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91.
Photogalvanic effects were studied in photogalvanic cells containing sodium lauryl sulphate as surfactant, EDTA as reductant
and azur-B as photosensitizer. The photopotential and photocurrent generated were 814#x00B7;0 mV and 255·0 μA respectively.
The observed conversion efficiency was 1·2% and the maximum power of cell was 207·57 μW. The storage capacity of the cell
was 26#x00B7;0 min in dark. The effect of different parameters on electrical output of the cell was observed. A mechanism
has been proposed here for the generation of photocurrent in photogalvanic cells 相似文献
92.
Viktor Kelemen Magdolna Csvs Judit Hotzi Mihly Herczeg Poonam Brijesh Rathi Pl Herczegh Nidhi Jain Anik Borbs 《化学:亚洲杂志》2020,15(6):876-891
The photoinitiated thiol?ene addition reaction is a highly stereo‐ and regioselective, and environmentally friendly reaction proceeding under mild conditions, hence it is ideally suited for the synthesis of carbohydrate mimetics. A comprehensive study on UV‐light‐induced reactions of 2,3‐unsaturated O‐, C‐, S‐ and N‐glycosides with various thiols was performed. The effect of experimental parameters and structural variations of the alkenes and thiols on the efficacy and regio‐ and stereoselectivity of the reactions was systematically studied and optimized. The type of anomeric heteroatom was found to profoundly affect the reactivity of 2,3‐unsaturated sugars in the thiol?ene couplings. Hydrothiolation of 2,3‐dideoxy O‐glycosyl enosides efficiently produced the axially C2‐S‐substituted addition products with high to complete regioselectivity. Moderate efficacy and varying regio‐ and stereoselectivity were observed with 2,3‐unsaturated N‐glycosides and no addition occurred onto the endocyclic double bond of C‐glycosides. Upon hydrothiolation of 2,3‐unsaturated S‐glycosides, the addition of thiyl radicals was followed by elimination of the thiyl aglycone resulting in 3‐S‐substituted glycals. 相似文献
93.
94.
The gas‐phase geometries of neutral, protonated, and deprotonated forms of some biologically important molecules, alanine (Ala), glycine (Gly), phenylalanine (Phe), and tyrosine (Tyr), were optimized using density functional theory at B3LYP/6‐311++G(d) and the ab initio HF/6‐311++G(d) level of theories. The neutral and different stable ionic states of Ala, Gly, Phe, and Tyr have also been solvated in aqueous medium using polarizable continuum model for the determination of solvation free energies in the aqueous solution. The gas‐phase acidity constants of above four molecules have been also calculated at both levels of theories and found that the values calculated at HF/6‐311++G(d) method are in good agreement with experimental results. A thermodynamic cycle was used to determine the solvation free energies for the proton dissociation process in aqueous solution and the corresponding pKa values of these molecules. The pKa values calculated at B3LYP/6‐311++G(d) method are well supported by the experimental data with a mean absolute deviation 0.12 pKa units. Additionally, the chemical hardness and the ionization potential (IP) for these molecules have been also explored at both the level of theories. The Tyr has less value of chemical hardness and IP at both levels of theories compared with other three molecules, Ala, Gly, and Phe. The calculated values of chemical hardness and IP are decreasing gradually with the substitution of the various functional groups in the side chain of the amino acids. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
95.
Vivekanand V Dwivedi P Pareek N Singh RP 《Applied biochemistry and biotechnology》2011,165(1):204-220
In solid-state fermentation, among various solid supports evaluated, banana peel was found to be an ideal support and resulted
into higher levels of laccase (6281.4 ± 63.60 U l−1) along with notable levels of manganese peroxidase production (1339.0 ± 131.23 U l−1) by Aspergillus fumigatus VkJ2.4.5. Maximum levels of laccase was achieved under derived conditions consisting of 80% of moisture level, 6 days of
incubation period, 6% inoculum level, and an aeration level of 2.5 l min−1. A column-tray bioreactor was designed to scale up and economize the enzyme production in three successive cycles of fermentation
using the same fungal biomass. Thermal and pH stability profiles revealed that enzyme was stable up to 50°C and at varying
pH range from 5–9 for up to 2 h. The apparent molecular weight of laccase was found to be 34 ± 1 kDa. MALDI-TOF/TOF analysis
of the protein showed significant homology with maximum identity of 67% to other laccases reported in database. 相似文献
96.
