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111.
Peter Schwendt Michal Sivák Andrey E. Lapshin Yury I. Smolin Yury F. Shepelev Dalma Gyepesov 《Transition Metal Chemistry》1994,19(1):34-36
Summary The monoperoxo complexes, M2[VO(HEDTA)(O2)]· 4H2O, where M is K+ or NH
4
+
and H4EDTA is ethylene-diaminetetraacetic acid, were prepared and characterized by Raman and i.r. spectra in the solid state and in aqueous solution. The single crystal X-ray study revealed a pentagonal bipyramidal anion structure with a tetradentate HEDTA(3—) ligand. The decomposition of complexes in aqueous solution to blue vanadium(IV) complexes as end products proceeds via a nonperoxo complex of vanadium. 相似文献
112.
Savel'eva Z. A. Popov S. A. Glinskaya L. A. Klevtsova R. F. Ikorskii V. N. Boguslavskii E. G. Tkachev A. V. Larionov S. V. 《Russian Journal of Coordination Chemistry》2004,30(2):115-123
Methyl 3-[(3,5-dimethylpyrazole-1-carbothioyl)-amino]propionate (L1) and the optically active derivative of natural monoterpene (+)-3-carene, (3bS,4aR)-3-[(3,4,4-trimethyl-3b,4,4a,5-tetrahydro-cyclopropa[3,4]cyclopenta[1,2-c]pyrazole-1-carbothioyl)-amino]propionate (L2), are synthesized. The paramagnetic CuL1Cl2 (I) and [Cu2L2
2Cl4] (II) complexes are obtained. According to the X-ray diffraction data, in mononuclear complex I, the L1 molecule performs a bidentate-cyclic function due to the coordination of the S atom of the C=S group and the N atom of the pyrazole cycle. The CuCl2NS coordination polyhedron is a distorted tetrahedron. Two molecules of complex I form an associate due to weak Cu···S interactions. Compound II is binuclear due to the bridging function of two Cl- ions, and analogous functions of the L1 and L2 ligands. The coordination polyhedron in complex II is CuCl3NS. The eff values for compounds I and II are equal to 1.81 and 1.79 B, respectively, and are constant in the interval from 78 to 300 K, indicating that noticeable exchange interactions between unpaired electrons of the Cu2+ ions are absent. The EPR spectra of the complexes in the solid phase are examined. 相似文献
113.
Alexander I. Popov Alfred J. Smetana Jean-Pierre Kintzinger Thi Thanh-Tam Nguyêen 《Helvetica chimica acta》1980,63(3):668-673
Complexation between crown ethers 12C4, 15C5, 18C6 and cryptand 222, and alkali cations Li+, Na+, K+ in various solvents were studied by 17O-NMR. spectroscopy. Small diamagnetic shifts arising from the cation electric field are observed. They increase according to the sequence K+ < Na+ < Li+. 17O-linewidth are discussed and compared to the 13C relaxation times. Linewidth modification results mainly from modifications of the effective correlation time. In general, for crown ethers, considerable line broadening occurs when the cation fits well into the cavity but line narrowing occurs when the cation is much smaller than the cavity. 相似文献
114.
A. Yermakova E. M. Sulman O. S. Popov O. B. Sannikov A. I. Gontar A. B. Dolzhenko 《Reaction Kinetics and Catalysis Letters》1985,29(2):409-415
A method for the calculation of fixed catalyst bed reactors by using a diffusion kinetic model is suggested. Correlation between calculated curves for the time distribution of the reaction mixture composition and experimental data is given.
=qo . .相似文献
115.
Konstantin Popov Alexei Popov Hannu Rönkkömäki Andrey Vendilo Lauri H. J. Lajunen 《Journal of solution chemistry》2002,31(6):511-520
A sequential NMR based approach is proposed for measurements of high log K values at low ionic strength. [31P] NMR technique is used to determine the protonation constants of 1,2-diaminoethane-N,N,N,N-tetra(methylenephosphonic acid) (EDTPH, H8L) at 25°C in 0.1 mol-dm–3 KNO3 and at 37°C in 0.15 mol-dm–3 NaCl at pH 11–14. For equilibrium L + H HL log K are found to be 13.3 (0.1) and 12.9 (0.1), respectively. 相似文献
116.
