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61.
Bekir Çak?r Yusuf Yakar Ayhan Özmen M. Özgür Sezer Mehmet ?ahin 《Superlattices and Microstructures》2010
The binding energy and wavefunctions of the 1s, 1p, 1d and 1f energy states of a spherical quantum dot (QD) with parabolic potential were calculated by using a method which is a combination of the quantum genetic algorithm (QGA) and the Hartree–Fock–Roothaan (HFR) approach. In addition, the linear and the third-order nonlinear optical absorption coefficients based on optical transitions in QDs with and without impurity were calculated. The results show that the parabolic potential has a great effect not only on the binding energies and but also on the optical absorption coefficients. Moreover, the calculated results also reveal that the linear and nonlinear optical absorption coefficients are strongly affected by the existence of impurity and the incident optical intensity. 相似文献
62.
Filiz Tascan Ahmet Bekir Murat Koparan 《Communications in Nonlinear Science & Numerical Simulation》2009,14(5):1810-1815
In this paper, we established travelling wave solutions for some (2 + 1)-dimensional nonlinear evolution equations. The first integral method was used to construct travelling wave solutions of nonlinear evolution equations. The travelling wave solutions are expressed by the hyperbolic functions, the trigonometric functions and the rational functions. The first integral method presents a wider applicability for handling nonlinear wave equations. 相似文献
63.
H. Ibrahim Ugras Ismet Basaran Turgut Kilic Umit Cakir 《Journal of heterocyclic chemistry》2006,43(6):1679-1684
64.
Applications of fractional complex transform and $\left( \frac{G^{\prime }}{G}\right) $-expansion method for time-fractional differential equations
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Ahmet Bekir Ozkan Guner Omer Unsal Mohammad Mirzazadeh 《Journal of Applied Analysis & Computation》2016,6(1):131-144
In this paper, the fractional complex transform and the $\left( \frac{G^{\prime }}{G}\right) $-expansion method are employed to solve the time-fractional modfied Korteweg-de Vries equation (fmKdV),Sharma-Tasso-Olver, Fitzhugh-Nagumo equations, where $G$ satisfies a second order linear ordinary differential equation. Exact solutions are expressed
in terms of hyperbolic, trigonometric and rational functions. These solutions may be useful and desirable to explain some nonlinear physical phenomena in genuinely nonlinear fractional calculus. 相似文献
65.
Naciye Bihter Taylan Bekir Sari Halil Ibrahim Unal 《Journal of Polymer Science.Polymer Physics》2010,48(12):1290-1298
This study covers the synthesis of conducting polyindole (PIN) homopolymer, poly(vinyl chloride)/polyindole (PVC/PIN) composites, and preparation of their freestanding films. PIN and composites were synthesized chemically by radicalic mechanism using FeCl3 as an initiator. Films of PVC and PVC/PIN composites were prepared by casting on glass Petri dishes. Mechanical properties of films were examined by stress–strain experiments. From FTIR spectra of polymers, it was revealed that polymerization reaction occurred by 2–3 mechanism. The conductivities of polymers at different temperatures were also measured by four‐probe technique and found in the range 10?4 to 10?5 S cm?1. Magnetic properties of the polymers were analyzed by Gouy scale measurements and were found that their conducting mechanisms are of polaron and bipolaron natures. Thermal properties of polymers were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) and found that they had shown adequate thermal stability. X‐ray diffraction (XRD) spectra showed the amorphous nature of the polymers. Scanning electron microscopy (SEM) was used for microstructural analysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1290–1298, 2010 相似文献
66.
