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11.
Thanikasalam Kanagasabapathy Panchanatheswaran Krishnaswamy Jeyaraman Ramasubbu 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(11):o579-o582
rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C26H27NOS, (I), and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C13H17NOS, (II), are both characterized by a planar configuration around the heterocyclic N atom. In contrast with the chair conformation of the parent benzothiazepine, which has no substituents at the heterocyclic N atom, the seven‐membered ring adopts a boat conformation in (I) and a conformation intermediate between boat and twist‐boat in (II). The molecules lack a symmetry plane, indicating distortions from the perfect boat or twist‐boat conformations. The supramolecular architectures are significantly different, depending in (I) on C—H...O interactions and intermolecular S...S contacts, and in (II) on a single aromatic π–π stacking interaction. 相似文献
12.
Jeyaraman Selvaraj Nirmalram Duraisamy Tamilselvi Packianathan Thomas Muthiah 《Journal of chemical crystallography》2011,41(6):864-867
Abstract
N 6-benzyladeninium nitrate, (1), C12H12N5 + NO3 − crystallizes in P2 1/c, with a = 15.0035(13), b = 5.3788(5), c = 16.8954(13) ?, β = 107.331(6)°, Z = 4 and N 6-benzyladeninium 3-hydroxy picolinate, (2), C12H12N5 + C6H4NO3 −, crystallizes in P1, with a = 8.3017(4), b = 14.6170(7), c = 14.7909 (8) ?, α = 78.801 (4), β = 81.979 (4),γ = 88.849 (4)°, Z = 4. In both the salts, the cation exists as N(7)H tautomer with protonation at the N3 atom. The dihedral angle of 76.64 (16)° for (1), 67.91(12)° for (cation A) and 68.27 (13)° for (cation B) in (2), between the adenine plane and phenyl ring plane, the distal orientation of the N6 substituent with respect to the imidazole ring and the free N1 position, make these benzyladeninium cations meet all the requirements necessary for cytokinin activity. The crystal structures are stabilized by N–H···N, N–H···O, C–H···O hydrogen bonds and C–H···π stacking interaction between symmetry related benzyladenine molecule. 相似文献13.
Jeyaraman Vikramathithan Sambandam Ravikumar Pandurangan Muthuraman Gali Nirmalkumar Sivalingam Shayamala Kotteazeth Srikumar 《Cellulose (London, England)》2012,19(4):1373-1383
Thermostable xylanase isoforms T70 and T90 were purified and characterized from the xerophytic Opuntia vulgaris plant species. The enzyme was purified to homogeneity employing three consecutive steps. The purified T70 and T90 isoforms yielded a final specific activity 134.0 and 150.8 U mg?1 protein, respectively. The molecular mass of these isoforms was determined to be 27 kDa. The optimum pH for the T70 and T90 xylanase isoforms was 5.0 and the temperature for optimal activity was 70 and 90 °C, respectively. The Km value of T70 and T90 enzyme isoforms was 3.49, 2.1 mg ml?1, respectively when oat spelt xylan was used as a substrate. The T70 had a Vmax of 10.4 μmol min?1 mg?1, and T90 had a Vmax of 8.9 μmol min?1 mg?1, respectively. In the presence of 10 mM Co2+, and Mn2+ the activity of T70 and T90 isoforms increased, where as 90 % inhibition was noted with of the use 10 mM Hg2+, Cd2+, Cu2+, Zn2+ while partial inhibition was observed in the presence of Fe3+, Ni2+, Ca2+and Mg2+. The T70 and T90 isoforms retained nearly 50 % activity in the presence of 2.0 M urea, while use of 40 mM SDS lowered the activity nearly 38–41 %. The substrate specificity of both T70 and T90 isoforms showed maximum activity for oat spelt xylan. Western blot, immunodiffusion, and in vitro inhibition assays confirmed reactivity of the T90 isoform with polyclonal anti-T90 antibody raised in rabbit, as well as cross-reactivity of the antibody with the T70 xylanase isoform. 相似文献
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16.
