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31.
Helmut Schönenberger Heinrich Thies und Kripanath Borah 《Fresenius' Journal of Analytical Chemistry》1970,251(5):294-298
Zusammenfassung Es wird die quantitative Bestimmung der 5 Amine rac-N,N-Dibutyl-,-diphenyläthylendiamin (A), meso-N,N-Dibutyl-,-diphenyläthylendiamin (B), 1-Phenyl-1-butylamino-2-methyl-propan (C), N-Butyl-benzylamin (D) und Butylamin (E) in Reaktionsgemischen durch 54- und 95 stufige Craig-Nach-fraktionierungsprozesse in einer Verteilungsbatterie mit 35 Elementen nach Hecker [1] beschrieben. Durch graphische Auswertung der überlappenden Verteilungskurven wird eine quantitative Bestimmung auch bei 54 stufigen Prozessen, d.h. bei unvollständiger Trennung möglich.
8.Mitteilung: Sohönenberger, H., Eder, M.: diese Z. 249, 117–120 (1970).
Wir danken der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie für die Förderung unserer Untersuchungen. 相似文献
Quantitative determination of amine mixtures by multiplicative distributionOn the separation of organic bases by Craig distribution. IX
The quantitative evaluation of the 5 amines, rac-N,N-dibutyl-,-diphenylethylenediamine (A), meso-N,N-dibutyl-,-diphenylethylenediamine (B), 1-phenyl-1-butylamino-2-methyl-propane (C), N-butyl-benzylamine (D) and butylamine (E) in reaction mixtures by Craig after-fractionation processes of 54 and 95 steps in a distribution machine with 35 elements by Hecker [1] is described. By graphic evaluation of the overlapping distribution curves a quantitative determination is achieved, even with processes of 54 steps, i. e. incomplete separation.
8.Mitteilung: Sohönenberger, H., Eder, M.: diese Z. 249, 117–120 (1970).
Wir danken der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie für die Förderung unserer Untersuchungen. 相似文献
32.
Hanuman Singh Akshay Chenna Upanshu Gangwar Julie Borah Gaurav Goel V. Haridas 《Chemical science》2021,12(47):15757
The development of synthetic scaffolds that nucleate well-folded secondary structures is highly challenging. Herein, we designed and synthesized a series of core-modified peptides (F1, F2, F3, and F4) that fold into β-strand structures. These bispidine-scaffolded peptides were studied by CD, IR, NMR, single crystal XRD, and Molecular Dynamics (MD) simulations to investigate their conformational preferences. Solid-state and solution studies revealed that bispidine is a versatile scaffold that could be placed either at the terminal or at the middle of the peptide strand for nucleating the β-strand structure. Scaffolds that nucleate an isolated β-strand conformation are rare. Bispidine placed at the C-terminus of the peptide chain could nucleate a β-strand conformation, while bispidine placed at the middle resulted in a β-arch conformation. This nucleation activity stems from the ability to restrict the psi torsion angle (ψ) through intramolecular C5 hydrogen bonding between the equatorial hydrogen(s) of bispidine and the carbonyl oxygen(s) of the amino acid close to the scaffold. Furthermore, the bispidine peptidomimetic with a super secondary structure, namely β-arch, assembled into single-hole submicron cages and spherical vesicles as evident from microscopic studies. The design logic defined here will be a significant strategy for the development of β-strand mimetics and super secondary structures.Bispidine is a versatile scaffold that could be placed either at the terminal or at the middle of the peptide strand for nucleating β-strand structures. These β-strand mimetics self-assemble to single hole submicron cages and vesicles. 相似文献
33.
A. Borah S. Ghosh S. Nandy 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):221-225
The novel inelastic collision properties of two-soliton interaction for an n-component coupled higher order nonlinear Schr?dinger equation are studied. Some interesting features of three soliton interactions,
related to the integrability of the n-component coupled higher order nonlinear Schr?dinger equation are also discussed.
Received 17 April 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: abhijit@iitg.ernet.in
RID="b"
ID="b"e-mail: sasanka@iitg.ernet.in
RID="c"
ID="c"e-mail: sudipta@iitg.ernet.in 相似文献
34.
Harjyoti Thakuria Ballav Moni Borah Avijit Pramanik Gopal Das 《Journal of chemical crystallography》2007,37(12):807-816
Abstract This paper describes the solid-state synthesis and systematic studies of versatile supramolecular self-assembly of 14 new
series of organic salt cocrystals. Hierarchical self-assembly in the solid state utilizes the cooperative interaction of hydrogen
bonding, electrostatic and π–π interactions. These salts are crystallized as a highly ordered self-assembly directed by intermolecular
non-covalent interaction.
Index Abstract Fourteen cocrystals of organic salt have been characterized by single crystal X-ray diffraction and their solid-state packing
pattern has been compared.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
35.
