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61.
Carboxypeptidase A immobilized on acid chloride of oxidized cellulose showed the following features: (a) as indicated by the
linearity of reaction kinetics, the immobilized enzyme action is not diffusion controlled; (b) greater flow rates are achievable
with less clogging during continual usage since the enzyme is attached to a porous screen; (c) ease of handling; and (d) no
apparent electrostatic interaction with the support material that is uncharged. The immobilized enzyme retained 60% of the
original activity. The half-life of free enzyme was only 20 min, whereas for immobilized enzyme it was enhanced up to 2 h
48 min. It could be recovered and repeatedly used. 相似文献
62.
Subasini Lenka Padma L. Nayak Suparna Ray 《Journal of polymer science. Part A, Polymer chemistry》1984,22(4):959-965
The aqueous polymerization of acrylic acid and acrylamide initiated by peroxydiphosphate–sodium thiosulfate redox system was investigated within the temperature range of 25–35°C. The rates of polymerization were measured at different concentrations of oxidant, activator and monomer. The monomer and the initiator exponents were evaluated to be 1.12 and 0.51. The rate of polymerization decreases with increasing thiosulfate concentration. On the basis of the experimental observation of the dependence of the rate of polymerization, Rp, on various variables, a suitable kinetic scheme has been proposed and the rate parameters have been evaluated. 相似文献
63.
Uncombined elemental sulphur in petroleum products such as kerosene, diesel, furnace and gear oil has been determined by conversion into copper(I) sulphide at 150-170 degrees . The copper(I) sulphide can be weighed, or its sulphur content determined by the iodimetric method. 相似文献
64.
S. Padma V. Mahadevan M. Srinivasan 《Journal of polymer science. Part A, Polymer chemistry》1986,24(4):793-801
A new class of aromatic and heterocyclic polyimides were synthesized from benzothiazoleamines benzidine, 4,4′-diaminodiphenyl ethane and 4,4′-diamino diphenyl sulfone with 4,4′-azodipthalic anhydride and/or pyromellitic dianhydride. The synthesis involved the reaction of the dianhydride with the respective diamine to yield an intermediate, soluble, open chain precursor polymer, the polyamic acid, which on cyclodehydration yielded the less soluble, heat resistant polyimides. All these polyimides were characterized by IR and NMR. Solubility, density, viscosity, and thermal stability of these polymers were also studied. 相似文献
65.
Macroreticular cation exchangers can be prepared by polymerizing sulfonated phenols with formaldehyde under acidic conditions. The resins are highly porous with large surface areas. Their properties compare well with those based on styrene and divinylbenzene copolymers. 相似文献
66.
Emilie Ferreira Pascal Le Poul Nolwenn Cabon Bertrand Caro Françoise Robin-Le Guen Yann Pellegrin Aurélien Planchat Fabrice Odobel 《Tetrahedron letters》2017,58(10):995-999
A series of new push-pull organic dyes incorporating a cyanoacrylic acid group as electron acceptor unit and α-chalcogenopyranylidene group (X = S; O) as electron donor unit has been synthesized, characterized and used as sensitizer for dye-sensitized solar cells (DSSCs). For the first time, α-pyranylidene and thiopyranylidene groups, have been evaluated in DSSC. To obtain the thermodynamic values of the solar cell, an investigation of their electrochemical (CV) and optical properties (UV–vis absorption spectroscopy) is also reported. 相似文献
67.
Raman Khurana Dr. Jyotirmayee Mohanty Dr. Narayanan Padma Dr. Nilotpal Barooah Dr. Achikanath C. Bhasikuttan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(61):13939-13944
Deaggregated perylenediimide (PDI) derivatives exhibit exceptionally high quantum yields, photostability and appropriate molecular features for organic electronics. This work demonstrates a metal–dye–metal framework with a large and stable negative differential resistance (NDR) at ambient conditions, built using a supramolecular strategy. The deaggregation achieved through the encapsulation of the bay-substituted phenyl groups of aggregated (l/d )-Phe-PDI dyes by the β-CD macrocyclic host is validated through detailed spectroscopic and imaging techniques. The host–guest interaction resulted in a dramatic enhancement in the emission yield from 0.28 to 0.90. In the thin film deposits, the β-CD/(l/d )-Phe-PDI complex displayed well-connected sheet-like morphology, whereas the uncomplexed (l/d )-Phe-PDI dye remained as scattered lumps. The large and reversible I–V characteristics displaying strong NDR behavior is attributed to the oxidation/reduction processes involving the rigid π-rich PDI core and is stable at least for about six months at ambient conditions, a promising system for organic electronics applications. 相似文献
68.
Megumi Kayanuma Narayan Bera Martina Sandroni Yann Pellegrin Errol Blart Fabrice Odobel Chantal Daniel 《Comptes Rendus Chimie》2012,15(2-3):255-266
The structures and electronic absorption spectra of newly synthesized heteroleptic copper (I) complexes [CuL1L2]+ (L1 = phen-imidazole and/or L2 = dipyrido [3,2-a:2’,3’-c] phenazine derivatives) are analyzed under the light of density functional theory (DFT) and time-dependent DFT (TD-DFT). The ground states geometries, characterized by π-stacking interactions, have been optimized using PBE-D functional taking into account dispersion correction. The UV-visible theoretical absorption spectra have been calculated using B3LYP functional in vacuum and taking into account solvent corrections by means of the polarized continuum model (PCM). Whereas the PBE-D functional is well adapted to the determination of the structures, it does underestimate drastically the transition energies. The spectra are characterized by high density of states, mainly metal-to-ligand-charge-transfer (MLCT) and intra-ligand (IL), between 600 nm and 250 nm. Most of the complexes show an intense band in the near-UV energy domain (~320 nm) corresponding to an IL transition. The lowest part of the absorption spectra, starting at 600 nm, corresponds to MLCT transitions leading to a shoulder observed experimentally between 400 and 500 nm. The upper part of the spectra, beyond 300 nm, puts in evidence strong mixing between ligand-to-ligand-charge-transfer (LLCT), IL and MLCT states. 相似文献
69.
An efficient and facile synthesis of 3-aryl thiophenes From disodium 2-aryl succinates using phosphorus penta sulphide-red phosphorus under phase transfer co-catalyst is reported in near quantitative yield. 相似文献
70.
Renato Fedele Dušan Jovanovi? Bengt Eliasson Padma K. Shukla 《Physics letters. A》2010,374(5):788-795
The possibility of the decomposition of the three-dimensional (3D) Gross-Pitaevskii equation (GPE) into a pair of coupled Schrödinger-type equations, is investigated. It is shown that, under suitable mathematical conditions, it is possible to construct the exact controlled solutions of the 3D GPE from the solutions of a linear 2D Schrödinger equation coupled with a 1D nonlinear Schrödinger equation (the transverse and longitudinal components of the GPE, respectively). The coupling between these two equations is the functional of the transverse and the longitudinal profiles. The applied method of nonlinear decomposition, called the controlling potential method (CPM), yields the full 3D solution in the form of the product of the solutions of the transverse and longitudinal components of the GPE. It is shown that the CPM constitutes a variational principle and sets up a condition on the controlling potential well. Its physical interpretation is given in terms of the minimization of the (energy) effects introduced by the control. The method is applied to the case of a parabolic external potential to construct analytically an exact BEC state in the form of a bright soliton, for which the quantitative comparison between the external and controlling potentials is presented. 相似文献