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191.
Avradeep Samanta Ishani Mitra Venkata P. Reddy B. Subhajit Mukherjee Sujay Mahata Wolfgang Linert 《Journal of Coordination Chemistry》2017,70(6):1032-1052
Kinetics of interaction between [Pt(pic)(H2O)2](ClO4)2, 2 (where pic = 2-aminomethylpyridine) with the selected ligands DL-methionine (DL-meth) and DL-penicillamine (DL-pen) have been studied spectrophotometrically in aqueous medium separately as a function of [2] as well as [ligand], pH and temperature at constant ionic strength. The association equilibrium constants (KE) for the outer sphere complex formation have been evaluated together with the rate constants for the two subsequent steps. Activation parameters (enthalpy of activation ΔH≠ and entropy of activation ΔS≠) were calculated from the Eyring equation. An associative mechanism of substitution is proposed for both reactions on the basis of the kinetic observations, evaluated activation parameters, and spectroscopic data. Structural optimizations, HOMO-LUMO energy calculation, and Natural Bond Orbital (NBO) analysis of 2–4 were carried out with Density Functional Theory. Bonding mode of thiol and thio-ether is confirmed by spectroscopic analyses and NBO calculation. Cytotoxic properties of 2–4 were explored on A549 carcinoma cell lines; DNA-binding properties of the complexes were also investigated by gel electrophoresis. 相似文献
192.
Bernhard Dung Fritz Vögtle 《Journal of inclusion phenomena and macrocyclic chemistry》1988,6(4):429-442
The syntheses of several macrotricyclic hexalactams (1–3) and of a corresponding hexalactone (4) are described in detail for the first time. The molecules have a basket shaped skeleton and contain a non-collapsible cavity, the size and shape of which is varied by use of spacer groups. Compounds1–3 selectively form crystalline adducts with ethanol as guest; the macrotricyclic hexaester4 does not. Evidence for an interaction of1 with ethanol was obtained by exchange experiments with perdeuteroethanol. Complexation experiments in solution did not show significant host/guest interactions with the guest chosen. 相似文献
193.
The carbodiphosphorane CO2 adduct ( 2 ) reacts slowly with 1, 2‐dichloroethane to give (HC{PPh3}2)Cl ( 5 ) as result of HCl abstraction along with the ester‐like salt (ClCH2CH2O(O)CC{PPh3}2)Cl ( 4 ) from nucleophilic substitution of one Cl– by 2 . Both compounds could be separated by fractional crystallization. Attempts to dissolve 2 in 1, 2‐difluorobenzene leads to small amounts of the hydrolysis product (HC{PPh3}2)(HCO3) · H2O ( 6· H2O) caused by some humidity in the solvent. All compounds could be crystallized and the structures studied by X‐ray analyses and 31P NMR spectroscopy. 相似文献
194.
《Analytical letters》2012,45(6):1195-1209
Abstract Several cyclodextrin/NaCl and trehalose/NaCl mixtures were investigated as solid matrices for obtaining room-temperature luminescence from a benzo(a)pyrene (B(a)P) guanosine adduct. Room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) intensities from the B(a)P-guanosine adduct were compared for different solid matrices. These results showed that 25% trehalose/NaCl, 1% α-cyclodextrin/NaCl, and 1% γ-cyclodextrin/NaCl solid matrices yielded strong fluorescence signals and moderately strong phosphorescence signals at room temperature from the B(a)P-guanosine adduct. In addition, the luminescence properties of pyrene, guanosine, guanosine 3′ -monophosphate free acid and guanosine 3′-monophosphate sodium salt on 1% α-, β-, and γ- cyclodextrin/NaCl solid matrices were obtained. 相似文献
195.
《Analytical letters》2012,45(15):2440-2455
This paper presents an enzymatic analysis method for selective detection of L-cysteine (L-Cys) without interferences from other thiols like cysteamine (CA) and mercaptoacetic acid (MAC). The amperometric biosensors are based on tyrosinase (Tyr) that converts catechol to o-quinone. The L-Cys detection is based on the fact that all thiols (including L-Cys) react with o-quinone producing electroinactive compounds and only interfering thiols (CA and MAC) inhibit Tyr. One sample was analyzed twice: with Tyr immobilized on WE surface to quantify enzyme inhibition by thiolic interferents and with Tyr free in solution to investigate the reactions between quinone and all thiolic compounds. 相似文献
196.
K. Fukao T. Horiuchi S. Taki K. Matsushige 《Molecular Crystals and Liquid Crystals》2013,570(2):405-416
The temperatures of the phase transition between orthorhombic and hexagonal structures of the urea adducts with n-paraffins, n-CnH2n+2 (n = 14–44), have been measured by differential thermal analysis for the pressure range up to 250MPa. The transition temperatures increase both with pressure and with the number of carbon atoms of the guest paraffins. The increasing rate of the transition temperatures with pressure is about half of that of pure paraffin crystals. The pressure dependences of the lattice constants have also been measured by X-ray diffraction. The specific volume changes discontinuously at the transition pressure; the result suggests that the phase transition of the urea adducts with n-paraffins is a first-order one. Furthermore, the specific volume change at the transition pressure decreases with the number of carbon atoms of the guest paraffins; 3.4 × 10-6 m3/Kg for n = 16 and 2.1 × 10-6 m3/Kg for n = 44. 相似文献
197.
198.
The anhydrous 12 triglyme:Dichloropicric acid adduct is triclinic, space group
; at 24°Ca=8.703(5),b=10.381(4), c=10.404(3) Å, =114.42(3), =99.69(5), =106.40(6)°,D
x=1.656 g cm–3, V = 776(2)Å3,Z=1. Bond lengths and angles are normal except that one C–C–O–C torsion angle in the triglyme is approximately 90° rather than the expected 60 or 180°. Each phenolic OH group hydrogen bonds with a terminal OCH3 of the polyether. The O...O distance, 2.557(3) Å, is in fair agreement with the 2.52 Å estimated from the single observed IRv (OH) stretch at 1714 cm–1. 相似文献
199.
《Magnetic resonance in chemistry : MRC》2002,40(4):273-278
The behavior of the methyl radical adduct of six β‐phosphorylated nitrones in the N‐benzylidene‐1‐diethoxyphosphoryl‐1‐methylethylamine N‐oxide series in the presence of sodium dodecyl sulfate (SDS) micelles was followed by electron paramagnetic resonance spectroscopy. Except when the highly hydrophilic trap 4‐PyOPN (2) was used, all the adducts were found to partition significantly between micelles and the bulk aqueous phase. The average correlation time τ of the exchange of spin adducts between SDS micelles and water was found to be in the range 5 × 10?8—4 × 10?7 s, which is in the region of the life time of an SDS monomer in the micelle structure. In each case, the adduct affinity for the micelles has been quantified by evaluating its micelle–water distribution coefficient Kd. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
200.
R. G. Kostyanovsky Yu. I. El'natanov I. I. Chervin S. V. Konovalikhin A. B. Zolotoi L. O. Atovmyan 《Russian Chemical Bulletin》1996,45(7):1707-1710
The title adduct (1) was synthesized, and its conformationally and configurationally rigid chiral structure in solution and in the crystal was established by NMR spectroscopy and by X-ray structural analysis. Atropoenantiomers of1 were observed by the1H NMR method in the presence of a chiral shift reagent. A barrier to their interconversïon was determined, Gx > Z5 kcal mol–1 (200 °C).Translated fromItvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1796–1799, July, 1996. 相似文献