3,5-Pyridyne (3) has been generated by flash vacuum pyrolysis of 3,5-diiodopyridine (20) and 3,5-dinitropyridine (21) and characterized by IR spectroscopy in cryogenic argon matrices. The aryne can clearly be distinguished from other side products by its photolability at 254 nm, inducing a rapid ring-opening presumably to (Z)-1-aza-hex-3-ene-1,5-diyne. As byproducts of the pyrolysis, HCN and butadiyne were identified, together with traces of acetylene, cyanoacetylene, (E)-1-aza-hex-3-ene-1,5-diyne, and the 3-iodo-5-pyridyl radical (from 20). Several pathways for rearrangements and fragmentations of 3 and of the parent meta-benzyne (1) have been explored computationally by density functional theory and ab initio quantum chemical methods. The lowest energy decomposition pathway of biradicals 1 and 3 is a ring-opening process accompanied by hydrogen migration, leading to (Z)-hex-3-ene-1,5-diyne [(Z)-10] and (Z)-3-aza-hex-3-ene-1,5-diyne [(Z)-24], respectively. Both reactions require activation energies of 45-50 kcal mol(-1). Mechanisms leading from (Z)-24 or directly from 3 to the experimentally observed byproducts are discussed. Upon replacement of the C(5)H moiety by N in meta-benzyne, high-level calculations predict a modest shortening of the interradical distance by 5-7 pm and a reduction of the singlet-triplet energy splitting by 3 kcal mol(-1), in good agreement with isodesmic equations, according to which the singlet ground state of 3 is destabilized relative to 1 by 3-4 kcal mol(-1). In contrast to 3,5-borabenzyne (2), which is found to be doubly aromatic, nucleus-independent chemical shifts of 3 are almost identical to that of pyridine, indicating the absence of paramagnetic ring current effects that may be associated with "in-plane antiaromaticity". As compared with 1, the overall perturbation caused by the nitrogen atom in 3 is weak, and four electron, three center interaction is of minor importance in this molecule. 相似文献
67.
The 1,5,6,7,8,8a‐hexahydroimidazo[1,5‐a]pyridine, 3, was quaternized with 2‐(bromomethyl‐1,3,5‐trimethylbenzene, 1,4‐bis(bromomethyl)‐2,3,5,6‐tetramethylbenzene, 2,4‐bis(bromomethyl)‐1,3,5‐trimethylbenzene, 1,3,5‐tris(bromomethyl)‐2,4,6‐trimethylbenzene and 1,3,5‐tris(bromomethyl)‐2,4,6‐triethylbenzene to obtain mono‐, bis‐ and tris‐imidazolinium salts (4–7) which were characterized by elemental analysis and NMR spectroscopy. In order to understand the effects of these changes on the N‐substituent and how they translate to catalytic activity, these new salts (4–7) with Pd(OAc)2 were applied as in situ catalysts for Suzuki‐Miyaura and Heck‐Mirozoki cross‐coupling reactions of aryl chlorides and aryl bromides, respectively. The tris‐imidazolinium salts (7) were found to be more efficient than the related analogs 4–6. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
68.
69.
Muhittin Aygün Engin Cetinkaya Yetkin G?k Engin Kendi Bekir Cetinkaya 《Analytical sciences》2003,19(7):1093-1094
In the title compound, C23H32N4Se, was synthesized and its crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in orthorhombic system, space group Pbca, a = 10.9960(10)A, b = 14.9460(9)A, c = 27.565(5)A and Z = 2. According to X-ray crystallographic studies, the diazepine ring is observed to be in a disordered state. The site-occupancy of the major compenent refined to 0.53(1). The C=Se bond length of 1.862(4)A is a double bond character. The dihedral angle between the two phenyl rings is 37.7(2) degrees. 相似文献
70.
New 1,3‐dialkylperhydrobenzimidazolinium and 1,3‐dialkylimidazolinium salts ( 2,4 ) as NHC precursors have been synthesized and characterized. These salts in combination with [RhCl(COD)]2 provided active catalysts for the addition of phenylboronic acid to aldehydes under mild conditions. The in situ prepared three‐component system [RhCl(COD)]2/imidazolinium salts ( 2,4 ) and KOBut catalyse the addition of phenylboronic acid to sterically hindered aldehydes affording the corresponding arylated secondary alcohols in good yields. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:461–465, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20132 相似文献