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排序方式: 共有620条查询结果,搜索用时 15 毫秒
581.
I. N. Garczyńska 《Solar physics》1991,131(1):129-135
The dependence of the maximum height achieved by sprays showing deceleration and stopping at the end of their propagation, on the velocity has been examined. It was assumed that the velocity is greatest at the beginning, so this maximum velocity defines the kinetic energy of each investigated knot at its start. The relation between the maximum height and maximum velocity was examined in 32 knots from 23 sprays. The problem of whether the maximum height achieved by a knot is determined by the gravitational field alone has been studied. The problem of stopping is important especially for knots which have initial velocities higher than the velocity of escape from the Sun. 相似文献
582.
Ewa Rydzyńska 《Astrophysics and Space Science》1990,173(2):241-249
In this paper, new ideas from our previous paper (Rydzyska, 1989)-i.e., problems connected with the new equivalence principle-have been developed. It is conformed, that certain static particles from Bellert's space-time are equivalent to a free particle from classic Milne's space-time. Mention is made of the algebraic structure of Bellert's space-time from (Rydzyska, 1990b). The space-time interval in this space-time, and its connection with a probability and the physical meaning of this interval and probability, has been defined. In the last section we derive dynamical equations for Bellert's space-time, i.e., we do the foundations of Bellert's general relativity theory. 相似文献
583.
T. Grabińska 《Astrophysics and Space Science》1992,191(1):23-42
The new reconstruction of special relativity (SR) is presented. The question of length and time measurements forms the basic plane of our search. The question why Milne's procedure, applied to clocks synchronization by means of light signal, supersedes the Einsteinian procedure by means of moving clock, is elaborated. According to H. E. Ives' hints the consistency of velocity notion in SR is reanalysed. The justification of the light postulate from the point of view of measurement procedures and anti-absolutistic heuristics of SR is discussed. The new correspondence relation between SR and Ives' space-time theory is presented. The fundamental problems related to operationistic interpretation of SR and to research programmes of kinematics are discussed in the new theoretical fashion. 相似文献
584.
Witold Szczuciński Przemysław Niedzielski Lidia Kozak Marcin Frankowski Anetta Zioła Stanisław Lorenc 《Environmental Geology》2007,53(2):253-264
Study on contamination of tsunami sediments deposited on 26 December 2004 conducted shortly after the tsunami in coastal zone
of Thailand revealed elevated contents of salts in water-soluble and some heavy metals and arsenic in bioavailable fractions
(Szczuciński et al. in Env Geol 49:321–331, 2005). Few months later rainy season started and effected in total rainfall of over 3,300 mm. This paper presents results of survey
repeated 1 year after the tsunami. To assess the effects of rainy season on mobilization of previously determined potential
contaminants, the same locations were sampled again and analysed with the same methods. The tsunami deposit layer was well
preserved but in many locations the sediments were coarser than just after tsunami due to washing out of finer fractions.
The water-soluble salts contents were strongly reduced after the rainy season. However, the concentrations of acid leachable
heavy metals and metalloids were still elevated in comparison to reference sample from an area not impacted by tsunami. It
is possible that the metals and metalloids are successively moved to more bioavailable fraction from forms which were more
resistant to mobilization. 相似文献
585.
The spread of a passive contaminant in an open-channel reach is considered with use of a two-dimensional advection-diffusion
equation with the included off-diagonal dispersion coefficients. This paper presents the calculation of truncation errors,
namely numerical diffusion and numerical dispersion for various finite difference schemes. The accuracy of the considered
finite-difference approximations is analysed by deriving and studying the relevant modified partial differential equation. 相似文献
586.
Karol Kuliński Joanna Święta-Musznicka Andrzej Staniszewski Janusz Pempkowiak Małgorzata Latałowa 《Journal of Paleolimnology》2007,38(4):555-567
The quantity and quality of lignin phenols (Σ8, Λ, S/V, C/V and (Ad/Al)v) in the sediments of three small Lobelia lakes with neither inlets nor outlets were investigated and compared with palynological data and lithology of the profiles.
