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141.
S. Kamila S. K. Kamilla S. K. Singh B. B. Swain 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(11):1789-1793
An acoustic study of the binary Alamine 308 (triisooctylamine)-benzene system was performed by measuring ultrasonic velocity,
viscosity and density. Interactions in the liquid mixture were explained on the basis of excess non-linearity parameters and
other relevant data, such as the degree of molecular interaction, molar sound velocity, etc. In addition, the experimental
velocities were compared with theoretical estimates using various empirical relations, and the relative merits of the corresponding
theories and relations were discussed in terms of percentage variations. The basic aim of this work was to assess the type
of solute-solvent interaction between a nonpolar extractant (Alamine 308) and a nonpolar diluent (benzene).
The text was submitted by the authors in English. 相似文献
142.
Poly(methyl methacrylate)/soy protein(PMMA/SP) composites were prepared by emulsion polymerization method using potassium persulphate(KPS) as the radical initiator.The interaction of soy protein with PMMA was evidenced by Fourier transformed infrared(FT1R) spectroscopy.The structure of PMMA/SP composites was investigated by X-ray diffraction(XRD) study and scanning electron microscopy(SEM).The thermal properties of soy protein and PMMA/SP composites were compared with soy protein and virgin PMMA sample.PMMA/SP composites were found to be flame retardant materials from the measurement of limiting oxygen index(LOI) of samples.The oxygen permeability of PMMA/SP composites was substantially decreased as compared to virgin PMMA. 相似文献
143.
Giulia Iadevaia Jonathan A. Swain Diego Núez-Villanueva Andrew D. Bond Christopher A. Hunter 《Chemical science》2021,12(30):10218
Oligomers equipped with complementary recognition units have the potential to encode and express chemical information in the same way as nucleic acids. The supramolecular assembly properties of m-phenylene ethynylene polymers equipped with H-bond donor (D = phenol) and H-bond acceptor (A = phosphine oxide) side chains have been investigated in chloroform solution. Polymerisation of a bifunctional monomer in the presence of a monofunctional chain stopper was used for the one pot synthesis of families of m-phenylene ethynylene polymers with sequences ADnA or DAnD (n = 1–5), which were separated by chromatography. All of the oligomers self-associate due to intermolecular H-bonding interactions, but intramolecular folding of the monomeric single strands can be studied in dilute solution. NMR and fluorescence spectroscopy show that the 3-mers ADA and DAD do not fold, but there are intramolecular H-bonding interactions for all of the longer sequences. Nevertheless, 1 : 1 mixtures of sequence complementary oligomers all form stable duplexes. Duplex stability was quantified using DMSO denaturation experiments, which show that the association constant for duplex formation increases by an order of magnitude for every base-pairing interaction added to the chain, from 103 M−1 for ADA·DAD to 105 M−1 for ADDDA·DAAAD. Intramolecular folding is the major pathway that competes with duplex formation between recognition-encoded oligomers and limits the fidelity of sequence-selective assembly. The experimental approach described here provides a practical strategy for rapid evaluation of suitability for the development of programmable synthetic polymers.One pot oligomerisation reactions give access to families of oligomers that allow facile analysis of folding propensity and assessment of suitability for sequence-selective duplex formation. 相似文献
144.
Hydrocyclones are used in mineral industries for classification and separation of solid particles of different sizes and densities suspended in water medium. In the present study an Eulerian–Eulerian CFD simulation of a solid–liquid hydrocyclone has been carried out taking into account two solid phases and one liquid phase. The average size of the larger particle was 0.6117 and that of the smaller particle was 0.09875 mm. Three separate momentum balance equations for the three phases have been considered unlike that in the mixture model where a single momentum equation is solved for the three phases. Two turbulent models i.e. the Reynolds stress model (RSM) and the standard k–ε model were studied. Comparison of the two turbulence models showed slight variation in prediction of the velocity profile and the separation efficiency. The maximum deviation between the two models was observed near the wall where the stress was maximum for larger size particles. 相似文献
145.