A comparison between spatial burning in the semiclassical theory of laser and the intensity contours of the fringes due to
multiple reflections in a Fabry-Perot cavity is presented. The concept of spatial hole burning is also used in a quantum well
system. 相似文献
36.
Debasish Borah Neeharika Das Nirmalendu Das Ankita Bhattacharjee Pampi Sarmah Kheyali Ghosh Madhurya Chandel Jayashree Rout Piyush Pandey Narendra Nath Ghosh Chira R. Bhattacharjee 《应用有机金属化学》2020,34(5):e5597
A facile, convenient and green method has been employed for the synthesis of silver nanoparticles (AgNPs) using dried biomass of a green alga, Chlorella ellipsoidea. The phytochemicals from the alga, as a mild and non-toxic source, are believed to serve as both reducing and stabilizing agents. The formation of silver nanoparticles was confirmed from the appearance of a surface plasmon resonance band at 436 nm and energy dispersive X-ray spectroscopy. The transmission electron microscopy images showed the nanoparticles to be nearly spherical in shape with different sizes. A dynamic light scattering study revealed the average particle size to be 220.8 ± 31.3 nm. Fourier transform infrared spectroscopy revealed the occurrence of alga-derived phytochemicals attached to the outer surface of biogenically accessed silver nanoparticles. The powder X-ray diffraction study revealed the face-centred cubic crystalline structure of the nanoparticles. The as-synthesized biomatrix-loaded AgNPs exhibited a high photocatalytic activity for the degradation of the hazardous pollutant dyes methylene blue and methyl orange. The catalytic efficiency was sustained even after three reduction cycles. A kinetic study indicated the degradation rates to be pseudo-first order with the degradation rate being 4.72 × 10−2 min−1 for methylene blue and 3.24 × 10−2 min−1 for methyl orange. The AgNPs also exhibited significant antibacterial activity against four selected pathogenic bacterial strains. 相似文献
37.
Geetika Borah Devajani Boruah Gayatri Sarmah Saitanya K. Bharadwaj Utpal Bora 《应用有机金属化学》2013,27(12):688-694
The reaction of N‐methylimidazole (N‐MeIm) and N‐butylimidazole (N‐BuIm) with the complexes [PdCl2(PPh2py–P,N)] and [PdCl2(PPh2Etpy–P,N)] in the presence of NH4PF6 under N2 at room temperature afforded four new cationic Pd(II) complexes [PdCl(PPh2py–P,N)(N‐MeIm)](PF6) ( 1 ), [PdCl(PPh2py–P,N)(N‐BuIm)](PF6) ( 2 ), [PdCl(PPh2Etpy–P,N)(N‐MeIm)](PF6) ( 4 ) and [PdCl(PPh2Etpy‐P,N)(N‐BuIm)](PF6) ( 5 ) in good yields, where PPh2py is 2‐(diphenylphosphino)pyridine and PPh2Etpy is 2‐{2‐(diphenylphosphino)ethyl}pyridine). The complexes were fully characterized. The catalytic activities of these complexes were investigated for Suzuki–Miyaura cross‐coupling reactions at room temperature. Complex 2 exhibited excellent activity compared to other analogs. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
38.
The reaction of p‐(N,N‐dimethylaminophenyl)diphenylphosphine [PPh2(p‐C6H4NMe2)] with [Fe3(CO)12], [Rh(CO)2Cl]2 and PdCl2 resulted in three new mononuclear complexes, {Fe(CO)4[η1‐(P)‐PPh2(p‐C6H4NMe2)]} ( 1a ), trans‐{Rh(CO)Cl[η1‐(P)‐PPh2(p‐C6H4NMe2)]2} ( 2 ) and trans‐{PdCl2[η1‐(P)‐PPh2(p‐C6H4NMe2)]2} ( 3 ), respectively. A small amount of dinuclear nonmetal‐metal bonded complex, {Fe2(CO)8[µ‐(P,N)‐PPh2(p‐C6H4NMe2)]} ( 1b ), was also isolated as a side product in the reaction of [Fe3(CO)12]. The complexes were characterized by elemental analyses, mass, IR, UV–vis, 1H, 13C (except 1b) and 31P{1H} NMR spectroscopy. The Pd complex 3 effectively catalyzes the Suzuki–Miyaura cross‐coupling reactions of aryl halides with arylboronic acids in water–isopropanol (1:1) at room temperature. Excellent yields (up to 99% isolated yield) were achieved. The effects of different solvents, bases, catalyst quantities were also evaluated. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
39.
Cerium(IV) ammonium nitrate (CAN) mediates oxidation of tetraalkylammonium bromide to tetraalkylammonium tribromide in greener reaction conditions using water as solvent. The procedure is simple, convenient, and environmentally benign for the synthesis of tetraalkylammonium tribromide with great yields. 相似文献
40.
Some novel 5-aminoalkylbarbituric acids and corresponding chromene derivatives were synthesized via a one-pot, three-component Mannich reaction starting from 1,3-dimethylbarbituric acid, arylaldehydes, and amines. 相似文献