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51.
A 285-pomt multi-reference configuration-interaction involving single and double excitations ( MRS DCI) potential energy surface for the electronic ground state of L12H is determined by using 6-311G (2df,2pd)basis set.A Simons-Parr-Finlan polynomial expansion is used to fit the discrete surface with a x2 of 4.64×106 The equn librium geometry occurs at Rc=0.172 nm and,LiHL1=94.10°.The dissociation energy for reaction I2H(2A)→L12(1∑g)+H(2S) is 243.910 kJ/mol,and that for reaction L12H(2A')→HL1(1∑) + L1(2S) is 106.445 kl/mol The inversion barrier height is 50.388 kj/mol.The vibrational energy levels are calculated using the discrete variable representation (DVR) method. 相似文献
52.
T. Vlase Gabriela Vlase A. Chiriac N. Doca 《Journal of Thermal Analysis and Calorimetry》2005,80(1):87-90
Summary In order to obtain catalysts, the thermal decomposition of the precursors is a compulsory step. However, kinetic analysis of the decomposition data obtained under non-isothermal conditions lead very seldom to the intimate reaction mechanism. There is also a lack of information because in non-isothermal kinetics, the compensation effect, is rather a rule and unfortunately a source of debate. In order to discriminate between these processes, and the influence of conversion, respectively temperature on the reaction rate, the NPK (non-parametric kinetic - Sempere and Nomen) method was used. This method is based on the singular value decomposition algorithm (SVD) applied on the matrix of reaction rate at corresponding conversion and temperature. This method allows a less speculative determination of the conversion functions and of the kinetic parameters. 相似文献
53.
54.
Sergey Y. Savinov Hwaung Lee Hyung Keun Song Byung-Ki Na 《Plasma Chemistry and Plasma Processing》2003,23(1):159-173
An experimental study of plasmachemical reaction involving CH4 and N2 molecules in rf discharge was studied in order to know the effect of vibrational excitation of N2 molecules. When the relative nitrogen concentration was greater than 0.8, the main product of CH4 decomposition was HCN, and the rate of methane decomposition at this condition was faster than that one in pure methane. These results could be confirmed through the mass spectroscopic method. The reason for these results is the vibrational energy of N2 excited by rf discharge. The chain reaction mechanisms of producing HCN by vibrational excitation of N2 were examined closely through numerical simulation. The rate-controlling step was the dissociation reaction of excited nitrogen molecule to the atomic nitrogen, so the process of HCN synthesis was limited by the value of reaction constant, kN. 相似文献
55.
L. A. Leites A. V. Zabula S. S. Bukalov P. S. Koroteev O. S. Maslennikova M. P. Egorov O. M. Nefedov 《Russian Chemical Bulletin》2005,54(5):1117-1120
The vibrational spectra of tetravalent metal halides (M = Si, Ge, Sn) and the corresponding dihalocarbene analogs MIIHal2, obtained by the authors, and the relevant published data are compared. The spectra of the MIIHal2 species exhibit inversion of the M-Hal stretching frequencies (νs(MIIHal) > ν as(MIIHal)). This can be used for analytical purposes and allows one to distinguish between the spectra of the MIV and MII halides. The IR and Raman spectra of the complexes of dihalogermylenes and -stannylenes with triphenylphosphine and 1,4-dioxane
also exhibit inversion of the ν(MHal) stretching frequencies. This confirms the conclusion drawn earlier based on the analysis
of the geometric parameters and reactivities of the complexes in question that the divalent state of the M atom in these species
is retained.
Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1089–1092, May, 2005. 相似文献
56.
Abdul -Latif K. Al-Jiburi Kisma H. Al-Niami Muthana Shanshal 《Theoretical chemistry accounts》1979,53(4):327-335
The harmonic force constants, vibrational frequencies and integrated intensity ratios of CH2, H2O, CH2O, C2H2, CO2, HCN, CH3, CH4, and C2H4 have been calculated using the MINDO—FORCES program and the Pulay method for the calculation of the molecular force constants. The results obtained are in general quite satisfactory when compared with available literature values. The results are, however, not as satisfactory in case of molecules containing heteroatoms, due to the neglect of some dipolar repulsion integrals for the heteroatoms by the MINDO/3 method. Calculated integrated intensities for CH3 and C2H4 agree well with experimental results. The calculated integrated intensities for other molecules are obtained for the first time and no comparison with published data is therefore possible.Part of the M.Sc. Thesis of K. H. A. 1978. 相似文献
57.
A High-Order Finite Difference Scheme for 3D Unsteady Convection Diffusion Reaction Equations北大核心CSCD
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针对三维非稳态对流扩散反应方程,构造了一种高精度紧致有限差分格式,对空间的离散采用四阶紧致差分方法,对时间的离散采用Taylor级数展开和余项修正技术,所提格式在时间上的精度为二阶、在空间上的精度为四阶。利用Fourier稳定性分析法证明了该格式是无条件稳定的。最后给出数值算例验证了理论结果。 相似文献
58.
Franck-Condon factor distributions for bound-to-continuum transitions of one-dimensional vibrational states are calculated
by a) using numerical integration, b) employing a finite number of square integrable harmonic oscillator functions. The methods
are generally applicable to any kind of bound or repulsive potential involved. Results are presented and compared to model
potential calculations previously reported by Krüger [1]. 相似文献
59.
Haiges R Vij A Boatz JA Schneider S Schroer T Gerken M Christe KO 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(2):508-517
The highly explosive molecules As(N(3))(3) and Sb(N(3))(3) were obtained in pure form by the reactions of the corresponding fluorides with (CH(3))(3)SiN(3) in SO(2) and purification by sublimation. The crystal structures and (14)N NMR, infrared, and Raman spectra were determined, and the results compared to ab initio second-order perturbation theory calculations. Whereas Sb(N(3))(3) possesses a propeller-shaped, pyramidal structure with perfect C(3) symmetry, the As(N(3))(3) molecule is significantly distorted from C(3) symmetry due to crystal packing effects. 相似文献
60.
The convection in atmosphere discussed in ref. [1] is rigorously treated by considering the variation of environmental temperature
with the height. This represents an example of applications of the elementary catastrophe theory in Hamiltonian systems. 相似文献