全文获取类型
收费全文 | 104篇 |
免费 | 1篇 |
专业分类
化学 | 72篇 |
物理学 | 33篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 7篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 15 毫秒
61.
62.
Anton N. Lukoyanov Iakov S. Fomenko Marko I. Gongola Lidia S. Shulpina Nikolay S. Ikonnikov Georgiy B. Shulpin Sergey Y. Ketkov Georgy K. Fukin Roman V. Rumyantcev Alexander S. Novikov Vladimir A. Nadolinny Maxim N. Sokolov Artem L. Gushchin 《Molecules (Basel, Switzerland)》2021,26(18)
A new monoiminoacenaphthenone 3,5-(CF3)2C6H3-mian (complex 2) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl2(dpp-mian)(CH3CN)] (3) and [VOCl(3,5-(CF3)2C6H3-bian)(H2O)][VOCl3(3,5-(CF3)2C6H3-bian)]·2.85DME (4) from [VOCl2(CH3CN)2(H2O)] (1) or [VCl3(THF)3]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF3)2C6H3-bian instead of 3,5-(CF3)2C6H3-mian. Secondly, it has a binuclear structure, in contrast to 3, in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3, non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36–3.40 Å) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3) and 27% (complex 4). Based on the data regarding the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh3). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of ●OH radicals. For complex 4 with electron-withdrawing CF3 substituents at the diimine ligand, an alternative mechanism, different from Fenton’s and involving a redox-active ligand, is assumed. 相似文献
63.
A. S. Saghiyan A. V. Geolchanyan S. M. Djamgaryan S. M. Vardapetyan V. I. Tararov N. A. Kuz'mina N. S. Ikonnikov Yu. N. Belokon M. North 《Russian Chemical Bulletin》2000,49(8):1460-1463
An efficient procedure was developed for the asymmetric synthesis ofS-alkyl derivatives of (R)-cysteine by nucleophilic addition of alkanethiols (BunSH, ButSH, ortert-C5H11SH) to the C=C bond of the dehydroalanine fragment in the NiII complex of the Schiff's base of Δ-Ala with (S)-2-N-(N-benzylprolyl)aminobenzophenone [(S)-BPB-Δ-Ala]NiII. Under conditions of thermodynamic control of the reaction, the diastereomeric excess of the complexes with the (S.R)-configuration was 88–96%. After decomposition of the complexes,(R)-S-butylcysteine,(R)-S-tert-butylcysteine, and(R)-S-tert-pentylcysteine were isolated with an enantiomeric purity of >97%.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1467–1470, August, 2000. 相似文献
64.
V. I. Sokolov L. A. Bulygina N. S. Khrushcheva N. S. Ikonnikov 《Russian Chemical Bulletin》2010,59(7):1400-1402
Two ferrocenyl palladacycles with bi-and tridentate (C,N) and (C,N,N) ligands were tested as possible catalysts for the Heck
reaction. The latter complex efficiently catalyzed reactions of aryl halides with ethyl acrylate. 相似文献
65.
A. S. Aleksandrovsky A. M. Vyunishev A. I. Zaitsev A. A. Ikonnikov G. I. Pospelov V. E. Rovskii V. V. Slabko 《Optics and Spectroscopy》2011,111(2):150-156
Using a nonlinear photonic crystal (NPC) of strontium tetraborate, we obtained the second-harmonic generation of femtosecond
pulses in the nonlinear diffraction regime with an efficiency of 1.9% that is tunable in the near-UV spectral range, as well
as fourth-harmonic generation under the conditions of random quasi-phase-matching with maximum efficiency of 10−5 that is tunable in the far-UV spectral range. The efficiency of second-harmonic generation in strontium tetraborate NPC under
the conditions of random quasi-phase-matching was significantly lower. The fourth-harmonic was tunable between 187.5 and 232.5
nm. The previously predicted red shift of spectral components in the generated radiation spectrum upon NPC rotation is demonstrated
experimentally. 相似文献
66.
Zavin B. G. Trankina E. S. Kondrashova A. A. Kagramanov N. D. Ikonnikov N. S. Muzafarov A. M. 《Russian Chemical Bulletin》2016,65(3):767-773
Russian Chemical Bulletin - Нydrolytic polycondensation of organochlorosilanes (OCS) RR´SiCl2, where R,R´= Me, Et, C2H3, and H, in an acetone—carbamide non-aqueous system was... 相似文献
67.
E. E. Said-Galiev M. S. Rubina A. V. Naumkin N. S. Ikonnikov A. Yu. Vasil’kov 《Doklady Physical Chemistry》2018,482(1):130-133
A novel material for biomedical applications was obtained from a collagen–chitosan composite and ibuprofen by a fluid process using supercritical carbon dioxide. The material was characterized by IR and X-ray photoelectron spectroscopy. The applicability of XPS analysis of biomaterials for quantification of loaded therapeutic agents is demonstrated. 相似文献
68.
L. S. Bovkun A. V. Ikonnikov V. Ya. Aleshkin S. S. Krishtopenko N. N. Mikhailov S. A. Dvoretskii M. Potemski B. Piot M. Orlita V. I. Gavrilenko 《JETP Letters》2018,108(5):329-334
Spectra of magnetoabsorption and Faraday rotation in HgTe/CdHgTe heterostructures with single and double quantum wells in high magnetic fields up to 11 T have been studied by the Fourier-transform spectroscopy method. The study of Faraday rotation spectra makes it possible to determine the sign of resonance circular polarization of transitions between Landau levels of carriers, which allows identifying observed intraband and interband transitions in the far and middle infrared ranges. 相似文献
69.
Resonant ultrasound spectroscopy was used to measure the elastic constants of bcc Ta0.33V0.67 over the temperature range 3.5–300?K; the results were compared to earlier measurements on C15 TaV2. The temperature dependence of the polycrystalline shear modulus is completely different in the two phases; that of the bcc phase decreases with temperature whereas that of the C15 phases increases in an anomalous fashion. This difference is consistent with a model involving doubly-degenerate levels at the X point of the Brillouin zone in the C15 phase with the Fermi level lying near the doubly degenerate level. This model accounted for the unusual behaviour of the C15 phase. Debye temperatures were determined from the ultrasonic measurements: 295?K for the C15 phase and 315?K for the bcc phase. 相似文献
70.