Raman spectra of an aqueous solution of glycine (Gly) have been recorded in the range of 400-2000 cm−1. In aqueous solution, glycine molecules exist in their zwitterionic form, having two opposite charged poles, COO− and NH3+. The zwitterionic structure of glycine (ZGly) is stabilized by the hydrogen bond interaction of water (W) molecules. In the present report, we have optimized the ground state geometries of different hydrogen bonded complexes of [ZGly + (W)n=1-5] in aqueous medium using DFT calculations at the B3LYP/6-311++G(d) level of theory. A comparative discussion on the structural details and binding energies (BEs) of each conformer has been also done. The theoretical Raman spectra were calculated corresponding to the most stable [ZGly + (W)n=1-5] conformers. The theoretically simulated Raman spectra of each stable conformer were compared with experimentally observed Raman spectra to explore the number of water molecules needed for stabilizing the structure of ZGly. The theoretically simulated Raman spectra corresponding to the most stable conformer of [ZGly + (W)5] having a BE of −22.8 kcal/mol, are matching nicely with the experimentally observed Raman spectra. Thus, on the basis of the above observations, we conclude that the conformer, [ZGly + (W)5] is the most probable conformer in the aqueous medium. We also believe that in the conformer, [ZGly + (W)5] the five water molecules are arranged around the ZGly in such a way that the effect of steric hindrance is less compared to the other conformers. The dipole-dipole interaction potential (DDP) is also calculated corresponding to the strongest hydrogen bond for each [ZGly + (W)n=1-5] conformer. 相似文献
97.
98.
Computational calculations of the hetero-Diels–Alder (HDA) reactions of benzaldehyde with 2,3-dimethyl-1,3-butadiene (DMB) catalyzed by BF3, EtAlCl2 or TiCl4 at the density functional theory (DFT) (B3LYP/6-31G(d,p)) level reveal that the reactions involve activation energy barriers of 14.59, 14.34, and 17.44 kcal mol−1, respectively. In the first two cases, reaction occurs through a concerted mechanism, whereas in the presence of TiCl4, stepwise mechanism involving zwitterionic intermediate is followed. The reaction with isoprene proceeds with complete regioselectivity leading to the expected regioisomer having O/Me in 1:4 positions. The computational results have been verified experimentally when aromatic aldehydes react with 1,3-dienes in the presence of a catalyst to give 3,6-dihydro-2H-pyran derivatives in high yields. 相似文献
99.
Kamlesh Pandey Mrigank Mauli Dwivedi Sharda Sundaram Sanjay Nidhi Asthana 《Ionics》2017,23(1):113-120
To develop porous polymeric membrane, we have used poly(vinylidene-co-hexafluoropropylene) (P(VdF-HFP)) as a host matrix and the ionic liquid 1-ethyl-3-methylimidazolium tosylate as salt for the source of charge carriers in the polymer electrolyte system. Appropriate weight of mica (muscovite) has been added to the highest conducting polymer–salt electrolyte. The composite membrane has been prepared by breath figure method through controlling evaporation time and then tested this membrane for water filtration. The composite polymeric membrane has been characterized by X-ray diffraction, FTIR spectrometry, SEM, and electrochemical impedance spectroscopy. The pore volume in the mica-based film has been calculated, and it is found to be 64.3 % in the filler-dispersed membrane. 相似文献
100.
Present research work focuses on study of self‐focusing and self‐trapping of Hermite cosh Gaussian (HchG) laser beams in rippled density plasma by considering relativistic non‐linearity. The coupled non‐linear differential equations for the beam width parameters (for modes m = 0, 1, and 2) were derived by employing higher‐order correction in comparison to paraxial ray theory by expanding dielectric function and eikonal up to r4 terms. It is observed that the inclusion of higher‐order terms significantly influence the off‐axial properties for m ≥ 1 mode indices. Furthermore, the effect of parameters including beam intensity, ripple factor, depth of density modulation, and decentred parameter on self‐focusing and self‐trapping is analysed and discussed both analytically and numerically. 相似文献