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991.
992.
1,3-Bis[(triethoxysilyl)methyl]tetrahydropyrimidin-2-one and 1,3-bis[(dimethoxysilyl)methyl]tetrahydro-pyrimidin-2-one have
been synthesized on interacting urea with N,N′-bis(silylmethyl)propylenamines (EtO)3−nMenSiCH2NH(CH2)3NHCH2SiMen(OEt)3−n (n = 0, 2). Their interaction with boron trichloride has been studied. The structures of all the compounds synthesized have
been demonstrated by multinuclear NMR spectroscopy.
Dedicated to the 50th Anniversary of the Latvian Institute of Organic Synthesis
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 238–244, February, 2007. 相似文献
993.
994.
G. Fritz St. Lauble R. Befurt K. P. Peters E.-M. Peters F. H. G. von Schnering 《无机化学与普通化学杂志》1993,619(9):1494-1511
Formation of Organosilicon Compounds. 110. Reactions of (Cl3Si)2CCl2 and its Si-methylated Derivatives as well as of (Cl3Si)2CHCl, (Cl3Si)2C(Cl)Me and Me2CCl2 with Silicon (Cu cat.) The reactions of (Cl3Si)2CCl2 1 , its Si-methylated derivatives (Me3Si)2CCl2 8 , Me3Si? CCl2? SiMe2Cl 9 , (ClMe2Si)2CCl2 10 , Me3Si? CCl2? SiMeCl2 11 , Cl2MeSi? CCl2? SiCl3 12 as well as of (Cl3Si)2CHCl 38 , (Cl3Si)2CClMe 39 and of Me2CCl2 with Si (Cu cat.) in a fluid bed reactor ( 38 and 39 also in a stirred solid bedreactor) arc presented. While (Cl3Si)2CCl2 1 yields C(SiCl3)4 2 the 1,1,3,3-tetrachloro-2,2,4,4-tetrakis(trichlorsilyl)-1,3-disilacyclobutane Si6C2Cl16 3 and the related C-spiro linked disilacyclobutanes Si8C3Cl20 4 , Si10C4Cl24 5 , Si12C5Cl28 6 , Si14C6Cl32 7 this type of compounds is not obtained starting from the Si-methylated derivatives 8, 9, 10, 11 They Produce a number of variously Si-chlorinated and -methylated tetrasila- and trisilamethanes. However, Cl2MeSi? CCl2? SiCl3 12 forms besides of Si-chlorinated trisilamethanes also the disilacyclobutanes Si6C2Cl15Me 34 and cis- and trans Si6C2Cl14Me2 35 as well as the spiro-linked disilacyclobutanes Si8C3Cl19Me 36 , Si8C3Cl18Me2 37 . (Cl3Si)2CHCl 38 mainly yields HC(SiCl3)3 31 and also the disilacyclobutanes cis- and trans-(Cl3Si)HC(SiCl2)2CH(SiCl3) 41 and (Cl3Si)2C(SiCl2)2CH(SiCl3) 45 the 1,3,5-trisilacyclohexane [Cl3Si(H)C? SiCl2]3 44 as well as [(Cl3Si)2CH]2SiCl2, and (Cl3Si)2CClMe 39 mainly yields (Cl3Si)2C?CH2and (Cl3Si)2besides of HC(SiCl3)3, MeC(SiCl3)3and (Cl3Si)3C? SiCl2Me.,. Me2CCl2 59 mainly yields Me(Cl)C?CH2, Me2CHCl and HCl2Si? CMe2? SiCl3, besides of Me2C(SiCl3)2 and Me2C(SiCl2H)2 Compound 3 crystallizes triclinically in the space group P1 (Nr. 2) mit a = 900,3, b = 914,0, c = 855,3 pm, α = 116,45°, β = 101,44°, γ = 95,86° and one molecule per unit cell. Compound 4 crystallizes monoclinically in thc space group C2/c (no. 15) with a = 3158.3,b = I 103.7, c = 2037.4 pm, β = 1 16.62° and 8 molecules pcr unit cell. The disilacyclobutane ring of compound 3 is plane, showing a mean distance of d (Si-C) =19 1.8 pm and the usual deformations of endocyclic angles: αSi = 94,2°> 85,8° = αC.The spiro-linked disilacyclobutane rings of compound 4 are slightly folded by a mean angle of (19.0°). Their mean distances were found to be d (Si? C) = 190.4 pm relating to the central carbon atom and 192.0 pm to the outer ones, respectively. The deformations of endocyclic angles: αSi = 93,9°> 84,4° = αC are comparable to those of compound 3. 相似文献
995.
