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61.
Yu. S. Simanenko E. A. Karpichev T. M. Prokop’eva V. A. Savelov A. F. Popov 《Theoretical and Experimental Chemistry》1998,34(2):76-80
A detailed extrathermodynamic analysis of the behavior of oximate ions (pKa≈7–13) in reactions with various types of substrate was undertaken. For oximate ions with pKa≥9.0, irrespective of the nature of the acyl group, the reactivity of the oximes tends toward that of the alcoholate ions,
and their α-effect disappears. The reason for this is the unfavorable solvation effects of the solvent.
Institute of Physical Organic Chemistry and Coal Chemistry, National Academy of Sciences of Ukraine, 70 R. Lyuksemburg ul.,
Donetsk 340114, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 2, pp. 86–90, March–April,
1998. 相似文献
62.
Popov A. F. Lobanova O. V. Savelova V. A. Sadovskii Yu. S. Solomoichenko T. N. Piskunova Zh. P. 《Russian Journal of Organic Chemistry》2002,38(11):1624-1628
For amides belonging to series RCONH2 (I), RCONHMe (II), RCONHPh (III), and RCONMe2 (IV) rate constants k1 (l mol-1 s-1) were determined (in acetonitrile at 25°C) specifying the nucleophilic reactivity of the oxygen atom in amides toward benzoyl chloride and diphenyl chlorophosphate. The lack of substrate selectivity in the reactions in question was established. For equal values of inductive constants * of the R substituents the reactivity sequence of amides with respect to both substrates is the same (I >>
IV >
II, and III >
II), and it does not follow the corresponding sequence of basicities. A conclusion was drawn that both groups of reactions proceed through cyclic transition states resembling reagents: six-membered with amides I and III, and five-membered with amides II and IV. 相似文献
63.
An influence of tensile stress on the rate of oxidative destruction of polydienes and polyolefins under the action of ozone has been found; the influence of molecular and submolecular parameters and macrochain segmental mobility on the kinetics of oxidation of polymers is discussed. It is shown that chemical processes, with sp3 to sp2 carbon atom rehybridization in the main chain, can change the reactivity of molecules under the action of structural deformations. Both acceleration and deceleration of bimolecular reactions have been found. 相似文献
64.
A. P. Popov N. S. Shelekhov O. V. Bandyuk O. B. Ratner T. M. Vember A. O. Rebezov G. I. Lashkov 《Theoretical and Experimental Chemistry》1986,22(2):219-224
Sensitized photooxidation of a series of compounds with an anthracene structure in a block poly(methyl methacrylate) (PMMA) containing a tetrapyrrole pigment (TPP) or anthraquinone dyes as spectral sensitizers, was studied. The values of changes in the molar refraction at equal to 441 and 633 nm were determined experimentally. They satisfactorily agreed with the theoretical values calculated from dispersional relationships. The initial quantum yields of the photooxidation (0ox) of the anthracene compounds were measured both in solution and in PMMA blocks. The lack of correlation between the 0ox values in the solid polymers and in the liquid solution indicates the dominating role of the polymeric matrix in determining the effectiveness of photooxidation process taking place. In the selection of the optimal polymerization conditions for the synthesis of the polymeric blocks, the values of 0ox of certain anthracene compounds can be up to 1. In the series of the anthraquinone dyes used, 1,4-dihydroxy and 2-aminoanthraquinones, whose 0ox reaches the values of 0.2–0.25 have the highest sensitizing ability.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 2, pp. 235–240, March–April, 1986. 相似文献
65.
I. V. Komarov A. V. Turov S. V. Popov Yu. L. Slominskii M. Yu. Kornilov 《Theoretical and Experimental Chemistry》1991,27(2):179-182
It was established by PMR with lanthanide shift reagents that the charge in anionic cyanine dyes with a linear chromophore is concentrated at the ends of the polymethine chain, while in compounds containing a vinylene group in the chromophore it is concentrated in the region of the five-membered ring. The results are compared with the data from13C NMR spectroscopy and relaxation measurements in the presence of Gd(fod)3. The validity of the conclusions is also considered.Kiev University. Institute of Organic Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Teoreticheskaya i Éksperimental'naya, Vol. 27, No. 2, pp. 197–201, March–April, 1991. Original article submitted December 20, 1989. 相似文献
66.
