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61.
Enzymatic or In Vivo Installation of Propargyl Groups in Combination with Click Chemistry for the Enrichment and Detection of Methyltransferase Target Sites in RNA 下载免费PDF全文
62.
A theoretical approach to the analysis of magnetostructural phase transitions of chain polymeric heterospin complexes is suggested. The approach is based on a model of the spin-Peierls transition in chains of exchange clusters. The chain elasticity parameter is found to be a main factor determining the order of phase transition. 相似文献
63.
A. D. Fedorenko L. N. Mazalov I. M. Oglezneva E. Yu. Fursova V. I. Ovcharenko 《Journal of Structural Chemistry》2016,57(6):1121-1126
The electronic structure of free radicals and Cu(II) complexes with the nitronyl nitroxide radical and aminonitrone is studied by X-ray photoelectron spectroscopy (XPS). N1s XPS spectra of nitrogen atoms of Cu(II) complexes with aminonitrones confirm the diamagnetic nature of the ligands. The binding energies of the main peak and the intense satellite structure in the Cu2p 3/2,1/2 spectra of the complexes under study correspond to the Cu(II) state. The structure of the satellite in the Cu2p 3/2,1/2 spectrum depends on the environment of the metal ion. 相似文献
64.
Klika KD Kivelä H Ovcharenko VV Nieminen V Sillanpää R Arpalahti J 《Dalton transactions (Cambridge, England : 2003)》2007,(35):3966-3970
The reaction of tetrapyrazine Pt(II) with adenine under basic conditions yielded two products both disubstituted by adenine and bound in all cases to the N-9 nitrogen of adenine. Crystals amenable to X-crystallographic analysis were obtained for one product which was consequently identified as trans-[Pt(II)(N9-adeH)2(pz)2](NO3)(4).H2O. The other product, though, was identified as the cis isomer based on extensive and comparative NMR structural studies whereby the two compounds were examined as both neutral and tetraprotonated species in solution. The major product of the reaction was unexpectedly the cis isomer, thus obtained in contrast to the trans effect, and the reason for this result is speculated on. Computational calculations using DFT at the B3LYP/TZVP-MARI-J level of theory provided the head-to-tail conformer as the overwhelmingly more stable species over the head-to-head conformer for both compounds whilst the trans product was found to be more stable than the cis. Thus the reaction does not follow a thermodynamic course and rather is kinetically controlled in concert with the speculated mode of reaction. 相似文献
65.
V. A. Chertkov S. V. Zubkov A. A. Ovcharenko A. V. Karchava M. A. Yurovskaya 《Chemistry of Heterocyclic Compounds》1999,35(11):1308-1312
On the basis of the overall signal line shape in the1H NMR spectra of [6,6]-closed and [5,6]-open fullerene-C60 cycloadducts with 1-(4-nitrophenyl)-3-phenylnitrile ylide we determined the values of the long range spin-spin coupling for the aliphatic proton of the heterocyclic fragment with the aromatic protons.M. V. Lomonosov State University, Moscow 119899, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1500–1505, November, 1999. 相似文献
66.
