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21.
J. Jayabharathi V. Kalaiarasi V. Thanikachalam K. Vimal 《Journal of fluorescence》2014,24(5):1379-1387
An intramolecular excited charge transfer (CT) analysis of imidazole derivatives has been made. The determined electronic transition dipole moments has been used to estimate the electronic coupling interactions between the excited charge transfer singlet state (1CT) and the ground state (S0) or the locally excited state (1LE). The properties of excited 1CT state imidazole derivatives have been exploited by the significant contribution of the electronic coupling interactions. The excited state intramolecular proton transfer (ESIPT) analysis has also been discussed. 相似文献
22.
Highly Efficient One‐Pot Preparation of 1,2,4‐Oxadiazoles in the Presence of Diazabicycloundecene 下载免费PDF全文
New highly efficient method for the cyclization of acylamidoximes in the presence of diazabicycloundecene was developed and incorporated into a general and practical one‐pot synthesis of 1,2,4‐oxadiazoles (11 examples, 85–97% yields). 相似文献
23.
Vimal K. Tiwari Ravindra V. Ghorpade Kang Lib Kim Giyoung Song Taehee Kim Haksoo Han Cheolmin Park 《Journal of Polymer Science.Polymer Physics》2016,54(23):2401-2411
We report an efficient route for ferroelectric polar β phase generation in poly(vinylidene fluoride) (PVDF) through incorporation of amine functionalized, porous silica (MCM‐41 and fumed silica) based nanofillers. These porous highly functionalized surfaces exhibit the efficient secondary interaction with polymer chain via hydrogen bonding. Structural analysis through FTIR, XRD, and TEM confirm high degree of ferroelectric polar β phase generation of PVDF through incorporation of amino modified porous silica nanofillers. Optimized loading (5 wt %) of amine functionalized, porous silica in PVDF matrix enhances relative intensity of β phase up to 75%. Disappearance of spherulite structure of PVDF with amino modified porous silica nanofillers, as confirmed through POM, TEM, SEM and AFM studies also supports the above conclusion. The P‐E hysteresis loop at sweep voltage of ±50 V of a thin PVDF‐amino modified porous nanofiller film shows excellent ferroelectric property with nearly saturated high remnant polarization 2.8 µC.cm?2 owing to its large proportion of β PVDF, whereas, a nonpolar pure PVDF thin film shows unsaturated hysteresis loop with 0.6 µC.cm?2 remnant polarization. PVDF films with the nanofillers exhibit strong adhesive strength over different metallic substrates making them have edge over PVDF in various thin film applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 2401–2411 相似文献
24.
Vimal Chandra Srivastava Indra Deo Mall Indra Mani Mishra 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,312(2-3):172-184
The present study reports the competitive adsorptive removal of cadmium (Cd(II)) and zinc (Zn(II)) ions from binary systems using rice husk ash (RHA), a waste obtained from the rice husk-fired furnaces, as an adsorbent. The initial pH (pH0) affects significantly the capacity of RHA for adsorbing the metallic ions in the aqueous solution. The pH0 ≈ 6.0 is found to be the optimum for the removal of Cd(II) and Zn(II) ions by RHA. The single ion equilibrium adsorption from the binary solution is better represented by the non-competitive Redlich–Peterson (R–P) and the Freundlich models than by Langmuir model in the initial metal concentration range of 10–100 mg/l. The adsorption of Zn(II) ion is more than that of Cd(II) ion, and this trend is in agreement with the single-component adsorption data. The equilibrium metal removal decreases with increasing concentrations of the other metal ion and the combined effect of Cd(II) and Zn(II) ions on RHA is generally found to be antagonistic. Non-modified Langmuir, modified Langmuir, extended-Langmuir, extended-Freundlich, Sheindorf–Rebuhn–Sheintuch (SRS), non-modified R–P and modified R–P adsorption models were tested to find the most appropriate competitive adsorption isotherm for the binary adsorption of Cd(II) and Zn(II) ions onto RHA by minimizing the Marquardt's percent standard deviation (MPSD) error function. The extended-Freundlich model satisfactorily represents the adsorption equilibrium data of Cd(II) and Zn(II) ions onto RHA. 相似文献
25.
