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1.
Recently, Chawla et al. described a second order finite difference method for the class of singular two-point boundary value problems:
相似文献
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3.
M. M. Chawla 《BIT Numerical Mathematics》1981,21(2):190-193
A family of symmetric (hybrid) two-step fourth order methods is derived fory'=f(x,y). We then show the existence of a sub-family of these methods which when applied toy'=–
2
y, real, areP-stable. We also note that a general (order) symmetric two-step method isP-stable iff it is unconditionally stable. 相似文献
4.
M. M. Chawla 《BIT Numerical Mathematics》1977,17(2):128-133
We present a new sixth order finite difference method for the second order differential equationy=f(x,y) subject to the boundary conditionsy(a)=A,y(b)=B. An interesting feature of our method is that each discretization of the differential equation at an interior grid point is based onfive evaluations off; the classical second order method is based on one and the well-known fourth order method of Noumerov is based on three evaluations off. In case of linear differential equations, our finite difference scheme leads to tridiagonal linear systems. We establish, under appropriate conditions, the sixth order convergence of the finite difference method. Numerical examples are considered to demonstrate computationally the sixth order of the method. 相似文献
5.
An eighth order tridiagonal finite difference method for nonlinear two-point boundary value problems
M. M. Chawla 《BIT Numerical Mathematics》1977,17(3):281-285
We present an eighth order finite difference method for the second order nonlinear boundary value problemy=f(x, y), y(a)=A, y(b)=B; the method iseconomical in the sense that each discretization of the differential equation at an interior grid point is based on seven evaluations off. For linear differential equations, the scheme leads to tridiagonal linear systems. We showO(h
8)-convergence of the method and demonstrate computationally its eighth order. 相似文献
6.
Molecular weight distribution studies. I. Radiation-induced polymerization of liquid α-methylstyrene
A. S. Chawla Robert Y. M. Huang 《Journal of polymer science. Part A, Polymer chemistry》1975,13(6):1271-1284
The concentration of water in purified and BaO-dried α-methylstyrene was found to be 1.1 × 10?4M. The radiation-induced bulk polymerization of the α-methylstyrene thus prepared was studied in the temperature range of ?20°C to 35°C. The polymerization rate varied as the 0.55 power of the dose rate. The theoretical molecular weights and molecular weight distribution were calculated from a proposed kinetic scheme and these values were then compared with those found experimentally. The agreement between these two was reasonably close, and therefore it was concluded that, from the molecular weight distribution point of view, the proposed kinetic scheme for the cationic polymerization of α-methylstyrene is an acceptable one. The rate constant for chain transfer to monomer kf changed with temperature and was found to be responsible for the decrease in the molecular weight of the polymer with increase in temperature. kf and kp at 20°C were found to be 0.95 × 104 l./mole-sec and 0.99 × 106 l./mole-sec, respectively. 相似文献
7.
Narula Suraj P. Soni Sajeev Malhotra Rajesh Meenu Puri Jugal K. 《Transition Metal Chemistry》2002,27(7):795-798
Si(NHC6H4F-o)4 · 3TiCl4
(1) has been obtained from the disproportionation of (CF3CH2O)3SiNHC6H4F-o and TiCl4 in petroleum ether (40–60 °C) at –10 °C. The analytical (elemental analysis, molar conductance) and spectral (i.r., 1H- and 19F-n.m.r.) data suggested that (1) behaves as [Si(NHC6H4F-o)4 · Ti2Cl7]+ [TiCl5]–. The presence of these ions has been confirmed by characterising the products of metathetical reactions of (1) with R4NX (R = Bu and Et; X = I and Br) and with AgNO3. The data suggest the presence of a new titanium cation [Ti2Cl7]+. 相似文献
8.
Excess volumes of mixing, VE, for binary mixtures of tetrahydrofuran (THF) with methanol, ethanol, n-butanol, tert-butanol, 2-bromoethanol and ethylene glycol have been determined from the experimental density measurements at 298.15 K over the entire composition range. The VE data follow the order: ethylene glycol < 2-bromoethanol < methanol < ethanol < n-butanol < tert-butanol. The results have been explained in terms of self-association and the hydrogen bond-donating abilities of alcohols. 相似文献
9.
Complexes of CoII with N,N-bis-(3-carboxy-1-oxopropanyl)-1,2-ethylenediamine(L1), N,N-bis-(3-carboxy-1-oxopropanyl)-1,2-phenylenediamine(L2), N,N-bis-(2-carboxy-1-oxophenelenyl)-1,2-phenylenediamine(L3) and N,N-bis-(3-carboxy-1-oxoprop-2-enyl)-1,2-phenylenediamine(L4) have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, electronic spectra and thermal studies. Stability constants of the complexes have been evaluated potentiometrically. Vibrational spectra indicate coordination of amide and carboxylate oxygens of the ligands along with two water molecules giving a MO6 weak field octahedral chromophore. Electronic spectra support octahedral geometry around CoII. The [Co(L1)-(H2O)2] · 2H2O complex has the maximum activation energy and [Co(L3)(H2O)2] complex has the minimum activation energy. The order of stability constants of the CoII complexes with various ligands is due to their -donor abilities. 相似文献
10.
Rakesh?Kumar?MahajanEmail author Jyoti?Chawla Mandeep?Singh?BakshiEmail author 《Colloid and polymer science》2004,282(10):1165-1168
Cloud point (CP) measurements of Tween 20 and Tween 80 were carried out in the presence of various glycol oligomers and triblock polymers (TBP). The cloud points of both Tween 20 and 80 decrease in the presence of both types of additives. Among the glycol oligomeric additives, ethylene glycol monobutyl ether was found to reduce the CP maximum. An increase in the repeating units of polymeric glycol additives leads to a decrease in CP. Reduction in the CP in the presence of TBP depends upon the increase in hydrophobic/hydrophilic ratio among the polypropylene to polyethylene units. 相似文献
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