Ignatov S. K. Sennikov P. G. Chuprov L. A. Razuvaev A. G. 《Russian Chemical Bulletin》2003,52(4):837-845
The energies and thermodynamic parameters of elementary steps in the proposed mechanism of silicon tetrafluoride hydrolysis in the gas phase were calculated by the ab initio quantum-chemical method (MP4//MP2/6-311G(2d,2p)) and the density functional theory (B3LYP/6-311G(2d,2p)). The proposed mechanism of gas-phase hydrolysis involves the formation of mono- and dihydroxy derivatives, hexafluorodisiloxane (SiF3OSiF3), and linear and cyclic siloxane polymers with the chain length from three to six Si—O and difluorosilanone units. According to the calculations, all reactions considered are endothermic and are characterized by positive Gibbs free energies. The initial hydrolysis steps can be presented with a high accuracy by two parallel processes: formation of trifluorohydroxysilane (SiF3OH) and SiF3OSiF3. These are the most thermodynamically favorable among all reaction channels. The transition states of these elementary steps were found and their kinetic parameters were estimated (G
= 132 and 147 kJ mol–1, respectively). The calculation results were verified using FTIR spectroscopy of a mixture of gas-phase SiF4 and water vapor. The comparison of the theoretical (absolute) intensities of bands in the IR spectra and integral absorption coefficients in the experimental IR spectrum made it possible to calculate the equilibrium concentrations of the reactants and equilibrium constants of elementary steps of formation of SiF3OH and SiF3OSiF3, which agree with the theoretical values. The role of different derivatives in deep hydrolysis and possibilities of experimental detection of particular intermediates in the gas phase were discussed. 相似文献
996.
半导体材料硅,在第三周期IVA族,核外有4个电子,具有较稳定的结构。简述了硅的发展应用史;从化学角度,对单质硅材料、二氧化硅材料、有机硅材料等几个典型材料的元素结构、制备工艺、反应机理和应用机理等方面进行详细分析;总结展望了硅元素未来的发展。 相似文献
997.
Summary Double even tempering (DET) of orbital exponents is proposed as a useful generalization of even tempering (ET). The DET scheme uses two sets of basis functions for each angular momentum. The two sets have different principal quantum numbers and their exponents are generated by two different geometric sequences. Roothaan-Hartree-Fock (RHF) calculations on the atoms from He through Xe using both ET and DET Slater-type basis sets of the same size are carried out to demonstrate the substantial improvement offered by the DET scheme. The DET scheme reduces the maximum deviation of the RHF energies relative to the Hartree-Fock limit from 1.4 to 0.3 millihartrees. 相似文献
998.
半导体硅上激光诱导选择性电镀铜 总被引:4,自引:1,他引:4
在p型硅上利用氩离子激光进行了选择性电镀铜的研究,考察了半导体表面处理条件、阴极偏压和激光强度对阴极光电流及空间选择性的影响.表面氧化膜和阳极钝化膜的存在使光电流降低近一个数量级,少量氧化膜可使选择性提高.外加阴极偏压和激光强度的增加导致光电流增大,选择性降低.将氢氟酸处理的硅片在电解液中放置10~20min,于稳定电位附近,用较弱激光照射可获得选择性铜镀层 相似文献
999.
Kharlamov A. I. Kirillova N. V. Karachevtseva L. A. Kharlamova A. A. 《Theoretical and Experimental Chemistry》2003,39(6):374-379
A new model is proposed for reactions between solids assuming formation of product in the gas phase (pores) due to the reaction of vaporizing reagents. Experimental results are given for the first time, which convincingly show that the reaction between solid-phase silicon and carbon below 1050 °C to give thread-like silicon carbide occurs due to rapidly vaporizing silicon and carbon atoms. 相似文献
1000.
I. V. Shmygol’ S. V. Snegir V. A. Pokrovskii 《Theoretical and Experimental Chemistry》2007,43(4):272-277
A comparative analysis of the laser desorption/ionization of vitamin B12 by matrix-assisted laser desorption/ionization (MALDI) and desorption/ionization on porous silicon (DIOS) was carried out.
The mass spectra obtained were interpreted and the pathways for ion formation and decomposition were established. The MALDI
fragmentation of the positive vitamin B12 ions is more extensive than the DIOS fragmentation. The most extensive fragmentation was found using the MALDI method for
negative vitamin B12 ions, which are lacking when using the DIOS method.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 4, pp. 251–256, July–August, 2007. 相似文献