Veda Ramaswamy Vimal Kothiyal Indra D. Singh Rajamani Krishna 《Fresenius' Journal of Analytical Chemistry》1988,332(4):358-361
Summary A simple and fast column chromatographic procedure for the separation of vacuum residues into saturates, mono-, di-, polyaromatics and polars has been standardized using silica-alumina-bauxite adsorbents and gradient elution with n-pentane, benzene, and methanol. The cut points have been monitored employing ultraviolet and infrared spectroscopy. The method is applicable for preparative separation of short residues from processed products.
Rasche Trennung der Kohlenwasserstofftypen von Vakuum-RückstÄnden相似文献
26.
Howard C. Clark George Ferguson Vimal K. Jain Masood Parvez 《Journal of organometallic chemistry》1984,270(3):365-373
Compounds of the types Me3PtX(NN) (where X = Cl, I, OAc, NO3; NN = bis(1-pyrazolyl)methane (pz2CH2), bis(3,5-dimethyl-1-pyrazolyl)methane ((Me2pz)2CH2), or bis(2-pyridyl)methane (py2CH2)), [Me3Pt(NNN)][PF6] (where NNN=tris(1-pyrazolyl)methane (pz3CH), or tris(2-pyridyl)methane (py3CH)), and [Me3Pt((Me2pz)2CH2(py)][PF6] have been prepared and characterized by elemental analyses and 1H and 13C NMR spectroscopy; the structure of Me6PtI[(Me2pz)2CH2] (1) has also been determined by X-ray crystallography. Crystals of 1 are orthorhombic, space group Pcmn with four molecules in a unit cell of dimensions a 11.936(5), b 14.462(4), c 10.138(5) Å. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations to R = 0.022 for 1719 observed data. The molecule has crystallographic mirror symmetry. The Pt atom has octahedral geometry with one methyl group trans to iodine and two methyl groups trans to the N atoms of the bidentate ligand (Pt---I 2.843(1), Pt---N, 2.236(4), Pt---C 2.077(6) (trans to I) and 2.032(5) Å (trans to N)). 相似文献
27.
Shirvi Vimal D. Channabasavaraj Kupsad P. Kumar G. Vijaya Mani T. Tamizh 《平面色谱法杂志一现代薄层色谱法》2010,23(5):369-372
JPC – Journal of Planar Chromatography – Modern TLC - A simple, precise, accurate, and rapid HPTLC method for quantitative analysis of venlafaxine hydrochloride in the tablet dosage... 相似文献
28.
Vimal Singh 《Nonlinear Analysis: Real World Applications》2013,14(1):684-689
A criterion for the global asymptotic stability of direct-form digital filters using two’s complement arithmetic is presented. The criterion is in the form of a linear matrix inequality (LMI) and, hence, computationally tractable. Splitting the two’s complement nonlinearity sector [?1,1] into two smaller sectors, [0, 1] and [?1,0], together with using a type of “generalized” sector condition by involving saturation nonlinearity, is the novel feature in the present proof. A special case of the criterion is highlighted. The effectiveness of the present approach is demonstrated by showing its ability to establish the two’s complement overflow stability region, in the parameter space, for a second-order digital filter. 相似文献
29.
Vimal K. Jain 《Polyhedron》1985,4(12):2089-2096
The nature of the 8-quinolinato ligand in various forms has been examined by 15N, 13C and 119Sn NMR spectroscopy, with evidence also from electronic spectroscopy. These forms include 8-quinolinol (HQ), 8-quinolinate, the 8-hydroxyquinolinium ion, O- and N-methyl derivatives, 8-methoxyquinoline (MeQ), the zwitterionic N-methylquinolinium-8-olate and the N-methylquinolinium ion, and the chelating ligand in organotin(IV) complexes. The 15N shift from MeQ to HQ affords a measure of the intramolecular hydrogen bonding in HQ. The 15N shifts and 2J(15N1H) couplings afford criteria of chelation, and the O- and N-methyl compounds provide useful reference points for its assessment. Evidence for chelation is demonstrated in three groups of compounds, [SnR2Q2] (R = Me, Et, Bun, Octn or Ph), [SnR3Q] (R = Me, Et, Bun or Ph) and [SnR2ClQ] (R = Me, Et, Bun or Octn), the 15N and 119Sn shielding increasing from the [SnR3Q] to the [SnR2Q2] compounds. 相似文献
30.