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51.
The Constant Modulus Algorithm (CMA), although it is the most commonly used blind equalization technique, converges very slowly.
The convergence rate of the CMA is quite sensitive to the adjustment of the step size parameter used in the update equation
as in the Least Mean Squares (LMS) algorithm. A novel approach in adjusting the step size of the CMA using the fuzzy logic
based outer loop controller is presented in this paper. Inspired by successful works on the variable step size LMS algorithms,
this work considers designing a training trajectory that it overcomes hurdles of an adaptive blind training via controlling
the level of error power (LOEP) and trend of error power (TOEP) and then obtains a more robust training process for the simple
CMA algorithm. The controller design involves with optimization of training speed and convergence rate using experience based
linguistic rules that are generated as a part of FLC. The obtained results are compared with well-known versions of CMA; Conventional
CMA, Normalized-CMA [Jones, IEEE conference record of the twenty-ninth asilomar conference on signals, systems and computers (Vol. 1, pp. 694–697), 1996], Modified-CMA [Chahed, et al., Canadian conference on electrical and computer engineering (Vol. 4, pp. 2111–2114), 2004], Soft Decision Directed-CMA (Chen, IEE Proceedings of Visual Image Signal Processing, 150, 312–320, 2003) for performance measure and validation. 相似文献
52.
Ali Bilici smet Kaya Fatih Doan 《Journal of polymer science. Part A, Polymer chemistry》2009,47(12):2977-2984
Catalytic oxidative polymerization of 2,2′‐dihydroxybiphenyl (DHBP) was performed by using both the Schiff base monomer‐Cu(II) complex and Schiff base polymer‐Cu(II) complex compounds as catalysts and hydrogen peroxide as oxidant, respectively. The dependence of monomer conversion and molecular weight distribution on various reaction parameters, including time, temperature, solvent as well as the amount of catalyst and oxidant were investigated. The structure of the poly‐2,2′‐dihydroxybiphenyl (PDHBP) was confirmed by UV‐vis, IR, 1H and 13C NMR spectroscopy techniques. The electrochemical and thermal properties of PDHBP were also studied. DSC data revealed that PDHBP was amorphous. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2977–2984, 2009 相似文献
53.
We compare the exact and perturbative results in two metrics and show that the spurious effects due to the perturbation method do not survive for physically relevant quantities such as the vacuum expectation value of the stress-energy tensor. 相似文献
54.
We formulate a subgrid eddy viscosity method for solving the steady‐state incompressible flow problem. The eddy viscosity does not act on the large flow structures. Optimal error estimates are obtained for velocity and pressure. The numerical illustrations agree completely with the theoretical results. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005 相似文献
55.
Murat Kaya Mehmet Gökhan Halıcı Fatih Duman Sevil Erdoğan Talat Baran 《Natural product research》2015,29(13):1280-1284
Lichens are symbiotic associations formed mainly by ascomycete fungi and green algae or cyanobacteria. The presence of chitin in the fungal cell wall has been revealed by previous studies. Considering the presence of fungi in the lichens, this work determines the presence of chitin in a cosmopolitan lichen species Xanthoria parietina. In this study, chitin was derived from a lichen species for the first time and its physicochemical properties were determined by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and elemental analysis. The dry weight chitin content of X. parietina was 4.23%, and this chitin was in the α-form. The crystalline index value of the lichen chitin was calculated as 70.1%. The chitin from X. parietina had a smooth surface. 相似文献
56.
Opening Enediyne Scissors Wider: pH‐Dependent DNA Photocleavage by meta‐Diyne Lysine Conjugates 下载免费PDF全文
Photochemical activation of meta‐diynes incapable of Bergman and C1–C5 cyclizations still leads to efficient double‐strand DNA cleavage. Spatial proximity of the two arylethynyl groups is not required for efficient DNA photocleavage by the enediyne‐lysine conjugates. Efficiency of the cleavage is a function of the external pH and DNA damage is strongly enhanced at pH < 7. The pH‐dependence of the DNA photocleavage activity stems from the protonation states of lysine amino groups, the internal electron donors responsible for intramolecular PET quenching and deactivation of the photoreactive excited states. DNA‐binding analysis suggests intercalative DNA binding for phenyl substituted conjugate and groove binding for TFP‐substituted conjugate. Additional insights in the possible mechanism for DNA damage from the ROS (Reactive Oxygen Species) scavenger experiments found that generation of singlet oxygen is partially involved in the DNA damage. 相似文献
57.
