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11.
We have investigated the frustule ultrastructure of Baikalian Aulacoseira: A.baicalensis (K.Meyer) Sim. and of thin-wall, spore-producing Aulacoseira which has long been designated as A. islandica (O.Muller) Sim. or A.islandica ssp. helvetica (O.Muller) Sim. (now A.skvortzowii Edlund, Stoermer,Taylor). It was found that the disagreement on the name of spore-forming Aulacoseira is due to the destruction of its vegetative frustules in the process of breaking free of the organic content, while ultrastructure data on A.islandica from different Russia''s regions can reflect signatures of different species.A. baicalensis is characterized by great polymorphism. A. baicalensis starts its development from the initial cell (auxospore). The morphological characteristics of the frustule undergo the drastic changes in the course of the life cycle. It sequentially changes the morphology and structure of its valves. Its cells evolve through several stages of development:from cyclotella-like cells to narrow and short reproducing cells. In the influence zone of the Baikalsky Pulp-and-Paper Plant (BPPP), waste waters, disturbances in the frustule structure both in vegetative and generative cells have been detected. 相似文献
12.
Galina L. Kirillova 《Island Arc》2018,27(2)
The Cretaceous tectonic and geodynamic settings of the southeastern Russian continental margin are discussed using data generated during several recent geological studies. The structural patterns of the East Asian Cretaceous continental margin are the result of the influence of global and regional processes. The interaction and reorganization of the Eurasian, Pacific and other related plates induced intraplate tectonic processes such as rifting, subduction, collision, transform faulting, and basin formation. Three major basin types are recognized in this area: (i) mainly marine active continental margins associated with shear components (Sangjian–Middle Amur Basin); (ii) passive continental margins (Bureya, Partizansk, and Razdolny basins); (iii) intracontinental basins (Amur–Zeya Basin). The evolution of the biota in this region allows the examination of Early and Late Cretaceous biostratigraphy, faunal and floral changes, and the phytogeography of the southeastern Russian continental margin. 相似文献
13.
Vitaly Salnikov Galina Turulin Svetlana Polyakov Marat Moldahmetov Lyazzat Mahmudova 《寒旱区科学》2013,5(1):0109-0113
Methods of calculating the basic hydrological characteristics of a water resource assessment, as well as the planning and management
of their long-term use are based upon the concept of stationarity of long-term flow fluctuations. However, data of researches
by hydrologists and climatologists clearly indicate that there are long-period changes in the characteristics of precipitation and river
flow. This article discusses the variations of annual precipitation and river flow in the Ishim River Basin in Kazakhstan, based
on the W, C and E classification developed by G.Y. Vangengeim who analyzed the long-term variability of anomalies by the number
of days with some form of atmospheric circulation. From this study, the largest anomaly of the macro-circulation processes
was revealed, and a comparative analysis of the number of days with various forms of atmospheric circulation and precipitation
anomalies was made. It was demonstrated that the nature of atmospheric circulation depends on the distribution of precipitation;
however, precipitation is also highly dependent on local physiographic conditions. The analysis of anomalous precipitation during
the maximum number of days of positive anomalies with various forms of atmospheric circulation was also carried out. This study
presents some results from the preliminary analysis of annual river flow linked with forms of atmospheric circulation. 相似文献
14.
Alexander G. Sokol Galina A. Palyanova Yury N. Palyanov Anatoly A. Tomilenko Vasiliy N. Melenevsky 《Geochimica et cosmochimica acta》2009,73(19):5820-5834
The composition and potential diamond productivity of C–O–H fluids that could exist in the reduced regions of the Earth’s upper mantle and in the mantles of Uranus and Neptune were studied in experiments at 6.3 GPa and 1400–1600 °C and durations of 15–48 h. Hydrogen fugacity in the fluid phase was controlled by the Mo–MoO2 or Fe–FeO buffers, using a specially modified double-capsule method. The oxygen fugacity in the samples was controlled by adding different amounts of water, stearic acid, anthracene, and docosane to a graphite charge. At high P–T conditions, the degree of decomposition of the heavy hydrocarbons added to the charge was 99.9%. The composition of the fluids coexisting with graphite/diamond in the buffered experiments varied from H2O H2 > CH4 (at fO2 somewhat lower than the “water maximum”) to H2 > CH4 > (C2H4 + C2H6)>C3H8 (in C–H system). In the C–H system the maximum concentrations of major species in the synthesized fluid were: H2 = 79 mol.% and CH4 = 21 mol.%. The composition of the H2-rich fluids, which were synthesized at 6.3 GPa and 1400–1600 °C for the first time, differs considerably from that of the ultra-reduced CH4-rich fluids stable at 2.0–3.5 GPa and 1000–1300 °C. Thermodynamic calculations of the reduced C–O–H fluids at the P–T conditions of the experiments revealed CH4-rich compositions (CH4 H2 > (C2H4 + C2H6)>C3H8), which however drastically differed from the synthesized compositions. The rates of diamond nucleation and growth in the experiments depended on the fluid composition. Diamond crystallization had a maximum intensity in the pure aqueous fluids, while in the H2-rich fluids no diamond formation was observed. Only metastable graphite precipitated from the ultra-reduced fluids. The type of the initial hydrocarbon used for the fluid generation did not affect this process. 相似文献
15.
