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排序方式: 共有238条查询结果,搜索用时 15 毫秒
1.
2.
Minkin V. I. Gribanova T. N. Starikov A. G. Minyaev R. M. 《Russian Chemical Bulletin》2003,52(3):519-525
The electronic and molecular structure of planar (cyclic and linear) tetra- and hexaatomic clusters (XY)
n
(XY = CC, BN, BeO, LiF; n = 2, 3) was studied using the ab initio CCD(full)/6-311+G** method and density functional approach (B3LYP/6-311+G**). The stability of cyclic clusters C6, B3N3, and Be3O3 with D3h
symmetry is mainly determined by the aromaticity of their -electron systems. 相似文献
3.
Vl. G. Tyuterev A. V. Burenin V. I. Perevalov V. I. Starikov 《Russian Physics Journal》1985,28(8):633-637
A general method for reducing the effective rotational Hamiltonian for moleculesH
rot to the empirically constructed form in the {J±, Jz} representation (molecules of the asymmetric-top type), applicable to Hamiltonians having improved convergence with nonpolynomial dependence on the angular momentum J, is developed. Rational forms for the reducedHrot and reduced Padé approximants for the rotational energy operator of the molecules are proposed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 32–37, August, 1985. 相似文献
4.
Igor E. Uflyand Andrei G. Starikov Vladimir S. Savostjanov Anatoly D. Pomogailo 《Transition Metal Chemistry》1991,16(1):126-129
Summary The spatial and electronic structures of the complexes [Co(AAm)4(H2O)2](NO3)2 (1), Co(AAm)4Cl2 (2), [Ni(AAm)4(H2O)2](NO3)2 (3) and Ni(AAm)4Cl2 (4), where AAm is acrylamide, and the products of their radical, frontal and post-grafting polymerization have been studied by electronic spectroscopy. The complexes (1), (3) and (4) were found to have pseudooctahedral structures in both the solid and solution phases. A change in the spatial structure of complex (2) was established in going from the crystal (tetragonally distorted octahedral) to solution (tetrahedral). The coordination environment of the metal centre does not change markedly during polymerization of the metal-containing monomers. 相似文献
5.
Group-theoretical methods are used to identify the nonvanishing parameters and establish relations between them in the effective Hamiltonians which describe rotation and motion with large amplitude. The cases considered are 1) bending vibration in molecules of the type XY2 and XYZ and 2) inversion vibration in pyramidal molecules of the type XY3. For the latter type of molecule, the symmetry properties of the parameters in the effective centrifugal Hamiltonian for quasidegenerate inversion states are investigated. The general form of this Hamiltonian and its symmetry properties are established and studied in an arbitrary order in the small parameter.Translated from Izvestiya Vysshikh Uchebnykh Zavednii, Fizika, No. 2, pp. 22–26, February, 1981. 相似文献
6.
The gradient pathways of the reactions of nucleophilic addition of H2O and HF molecules to formaldehyde in the gas phase and in the XH…H2CO…HC(O)OH complex (X=OH, F) were calculated by theab initio RHF/6-31G**, MP2(fc)/6-31G**, and MP2(full)/6-311++G** methods. Both reactions proceed concertedly. The formation of H-bonded bimolecular pre-reaction complexes is the initial
stage of the gas-phase reactions; at the same time, no indications of the formation of stable π-complexes were found on the
potential energy surfaces of systems under study. The calculated energy barriers to the gasphase reactions exceed 40 kcal
mol−1, while those to reactions in the complex XH…H2CO…HC(O)OH (X=OH, F) become more than halved.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2146–2154, November, 1998. 相似文献
7.
A. N. Yunuskhodzhaev EB. Shamuratov A. S. Batsanov S. A. Talipov 《Chemistry of Natural Compounds》1992,27(6):743-744
A single crystal of (RS)-carnitine hydrochloride has been obtained, and its crystal structure has been refined by an x-ray structural experiment.Tashkent Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 842–844, November–December, 1991. 相似文献
8.
Quantum chemical study of mixed-ligand (1: 1) adducts of tetracoordinated cobalt complexes (diketonates, bis-aminovinylketonates, and bis-salicylaldiminates) with pyrene-4,5-diimines using density functional theory (DFT B3LYP*/6-311++G(d,p)) revealed compounds possessing valence tautomeric properties. The mechanisms of intramolecular electron transfer accompanied by changing magnetic properties of the complexes under consideration were studied. It was shown that the variation of substituents at the nitrogen atoms of the diimine ligand and the donor groups in the cobalt bischelate, as well as the annulation of five- and six-membered rings to the azomethine fragment exerts a considerable influence on the stability of the formed adducts and the energy difference between their low- and high-spin isomers. 相似文献
9.
D. V. Steglenko I. S. Ryzhkina A. I. Konovalov A. G. Starikov V. I. Minkin 《Russian Chemical Bulletin》2014,63(1):54-59
Self-association of α-tocopherol molecules in the gas phase was simulated using quantum chemical calculations in the B3LYP/6-31G(d,p)/6-31G(d) approximation. The influence of electric field on the energy characteristics of oligomerization of α-tocopherol was also considered. 相似文献
10.
Adducts based on the cobalt azomethine bis-chelates and acenaphthene-1,2-diimines have been studied using the density functional theory method [DFT B3LYP*/6-311++G(d,p)]. It has been shown that the stability of the formed complexes with respect to dissociation and the ability to demonstrate valence tautomeric properties can be controlled by functionalization of the ligands. Compounds have been revealed whose magnetic properties vary due to intramolecular redox process. 相似文献