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1.
Lev Buhovsky 《Israel Journal of Mathematics》2004,143(1):181-187
In this paper we find homological restrictions on Lagrangians in cotangent bundles of spheres and Lens spaces.
This research was supported by the Israel Science Foundation (grand No. 205/02). 相似文献
2.
The main results of the paper are as follows: covering characterizations of wQN-spaces, covering characterizations of QN-spaces and a theorem saying that Cp(X) has the Arkhangel'ski?ˇ property (α1) provided that X is a QN-space. The latter statement solves a problem posed by M. Scheepers [M. Scheepers, Cp(X) and Arhangel'ski?ˇ's αi-spaces, Topology Appl. 89 (1998) 265-275] and for Tychonoff spaces was independently proved by M. Sakai [M. Sakai, The sequence selection properties of Cp(X), Preprint, April 25, 2006]. As the most interesting result we consider the equivalence that a normal topological space X is a wQN-space if and only if X has the property S1(Γshr,Γ). Moreover we show that X is a QN-space if and only if Cp(X) has the property (α0), and for perfectly normal spaces, if and only if X has the covering property (β3). 相似文献
3.
Backscattered-particle production is studied by means of a detailed simulation of cascade processes in a dense medium. The energy dependence of the albedo and the spatial and angular distributions of various components of this flux are analyzed. 相似文献
4.
L. P. Rapoport 《JETP Letters》1998,68(3):198-203
A new representation is found for the interaction of intense circularly polarized light with an atom. A stationary centrosymmetric
part, which depends on the field parameter a
0=F/ω2, is separated out from the atom-field interaction. The time-dependent part of the interaction is represented in the form
of a multipole expansion with a
0 taken into account. The application of this representation for calculating the nonlinear dynamic polarizability of a complicated
atom in the random-phase approximation with exchange is studied.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 3, 189–193 (10 August 1998) 相似文献
5.
R. B. Gelfand V. A. Gordeev Yu. V. Gorelkinsky S. A. Kuten A. V. Mudry N. N. Nevinny V. I. Rapoport A. G. Ulyashin 《Hyperfine Interactions》1991,64(1-4):579-584
The electronic structure of muonium (Mu) located at the bond-centered sites of the silicon and diamond crystals is calculated
by the intermediate neglect of differential overlap method. Calculations of the electronicg- and hyperfine interaction tensors of the impurity atom are performed. The results obtained are compared to the experimental
properties of “anomalous” muonium Mu*. It is shown that the properties of Mu located at the bond-centered sites of the Si and C lattices are in qualitative agreement
with the observed properties of Mu*. 相似文献
6.
The relativistic correction to the triton binding energy approximated to the order (v/c)2 is calculated in the framework of relativistic Hamiltonian dynamics. We discuss the generator representation of the Poincaré group for three relativistic particles and its connection with the Feynman diagrams in the infinite-momentum frame (the light-front dynamics). The relativistic correction enhances the attraction in the three-nucleon system. The five-channel calculation with the Reid soft-core potential yeilds the result =–0.54 MeV, which is governed mainly by theD-wave contribution. TheS-wave contributions to are only –0.10 MeV. 相似文献
7.
S. V. Lev R. P. Zakirova Z. Saatov M. V. Gorovits N. K. Abubakirov 《Chemistry of Natural Compounds》1990,26(1):40-41
The possibility has been studied of obtaining ecdysteroids — ecdysterone and turkesterone — with the aid of a culture of the tissues and cells of the plantAjuga turkestanica. Conditions have been selected under which the yield of ecdysteroids in the culture of tissues and cells is comparable with amounts of the same substances in the organs of the whole plant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–52, January–February, 1990. 相似文献
8.
A new method is reported for the chirospecific preparation of optically pure 1-carboxy-7-azabicycloheptane amino acids for the generation of peptidomimetics as conformational probes. The method allows for the multigram preparation of these amino acid analogues through use of a thiolactam sulfide contraction and a transannular alkylation sequence as the key C-C bond-forming steps, starting from L-glutamic acid. The route provides access to two common intermediates, 7-(benzyloxycarbonyl)-1-carboxy-7-azabicyclo[2.2.1]-3-heptane and (1S,4R)-7-(benzyloxycarbonyl)-1-carboxy-7-azabicyclo[2.2.1]-3-heptanone tert-butyl ester, for elaboration to symmetrical and chiral amino acid homologues, respectively. Decarboxylation of the C-1 carboxy unit of the latter intermediate also demonstrated the applicability of the method for a short, chirospecific preparation of a (+)-epibatidine intermediate, (1S,4R)-7-(tert-butyloxycarbonyl)-1-carboxy-7-azabicyclo[2.2.1]-3-heptanone. 相似文献
9.
10.
J Deutsch L Hegedus N H Greig S I Rapoport T T Soncrant 《Journal of chromatography. A》1992,579(1):93-98
Nicotine and its metabolite, cotinine, were measured in rat plasma and brain by gas chromatography-mass spectrometry. Both agents were extracted from plasma and brain, separated on a capillary column, and quantified by single-ion monitoring. The major fragment ions of nicotine and cotinine at m/z 84 and m/z 98, respectively, were monitored by electron-impact ionization detection and the protonated molecular ions at m/z 163 and m/z 177, respectively, were monitored by chemical ionization detection. Both compounds were quantified using deuterium-labeled nicotine and cotinine, respectively, as internal standards. 相似文献