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11.
In this study, methanol extracts (MEs) and essential oil (EO) of Angelica purpurascens (Avé-Lall.) Gill obtained from different parts (root, stem, leaf, and seed) were evaluated in terms of antioxidant activity, total phenolics, compositions of phenolic compound, and essential oil with the methods of 2,2-azino-bis(3ethylbenzo-thiazoline-6-sulfonic acid (ABTS•+), 2,2-diphenyl-1-picrylhydrazil (DPPH•) radical scavenging activities, and ferric reducing/antioxidant power (FRAP), the Folin–Ciocalteu, liquid chromatography−tandem mass spectrometry (LC−MS/MS), and gas chromatography-mass spectrometry (GC−MS), respectively. The root extract of A. purpurascens exhibited the highest ABTS•+, DPPH•, and FRAP activities (IC50: 0.05 ± 0.0001 mg/mL, IC50: 0.06 ± 0.002 mg/mL, 821.04 ± 15.96 µM TEAC (Trolox equivalent antioxidant capacity), respectively). Moreover, EO of A. purpurascens root displayed DPPH• scavenging activity (IC50: 2.95 ± 0.084 mg/mL). The root extract had the highest total phenolic content (438.75 ± 16.39 GAE (gallic acid equivalent), µg/mL)). Twenty compounds were identified by LC−MS/MS. The most abundant phenolics were ferulic acid (244.39 ± 15.64 μg/g extract), benzoic acid (138.18 ± 8.84 μg/g extract), oleuropein (78.04 ± 4.99 μg/g extract), and rutin (31.21 ± 2.00 μg/g extract) in seed, stem, root, and leaf extracts, respectively. According to the GC−MS analysis, the major components were determined as α-bisabolol (22.93%), cubebol (14.39%), α-pinene (11.63%), and α-limonene (9.41%) among 29 compounds. Consequently, the MEs and EO of A. purpurascens can be used as a natural antioxidant source. 相似文献
12.
The quantum mechanics of an electron-nuclear system with strong electron-phonon coupling is considered. First, a two-site model is treated in the adiabatic approximation. As the coupling constant increases, electron transfer undergoes qualitative changes; more specifically, a potential barrier forms in the adiabatic potential, the electron transfer becomes associated with the tunneling of nuclei through the barrier, and the level splitting in the system falls off exponentially. The properties of a similar crystal model are discussed. It is shown that electron transfer in a crystal in the case of strong coupling is likewise associated with the tunneling of nuclei through barriers in the deformation space. Strong coupling modifies the electron-electron interaction terms. The Hamiltonian (exchange) terms, which are not associated with electron transfer, are only weakly modified. At the same time, the terms involving transfer (the band terms) undergo exponential reduction and vanish in the limit as M → ∞ (M is the ion mass) and the carriers become small polarons. This reduction provides a basis for the natural mechanism of enhancement of the isotope effect. 相似文献
13.
Dmitry S. Perekalin Valentin V. Novikov Maddalena Corsini Alexander R. Kudinov 《Journal of organometallic chemistry》2010,695(8):1200-1204
The reactions of benzo-15-crown-5 and dibenzo-18-crown-6 with 1 equiv. of [(mes)Ru(MeNO2)3]2+ (mes = 1,3,5-C6H3Me3) give the mononuclear complexes [(mes)Ru(η6-benzo-15-crown-5)]2+ (1) and [(mes)Ru(η6-dibenzo-18-crown-6)]2+ (2) in 50% yield. Similar reaction with 2 equiv. of [(mes)Ru(MeNO2)3]2+ produces the dinuclear complex [(μ-η6:η6-dibenzo-18-crown-6)Ru2(mes)2]4+ (3) in 96% yield as a 2:3 mixture of cis- and trans-isomers. Structures of 2(OTf)2 and trans-3(OTf)4 were confirmed by X-ray diffraction. The NMR titration showed that mononuclear dications 1 and 2 bind Na+ ion less effective (Ka = 600 and 250 M-1) than free benzo-15-crown-5 and dibenzo-18-crown-6 (Ka = 2 × 105 and 5 × 106 M−1). The dinuclear tetracation 3 does not bind Na+ within measurable limits of NMR titration method. The electrochemical behaviour of complexes 1-3 was studied in propylene carbonate solution. They exhibit a partially chemically reversible Ru(II)/Ru(I) reduction, which in the case of the dinuclear complex 3 proceeds through two slightly separated steps. The redox activity of the complexes is substantially unaffected by the presence of sodium ion. 相似文献
14.
