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231.
K. Rühlmann J. Brumme U. Scheim H. Grosse-Ruyken 《Journal of organometallic chemistry》1985,291(2):165-178
The kinetics of hydrolysis reactions of some chlorodisiloxanes and of the chloropentasiloxanes (Me3) SiO)2Si(Me)OSiAr(Cl)OSiMeAr′ (with Ar = Ph and Ar′ = p-ClC6H4, C6H5 or p-MeC6H4; or Ar′ = Ph and Ar = p-ClC6H4, C6H5 or p-MeC6H4 in dioxane were studied by 1H NMR spectroscopy.Because of their high hydrolysis rate the chlorodisiloxanes can be reacted only with equimolar amounts of H2O. The formal second order rate constants and also the ? value evaluated can be used only in a tentative way.From hydrolysis reactions of the chloropentasiloxanes with an excess of H2O and different amounts of HCl or HClO4 the following results were obtained: hydrolysis is catalysed by HCl and HClO4. The reaction is of first order with respect to chlorosiloxane. With respect to HCl at a tenfold excess of H2O the order is in the range 0.5–0.7. Our results indicate, that there is a “non-catalysed” hydrolysis besides the acid catalysed reaction, ?-Values for the variation of Ar (0.7) and Ar′ (0.3) can be derived from the rate constants of the acid catalysed reactions of chloropentasiloxanes with a tenfold amount of water. The results are interpreted in mechanistic terms. 相似文献
232.
The annealing induced morphological changes in isotropic block copoly(etherester)s are investigated by small angle X-ray scattering methods. The observed results are consistent with a lamellar model which is comprised of a crystalline core of thickness 35 to 45 Å, a diffuse boundary zone of width 9 Å, and an amorphous layer which is varying strongly in thickness. The enhanced crystallinity of the samples annealed at higher temperatures is mainly due the lateral growth of the lamellae; the long period increases by not more than 20%. The scattering power of the samples is explained by means of an equivalent two-phase model in which the crystalline phase has the same structure as theα-form of poly(butylene terephthalate), whereas the amorphous phase is a mixture of the uncrystallized ester segments and the ether segments. The crystallinity determined from the scattering power is very much higher than that determined from thermoanalytical investigations. 相似文献
233.
U. M. Dzhemilev R. I. Khusnutdinov Z. S. Muslimov O. M. Nefedov G. A. Tolstikov 《Russian Chemical Bulletin》1988,37(11):2337-2343
Conclusions The homodimerization of spiro{bicyclo[2.2.1]hepta-2,5-diene-7,1-cyclopropane} (I) has been investigated in the presence of Ni-, Fe-, Co-, Rh-, and Ir-based metal complex catalysts. Depending on the nature of the metal and its ligand environment cyclodimerization of (I) can take place via [2+2]-, [2+2+2]-, and [4+4]-cycloaddition schemes, to give high yields of hepta-, octa-, and nonacyclic strained hydrocarbons.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2592–2599, November, 1988. 相似文献
234.
A classification of the shape resonances in the photoionization of diatomic molecules into two types is proposed: the well known molecular shape resonances which appear in the σ u channel for the photoionization of the σ g shells of light molecules like 3σ g in N2 or in O2, and the atomic-like shape resonances. To illustrate this last class of shape resonances, calculations in the frozen core static exchange approximation of thed inner shell photoionization cross sections, σ, and of the angular distribution parameters, β, are performed for both HBr and HI. In our model, the σ and β curves look roughly like that of the isoelectronic Kr and Xe rare gases, but in order to obtain quantitative agreement with experiment, an approach including interchannel interactions, i.e. similar to that used for the halogen atoms would be probably necessary. 相似文献
235.
First-order Raman spectra have been recorded at room temperature for the anatase and rutile phases of polycrystalline titanium dioxide using an argon ion laser as exciter. The high-temperature rutile phase was found to be stabilized at temperatures below 450°C. Anatase transforms to rutile phase at ~750°C. All the Raman active fundamentals predicted by group theory are observed. 相似文献
236.
237.
The ESCA spectrum of C3O2 excited by Mg Kα radiation, 1253.6 eV, has been obtained for both gaseous and solid samples. The chemical shifts of the C1s and O1s levels have been used to calculate the gross atomic charges. The valence region of the spectrum has been recorded and the ordering of the orbitals has been decided on the basis of an ab initio calculation and the intensities of the observed peaks. An unusually intense shake-up spectrum has also been observed and is discussed. The relative spacing of the valence peaks has been found to be different for the solid and gas. 相似文献
238.