Adsorption of methylene blue onto jute fiber carbon: kinetics and equilibrium studies 总被引:5,自引:0,他引:5
Senthilkumaar S Varadarajan PR Porkodi K Subbhuraam CV 《Journal of colloid and interface science》2005,284(1):78-82
Jute fiber obtained from the stem of a plant was used to prepare activated carbon using phosphoric acid. Feasibility of employing this jute fiber activated carbon (JFC) for the removal of Methylene blue (MB) from aqueous solution was investigated. The adsorption of MB on JFC has found to dependent on contact time, MB concentration and pH. Experimental result follows Langmuir isotherm model and the capacity was found to be 225.64 mg/g. The optimum pH for the MB removal was found to be 5-10. The kinetic data obtained at different concentrations have been analyzed using a pseudo-first-order, pseudo-second-order equation, intraparticle diffusion and Elovich equation. Among the kinetic models studied, the intraparticle diffusion was the best applicable model to describe the adsorption of MB onto JFC. 相似文献
17.
R. Jeyaraman Cooksley Baldwin Jawaharsingh S. Avila K. Ganapathy Ernest L. Eliel Muthiah Manoharan Susan Morris-Natschke W. R. Kenan 《Journal of heterocyclic chemistry》1982,19(3):449-458
The 13C nmr spectra of 4 cis-2,4-diphenyl-3-azabicyclo[3.3.1]nonanes, 11 cis-2,4-diaryl-3-azabicyclo[3.3.1]-nonan-9-ones, 26 cis-2,4-diaryl-3-azabicyclo[3.3.1]-nonan-9-ols or acetates thereof, 5 cis-2,4-diaryl-3-azabi-cyclo[4.3.1]decan-10-ones or -10-ols and 5 cis-2,4-diphenyl-3-aza-7-thiabicyclo[3.3.1]nonan-9-ones, -9-ols or 9-yl acetates have been recorded. Except for the 7-thia compounds, which appear to exist mainly in the configuration and conformation with the nitrogen-containing ring in the boat form, these compounds seem to exist overwhelmingly in chair-chair conformations. The configuration of the 9-ols and their acetates (syn or anti to the nitrogen-containing ring) has been deduced from the spectra. In a number of cases, the structures assigned differ from those earlier postulated. Broadening of one set of aryl signals (probably those due to the ortho carbons) in the case of N-methyl (but not N-H) compounds without ortho substituents is ascribed to restricted phenyl rotation. 相似文献
18.
Rath H Sankar J Prabhuraja V Chandrashekar TK Joshi BS Roy R 《Chemical communications (Cambridge, England)》2005,(26):3343-3345
The synthesis and structural characterization of the first examples of aromatic core-modified figure-eight octaphyrins with six meso links and their formation with and without acid catalysts are highlighted. 相似文献
19.
Jeyaraman Chandrasekhar Prem Kishore Mehrotra Sankaran Subramanian Periakaruppan T. Manoharan 《Theoretical chemistry accounts》1979,53(3):293-296
Siegbahn's potential model as extended by Ellison et al. is used with density matrix elements calculated by the NDDO/2 procedure, to correlate the K-shell binding energy shifts of C, N and O atoms in a few molecules containing only the first-row atoms. The correlation is not superior to that obtained with the CNDO/2 method when only the monopole term is retained in calculating the Madelung potential energy. However, the results are in excellent agreement with experiment when the two-parameters model including the dipole and quadrupole terms is used. 相似文献
20.
L. Vijayalakshmi V. Parthasarathi M. Venkatraj R. Jeyaraman 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1240-1241
The crystal structure of the title compound, C22H25NO, confirms that the bicyclic ring system adopts the chair–chair conformation. The phenyl rings are equatorially disposed with respect to the bicyclic ring. There is a slight deviation from the chair conformation in the case of the cyclohexane ring. 相似文献