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21.
Conclusions The thermal gross decomposition of dimethylacetamide hydroperoxide (ROOH) in dimethylacetamide (RH) as the medium proceeds in harmony with the equation: Wp=kind [ROOH]0
m/[RH]0
n, where m=1.5–2; n=2–0.5. Alkyl radicals with a chain length of 195–3 units are mainly responsible for the induced decomposition. We determined the ratio between the molecular and radical directions of the decomposition and kind in the range 80–132°.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 967–970, April, 1978. 相似文献
22.
Conclusions It was shown by a study of the kinetics of the oxidation of cumene in the presence of the hyeroperoxide and p-methoxyphenol that in the reaction of the hydroperoxide with p-methoxyphenol, radicals are formed with an efficiency equal to 0.54 (120°).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2191–2194, October, 1972. 相似文献
23.
24.
Interatomic distances in the transition state were estimated for the reactions of radical abstraction: H· + H2, H· + HCl, H· + CH4, N·H2 + NH3, HO· + H2O, HO2
· + HOOH, and C·H3 + SiH4. The calculation was performed by the quantum-chemical density functional method or coupled clusters method (QCH), as well as by the methods of intersecting parabolas (IPM) and Morse curves (IMM), using experimental data (activation energies and reaction enthalpies). The results of the latter two methods are close to the quantum-chemical calculation and differ only by the increment a: r(IPM or IMM) = a + r(QCH), where a = –4.5·10–12 m for IPM and a = +1.9·10–12 m for IMM. 相似文献
25.
V. V. Ammosov A. G. Denisov G. S. Gapienko V. A. Gapienko V. I. Klyukhin V. I. Koreshev P. V. Pitukhin V. I. Sirotenko Z. U. Usubov V. G. Zaetz A. E. Asratyan A. V. Fedotov P. A. Goritchev S. P. Krutchinin M. A. Kubantsev I. V. Makhlueva V. I. Shekelyan V. G. Shevchenko A. B. Krebs 《Zeitschrift fur Physik C Particles and Fields》1987,36(3):377-381
The cross section of the quasi-elastic reactions \(\bar v_\mu p \to \mu ^ + \Lambda (\Sigma ^0 )\) in the energy range 5–100 GeV is determined from Fermilab 15′ bubble chamber antineutrino data. TheQ 2 analysis of quasi-elastic Λ events yieldsM A=1.0±0.3 GeV/c2 for the axial mass value. With zero µΛ K 0 events observed, the 90% confidence level upper limit \(\sigma (\bar v_\mu p \to \mu ^ + \Lambda {\rm K}^0 )< 2.0 \cdot 10^{ - 40} cm^2 \) is obtained. At the same time, we found that the cross section of reaction \(\bar v_\mu p \to \mu ^ + \Lambda {\rm K}^0 + m\pi ^0 \) is equal to \(\left( {3.9\begin{array}{*{20}c} { + 1.6} \\ { - 1.3} \\ \end{array} } \right) \cdot 10^{ - 40} cm^2 \) . 相似文献
26.
Absorption spectra of the photoexcited (2-C60)Pd(PPh3)2 complex in benzene were obtained by picosecond and nanosecond laser photolysis. The spectra are compared with those observed for photoexcited states of fullerene C60 and charge-transfer states of C60 complexes with ternary amines. The relaxation kinetics of excited (2-C60)Pd(PPh3)2 complex has three components with characteristic lifetimes 1 = 43 ps, 2 = 1500 ps, and 3 = 1.17 s. The results are discussed in terms of the four-level scheme of the excited complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1163–1166, May, 1996. 相似文献
27.
E. T. Denisov 《Russian Chemical Bulletin》2004,53(8):1602-1608
The transition state of addition of free radicals and atoms to multiple bonds is considered as a result of intersecting of two parabolic potential curves. One of them characterizes the stretching vibration of the attacked multiple bond, and another curve characterizes the stretching vibration of the bond formed in the transition state. The force constant of the latter is calculated by an empirical equation that correlates the force constant with the bond dissociation energy. In the framework of this model, the thermally neutral activation energy (E
e0) and the elongation of the attacked and formed bonds (r
e) in the transition state were calculated from the experimental data (activation energy (E
e) and enthalpy of reaction (H
e)) for the addition of an H atom and methyl, alkoxyl, aminyl, triethylsilyl, and peroxyl radicals to the C=C bond and the addition of H and CH3 to the C=O and CC bonds. Analysis of the data obtained showed that E
e0 depends linearly on the |H
e| + Ee sum, i.e., Ee0/kJ mol–1 = 14.2 + 0.61 · (Ee – H
e), and the bond elongation in the transition state for addition of the most part of radicals to ethylene and acetylene vary within (0.65–0.87)·10–10 m. The factors affecting the activation energy of the radical addition reactions are discussed.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1542–August, 2004. 相似文献
28.
S. F. Bureiko N. S. Golubev G. S. Denisov S. Yu. Kucherov P. M. Tolstoi 《Russian Journal of General Chemistry》2005,75(11):1821-1829
3,5-Dimethylpyrazole and halogen-containing carboxylic acids in solution give rise to equilibrium between the free molecules and 1 : 1 and 1 : 2 H-complexes. These complexes either have a ion pair-like structure with two equivalent hydrogen bonds O??HN+ (1 : 1) or include homoconjugate anion with strong hydrogen bond C-O-H?O-C (1 : 2). At low temperatures, 2 : 1 complexes were detected. The structure and harmonic vibration frequencies of the complexes were calculated in terms of the density functional theory. 相似文献
29.
The kinetics of formation and cleavage of hydrogen bonds in complexes of carboxylic acids with proton acceptors have been studied by PMR spectroscopy over the range –100 to 150°C. The activation parameters of the processes have been measured.
1H –100° ÷–155°C . .相似文献
30.
The suitability of the contact method for drying moist finely ground product classed, according to its properties, with pastes was considered. The rheological characteristics of microcrystalline cellulose pastes were studied experimentally in relation their moisture content. The study was based on the Metzner procedure with the moist product with mechanical stirrers in a mixer. 相似文献