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71.
Vladimir A. Alfonsov Charles E. McKenna Evgenia V. Bayandina Boris Kashemirov Liliya N. Yarmieva Olga N. Kataeva 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2647-2648
A new and efficient route for the synthesis of cyclic aminophosphonic acids by the reaction of dialkylchlorophosphites with β-aldiminoalcohols has been described. 相似文献
72.
Liliya Frolova Reinchard Schmutzzer 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Reactions of triphenyltrithiophosphite (PhS)3P with copper (I) and copper (II) halides (CuHal, CuHal2, where Hal=Cl, Br) have been investigated. 相似文献
73.
Vladimir Mironov Gulnara Ivkova Liliya Abdrakhmanova Liliya Burnaeva Kristina Kuzmina 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):162-163
Abstract 2-(5-Methyl-2-phenyl-2Н-1,2,3-diazaphosphol-4-yl)-4H-benzo[d]-1,3,2-dioxaphosphorin-4-one 1 readily reacts with hexafluoroacetone, mesoxalic acid diethyl ester, trifluoropyruvic acid ethyl ester and chloral to give 2-(5-methyl-2-phenyl-2H-1,2,3-dizaphosphole-4-yl)-derivatives of 1,3,2- and 1,4,2-dioxaphosphepines. 相似文献
74.
Vladimir F. Mironov Aidar T. Gubaidullin Gulnara A. Ivkova Igor A. Litvinov Boris I. Buzykin Liliya M. Burnaeva 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract [3+2]-Cycloaddition of N,N-dimethylhydrazone benzaldehyde (I) to 2-RFO-4-oxo-5,6-benzo-l,3,2-dioxaphosphorinanes (II) yields the new heterocycle - 2-RFO-4-Me2N-2,5-dioxo-3-phenyl-6,7-benzo- 1,4,2-dioxaphosphepine (III) [RF = C6F5, CH(CF3)2) with high stereoselectivity (above 94%). The reaction is likely to involve the initial interaction of nitrogen as a nucleophile with wbonyl carbon as an electrophile. The hydrolysis of (III) leads to phosphonic acid (IV) (ORF = OH). 相似文献
75.
Teschner T Yatsunyk L Schünemann V Paulsen H Winkler H Hu C Scheidt WR Walker FA Trautwein AX 《Journal of the American Chemical Society》2006,128(4):1379-1389
Crystalline samples of four low-spin Fe(III) octaalkyltetraphenylporphyrinate and two low-spin Fe(III) tetramesitylporphyrinate complexes, all of which are models of the bis-histidine-coordinated cytochromes of mitochondrial complexes II, III, and IV and chloroplast complex b(6)f, and whose molecular structures and EPR spectra have been reported previously, have been investigated in detail by M?ssbauer spectroscopy. The six complexes and the dihedral angles between axial ligand planes of each are [(TMP)Fe(1-MeIm)(2)]ClO(4) (0 degree), paral-[(OMTPP)Fe(1-MeIm)(2)]Cl (19.5 degrees), paral-[(TMP)Fe(5-MeHIm)(2)]ClO(4) (26 degrees, 30 degrees for two molecules in the unit cell whose EPR spectra overlap), [(OETPP)Fe(4-Me(2)NPy)(2)]Cl (70 degrees), perp-[(OETPP)Fe(1-MeIm)(2)]Cl (73 degrees), and perp-[(OMTPP)Fe(1-MeIm)(2)]Cl (90 degrees). Of these, the first three have been shown to exhibit normal rhombic EPR spectra, each with three clearly resolved g-values, while the last three have been shown to exhibit "large g(max)" EPR spectra at 4.2 K. It is found that the hyperfine coupling constants of the complexes are consistent with those reported previously for low-spin ferriheme systems, with the largest-magnitude hyperfine coupling constant, A(zz), being considerably smaller for the "parallel" complexes (400-540 kG) than for the strictly perpendicular complex (902 kG), A(xx) being negative for all six complexes, and A(zz) and A(xx) being of similar magnitude for the "parallel" complexes (for example, for [(TMP)Fe(1-MeIm)(2)]Cl, A(zz) = 400 kG, A(xx) = -400 kG). In all cases, A(yy) is small but difficult to estimate with accuracy. With results for six structurally characterized model systems, we find for the first time qualitative correlations of g(zz), A(zz), and DeltaE(Q) with axial ligand plane dihedral angle Deltavarphi. 相似文献
76.
Cross-correlated relaxation (CCR) in multiple-quantum coherences differs from other relaxation phenomena in its theoretical ability to be mediated across an infinite distance. The two interfering relaxation mechanisms may be dipolar interactions, chemical shift anisotropies, chemical shift modulations or quadrupolar interactions. These properties make multiple-quantum CCR an attractive probe for structure and dynamics of biomacromolecules not accessible from other measurements. Here, we review the use of multiple-quantum CCR measurements in dynamics studies of proteins. We compile a list of all experiments proposed for CCR rate measurements, provide an overview of the theory with a focus on protein dynamics, and present applications to various protein systems. 相似文献
77.
The first full assignment of (1)H NMR chemical shifts for iron corroles and the first synthesis of a series of (halogeno)iron corroles reveal very large effects of the axial ligands on the corresponding spectra, which apparently reflect differences in the relative importance of metal-to-corrole and corrole-to-metal pi-donation. These findings pave the way for a thorough analysis of the electronic structures of such complexes. 相似文献
78.
Simkhovich L Iyer P Goldberg I Gross Z 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(11):2595-2601
In the present work we report on the detailed structural features of the chiral N21- and N22-substituted benzyl and picolyl derivatives of tris(pentafluorophenyl)corrole [H3(tpfc)]. The main difference between the isomers is that substitution on N22 creates a much more crowded environment, reflected in higher deformation of the corrole ring from planarity and of the meso-aryls from perpendicular orientation. The effects of metal-ion chelation on corrole geometry are demonstrated by structural investigations of the zinc(II) and rhodium(I) complexes of the N21- and N22-alkylated corroles. The major finding is the intramolecular coordination of the pyridine moiety of the picolyl substituent in the case of [ZnII(N21-picolyl-tpfc)]. This pyridine is readily attracted to the zinc ion as an axial ligand, thus replacing the external pyridine molecule of the precursor [ZnII(N21-benzyl-tpfc)(py)]. The change is associated with a considerable flattening of the corrole ring in order to allow a more convenient coordination of the zinc ion to all four pyrrole nitrogen atoms (at Zn-N(pyr-role) distances of 1.956-1.987 A for the nonsubstituted sites, and 2.224-2.247 A for the substituted sites). These structural investigations also aid a good understanding of the spectroscopic characteristics of the derivatives. 相似文献
79.
The hydrodynamic stability of Poiseuille flow of a viscoplastic fluid is investigated. The flow is shown to be stable for infinitesimal disturbances.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 152–154, November–December, 1974.In conclusion the authors thank S. A. Regirer for critical remarks. 相似文献