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711.
Rajiv Kumar S. P. Tripathi G. K. Chaturvedi 《Monatshefte für Chemie / Chemical Monthly》1984,115(3):283-288
Mixed-ligand ternary complexes of La(III), Pr(III), Nd(III), Gd(III), and Dy(III) with iminodiacetic acid (IMDA) and citraconic (CCA) or maleic acid (MIA), have been studiedpH-metrically. Their formation takes place through the stepwise addition of the secondary ligand (IMDA) to the initially formed 1:1, Ln(III)—CCA/MIA binary species. The resulting ternary complexes undergo hydrolysis to form their hydroxo derivatives simultaneously. The stability constants of the hydroxo species are calculated for constant temperature (27 ± 1°C) and ionic strength (I=0.1M KNO3). The relative order of stability is: La(III)
Gleichgewichtsuntersuchungen an einigen Heteroliganden-Hydroxo-Komplexen von Lanthanid-Ionen mit Iminodiessigsäure und Citracon- oder Maleinsäure
Zusammenfassung Es wurden ternäre Komplexe von La(III), Pr(III), Nd(III), Gd(III) und Dy(III) mit gemischten Liganden [Iminodiessigsäure (IMDA) und Citraconsäure (CCA) oder Maleinsäure (MIA)] mittelspH-metrischer Methoden untersucht. Diese Komplexe werden über die stufenweise Addition des Sekundärliganden (IMDA) zu den primär gebildeten 1:1 Ln(III)—CCA/MIA Spezies gebildet. Zugleich erleiden die resultierenden ternären Komplexe Hydrolyse und gehen in die entsprechenden Hydroxo-Komplexe über. Die Stabilitätskonstanten der Hydroxo-Komplexe wurden für konstante Temperatur (27 ± 1°C) und Ionenstärke (I=0.1M KNO3) berechnet. Die relative Reihung bezüglich der Stabilitäten ergab sich folgendermaßen: La(III)相似文献
712.
The reactions of oxybis(diacetoxyborane) with the aldimines, N-(2-hydroxyethyl) salicylaldimine N-(2-hydroxy-1-propyl) salicylaldimine, N-(3-hydroxy-1-propyl) salicylaldimine, N-(o-hydroxyphenyl) salicylaldimine. N-(m-hydroxyphenyl) salicylaldimine, N(2-hydroxyethyl)-2-hydroxy-1-naphthaldimine and N(2-hydroxy-1-propyl) 2-hydroxy-1-naphthaldimine have been carried out in 1: 1 and 1: 2 molar ratios. All the compounds except those derived from N-(3-hydroxy-1-propyl) salicylaldimine have been found to be sparingly soluble in benzene and nonelectrolytes in anhydrous DMF. The newly synthesized derivatives have been characterized by elemental analysis, molecular weight determinations and infrared, proton magnetic resonance, ultraviolet, visible and 11B nuclear magnetic resonance spectral studies. 相似文献
713.
The crystal structures of strontium exchanged sodium titanosilicates in relation to selectivity for nuclear waste treatment 总被引:1,自引:0,他引:1
The exchange of Sr2+ into the proton form of the ion exchanger Na2Ti2O3(SiO4)·2H2O was examined by means of X-ray powder diffractometry. This material has a sitinakite framework structure enclosing a tunnel parallel to the c-axis. At the 25% Sr2+ exchange level, the strontium ion was found near an oxo-framework oxygen midway between two adjacent faces of the tetragonal unit cell. It is bonded to five framework oxygen atoms and five water molecules. The Sr coordination number (CN) is reduced to nine in a sitinakite phase for which 16 mol% of the Ti (IV) was replaced by Nb (V). It has been previously shown that at a higher level of Nb substitution (25 mol%), the CN was further reduced to seven. This change in CN is opposite to what is observed for Cs+ where the CN is eight for the Ti phase and 12 for the Ti1.5Nb0.5 phase. The changes in CN are accompanied by a series of changes in the space group to accommodate occupancy of the exchange sites by the cations and water molecules. The selectivity of exchanger is governed by the strength and number of bonds formed by the exchange reactions. 相似文献
714.