15.
A. V. Kudinov Yu. G. Kusraev B. P. Zakharchenya V. N. Yakimovich 《Physics of the Solid State》1998,40(5):823-825
Polarized photoluminescence of Cd1−x
MnxTe crystals in a weak magnetic field has been studied in Faraday and Voigt geometries. A simple method is proposed to determine
the exciton mobility edge and excitonic magnetic-polaron energy. “Forbidden” polarization components of the recombination
radiation have been experimentally detected. It has been established that the moments of magnetic polarons are oriented predominantly
along the {111} axes.
Fiz. Tverd. Tela (St. Petersburg) 40, 894–896 (May 1998) 相似文献
16.
Conclusions A method was developed for the synthesis of ruthenium bisarene cations with various arenes [C6H6RuArene]2+ by heating [C6H6RuCl2]2 with the corresponding arene in heptane in the presence of AlCl3.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1423–1425, June, 1985. 相似文献
17.
A. R. Kudinov D. V. Muratov P. V. Petrovskii M. I. Rybinskaya 《Russian Chemical Bulletin》1999,48(4):794-795
The first unsymmetrical 34-electron cationic cobalt-nickel triple-decker complex with a central cyclopentadienyl ligand [(η-C6Me6)Co(μ-η:η-C5H5)Ni(η-C5)PF6 was prepared by the reaction of [(η-C6Me6)2Co]PF6 with nickelocene.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 798–799, April, 1999. 相似文献
18.
The results of our recent studies devoted to the synthesis of cationic triple-decker complexes are summarized. The stacking
reactions of cationic metallofragments with sand-with compounds can be used as a general method for the synthesis of these
complexes. This method was used for the preparation of 30- and 34-electron cationic triple-decker complexes containing cyclopentadienyl
and pentaphospholyl ligands in the bridging position and carbocycles C
n
H
n
(n=4–7) and carboranes as terminal ligands.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1636–1642, September, 1999. 相似文献
19.
AR Engel 《Contemporary Physics》2013,54(6):523-526
This article reviews some of the applications of physics to the solution of archaeological problems. The use of magnetic, resistivity and electromagnetic surveying techniques for the location of buried features is described. Various methods of age determination are outlined while the problems associated with radiocarbon dating of organic material and thermoluminescent dating of pottery are discussed in detail. The techniques, including petrological examination, chemical analysis and isotopic analysis, employed in the physical examination of archaeological artefacts are described. Examples of the application of these techniques in establishing the source of the raw materials used in pottery, metal and stone implements and in elucidating the techniques of manufacture of pottery and metal objects are also given. 相似文献
20.
Dmitry S. Perekalin Pavel V. Petrovskii Bohumil Štíbr Alexander R. Kudinov 《Journal of organometallic chemistry》2005,690(11):2775-2779
The reaction of the tricarbollide salt Tl[7-tBuNH-7,8,9-C3B8H10] (Tl1) with [(cod)Rh(THF)x]+ gives the rhodium complex [1-(cod)-12-tBuNH-1,2,4,12-RhC3B8H10] in almost quantitative yield. Analogous reactions of Tl1 with [(ring)M(THF)x]2+ ((ring)M = Cp*Rh and (1,3,5-C6H3Me3)Ru) afford the corresponding metallatricarbollides [1-(ring)-12-tBuNH-1,2,4,12-MC3B8H10] in ca. 50% yield. Refluxing Tl1 with [Mn(CO)3(MeCN)3]+ in THF give the tricarbollide analogue of cymantrene, [1,1,1-(CO)3-12-tBuNH-1,2,4,12-MnC3B8H10], the structure of which was determined by single-crystal X-ray diffraction analysis. In all cases, the formation of the metallatricarbollide complexes is accompanied by polyhedral rearrangement leading to the maximum separation of the cage carbon atoms. 相似文献