Ovcharenko V Fursova E Romanenko G Eremenko I Tretyakov E Ikorskii V 《Inorganic chemistry》2006,45(14):5338-5350
New polynuclear nickel trimethylacetates [Ni6(OH)4(C5H9O2)8(C5H10O2)4] (6), [Ni7(OH)7(C5H9O2)7(C5H10O2)6(H2O)] x 0.5 C6H14 x 0.5 H2O (7), [Ni8(OH)4(H2O)2(C5H9O2)12] (8), and [Ni9(OH)6(C5H9O2)12(C5H10O2)4] x C5H10O2 x 3 H2O (9), where C5H9O2 is trimethylacetate and C5H10O2 is trimethylacetic acid, have been found. Their structures were determined by X-ray crystallography. Because of their high solubility in low-polarity organic solvents, compounds 6-9 reacted with stable organic radicals to form the first heterospin compounds based on polynuclear Ni(II) trimethylacetate and nitronyl nitroxides containing pyrazole (L(1)-L(3)), methyl (L(4)), or imidazole (L(5)) substituent groups, respectively, in side chain [Ni7(OH)5(C5H9O2)9(C5H10O2)2(L(1))2(H2O)] x 0.5 C6H14 x H2O (6+1a), [Ni7(OH)5(C5H9O2)9(C5H10O2)2(L2)2(H2O)] x H2O (6+1b), [Ni7(OH)5(C5H9O2)9(C5H10O2)2(L(3))2(H2O)] x H2O (6+1c), [Ni6(OH)3(C5H9O2)9(C5H10O2)4(L(4))] x 1.5 C6H14 (6'), and [Ni4OH)3(C5H9O2)5(C5H10O2)4(L(5))] x 1.5 C7H8 (4). Their structures were also determined by X-ray crystallography. Although Ni(II) trimethylacetates may have varying nuclearity and can change their nuclearity during recrystallization or interactions with nitroxides, this family of compounds is easy to study because of its topological relationship. For any of these complexes, the polynuclear framework may be derived from the [Ni6] polynuclear fragment {Ni6(mu4-OH)2(mu3-OH)2(mu2-C5H9O2-O,O')6(mu2-C5H9O2-O,O)(mu4-C5H9O2-O,O,O',O')(C5H10O2)4}, which is shaped like an open book. On the basis of this fragment, the structure of 7-nuclear compounds (7 and 6+1a-c) is conveniently represented as the result of symmetric addition of other mononuclear fragments to the four Ni(II) ions lying at the vertexes of the [Ni6] open book. The 9-nuclear complex is formed by the addition of trinuclear fragments to two Ni(II) ions lying on one of the lateral edges of the [Ni6] open book. This wing of the 9-nuclear complex preserves its structure in another type of 6-nuclear complex (6') with the boat configuration. If, however, two edge-sharing Ni(II) ions are removed from [Ni6] (one of these lies at a vertex of the open book and the other, on the book-cover line), we obtain a 4-nuclear fragment recorded in the molecular structure of 4. Twinning of this 4-nuclear fragment forms highly symmetric molecule 8, which is a new chemical version of cubane. 相似文献
67.
E. V. Tretyakov S. V. Fokin G. V. Romanenko V. N. Ikorskii A. V. Podoplelov V. I. Ovcharenko 《Russian Chemical Bulletin》2006,55(1):66-73
An efficient procedure was developed for the synthesis of alkyltetrazolyl-substituted nitronyl nitroxides (L
1 and L
2). These compounds were used to prepare the first alkyltetrazolyl-substituted imino nitroxides (L
3 and L
4). The molecular structures of L
3 and L
4 were confirmed by X-ray diffraction. Investigation of the products prepared by the reaction of copper(II) bis(hexafluoroacetylacetonate), Cu(hfac)2, with nitroxides made it possible to divide ligands L
1—L
4 into two groups. The reactions of spin-labeled tetrazoles L
1—L
3 with Cu(hfac)2 afford the heterospin complexes Cu(hfac)2L2, whereas L
4 serves as a bidentate ligand in the Cu(hfac)2
L
4 complex. In the solid Cu(hfac)2L2 complexes, antiferromagnetic exchange interactions between the unpaired electrons of the nitroxide fragments of the adjacent
molecules prevail, due to which μeff decreases with decreasing temperature, and the spins of nitroxides are completely compensated at 5–10 K. The Cu(hfac)2
L
4 complex displays strong intramolecular ferromagnetic coupling, due to which μeff at room temperature is close to 2.9 μB.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 64–70, January, 2006. 相似文献
68.
