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31.
In this paper we study ω-distributive modules, where ω is a cardinal number. We extend a characterization of distributive modules to ω-distributive modules. In particular, the case in which ω = n is a finite cardinal is considered. We apply the results to the case n = 2, obtaining new characterizations for distributive modules and rings. Special attention is given to saturated submodules and ideals. 相似文献
32.
S. Alessio L. Briatore R. Cremonini E Ferrero C. Giraud A. Longhetto O. Morra R. Purini 《Il Nuovo Cimento C》1995,18(6):603-627
Summary This paper presents the results of laboratory experiments designed to simulate some basic process of large-scale flows interacting
with obstacles, also in order to better understand details of subsynoptic disturbances that are created in the lee of large
topographic features. For this event, the experimental facilities of the Istituto di Cosmogeofisica of Consiglio Nazionale
delle Ricerche (CNR) were exploited, consisting in a hydraulic channel mounted on a rotating platform, along whose longitudinal
axis a hemispherical obstacle was towed at various speeds. Because of the conversion of potential vorticity, the experimental
results showed, as expected, the existence of a region of anticyclonic circulation, located above the obstacle; however, also
an asymmetric pattern of positive vorticity located downwind of the obstacle did appear, which cannot be interpreted in terms
of simple quasi-geostrophic inviscid dynamics. This behaviour is not surprising, if one considers that the real flow near
the obstacle could hardly ever match the conditions of inviscid quasi-geostrophy (Ro≪1,E∼0), but was similar to that characterising the zone close to the surface of the obstacle, where inertial and viscous effects
are not negligible. Finally, in order to investigate the importance of these effects on the interaction processes, simple
numerical and analytical models were applied, by which the consistency of some laboratory simulations, chosen among the most
significant ones, could be compared. 相似文献
33.
We claim that physics has been constructed because three “philosophical” principles have been respected, namely, realism,
locality, and consistency. These principles lead to an interpretation of quantum mechanics (QM) in terms of local hidden-variables
theories (LHV). In order to prove that LHV have not been refuted, we analyze the empirical proofs of Bell's inequalities and
we argue that none is loophole-free. Then we propose a restricted QM that does not contain measurement postulates and that
does not claim that all state vectors (self-adjoint operators) are states (observables). The contradiction of such restricted
QM with Bell's inequality cannot be shown as a theorem, but only by the design of a loophole-free experiment. Finally, we
argue that noise has been underestimated in quantum theory. It does not appear in QM, but it is essential in quantum field
theory. We conjecture that noise will prevent the violation of Bell's inequality. 相似文献
34.
A. Longhetto G. Chabert D'Hieres L. Briatore H. Didelle E. Ferrero C. Giraud 《Il Nuovo Cimento C》1996,19(4):561-578
Summary One of the most intriguing problems concerning the interaction of subsynoptic and synoptic atmospheric flows with topographic
features is orographic cyclogenesis. A fully satisfactory prediction theory is not yet available, but a lot of efforts have
been made by theoreticians to implement reliable numerical models simulating the different phases of this complex phenomenon.
An attempt to perform a laboratory experiment to simulate physically this kind of interaction has been made by us, through
the generation of a baroclinic frontal system in the rotating hydraulic platform of the ?Coriolis Laboratory—LEGI-IMG—Grenoble?.
The adopted technique consists in a device which produces, at the interface separating two water layers of different density
(ϱ1 and ϱ2), a stream of stratified fluid whose density has an intermediate value ϱ1 < ϱm < ϱ2. This stream is generated at the height of the interface between the two layers; due to the rotation of the platform, the
attainment of geostrophic equilibrium brings about an intermediate-water flow running along a wall, giving rise to a three-layer
baroclinic structure which can represent some of the main outstanding features of an atmospheric frontal system impinging
on a mountain. In a well-defined range of the Rossby and Burger numbers, the instability of this current gives rise to a couple
of persistent cyclonic and anticyclonic vortices, whose horizontal dimensions and vertical extents reproduce quite faithfully
the synoptic situation supporting the onset of the orographic cyclogenesis, with its characteristic cold front stretching
between the two vortex structures. It is enough to place an obstacle of a suitable size in the proper geographic position,
to make the cyclogenesis start. The first results of our simulations have been encouraging, showing the occurrence of lee
cyclogenesis when the stream conditions in our model correspond to the synoptic features which have been recognized as the
precursors of orographic cyclogenesis in the lee of the Alps. 相似文献
35.
In this paper, we study prime ideals and radicals of centred extensions of rings. Obtained results are applied to tensor products
of algebras over commutative rings.
This research was partially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil. The
second-named author was also supported by KBN grant 2 P301 035 06. 相似文献
36.
The kinetics of the gas-phase thermal isomerization between trans- and cis-1,2-bis(trifluoromethyl)-1,2,3,3-tetrafluorocyclopropane as well as their decomposition to trans- and cis-perfluoro-2-butene, respectively, and CF2, was studied in the temperature range of 473–533°K, with an initial pressure of reactant of 1.5 to 7.0 Torr. Some runs were also made with the addition of SF6 as an inert gas up to a total pressure of 100 Torr. The reactions are first order and homogeneous. The rate constants for the geometrical isomerization fit the following Arrhenius relations: and the corresponding equations for the decomposition of the trans and cis-cyclopropane are . 相似文献
37.
Summary Joerchel's method is applied to SAXS spectra of a poly(amido-amine)-heparin complex in aqueous non diluted solutions, showing a noticeable interference effect. The results are compared with those obtained by the classical Guinier analysis applied to diluted solutions of the complex.
Zusammenfassung SAXS-Spektren eines Poly(amido-amin)-Heparin-Komplexes in nicht verdünnten wäßrigen Lösungen, die bemerkenswerte Interferenzeffekte zeigen, wurden mittels der Joerchel'schen Methode analysiert. Die Ergebnisse wurden mit den durch die klassische Analyse von Guinier an verdünnten wäßrigen Komplexlösungen erhaltenen verglichen.相似文献
38.
Methylvinylpyridine-butadiene copolymers vulcanized by various α, ω dibromo-alkanes were investigated by X-ray small angle scattering. In these systems, employing the Hosemann-Joerchel analysis, only one cluster dimension of about 45 Å has been found with a polydispersity not exceeding 35 per cent. Stretched rubbers show interference effects both in the meridional and equatorial directions. 相似文献
39.
M. Dehlinger C. Fauquet F. Jandard A. Bjeoumikhov S. Bjeoumikhova R. Gubzhokov A. Erko I. Zizak D. Pailharey S. Ferrero B. Dahmani D. Tonneau 《X射线光谱测定》2013,42(6):456-461
Capillary optics are used for X‐ray fluorescence micro‐analysis using the Cu Kα line provided by a rotating anode. The excitation beam is focused using a polycapillary lens on a Co–Ti sample. Cylindrical glass capillaries of various diameters are fitted to the X‐ray detector (Energy Dispersive X‐Ray (EDX) analyzer) and displaced along the irradiated zone of the sample. The fluorescence is studied as a function of capillary position. Good agreement is found between experimental and calculated lateral widths of the fluorescence collection, taken into account the cylindrical capillary critical angles relevant in the experiment. The influence of the cylindrical capillary diameter on the signal level detected is studied to estimate the possibility of lateral resolution increase of X‐ray fluorescence technique both in‐lab and in synchrotron environment. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
40.