T. M. Zubareva T. M. Prokop’eva I. V. Kapitanov I. A. Belousova N. G. Razumova A. F. Popov 《Theoretical and Experimental Chemistry》2007,43(4):247-254
Neutral forms of hydroxylamine, N-methylhydroxylamine, and N,N-dimethylhydroxylamine are typical α-nucleophiles in water.
In comparison with aryl anions of similar basicity their rate of reaction in the decomposition of 4-nitrophenyl diethylphosphonate
is increased by about 102 times. Decomposition of the substrate is accelerated in cetyltrimethylammonium bromide micelles (about 4 to 30 fold). Hydroxylamine
and its N-alkyl derivatives are the most effective low basicity nucleophiles. The sole factor responsible for the micellar
effects is the concentration of the reagent in the surfactant micelles.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 4, pp. 231–236, July–August, 2007. 相似文献
67.
L. D. Popov Yu. P. Tupolova S. I. Levchenkov V. V. Lukov V. A. Kogan 《Russian Journal of Coordination Chemistry》2007,33(3):208-212
A series of novel mono-and binuclear copper(II) complexes with substituted salicylaldehyde acylhydrazones H2L of the formula CuL · xH2O (x = 0 and 1) and [Cu(HL)](ClO4)(CH3OH) were synthesized. The isolated dimeric complexes of copper acetate were found to exist as isomers with different bridging atoms. In dimers showing a superexchange between the paramagnetic centers through bridging phenoxide O atoms, the antiferromagnetic exchange couplings were much stronger than those in complexes with bridging O atoms of the a-oxyazine fragment. 相似文献
68.
Krause M Popov VN Inakuma M Tagmatarchis N Shinohara H Georgi P Dunsch L Kuzmany H 《The Journal of chemical physics》2004,120(4):1873-1880
Metal-carbon cage vibrations of crystalline endohedral D2d-M2@C84 (M=Sc,Y,Dy) dimetallofullerenes were analyzed by temperature dependent Raman scattering and a dynamical force field model. Three groups of metal-carbon cage modes were found at energies of 35-200 cm(-1) and assigned to metal-cage stretching and deformation vibrations. They exhibit a textbook example for the splitting of molecular vibrations in a crystal field. Induced dipole-dipole and quadrupole-quadrupole interactions account quantitatively for the observed mode splitting. Based on the metal-cage vibrational structure it is demonstrated that D2d-Y2@C84 dimetallofullerene retains a monoclinic crystal structure up to 550 K and undergoes a transition from a disordered to an ordered orientational state at a temperature of approximately 150 K. 相似文献
69.
Sharutin V. V. Pakusina A. P. Egorova I. V. Platonova T. P. Bukvetskii B. V. Popov D. Yu. 《Russian Journal of Coordination Chemistry》2002,28(12):827-830
Tetraphenylantimony nitrite was synthesized by reacting pentaphenylantimony with triphenylantimony dinitrite at a molar ratio of 1 : 1 in toluene, and its structure was determined using X-ray diffraction analysis. The Sb atom is coordinated to the oxygen atom of the axial nitrite group to form a trigonal bipyramid. The Sb–C(Ph)eq distances vary within the 2.103–2.111(3) Å range, and the S–O(1) and Sb–C(41) bond lengths are equal to 2.386(3) and 2.156(3) Å, respectively. The Sb...N distance and the axial C(41)SbO(1) angle are equal to 3.133(4) Å and 174.7(1)°, respectively. 相似文献
70.
I. I. Popov A. M. Simonov S. N. Kolodyazhnaya 《Chemistry of Heterocyclic Compounds》1970,6(11):1463-1465
3-(1-Methyl-2-benzimidazolyl)acrylic acid was obtained by the reaction of 1,2-dimethylbenzimidazole with chloral and subsequent hydrolysis of the condensation product. The hydrochloride of the chloride of this acid and its esters and amides were synthesized. The methyl and ethyl esters of the acid were synthesized by the Wittig reaction. The IR and UV spectra of the compounds obtained are presented.See [9] for Communication XXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1566–1568, November, 1970. 相似文献