Bibhu P. Swain Bhabani S. Swain Yung-Bin Chung Nong M. Hwang 《Solid State Sciences》2009,11(8):1408-1411
Nanocrystalline silicon (nc-Si) embedded a-SiC:H films were deposited by hot-wire chemical vapor deposition (HWCVD) using SiH4, CH4 and H2 gas precursors. The films were characterized by small-angle X-ray scattering, X-ray diffraction (XRD) and Raman spectroscopy to analyze their structural and fractal nature. The analysis of a-SiC:H films indicated the scattering from mass fractal aggregates of amorphous and nanocrystalline domains of nano-Si. The XRD results indicated that the size and crystallite fraction of nanocrystallites decreased with increasing CH4 flow rate. Nc-Si changed from the mass fractal to the surface fractal with increasing CH4 flow rate. The inter-diffusion correlation length between nc-Si embedded a-SiC:H varies from 2.4 nm to 5.7 nm with a CH4 flow rate. 相似文献
146.
We study the absorption spectrum of a two-level atom driven by a resonant laser field and damped by a broadband squeezed vacuum. We show that for some values of the Rabi frequency of the driving field the central component of the absorption spectrum can switch from absorption to amplification. We find that the presence of the squeezed vacuum field is essential for the gain at the central component. Moreover, the gain is not attributed to any population inversion in both the atomic bare states and in the dressed atomic states. We show that the gain originates from the coherent population oscillations, which are significantly enhanced when the atom is damped by a broadband squeezed vacuum. 相似文献
147.
In the theory of multiple quantum transitions in alkali metals, we show that overlap effects from resonances in a different hyperfine level may profoundly affect the line shift and profile. 相似文献
148.
A. Ashkin P. W. Smith J. M. Dziedzic W. J. Siekhaus W. H. Lowdermilk J. E. Swain R. L. Cone D. A. Ender M. S. Otteson Paula L. Fisher J. M. Friedman H. J. Guggenheim Liang Peihui Gu Zhongmin Zhang Weiqing J. -M. Halbout C. L. Tang S. D. Durbin S. M. Arakelian M. M. Cheung Y. R. Shen M. W. Sigrist V. G. Mikhalevich Liu Songhao Ho Kexlang Hui Lingkai Cui Junwen Li Qun D. G. Seiler D. Heiman R. Feigenblatt R. L. Aggarwal B. Lax H. P. Trommsdorff L. R. Andrews R. M. Hochstrasser R. Reinisch M. Nevière 《Applied physics. B, Lasers and optics》1982,28(2-3):142-149
149.
Bibhu P. Swain 《Applied Surface Science》2007,253(21):8695-8698
Hydrogenated amorphous silicon carbon alloys (a-SiC:H) films were deposited by hot wire chemical vapour deposition (HWCVD) using SiH4 and C2H2 as precursor gases. a-SiC:H films were characterized by Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Solid-state plasmon of Si network shifts from 19.2 to 20.5 eV by varying C2H2 flow rate from 2 to 10 sccm. Incorporation of carbon content changes the valence band structure and s orbital is more dominant than sp and p orbital with carbon incorporation. 相似文献
150.
Radical polymerization of acrylonitrile was carried out in an emulsifier-free condition initiated by KHSO5 catalyzed with Cu(II)/bis-salicylidene ethylene diamine (H2 Salen) complex. The Cu(II) salt alone, Cu(II)/salicylaldehyde and Cu(II)/ethylene diamine have a retarding effect on the polymerization reaction, while the chelate of Cu(II) with the tetradentate Schiff base ligand, H2 Salen has a catalytic effect. Prior to this, the catalytic effect of various bivalent transition metal salts and their couple with the Schiff base, H2 Salen on the polymerization reaction has been examined to be not significant. The in situ developed complex produces the stable emulsion leading to high conversion. In the polymerization, the variables studied were the concentration of monomer, initiator, Cu(II), H2 Salen and temperature. The overall activation energy was computed to be 13.1 kcal/mol. From the kinetic and spectral analyses, the mechanism of the initiator decomposition and initiation of polymerization by Cu(II)/H2 Salen complex were suggested. The rate of polymerization (Rp) was found to be dependent on the monomer, initiator, Cu(II) ion, H2 Salen concentrations to the 1.4, 0.3, 1.6, 1.5 power respectively. The polymers are characterized by IR and molecular weight by viscosity and GPC methods. 相似文献