Ishar Singh Ahuja Shailendra Tripathi Chhote Lal Yadava 《Transition Metal Chemistry》1988,13(2):140-142
Summary Coordination compounds formed by the interaction of manganese(II), cobalt(II), nickel(II) and copper(II) chloride and bromide with 4-cyanoaniline (4-CA) have been prepared and characterized by molar conductance, magnetic susceptibilities, electronic and i.r. spectral measurements down to 200 cm–1 in the solid state. The isolated complexes are M(4-CA)2X2 except for nickel(II) bromide which is NI(4-CA)4Br2. I.r. spectra, indicate that 4-CA, though a potentially bidentate ligand, nevertheless acts only as a terminally aniline (NH2) bonded monodentate ligand in all the complexes. Tentative stereochemistries of the complexes have been suggested in the solid state. 相似文献
715.
Atri Deo Tripathi 《Journal of solution chemistry》1994,23(7):769-776
Relative permittivities are reported for binary liquid mixtures of acetylene tetrachloride (ATC) with toluene and acetone at 35°C. Measurements of refractive indices have also been made for the mixtures. The values of the quantity , the deviations of the relative permittivities of these mixtures from ideality, have been calculated. The negative values of obtained for ATC+ toluene mixtures may be explained as being due to a decrease in the degree of alignment of the molecular dipoles with changing composition of the mixture, whereas the positive values of obtained for ATC+acetone mixtures are attributed to the formation of molecular complex between acetone and CHCl2CHCl2. The values of the Kirkwood correlation parameter g for both sets of mixtures have been calculated using the relative permittivity data. 相似文献
716.
Assignments of a certain number of vibrational bands of (CO)Fe(PF3)4 are made with reference to the C3v and C2v isomers. A study of the Raman and
spectra at low temperature revealed that in the solid state only one isomer exists. Furthermore, a comparative study of liquid (CO)Fe(PF3)4 and HCo(PF3)4 of molecular symmetry C3v was made. These two approaches made it possible to determine the difference in enthalpy between the two isomers of the iron complex (+0-52±0.05 kcal.mole−1) in the liquid state, as well as to verify the assignments proposed previously. The greater stability of the C2v isomer is discussed. 相似文献
717.
Nickel(II) chalcogenolate complexes [Ni(L-L)2(dppe) Cl2] (1, 2) have been prepared in high yields by reacting 1,2-diarylchalcogenolato-o-xylene, o-C6H4(CH2EAr)2 (E = Se or Te; Ar = Ph, C6H4OMe-4 and C6H4OEt-4), generated in situ, with Ni(dppe)Cl2 [dppe = 1,2-bis(diphenylphosphino)ethane] in benzene. The structures were established by elemental analyses, molar conductance, i.r. and
Raman, electronic 1H- and 31P-n.m.r. and mass spectral data. The analytical and spectroscopic data are consistent with an octahedral geometry around nickel
in (1) and (2). The 31P-n.m.r. spectra indicate their cis configuration in solution.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
718.
Tripathi GN 《The Journal of chemical physics》2005,122(7):071102
The reactions of the aqueous proton with the zwitterionic p-aminophenoxyl radical in strongly basic to extremely acidic aqueous solutions have been investigated using time-resolved resonance Raman spectroscopy. The dynamic stability of the different protonation forms of the radical, observed on the microsecond time scale in this work, has been achieved by controlling the proton exchange rate in water. In strongly acidic solutions we observe a rare ring-H+ bonded dication species, a key intermediate in the amine hydrolysis. The neutral p-aminophenoxyl radical undergoes NH2-deprotonation in strongly basic aqueous solutions, which has no analogues in closed-shell amines. 相似文献
719.
A. N. Tripathi Vedene H. Smith Ajit J. Thakkar 《International journal of quantum chemistry》1989,35(6):869-885
Self-consistent-field (SCF ) wave functions are used to calculate cross sections for the elastic and inelastic scattering of fast electrons and x-rays from CH4 and C2H2 molecules. The effects of basis set choice and free rotation on these cross sections are investigated. The utility of an approximate scheme to correct SCF inelastic cross sections for the effects of electron correlation is examined. The probability density for the interelectronic distance, or radial intracule density, is obtained and discussed. 相似文献
720.
Summary The monodentate ligands, L, ethylamine, butylamine, cyclohexylamine, benzylamine, piperidine and morpholine, and bidentate ligands, L, 1,10-phenanthroline and 2,2-bipyridyl react with tetracarbonylbis(-cyclopentadienyl)diiron to give monosubstituted derivatives, (-C5H5)2Fe2(CO)3L, and with iododicarbonyl(-cyclopentadienyl)iron to yield ionic products, [(-C5H5)Fe(CO)2L]I. I.r. spectral studies suggest that two isomeric (-C5H5)2-Fe2(CO)3L molecules exist. 相似文献