of the Cambrian (545 Ma). Finally, they moved to the northwest until they reached the Arabian Peninsula in the Early Ordovician. Palaeolatitudes indicate that Baltica situated near the equator from the Cryogenian through to the Ediacaran moving gradually to the south at c. 1 cm/yr. During the Late Early Ediacaran, the plate suddenly began to drift northward at c. 8 cm/yr and in the boundary with the Cambrian it was positioned in low to intermediate latitudes. Finally, Baltica began to move back to the south at c. 13 cm/yr until in the Early Ordovician, reaching intermediate to high southern latitudes. 相似文献
66.
M. V. Popov A. D. Kuz’min O. M. Ul’yanov A. A. Deshpande A. A. Ershov V. V. Zakharenko V. I. Kondrat’ev S. V. Kostyuk B. Ya. Losovskiĭ V. A. Soglasnov 《Astronomy Reports》2006,50(7):562-568
The results of simultaneous multifrequency observations of giant radio pulses from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses detected at 111 MHz, 21 were identified with counterparts observed simultaneously at 600 MHz. The spectral indices for the power-law frequency dependence of the giant-pulse energies are from ?3.1 to ?1.6. The mean spectral index is ?2.7 ± 0.1 and is the same for both frequency combinations (600–111 MHz and 600–23 MHz). The large scatter in the spectral indices of the individual pulses and the large number of unidentified giant pulses suggest that the spectra of the individual giant pulses do not actually follow a simple power law. The observed shapes of the giant pulses at all three frequencies are determined by scattering on interstellar plasma inhomogeneities. The scatter-broadening of the pulses and its frequency dependence were determined as τ sc = 20(ν/100)?3.5±0.1 ms, where frequency ν is in MHz. 相似文献
67.
A. D. Kuzmin V. I. Kondrat’ev S. V. Kostyuk B. Ya. Losovsky M. V. Popov V. A. Soglasnov N. D’Amico S. Montebugnoli 《Astronomy Letters》2002,28(4):251-256
We measured the frequency dependence of the pulsar pulse broadening by scattering over a wide frequency range, from 40 to 2228 MHz, based on direct measurements of this parameter using giant pulses from the pulsar PSR B0531+21 in the Crab Nebula. Our measurements were carried out at the following seven frequencies: 40, 60, and 111 MHz at the Pushchino Radio Astronomy Observatory (Astrospace Center, Lebedev Physical Institute, Russian Academy of Sciences), 406 MHz at the Medicina Observatory (Instituto di Radioastronomia, Italy), and 594, 1430, and 2228 MHz at the Kalyazin Radio Astronomy Observatory (Astrospace Center, Lebedev Physical Institute, Russian Academy of Sciences). The measured frequency dependence of the pulse broadening by scattering τSC (υ) ? υγ, where γ=?3.8±0.2, agrees with a model Gaussian distribution of interstellar inhomogeneities (γ=?4) but falls outside the error limits of correspondence to a Kolmogorov model spectrum of inhomogeneities (γ=?4.4). 相似文献
68.
G. S. Bisnovatyi-Kogan Yu. P. Popov A. A. Samochin 《Astrophysics and Space Science》1976,41(2):287-320
The calculations of supernova explosion are made, using the one-dimensional nonstationary equations of magnetic hydrodynamics for the case of cylindrical symmetry. The energy source is supposed to be the rotational energy of the system (the neutron star in the centre and the surrounding envelope). The magnetic field plays the role of a mechanism of the transfer of rotational momentum. The calculations show that the envelope split up during the dynamical evolution of the system, the main part of the envelope joins the neutron star and becomes uniformly rotating with it, the outer part of the envelope (10% mass) expands with large velocity, carrying out a considerable part of rotational energy and rotational momentum.These results correspond qualitatively with the observational picture of supernovae explosions. 相似文献
69.
Gutnikov S. I. Popov S. S. Efremov V. A. Ma Peng-Cheng Lazoryak B. I. 《Natural Resources Research》2021,30(2):1105-1119
Natural Resources Research - This paper presents a study of the influence of basalt rocks’ phase composition, acidity modulus, and structural parameter NBO/T on the tensile strength and... 相似文献
70.
Kulichkov S. N. Chunchuzov I. P. Popov O. E. Perepelkin V. G. Golikova E. V. Bush G. A. Repina I. A. Tsybulskaya N. D. Gorchakov G. I. 《Izvestiya Atmospheric and Oceanic Physics》2019,55(2):167-177
Izvestiya, Atmospheric and Oceanic Physics - Data on internal gravity and infrasound waves recorded during the passage of both warm and cold fronts throughout Moscow, which are associated with the... 相似文献