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491.
Romanenko KV Py X d'Espinose de Lacaillerie JB Lapina OB Fraissard J 《The journal of physical chemistry. B》2006,110(7):3055-3060
(129)Xe NMR has been used to study a series of homologous activated carbons obtained from a KOH-activated pitch-based carbon molecular sieve modified by air oxidation/pyrolysis cycles. A clear correlation between the pore size of microporous carbons and the (129)Xe NMR of adsorbed xenon is proposed for the first time. The virial coefficient delta(Xe)(-)(Xe) arising from binary xenon collisions varied linearly with the micropore size and appeared to be a better probe of the microporosity than the chemical shift extrapolated to zero pressure. This correlation was explained by the fact that the xenon collision frequency increases with increasing micropore size. The chemical shift has been shown to vary very little with temperature (less than 9 ppm) for xenon trapped inside narrow and wide micropores. This is indicative of a smooth xenon-surface interaction potential. 相似文献
492.
There have been synthesized Pt(II) stereoisomeric complexes with hydroxy-α-amino acid serine (SerH = NH2CH(CH2OH)COOH is α-amino-β-hydroxypropionic acid): trans-[Pt(S-SerH)2Cl2], trans-[Pt(R-SerH)(S-SerH)Cl2] with monodentately (through NH2 group ) bound SerH and cis-, trans-[Pt(R-Ser)(S-Ser)], trans-[Pt(S-Ser)2] with bidentately bound (through groups NH2 and COO) ligands (R, S is the absolute configuration of asymmetric carbon atom). The successive phases in the synthesis of Pt(II) stereoisomeric complexes with serine were studied by 195Pt NMR spectroscopy. To identificate the compounds synthesized the method of elemental analysis, IR and NMR (195Pt, 13C, 1H) spectroscopy were used. For trans-[Pt(R-Ser)(S-Ser)] the X-ray diffraction data were obtained. 相似文献
493.
I. N. Voropaev P. A. Simonov A. V. Romanenko 《Russian Journal of Inorganic Chemistry》2009,54(10):1531-1536
Platinum catalysts with the active component content of 5–40 wt % on various carbon supports have been synthesized by the
reductive hydrolysis of platinum chloro complexes. The degree of dispersion of the supported platinum decreases with an increasing
weight percentage of the metal in the catalyst. The following mechanism of Pt/C catalyst formation is deduced from experimental
data: H2PtCl6 adsorption on the support surface generates platinum nuclei, which then grow owing to the deposition of platinum ions under
the action of an alkali and a reductant. 相似文献
494.
The new compound Ni(8)Bi(8)SI(2) has been synthesized and its crystal structure determined by X-ray crystallography. The structure contains one-dimensional (1D) cations (1)( infinity )[Ni(8)Bi(8)S](2+) separated by iodine anions. The geometry of the columns is similar to that of the recently reported (1)( infinity )[Ni(8)Bi(8)S](+), and the main difference between them is only their formal charge. Electronic structure calculations and physical properties measurements were performed to analyze the influence of the number of valence electrons on the bonding and properties of compounds containing these 1D cations. It was shown that the removal of one electron (i.e., (1)( infinity )[Ni(8)Bi(8)S](+) --> (1)( infinity )[Ni(8)Bi(8)S](2+)) mainly affects the Ni-S bonding within the cation and essentially has no influence on the intermetallic Ni-Bi bonding. It was found that Ni(8)Bi(8)SI(2) containing double-charged columns has conductivity properties more similar to a pure 1D metal than the congener Ni(8)Bi(8)SI containing mono-charged columns. 相似文献
495.