Ott T Kern A Schuffenhauer A Popov M Acklin P Jacoby E Stoop R 《Journal of chemical information and computer sciences》2004,44(4):1358-1364
For the clustering of chemical structures that are described by the Similog, ISIS count, and ISIS binary fingerprints, we propose a sequential superparamagnetic clustering approach. To appropriately handle nonbinary feature keys, we introduce an extension of the binary Tanimoto similarity measure. In our applications, data sets composed of structures from seven chemically distinct compound classes are evaluated and correctly clustered. The comparison, with results from leading methods, indicates the superiority of our sequential superparamagnetic clustering approach. 相似文献
117.
I. I. Polzunov Altai State Technical University. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 4, pp. 737–739, July–August, 1995. 相似文献
118.
Sharutin V. V. Sharutina O. K. Platonova T. P. Pakusina A. P. Gerasimenko A. V. Gerasimenko E. A. Bukvetskii B. V. Popov D. Yu. 《Russian Journal of Coordination Chemistry》2003,29(1):11-15
Tetraphenylantimony N,N-dimethyldithiocarbamate (I) and tetra-p-tolylantimony N,N-dimethyldithiocarbamate (II) were synthesized via the reaction of tetraarylantimony chloride Ar4SbCl (Ar = C6H5 or C6H4Me-4) with sodium N,N-dimethyldithiocarbamate in water. According to the X-ray diffraction data, the tetraarylantimony N,N-dimethyldithiocarbamate molecules have a distorted octahedral configuration. The Sb–S bond lengths are equal to 2.7158(5) Å, 2.7440(5) Å and 2.761(2) Å, 2.8002(2) Å for I and II, respectively. 相似文献
119.
The reduction of Pt(IV) complexes followed by the oxidative addition of dimethyl sulfate to Pt(II) affords Cs2PtMe2Cl4, a complex of dimethylplatinum(IV). On treatment with such nucleophiles as Cl–, Br–, I–, and PtCl4
2– in aqueous solutions at 368 K this complex undergoes reductive elimination to give MeX and PtIIMe as a transient species. The latter is further converted to methane upon protolysis, whereas in the presence of an oxidant (Na2PtCl6) it gives rise to the PtIVMe species. The kinetics of decomposition of Cs2PtMe2Cl4 in aqueous HCl-KCl systems (2M or 3M in Cl–; [PtIVMe2][Cl–]) were studied. The reaction takes place as anS
N
2 attack of X– on the carbon atom of a methyl group located with thetrans position with respect to the aqua-ligand of the [PtMe2Cl3(H2O)]– complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 389–395, February, 1993. 相似文献
120.
Eremets MI Popov MY Trojan IA Denisov VN Boehler R Hemley RJ 《The Journal of chemical physics》2004,120(22):10618-10623
The high-pressure behavior of nitrogen in NaN(3) was studied to 160 GPa at 120-3300 K using Raman spectroscopy, electrical conductivity, laser heating, and shear deformation methods. Nitrogen in sodium azide is in a molecularlike form; azide ions N(3-) are straight chains of three atoms linked with covalent bonds and weakly interact with each other. By application of high pressures we strongly increased interaction between ions. We found that at pressures above 19 GPa a new phase appeared, indicating a strong coupling between the azide ions. Another transformation occurs at about 50 GPa, accompanied by the appearance of new Raman peaks and a darkening of the sample. With increasing pressure, the sample becomes completely opaque above 120 GPa, and the azide molecular vibron disappears, evidencing completion of the transformation to a nonmolecular nitrogen state with amorphouslike structure which crystallizes after laser heating up to 3300 K. Laser heating and the application of shear stress accelerates the transformation and causes the transformations to occur at lower pressures. These changes can be interpreted in terms of a transformation of the azide ions to larger nitrogen clusters and then polymeric nitrogen net. The polymeric forms can be preserved on decompression in the diamond anvil cell but transform back to the starting azide and other new phases under ambient conditions. 相似文献