U. I. Safronova A. N. Ivanova V. N. Kharitonova 《Theoretical and Experimental Chemistry》1969,5(3):209-216
Transition probabilities and oscillator strengths are calculated for the configurations 1s2 2sn1 and 1s2 2sn1-1 2pn2+1, which are, respectively, of the form P=a/Z (1+/Z+) andf=/Z (1+/Z+). Numerical values are given fora, ,, and. 相似文献
239.
The ESR. spectra of the radical anions of trimethylsilyl-substituted derivatives of p-benzoquinone, phenylketone, diimine, p-benzoquinone-diimide, aniline and p-phenylenediamine are reported. In most cases the coupling constants of 29Si isotopes in natural abundance have been measured. The comparison of the ESR. data for the radical anions of the trimethylsilyl derivatives with those for the radical anions of the corresponding parent hydrocarbons and/or alkyl-substituted compounds provide additional evidence for the overall electron withdrawing effect of the trimethylsilyl substituent (Si←Cπ and Si←nπ delocalization). 相似文献
240.
F. Asinger D. Neuray A. Saus J. Gräber U. Lames 《Monatshefte für Chemie / Chemical Monthly》1972,103(2):406-417
Zusammenfassung Aliphatische Amine bzw. Alkohole reagiren (in Gegenwart von PbO) mit 2-Methyl-2,5-diphenyl-imidazolin-4-thion (1) glatt zu 4-Alkylamino-2H-imidazolen (2 a-f, 7) bzw. 4-Alkoxy-2H-imidazolen (9 a-g). Die Darstellung von 4-Arylamino-2H-imidazolen (4 a-j) bzw. 4-Aroxy-2H-imidazolen (10 a-t) gelingt in guten Ausbeuten durch Umsetzung von 2-Methyl-2,5-diphenyl-4-chlor-2H-imidazol (3) mit aromatischen Aminen in siedenden Lösungsmitteln (Petroläther, Aceton) bzw. mit Phenolen in siedendem Aceton in Gegenwart von HCl-Acceptoren (K2CO3, Dabco). Die Umsetzung von3 mit Anthranilsäure liefert in 83proz. Ausbeute 1-Methyl-1,3-diphenyl-1H, 9H-imidazo[5,1-b]chinazolin-9-on (6). Aus3 und Thiophenol erhält man glatt 2-Methyl-2,5-diphenyl-4-phenylthio-2H-imidazol (11).
Herrn Prof. Dipl.-Ing., Dr. techn., Dr. e. h.Otto Kratky zum 70. Geburtstag herzlichst gewidmet.
Teil der DiplomarbeitJ. Gräber, Techn. Hochschule Aachen, 1970.
Teil der DiplomarbeitU. Lames, Techn. Hochschule Aachen, 1971. 相似文献
On the reaction of 2-Methyl-2,5-diphenyl-imidazoline-4-thione and 2-Methyl-2,5-diphenyl-4-chloro-2H-imidazole with aliphatic and aromatic amines, alcohols and phenols (joint action of elemental sulfur and gaseous ammonia upon ketones, LXXVI
Aliphatic amines and alcohols (in the presence of PbO) easily react with 2-methyl-2.5-diphenyl-imidazoline-4-thione (1) to 4-alkylamino-2H-imidazoles (2 a-f, 7) and 4-alkoxy-2H-imidazoles (9 a-g), resp. 4-arylamino-2H-imidazoles (4 a-j) are prepared in good yields by the reaction of 2-methyl-2.5-diphenyl-4-chloro-2H-imidazole (3) with aromatic amines under reflux in light naphtha or acetone; in the same manner 4-aroxy-2H-imidazoles (10 a-t) are obtained from3 and phenols in boiling acetone in the presence of HCl-acceptors (K2CO3, Dabco). Reaction of3 with anthranilic acid leads to1-methyl-1.3-diphenyl-1H.9H-imidazo[5.1-b]chinazoline-9-one (6) in 83% yield. By reaction of thiophenol with3 2-methyl-2.5-diphenyl-4-phenylthio-2H-imidazole (11) is easily obtained.
Herrn Prof. Dipl.-Ing., Dr. techn., Dr. e. h.Otto Kratky zum 70. Geburtstag herzlichst gewidmet.
Teil der DiplomarbeitJ. Gräber, Techn. Hochschule Aachen, 1970.
Teil der DiplomarbeitU. Lames, Techn. Hochschule Aachen, 1971. 相似文献