A new method for determining viscosity of liquids is examined. The method employs the principles of vibration and measures the viscous damping due to the motion of a liquid placed in a cylindrical tube. The apparatus and the test liquid are treated as a dynamic system and the measured mechanical impedances are used to calculate energy dissipation due to the viscous damping. The newly designed apparatus is able to generate shear deformations in the liquid without using moving solid surfaces. A harmonic varying force with a frequency close to the resonance frequency of the system is applied through a piston and the resulting velocities of the oscillations generated in the system are measured. Liquids with higher viscosities result in lower velocities due to the higher damping. Analytical equations are provided to relate the viscous damping of the dynamic system to the viscosity of the liquids. The viscosities obtained from the proposed method are in good agreement with the ones obtained from standard rotational viscometry using a cone and plate geometry. 相似文献
58.
Hierarchical Zeolite: Catalyst Design by NH4OH Treatment of USY Zeolite (Adv. Funct. Mater. 46/2015) 下载免费PDF全文
Joost Van Aelst Danny Verboekend An Philippaerts Nicolas Nuttens Mert Kurttepeli Elena Gobechiya Mohamed Haouas Sreeprasanth P. Sree Joeri F. M. Denayer Johan A. Martens Christine E. A. Kirschhock Francis Taulelle Sara Bals Gino V. Baron Pierre A. Jacobs Bert F. Sels 《Advanced functional materials》2015,25(46):7244-7244
59.
Enthalpies (Δisom
H
(g)o), Gibbs free energies (Δisom
G
(g)o), and equilibrium constants (log K
isom) for the trans → cis isomerization of various 3,3′-, 4,4′-, and 5,5′- disubstituted 2,2′-diphenoquinones with a range of electron withdrawing
and releasing moieties (methyl, fluoro, chloro, bromo, trifluoromethyl, and amino) were calculated in the gas phase and in
the solvent phase (n-hexane, benzene, n-octanol, acetonitrile, and water). In the gas phase, the trans isomer of the parent and all substituted 2,2′-diphenoquinones is predicted to be more thermodynamically stable than the cis configuration, with log K
isom ranging from −2.8 to −7.0. For all compounds, increasing solvent polarity/proticity progressively favors shifting the cis/trans equilibrium towards greater contributions of the cis configuration and substantially increases the log K
isom by up to 5.1 units relative to the gas phase. In polar protic and polar aprotic solvents, the estimated log K
isom ranges as low as −0.4, indicating significant populations of the cis isomers should be present. The findings support the polar solvent phase mechanistic predictions for a cis configuration of 2,2′-diphenoquinones participating in the thermal transformation of trans-2,2′-diphenoquinones to oxepino[2,3-b]benzofurans. With limited exceptions for some amino derivatives, the cis-2,2′-diphenoquinone to oxepino[2,3-b]benzofuran isomerization is expected to be thermodynamically favorable for all substituents/phases
under consideration. The cis-2,2′-diphenoquinone to oxepino[2,3-b]benzofuran rearrangement is predicted to become less thermodynamically favored with
increasing solvent polarity/proticity. 相似文献
60.
Comparison of certain value-at-risk estimation methods for the two-parameter Weibull loss distribution 总被引:2,自引:0,他引:2
Omer L. Gebizlioglu Birdal ?eno?luYeliz Mert Kantar 《Journal of Computational and Applied Mathematics》2011,235(11):3304-3314
The Weibull distribution is one of the most important distributions that is utilized as a probability model for loss amounts in connection with actuarial and financial risk management problems. This paper considers the Weibull distribution and its quantiles in the context of estimation of a risk measure called Value-at-Risk (VaR). VaR is simply the maximum loss in a specified period with a pre-assigned probability level. We attempt to present certain estimation methods for VaR as a quantile of a distribution and compare these methods with respect to their deficiency (Def) values. Along this line, the results of some Monte Carlo simulations, that we have conducted for detailed investigations on the efficiency of the estimators as compared to MLE, are provided. 相似文献