The structure of the mid- and high-latitude ionosphere during the November 2004 storm event obtained from GPS observations 总被引:1,自引:1,他引:1
Andrzej Krankowski Irk I. Shagimuratov Lubomir W. Baran Galina Yakimova 《Acta Geophysica》2007,55(4):490-508
GPS data from the International GNSS Service (IGS) network were used to study the development of the severe geomagnetic storm
of November 7–12, 2004, in the total electron content (TEC) on a global scale. The TEC maps were produced for analyzing the
storm. For producing the maps over European and North American sectors, GPS measurements from more than 100 stations were
used. The dense network of GPS stations provided TEC measurements with a high temporal and spatial resolution. To present
the temporal and spatial variation of TEC during the storm, differential TEC maps relative to a quiet day (November 6, 2004)
were created.
The features of geomagnetic storm attributed to the complex development of ionospheric storm depend on latitude, longitude
and local time. The positive, as well as negative effects were detected in TEC variations as a consequence of the evolution
of the geomagnetic storm. The maximal effect was registered in the subauroral/auroral ionosphere during substorm activity
in the evening and night period. The latitudinal profiles obtained from TEC maps for Europe gave rise to the storm-time dynamic
of the ionospheric trough, which was detected on November 7 and 9 at latitudes below 50°N. In the report, features of the
response of TEC to the storm for European and North American sectors are analyzed. 相似文献
16.
About twenty geographers from the Soviet Union and the United States of America have joined in a review of selected geographical approaches to the study of global change. Taking account of the new effort sponsored by the International Council of Scientific Unions under its International Geosphere-Biosphere Programme to investigate major alterations in the world environment, they examine relevant geographical experience. Rather than assembling a collection of papers by individual authors, the project encouraged the preparation of a joint set of findings and observations.A joint USSR-USA project Global Change: Geographical Approaches under the scientific leadership of Vladimir M. Kotlyakov and Gilbert F. White; John R. Mather and Galina V. Sdasyuk are the editors of a monograph to be published in 1990 by Progress Publishers, Moscow, in Russian and by the University of Arizona Press, Tucson, USA, in English.
相似文献
相似文献
17.
The seismicity of the northeastern part of the Indian Ocean in connection with the general structural peculiarities of the
main tectonic structures of the bottom is presented. The three main ranges of higher seismic activity at the depths of 0–17,
20–27, and 32–35 km divided by aseismic layers are revealed. The seismic activity at depths of more than 35 km is almost not
detected both for the ocean and for the Indian peninsula. The nature of the distribution of the seismicity as such in the
lithosphere is discussed. Using the results of anomalous au]gravitational field transformations, the prolongation of the East
Indian Ridge structure is revealed to 19 degrees north, while the relationship of the Afanasy Nikitin Rise and the 85th Degree
Ridge is not reflected at the tranforms. In the Cocos Basin, the mutually perpendicular disturbance zones of northeastern
and northwestern strike, as well as the point of their crossing, where the maximal number of earthquake foci are concentrated,
are distinguished. A conclusion concerning the substantial disturbance of the strength properties of the lithosphere in this
zone as a consequence of the geodynamical processes, which are accompanied by fracture tectonics, is reached. 相似文献
18.
19.
Ivar Murdmaa Elena Ivanova Jean-Claude Duplessy Michael Levitan Tatyana Khusid Maria Bourtman Galina Alekhina Tatyana Alekseeva Michael Belousov Valentina Serova 《Marine Geology》2006,230(3-4):275-303
Twenty-two sediment cores raised from the central and eastern parts of the Barents Sea have been studied to reconstruct the evolution of the facies system since the Late Weichselian glaciation. Multiproxy records reveal four lithostratigraphic units, which reflect major development stages of paleoenvironments. Age control is provided by 23 AMS 14C dates for Holocene sections of four cores. Continental moraine deposits of the last glaciation are overlain by proximal glaciomarine facies of the initial deglaciation phase. During this phase, the Barents Sea ice sheet detached from the ground resulting in seawater penetration into troughs, iceberg calving, deposition of IRD and fine-grained glacier meltwater load in newly formed marine basins. The main deglaciation phase is characterized by pulsed sedimentation from various gravity flows resulting in accumulation of distal glaciomarine facies comprising laminated clay and sand sequences with minor IRD. Redistribution of fine-grained suspended matter by bottom currents and brine-induced nepheloid flows combined with biogenic processes and minor ice rafting caused facies diversity of the Holocene marine sediments. The Holocene facies of shelf depressions reflect rather high, but variable productivity responding to climate changes and variations of Atlantic water inflow into the Barents Sea. 相似文献
20.
An analysis of the gravity field and geoid heights allowed us to distinguish a third buried basin filled with sediments located in the southwestern part of the sea in the regions adjacent to the Carlsberg Ridge. From the previously known basins, it is separated by saddles. The saddles correspond to a series of faults and are possibly related to the pulse character of the northwestward prograding of the spreading axes of the Carlsberg Ridge. The continental origin of the Laxmi ridge is confirmed. The results of an analysis of the gravity field and its transformants, together with the two-dimensional density modeling, agree with the possibility of the existence of a spreading type of the crust (I) in the region of the Laxmi Basin. An analysis of the geoid height anomalies allows us to suggest that, with respect to the upper layers of the lithosphere, the Laxmi Ridge is not connected with the Chagos-Laccadive Ridge. 相似文献