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排序方式: 共有211条查询结果,搜索用时 15 毫秒
1.
N. Moslemzadeh G. Beamson P. Tsakiropoulos J.F. Watts S.R. Haines P. Weightman 《Journal of Electron Spectroscopy and Related Phenomena》2006
High-energy X-ray photoelectron spectroscopy (XPS) is of particular importance for minimizing the effects of surface contamination by increasing photoelectron escape depths. In this study high-resolution high-energy Cu Kα1 and soft Al Kα1 XPS and Auger electron spectroscopy were used to compare the electronic structure of Ti in TiO2 powder and Ti metal. The Ti 1s in TiO2 XPS line is narrower and more symmetric than in Ti metal. A comparison of the relative intensities of the L23M23M45 and L23M23M23 Auger transitions in Ti metal and TiO2 is consistent with the expected transfer of Ti 3d electrons away from the Ti site in the oxide. The satellites accompanying the Ti 1s XPS line excited by Cu Kα1 X-rays occur at the same energies as the satellites accompanying the Ti 2s and 2p XPS lines excited by Al Kα1 X-rays indicating that they do not depend on the core-level, the experimental resolution or inelastic scattering processes. 相似文献
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The structure of the title compound has been determined by X-ray crystallography. The octahedral arrangement of ligands about the iron(II) centre is somewhat distorted, with the axial NC–Fe–CN bond angle being 174.3(4)°. The oxidation of the tricyano-2,2,6,2- terpyridylferrate(II) anion by the peroxodisulfate anion has been investigated in water and in binary aqueous mixtures. The reaction follows a second order rate law, with a second-order rate constant of 0.126± 0.001dm3mol–1s–1 at 295.2K. The enthalpy and entropy of activation in water are 51.3±1.8kJmol–1 and –89±5JK–1mol–1 respectively. The rate is retarded on addition of organic cosolvent. The transfer chemical potential of the initial state from water into mixed solvents has been determined from solubility measurements, and compared with the transfer potential of the transition state. Solvent effects on the reaction are discussed in terms of initial state versus transition state solvation. 相似文献
5.
Gary H. Posner Timothy P. Kogan Stephen R. Haines Leah L. Frye 《Tetrahedron letters》1984,25(25):2627-2630
A short, reliable, and practical synthesis of ()-(+)-2-(-tolylsulfinyl)-2-buten-4-olide has been developed, and the utility of this Michael acceptor for highly enantiocontrolled synthesis of 3-substituted 4-butanolides has been demonstrated. 相似文献
6.
Iminodiacetate resorc[4]arene is shown to produce gels that are pH-reversible. The gels formed are clear and stable to inversion. (The gels are not stable above a certain temperature, which varies with concentration.) When the pH of an iminodiacetate resorc[4]arene solution (concentration > 7.6 mM) is lowered to below 2.5, which is near one of the Ka values of the molecule, the dissolved molecules aggregate and cause gelation of water. 1H NMR showed that at the pH of gelation a change occurs in the chemical environment of the iminodiacetate group. Scanning electron microscopy showed that the gel is composed of long strands that interweave and create a molecular mesh. 相似文献
7.
LoSecco JM Bionta RM Biewitt G Bratton CB Casper D Chrysicopoulou P Claus R Cortez BG Errede S Foster GW Gajewski W Ganezer KS Goldhaber M Haines TJ Jones TW Kielczewska D Kropp WR Learned JG Lehmann E Park HS Reines F Schultz J Seidel S Shumard E Sinclair D Sobel HW Stone JL Sulak L Svoboda R van der Velde JC Wuest C 《Physical review letters》1985,54(21):2299-2301
8.
Bissessur R Haines RI Hutchings DR Brüning R 《Chemical communications (Cambridge, England)》2001,(17):1598-1599
A novel macrocycle-MoS2 nanocomposite has been synthesized and characterized using the exfoliation/restacking properties of LiMoS2, providing the first of a new family of intercalation compounds. 相似文献
9.
Gerard de Leeuw John S. Field Raymond J. Haines Beth McCulloch Elsie Meintjies Christiaan Monberg Gillian M. Olivier Praveen Ramdial Clifford N. Sampson Beate Sigwarth Nick D. Steen Kandasamy G. Moodley 《Journal of organometallic chemistry》1984,275(1):99-111
Reaction of [Fe2(CO)9] with a half molar amount of R2PYPR2 (Y = CH2, R = Ph, Me, OMe or OPri; Y = N(Et), R = OPh, OMe or OCH2; Y = N(Me), R = OPri or OEt) leads to the ready formation of a product which on irradiation with ultraviolet light rapidly decarbonylates to the heptacarbonyl derivative [Fe2(μ-CO)(CO)6{μ-R2PYPR2}]. Treatment of the latter with a slight excess of the appropriate ligand results, under photochemical conditions, in the formation of the dinuclear pentacarbonyl complex [Fe2(μ-CO)(C))4{μ-R2PYPR2}2] but under thermal conditions in the formation of the mononuclear species [Fe(CO)3{R2PYPR2}]. Reaction of [Ru3(CO)12] with an equimolar amount of (RO)2PN(R′)P(OR)2 (R′ = Me, R = Pri or Et; R′ = Et, R = Ph or Me) under either thermal or photochemical conditions produces [Ru3(CO)10{μ-(RO)2PN(OR)2}] which reacts further with excess (RO)2PN(R′)P(OR)2 on irradiation with ultraviolet light to afford the dinuclear compound [Ru2(μ-CO)(CO4{μ-(RO)2PN(R′)P(OR)2}2]. The molecular structure of [Ru2(μ-CO)(CO)4{μ-(MeO)2PN(Et)P(OMe)2}2], which has been determined by X-ray crystallography, is described. 相似文献
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