V. I. Ovcharenko S. V. Fokin G. V. Romanenko V. N. Ikorskii R. Z. Sagdeev D. S. Yachevskii D. L. Chizhov V. N. Charushin 《Russian Chemical Bulletin》2006,55(11):1904-1908
Heterospin complexes of bis(μ2-1,1,2,2,8,8,9,9-octafluorononane-3,5,7-trionato)dicopper(II) ([Cu2L2]) with nitronyl nitroxides 2-(1-methyl-1H-pyrazol-4-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl 3-oxide (2) and 4,4,5,5-tetramethyl-2-(3-pyridinyl)-4,5-dihydro-1H-imidazole-1-oxyl 3-oxide (1) were synthesized and structurally characterized. Crystals of the complexes are formed by the discrete bis[1-methyl-4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)-1H-pyrazole]-bis (μ2-1,1,2,2,8,8,9,9-octafluorononane-3,5,7-trionato)dicopper(II) etherate (3) and bis[3-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyridine]-bis (μ2-1,1,2,2,8,8,9,9-octafluorononane-3,5,7-trionato)dicopper(II) (4) molecules. Each Cu atom of the dinuclear chelate fragment coordinates one paramagnetic ligand through the N atom of the
pyrazole or pyridine fragment, respectively. In complex 3, the paramagnetic ligands are located on one side of the plane of the chelate fragment, whereas the ligands in complex 4 are located above and below the plane of the chelate fragment. The magnetic properties of complexes 3 and 4 are determined by dominant antiferromagnetic exchange interactions between the unpaired electrons of the CuII atoms in the dinuclear Cu2L2 moiety.
Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1836–1840, November, 2006. 相似文献
69.
Fedin MV Veber SL Gromov IA Ovcharenko VI Sagdeev RZ Schweiger A Bagryanskaya EG 《The journal of physical chemistry. A》2006,110(7):2315-2317
The complex of Cu(2+) hexafluoroacetylacetonate with two pyrazol-substituted nitronyl nitroxides represents an unusual exchange-coupled three-spin system. The antiferromagnetic exchange coupling, which already atT < 150 K is larger than the thermal energy kT, induces the transition from a total spin state S = (3)/(2) to a state S = (1)/(2) and produces static spin polarization. Anomalous electron paramagnetic resonance (EPR) spectra of an S = (1)/(2) state were detected experimentally and described theoretically. The effective g factor of the three-spin system is smaller than 2, despite the fact that all the individual components have g > 2. The observed signals with g < 2 are highly informative and can be employed for determination of the sign and value of the exchange interaction in three-spin nitroxide-copper-nitroxide clusters. 相似文献
70.
J. Adamczewski-Musch P. Akishin K. -H. Becker S. Belogurov J. Bendarouach N. Boldyreva C. Deveaux V. Dobyrn M. Dürr J. Eschke J. Förtsch J. Heep C. Höhne K. -H. Kampert A. Khanzadeev L. Kochenda J. Kopfer P. Kravtsov I. Kres S. Lebedev E. Lebedeva E. Leonova S. Linev T. Mahmoud J. Michel W. Niebur E. Ovcharenko V. Patel C. Pauly D. Pfeifer S. Querchfeld J. Rautenberg S. Reinecke Y. Riabov E. Roshchin V. Samsonov V. Schetinin O. Tarasenkova M. Traxler C. Ugur M. Vznuzdaev 《Physics of Particles and Nuclei Letters》2017,14(6):904-912
The CBM RICH detector is an integral component of the future CBM experiment at FAIR, providing efficient electron identification and pion suppression necessary for the measurement of rare dileptonic probes in heavy ion collisions. An overview of the CBM RICH readout and DAQ system prototype is given, consisting of the PADIWA preamplifier-discriminator board, the TDC-HUB board TRBv3, and DAQ and analysis code in the CbmRoot framework. The laboratory setup built for studying the timing characteristics of the readout chain and the analysis results obtained using the laboratory measurements are presented. The fine time calibration and inter-channel delay correction techniques and their implementation and effect are discussed. 相似文献