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41.
Chotima R Dale T Green M Hey TW McMullin CL Nunns A Orpen AG Shishkov IV Wass DF Wingad RL 《Dalton transactions (Cambridge, England : 2003)》2011,40(19):5316-5323
Reaction of [Pd(PPh(3))(4)] with 1,1-dichloro-2,3-diarylcyclopropenes gives complexes of the type cis-[PdCl(2)(PPh(3))(C(3)(Ar)(2))] (Ar = Ph 5, Mes 6). Reaction of [Pd(dba)(2)] with 1,1-dichloro-2,3-diarylcyclopropenes in benzene gave the corresponding binuclear palladium complexes trans-[PdCl(2)(C(3)(Ar)(2))](2) (Ar = Ph 7, p-(OMe)C(6)H(4)8, p-(F)C(6)H(4)9). Alternatively, when the reactions were performed in acetonitrile, the complexes trans-[PdCl(2)(NCMe)(C(3)(Ar)(2))] (Ar = Ph 10, p-(OMe)C(6)H(4)11 and p-(F)C(6)H(4)) 12) were isolated. Addition of phosphine ligands to the binuclear palladium complex 7 or acetonitrile adducts 11 and 12 gave complexes of the type cis-[PdCl(2)(PR(3))(C(3)(Ar)(2))] (Ar = Ph, R = Cy 13, Ar = p-(OMe)C(6)H(4), R = Ph 14, Ar = p-(F)C(6)H(4), R = Ph 15). Crystal structures of complexes 6·3.25CHCl(3), 10, 11·H(2)O and 12-15 are reported. DFT calculations of complexes 10-12 indicate the barrier to rotation about the carbene-palladium bond is very low, suggesting limited double bond character in these species. Complexes 5-9 were tested for catalytic activity in C-C coupling (Mizoroki-Heck, Suzuki-Miyaura and, for the first time, Stille reactions) and C-N coupling (Buchwald-Hartwig amination) showing excellent conversion with moderate to high selectivity. 相似文献
42.
T. Shih K. Reimann M. Woerner T. Elsaesser I. Waldmüller A. Knorr R. Hey K.H. Ploog 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):262
Radiative coupling of resonantly excited intersubband transitions in GaAs/AlGaAs multiple quantum wells can have a strong impact on the coherent nonlinear optical response, as is shown by phase and amplitude resolved propagation studies of ultrashort electric field transients. Upon increasing the driving field amplitude, strong radiative coupling leads to a pronounced self-induced absorption, followed by a bleaching due to the onset of delayed Rabi oscillations. A many-particle theory including light propagation effects accounts fully for the experimental results. 相似文献
43.
1, 3‐Diaminobenzene reacts readily with PPh2Cl to give N, N, N′, N′‐tetrakis(diphenylphosphanyl)‐1, 3‐diaminobenzene ( 1 ) in excellent yield. The dinuclear complex [1, 3‐{cis‐Mo(CO)4(PPh2)2N}2C6H4] ( 2 ) is obtained in high yield from 1 and cis‐[Mo(CO)4(NCEt)2]. Compounds 1 and 2 were characterized by NMR spectroscopy (1H, 13C, 31P) and by crystal structure determination. The latter shows the formation of a bis‐chelate complex with Mo‐P‐N‐P four‐membered rings. 相似文献
44.