Evgeny V. Tretyakov Svyatoslav E. TolstikovGalina V. Romanenko Artem S. BogomyakovDmitry V. Stass Marsil K. KadirovKirill V. Holin Oleg G. SinyashinVictor I. Ovcharenko 《Polyhedron》2011,30(18):3232-3237
An approach to the synthesis of nitronyl nitroxide 2,2′-(buta-1,3-diyne-1,4-diyl)bis(4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide 1-oxyl) (4) was developed. Compound 4 is the first diradical with nitronyl nitroxide groups directly linked through a diacetylene fragment. In solid phase the diradicals are arranged in stacks with parallel CC fragments, with the distances between the terminal carbon atoms of the neighboring diacetylene groups (T and d) being 6.170 and 4.466 Å, respectively, and the angle between the translation vector and the median line passing through the CCCC fragment of 45.9°. The values of T and d are outside the range of structural criteria allowing a topochemical reaction. Thus UV irradiation does not initiate solid phase polymerization of 4. After exposure at 373 K for 1 h the crystals of 4 turn dark-brown, become X-ray amorphous and lose the majority of their paramagnetic centers without significantly changing their mass. Upon further heating up to 400-420 K the product explodes, releasing about 360 kJ/mol of heat. A diluted solution of 4 in 1,4-dioxane produces an EPR spectrum typical of a strong exchange (a multiplet of nine broadened lines with A4N = 0.35 mT), indicating the efficiency of the CCCC fragment as an exchange channel. The character of the experimental μeff(T) dependence for 4 indicates a strong intramolecular antiferromagnetic-type exchange interaction (J/kB ∼ −104 K) and the dominating weak intermolecular ferromagnetic exchange. 相似文献
496.
We present analytical results and numerical simulations for the force exerted on moving atoms in the fields of two counterpropagating waves whose amplitudes or phases are described as stochastic processes. We assume that one field repeats the other with some delay, as would occur when the two fields derive from a common source through a beam splitter and mirrors. We show that, just as with the force exerted by the field of two counterpropagating sequences of π-pulses, or two counterpropagating bichromatic or frequency-modulated waves, the force on an atom in counterpropagating stochastic waves may considerably exceed the force exerted by the field of a single running wave. For comparison we also discuss the interaction of an atom with two counterpropagating waves when one of them is monochromatic and the other one has a stochastic phase. In this case the force substantially exceeds the force exerted by the field of a single running wave but appreciably smaller then the radiative force in the counterpropagating waves in which one field repeats the other with some delay. 相似文献
497.
L. N. Arzamaskova A. V. Romanenko Yu. I. Yermakov 《Reaction Kinetics and Catalysis Letters》1980,13(4):395-400
The kinetics of propane and isobutane oxidation by aqueous solutions of chromic acid in the presence of Ir(IV) chloride complexes has been studied. Reaction rate decreases with increasing Cl ion concentration and decreasing acidity. Ir(H2O)Cl
5
–
complexes are by an order of magnitude more active than IrCl
6
2–
.
Ir(IV). Cl- . Ir(H2O)Cl 5 – , IrCl 6 2– .相似文献
498.
499.
Dr. Svyatoslav E. Tolstikov Prof. Evgeny V. Tretyakov Dmitry E. Gorbunov Irina F. Zhurko Prof. Matvey V. Fedin Prof. Galina V. Romanenko Dr. Artem S. Bogomyakov Prof. Nina P. Gritsan Dr. Dmitry G. Mazhukin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14598-14604
It was shown that dipole‐stabilized paramagnetic carbanion lithiated 4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazol‐1‐oxyl 3‐oxide can be attached in a nucleophilic manner to either isolated or conjugated aldonitrones of the 2,5‐dihydroimidazole 3‐oxide and 2H‐imidazole 1‐oxide series to afford adducts the subsequent oxidation of which leads to polyfunctional mono‐ and diradicals. According to XRD, at least two polymorphic modifications can be formed during crystallization of the resulting paramagnetic compounds, and for each of them, geometric parameters of the molecules are similar. An EPR spectrum of the diradical in frozen toluene has a complicated lineshape, which can be fairly well reproduced by using X‐ray diffraction structural analysis and the following set of parameters: D=14.9 mT, E=1.7 mT; tensor a(14N)=[0.260 0.260 1.625] mT, two equivalent tensors for the nitronyl nitroxide moiety a(14N)=[0.198 0.198 0.700] mT, and g≈2.007. According to our DFT and ab initio calculations, the intramolecular exchange in the diradical is very weak and most likely ferromagnetic. 相似文献