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91.
In the present paper, we consider word maps w: G m → G and word maps with constants w Σ: G m → G of a simple algebraic group G, where w is a nontrivial word in the free group F m of rank m, w Σ = w 1 σ 1 w 2 ··· w r σ r w r + 1, w 1, …, w r + 1 ∈ F m , w 2, …, w r ≠ 1, Σ = {σ 1, …, σ r | σ i ∈ G Z(G)}. We present results on the images of such maps, in particular, we prove a theorem on the dominance of “general” word maps with constants, which can be viewed as an analogue of a well-known theorem of Borel on the dominance of genuine word maps. Besides, we establish a relationship between the existence of unipotents in the image of a word map and the structure of the representation variety R(Γw, G) of the group Γw = F m /<w>. 相似文献
92.
93.
94.
N. L. Gordeev 《Journal of Mathematical Sciences》1984,26(3):1872-1875
Let G be a finite subgroup of GL(V), where V is a finite-dimensional vector space over the field K and char KG. We show that if the algebra of invariants K(V)G of the symmetric algebra of V is a complete intersection then K(V)H is also a complete intersection for all subgroups H of G such that H={ Gv (v)=v for all v VH}.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 116, pp. 63–67, 1982. 相似文献
95.
K. Yu. Gordeev V. N. Filarin S. V. Bondarenko M. A. Kirpichenok N. A. Gordeeva I. I. Grandberg S. G. Batrakov 《Chemistry of Natural Compounds》1990,26(2):143-147
The Antarctic krillEuphausia superba Dana contains about 5% of its natural weight of extractable lipids, more than half of which are in the form of phospholipids — phosphatidylcholine (33–36% of the sum of the lipids), phosphatidylethanolamine (15–17%), lysophosphatidylcholine (3–4%), and others (2–3%) — while among the phosphorus-free components triacylglycerols predominate (32–35%). In the first two phospholipids the dominating fatty acid residue is the arachidonic acid residue (more than 40% of the sum of the acyl residues) and the amounts of residues of eicosapentaenoic acid (C20 : 5w3) are about 13 and 28%, respectively. A simple procedure for isolating the phosphatidylcholine and phosphatidylethanolamine is proposed. For the analysis of the fatty acid a new method was used, consisting of the HPLC of their (7-diethylaminocoumarin-4-yl)hydrazides, with fluorometric detection.Scientific Research Laboratory of Biologically Active Substances of Hydrobionts, USSR Ministry of Health, Moscow. K. A. Timiryazev Moscow Agricultural Academy. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 181–187, March–April, 1990. 相似文献
96.
E. G. Gordeev S. P. Knyazev M. V. Pecherskii A. S. Frenkel E. A. Chernyshev P. A. Storozhenko 《Journal of Structural Chemistry》2006,47(1):15-20
A quantum chemical study of spatial and electronic structures of molecules in the frame complexes, bis[3,3′(RR′)-ketiminepropyl]methylamine nickel dichlorides, where R = H, CH3, and R′ = H, CH3, has been performed by DFT(B3LYP/LANL2DZ) method. The molecules of these complexes were found to be in a triplet state. Energy stability of the endo form of the complex molecules was shown. In the molecule of bis[3,3′-aldiminopropyl]methylamine nickel dichloride (R = R′ = H), a considerable strengthening of the bond Ni-N(amine) takes place when passing from the diamagnetic into paramagnetic state, and all bonds Ni-N become equivalent with respect to interatomic distance values. The topology analysis of the electron density for the complexes with R = R′ =H and R = R′ = CH3 was carried out. It is stated that all Ni-N bonds are covalent in the molecules of paramagnetic complexes. 相似文献
97.
The temperature dependences of the resonance frequency and quadrupole spin-lattice relaxation time of the chlorine-35 nuclei
in crystalline CCl3C(O)OC6H2Cl3-2,4,6 were studied. Owing to the presence of resonant nuclei in various fragments of the molecules, the character of dynamics
of these molecular fragments and the entire molecule was established. It is shown that thermal librations of molecules are
quasiharmonic over the whole temperature range from 77 K to the melting point of the crystal. The reorientational motion of
the CCl3 group bonded to the three-coordinated carbon atom was revealed. This motion causes an exponential increase in the spin-lattice
relaxation time of the chlorine nuclei of this group and subsequent damping of NQR signals (chlorine-35 resonance signals
of the aryl radical were observed before melting of the sample). The activation energy of the reorientational motion is found;
its value, which is 27.3 kJ/mole, is considered in comparison with the activation energies obtained by the Cl NQR method in
solids for CCl3 reorientations in similar molecular structures. 相似文献
98.
É. A. Smorgonskaya R. N. Kyutt S. K. Gordeev A. V. Grechinskaya Yu. A. Kukushkina A. M. Danishevskii 《Physics of the Solid State》2000,42(6):1176-1181
The curves describing small-angle x-ray scattering at npor-C nanoporous carbon samples obtained from polycrystalline α-SiC, TiC, and Mo2C and a 6H-SiC single crystal have been analyzed. An algorithm is developed for taking into account the corrections to experimental curves for the intensity of the primary beam transmitted through the sample and the height of the inlet slit in these measurements. Two systems of nanoclusters observed in the npor-C structure differ in the type of stacking of structural elements: small-scale mass fractals of a dimension 1<D 2<3 and a size L 2=50–90 Å, which depend on the type of the initial carbide, and large-scale nanoclusters having a size L 1>550 Å. In most samples, large-scale nanoclusters can be regarded as objects with a fractal surface and a dimension 2<D 1<13, which also depends on the type of the initial carbide. Large-scale nanoclusters in npor-C obtained from Mo2C prove to be mass fractals with a dimension D 1>2. Peculiarities of the structure formation of nanoporous carbon obtained from various carbides are discussed. 相似文献
99.
LetG be a quasisimple Chevalley group. We give an upper bound for the covering number cn(G) which is linear in the rank ofG, i.e. we give a constantd such that for every noncentral conjugacy classC ofG we haveC
rd
=G, wherer=rankG.
Research supported in part by NSERC Canada Grant A7251.
Research supported in part by the Hermann Minkowski-Minerva Center for Geometry at Tel Aviv University. 相似文献
100.
The reactions of nonsubstituted or 2-aryl-substituted 3-hydroxytetrahydropyrimidin-4-ones (HTHP) with carboxylic acid chlorides,
tosyl chloride, or aryl isocyanates afford mainlyN,O-diacylated,N,O-ditosylated, orN,O-diarylcarbamoylated HTHP, respectively.N,O-Diacylated HTHP are also formed in the reactions of acid chlorides with Schiff's bases based on β-aminopropionohydroxamic
acid.N-Acylated HTHP can be obtained by treatingN,O-diacylated HTHP with ammonia. The reactions of 2,2-dialkyl(alkylene)-substituted HTHP with acid chlorides or phenyl isocyanate
giveN,O-diacylated orN,O-diphenyl-carbamoylated β-aminopropionohydroxamic acid, respectively.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2327–2332, December, 1999. 相似文献