Reaction of 2,2-Dimethylpropylidynephosphine with Molybdenum Pentachloride; Crystal Structure of [Mo2Cl6(α,α′-dipyridyl)3] 2,2-Dimethylpropylidynephosphine and molybdenum pentachloride dissolved in POCl3 react with oxydation of the phosphorus and reduction of the molybdenum atom to give the alkyne complex [Mo2Cl4(μ-Cl)2(μ-H9C4? C?C? C4H9)(OPCl3)2]. Addition of α,α′-dipyridyl or of methyltriphenylphosphonium chloride in dichloromethane results in a displacement of the ligands POCl3 and H9C4? C?C? C4H9 from this complex and in the formation of [Mo2Cl6(dipy)3] or [(H5C6? )3P? CH3]3[Mo2Cl9]. Besides the latter compound small amounts of [(H5C6? )3P? CH3]2[MoCl6] can be isolated from the reaction mixture. [Mo2Cl6(dipy)3] which has already been prepared by other methods crystallizes in the monoclinic space group P21/c with {a = 1612; b = 148; c = 1296 pm; γ 109.3°; Z = 4} at 20°C. As shown by a crystal structure determination the complex is built up from [MoCl2(dipy)2]+ cations and [MoCl4(dipy)]? anions. The molybdenum atoms are both octahedrally surrounded. With average values of 238 and 243 pm the Mo? Cl bond distances in the cation, where a cis-arrangement of the chlorine atoms is observed, and in the anion differ significantly from each other. [Mo2Cl6(dipy)3] which has already been prepared by other methods crystallizes in the monoclinic space group P21/c with {a = 1612; b = 148; c = 1296 pm; γ = 109.3°; Z = 4} at 20°C. As shown by a crystal structure determination the complex is built up from [MoCl2(dipy)2]+ cations and [MoCl4(dipy)]? anions. The molybdenum atoms are both octahedrally surrounded. With average values of 238 and 243 pm the Mo? Cl bond distances in the cation, where a cis-arrangement of the chlorine atoms is observed, and in the anion differ significantly from each other. 相似文献
45.
46.
The reaction of [Cp*MCl4] (M = Nb, Ta; Cp* = C5Me5) with PH2R in toluene at room temperature gives the primary phosphine complexes [Cp*MCl4(PH2R)] [Cp* = C5Me5; M = Nb: R = But ( 1a ), Ad ( 2a ), Cy ( 3a ), Ph ( 4a ), 2, 4, 6‐Me3C6H2 (Mes) ( 5a ); M = Ta: R = But ( 1b ), Ad ( 2b ), Cy ( 3b ), Ph ( 4b ), Mes ( 5b )] in high yield. 1—5 were characterized spectroscopically (NMR, IR, MS) and by crystal structure determinations. The starting material [Cp*TaCl4] is monomeric in the solid state, as shown by crystal structure determination. 相似文献
47.
We investigated the modulation of the optical properties of GaAs-based structures by a surface acoustic wave (SAW) by microscopic measurements of reflectance and photoluminescence. We demonstrate that for photon energies away from electronic resonances, the modulation of the optical properties is associated with the strain field of the SAW (elastooptical mechanism). Close to the E0 resonance, the electrooptical modulation due to the SAW piezoelectric fields becomes important and leads to a spatial modulation of the photoluminescence intensity. 相似文献
48.
Matthias Stender Hannes Oesen Steffen Blaurock Evamarie Hey‐Hawkins 《无机化学与普通化学杂志》2001,627(5):980-984
Synthesis and Molecular Structure of [{Cp′(μ‐η1 : η5‐C5H3Me)Mo(μ‐AlRH)}2] (Cp′ = C5H4Me, R = iBu, Et) [Cp′2MoH2] reacts with HAlR2 to give [{Cp′(μ‐η1 : η5‐C5H3Me)Mo(μ‐AlRH)}2] (Cp′ = C5H4Me, R = iBu ( 1 ), Et ( 2 )). Crystal structure determinations were carried out on [Cp′2MoH2] and 1 . 1 exhibits a direct Mo–Al bond (2.636(2) Å). 相似文献
49.
Insertion and Substitution Reaction of Methyl Formate with [Cp′2ZrCl(PHTipp)] – Molecular Structure of meso‐trans ‐[Cp′2ZrCl{OCH(PHTipp)2}] (Cp′ = η5‐C5MeH4, Tipp = 2,4,6‐Pri3C6H2) [Cp′2ZrCl(PHTipp)] ( 1 ) (Cp′ = η5‐C5MeH4, Tipp = 2,4,6‐Pri3C6H2) reacts with methyl formate with insertion and substitution to give [Cp′2ZrCl{OCH(PHTipp)2}] ( 2 ). 2 was characterized spectroscopically (1H, 31P NMR, IR, MS) and by X‐ray structure determination. Only the meso‐trans isomer is present in the solid state. 相似文献
50.
J. A. Baeta Segundo Heyder Hey Walter F. Wreszinski 《Journal of statistical physics》1994,76(5-6):1479-1493
We prove that the spectrum defined in terms of the autocorrelation function of a harmonic subject to a quasiperiodic perturbation, is, at resonance, transient absolutely continuous, covering the whole line. In the nonresonant case, and under some supplementary Diophantine condition, it is pure point, coinciding with the spectrum of a special almost-periodic function. 相似文献