The method of alkaline CuO oxidation was used. Substantial differences with respect to sedimentary lignin concentration and
provenance recorded along the profiles and among the sites are in good agreement with pollen data describing the dominant
type of vegetation and with indices of soil erosion in the lakes’ catchments. This relation shows that the compositions of
lignin degradation products in these lakes are closely related to the local environmental conditions. In all the lakes gymnosperm
wood is the main source of lignin products; however, each lake is characterized by different S/V index values. Especially
good correlations were obtained between pine pollen proportions in sediments and the S/V index. The correlation between the
C/V and (Ad/Al)v indices indicates a higher degradation of organic matter when non-woody tissue is more abundant. This pilot study illustrates
the usefulness and potential for a wider application of lignin oxidation products in palaeoecological reconstructions. This
kind of data would be of special importance when investigating local presence/absence of woody plants and the role of angiosperms/gymnosperms
in local vegetation. Estimates of lignin biodegradation levels, as well as the data on diagenetic processes, may afford supplementary
information on possible disturbances in sedimentation. 相似文献
587.
The amplitude of the ellipsoidal variability, the mass function and the evolutionary limits on the component masses have been used to constrain the binary system parameters of T Coronae Borealis. Contrary to all previous studies, our analysis shows that the mass ratio of T CrB is q ≡ M g / M h ≈0.6, which implies a low-mass binary system, with the stellar masses M g ∼0.7 M⊙ for the red giant and M h ∼1.2 M⊙ for the hot companion. This result strongly supports the thermonuclear runaway model for this recurrent nova, and solves all controversies about the nature of the hot component and the physical causes of its eruptions. 相似文献
588.
Hervé Cabot Christian Meynadier Dorota Sobczyńska Barbara Szabelska Jacek Szabelski Tadeusz Wibig 《Astroparticle Physics》1998,9(4):269-276
We describe the possible measurable difference in the Cherenkov light component of EAS induced by an electromagnetic particle (i.e., e+, e− or γ) and induced by a hadron (i.e., proton or heavier nuclei) in the TeV range. The method can be applied in experiments which use wave front sampling method of EAS Cherenkov light detection (e.g., THEMISTOCLE, ASGAT). 相似文献
589.
The interaction between the atmosphere and the underlying solid mantle is oneof the most important sources of changes in all three components of theEarth's rotation vector on different time scales. In this paper the NCEP/NCARreanalysis time series of four times daily atmospheric effective angularmomentum (EAM) estimates is used to investigate some selected aspects of theatmospheric influence on Earth rotation. Emphasis is placed on thecontroversial features which were difficult or impossible to study using theoperational EAM data, such as excitation of the free oscillations in polarmotion, the Chandler wobble (CW) and the free core nutation (FCN), or theroles of diurnal and semidiurnal atmospheric tides and atmospheric normalmodes in the rotational dynamics of the Earth. 相似文献
590.
Andrzej Grniak Piotr Zieliski Elbieta Jekatierynczuk‐Rudczyk Magdalena Grabowska Tomasz Suchowolec 《洁净——土壤、空气、水》2002,30(4):179-189
Long‐term studies were conducted on the polymictic Siemianówka reservoir (SR), situated in a seminatural forest‐peat catchment in NE Poland. The studies were started on the second year of the reservoir's existence. The records showed dissolved organic carbon (DOC) concentrations gradually increasing up to 25…30 mg/L. The largest DOC pool in the reservoir comes from the spring load input, supplemented by the excessive development of phytoplankton with cyanobacteria dominance. The DOC limited the range of the photic zone, eliminated the occurrence of aquatic plants, and was a significant carrier of nutrients, which were gradually released to water, bringing about the “humoeutrophication” of the reservoir. 相似文献