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991.
C. Ibanoĝlu A. Y. Ertan O. Tümer S. Evren Z. Tunca 《Astrophysics and Space Science》1985,112(1):133-143
The first photoelectric light curves of the RS CVn-type eclipsing binary RT CrB are presented. There is no indication about the existence of wave like distortion on its light curve. The light curves were analyzed by using Wood's and Nelson, Davis, and Etzel's methods. The radii of the components are nearly identical. The solutions indicate that the cooler component has a later spectral type between K0 and K2. 相似文献
992.
Marcelo Assumpção 《Geophysical Journal International》1980,60(1):77-84
Summary. A clear PS reflection was recorded in the northern section of the LISPB line (shot-point N1, profile ALPHA). Travel times of PS and PP phases reflected at the same part of the Moho were used to model the lower crustal structure. The observed high apparent velocity of the PS phase (8.4 km/s) is interpreted as due to a localized Moho dip of 7 per cent (4°) towards the north. This is supported by observations of Pn refractions from other shots. It is shown that PS reflections could be very useful for determination of Moho dips. 相似文献
993.
The volcanosedimentary units of Late Mesozoic-Tertiary age that outcrop in the Southeast Anatolian orogenic belt are commonly
referred to as the Maden complex. There is a long-lasting controversy over its definition, age, stratigraphic and structural
position, and the origin, and thus, the orogenic evolution. To solve this problem, large strips across the Southeast Anatolian
orogenic belt have been studied extensively, and different rock groups which were regarded previously as the Maden unit have
been differentiated. Their major characteristics and differences have been identified. The Maden unit sensu stricto is here
redefined as a volcanosedimentary succession of Middle Eocene age representing a short-lived back-arc basin which reached
the stage of an embryonic ocean. Presently, the Maden group occurs mainly within the lower nappe stack of the nappe zone of
the Southeast Anatolian orogen. It rests stratigraphically on an amalgamated nappe package consisting of the different metamorphic
tectonic units and, in turn, is overlain tectonically by the upper nappe units. 相似文献
994.
通过对沙漠边缘地区影响苹果高产高效和优质的生态因子的综合评估,在多项生产试验的基础上,提出了该区苹果幼树期、结果期两个阶段“两高一优”栽培管理技术规范。 相似文献
995.
996.
Artificial Neural Networks (ANN) have gained a solid status as a tool for modeling complex phenomena in different areas of research and engineering practice. In this paper, their applicability to estimate the mapping of seismic acceleration from bedrock to free surface in a complex soil profile is explored. Such a use is intended to serve as a hypothesis-free alternative to the dynamic amplification analysis, which is currently based on geophysical and soil dynamics procedures. Were the neural networks to be useful to such a mapping, they could in principle be employed for several purposes, such as soil identification using instrumental data, design of early warning systems and estimation of probabilistic spectra via Monte Carlo simulation, in which the ANN act as an efficient solver surrogate. The conditions under which these ambitious purposes can be reached are discussed. Two classes of multi-layer perceptrons were tested, which are characterized by time-independent and time-dependent connections. It is shown that the first class of networks is useful for response spectrum mapping, while the second performs very well in the assessment of free-surface time series. It arises as the main conclusion that the most promising perspective of application of ANN in this respect is for the estimation of probabilistic free-surface spectra, which is an important goal for the modern trend of reliability-based aseismic design. The limitations to the other said applications are also highlighted. 相似文献
997.
Summary From a data set of sea-breeze observations corresponding to cases of no synoptic-scale flow in Barcelona during the period 1970–89, some features of this wind have been deduced. Maximum velocities of between 6–14 m/s generally occur during 12–16 SLT. Diurnal evolution gives a clockwise rotation of sea breeze so that this wind blows roughly parallel to the shoreline in late afternoon. The rate of the change of direction is in agreement with numerical results from a simple nonlinear sea breeze model.With 7 FiguresThis work has been supported by the DGICYT, Project No. PB87-0718. 相似文献
998.
E. Carreño J. Rueda C. López Casado J. Galán J. A. Peláez 《Pure and Applied Geophysics》1991,136(4):395-404
In recent years a network of 30 accelerographs has been installed through the zones of highest seismic activity of Spain. For the first time, digital strong motion records have been obtained in Spain, with a maximum horizontal acceleration value of 0.06 g. A comprehensive study is made of the strong motion recordings of an earthquake which occurred in southwest Spain, on December 20, 1989. The isoseismal map is drawn and the data confirm the main attenuation directions in the area observed in other shocks. 相似文献
999.
Backwater effects in the Amazon River basin of Brazil 总被引:4,自引:0,他引:4
Robert H. Meade José M. Rayol Sylvio C. Da Conceicão José R. G. Natividade 《Environmental Geology》1991,18(2):105-114
The Amazon River mainstem of Brazil is so regulated by differences in the timing of tributary inputs and by seasonal storage of water on floodplains that maximum discharges exceed minimum discharges by a factor of only 3. Large tributaries that drain the southern Amazon River basin reach their peak discharges two months earlier than does the mainstem. The resulting backwater in the lowermost 800 km of two large southern tributaries, the Madeira and Purús rivers, causes falling river stages to be as much as 2–3 m higher than rising stages at any given discharge. Large tributaries that drain the northernmost Amazon River basin reach their annual minimum discharges three to four months later than does the mainstem. In the lowermost 300–400 km of the Negro River, the largest northern tributary and the fifth largest river in the world, the lowest stages of the year correspond to those of the Amazon River mainstem rather than to those in the upstream reaches of the Negro River. 相似文献
1000.
Prof. Ing. Antonio Gião 《Pure and Applied Geophysics》1956,35(1):73-93
Résumé Le mémoire commence par la déduction de l'équation générale d'évolution des champs géostrophiques. Cette équation fait intervenir une fonction (S) du gradient de pression et de la température qui joue un rÔle essentiel dans la discussion des conditions de stabilité des champs de pression et de température.Les configurations théoriques du champ de pression, lorsqueS est spatialement constante, constituent des familles de champs auxquelles appartiennent les champs stationnaires. Ces familles permettent d'analyser tout champ de pression complexe en le décomposant en une somme de champs partiels simples possédant des propriétés de symétrie par rapport aux méridiens passant par leurs centres.On peut baser sur cette analyse géostrophique une méthode pour la classification rationnelle des types de temps, qui est appliquée ici aux champs moyens de Juillet et de Janvier en Europe.
Mémoire N 1 du CIRMM (Centre International de Recherches sur la Météorologie de la Méditerranée). 相似文献
Summary The paper begins with the deduction of a general equation for the evolution of the geostrophic fields. This equation leads to the definition of a function (S) of the pressure gradient and the temperature which plays an essential part in the discussion of the stability conditions of the pressure and temperature fields.The theoretical configurations of the pressure field, whenS is constant in space, form well defined families of fields comprising all the stationary fields. By means of these families any complex field can be analysed through its decomposition in a sum of simple fields with symmetry properties with respect to their central meridians.A method for the rational classification of weather types can be based on this geostrophic analysis and is applied here to the european mean pressure fields for the months of July and January.
Mémoire N 1 du CIRMM (Centre International de Recherches sur la Météorologie de la Méditerranée). 相似文献