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1.
A.-M. M. Abdel-Rahman 《General Relativity and Gravitation》1997,29(10):1329-1343
Aspects of the modified general relativity theory of Rastall, Al-Rawaf and Taha are discussed in both the radiation- and matter-dominated flat cosmological models. A nucleosynthesis constraint on the theory's free parameter is obtained and the implication for the age of the Universe is discussed. The consistency of the modified matter-dominated model with the neoclassical cosmological tests is demonstrated. 相似文献
2.
Laila H. Abdel-Rahman 《Transition Metal Chemistry》2006,31(7):943-950
A new series of N-phthaloylglycineate (N-phthgly) ternary complexes of cobalt(II) and nickel(II) with imidazole (imi), N-methylimidazole
(mimi) and 2,2′-bipyridyl (bipy) have been synthesized and characterized by elementary analyses, IR spectroscopy, thermogravimetric
analysis. X-ray crystal structure analyses of the three complexes of [Co(mimi)2(N-phthgly)2] (1), [Co(bipy)(OH2)4](N-phthgly)2
(2) and [Ni(imi)2(N-phthgly)2(OHCH3)2] (3) were also carried out. In complex (1), the Co(II) exists in a distorted tetrahedral enviroment, where two nitrogen atoms of two methylimidazole molecules and two
oxygen atoms of the carboxylate group of two N-phthaloylglycinate molecules are coordinated. On the other hand, in complex
(2) the cobalt atom coordinates a 2,2′-bipyridine molecule and four water oxygen atoms forming a distorted octahedral conformation.
A molecule of N-phthaloylglycinate is connected by van der waals contact and H-bonds. For complex (3), the nickel atom is surrounded by four oxygens (two oxygens of two different N-phthaloylglycinate molecules and two of methanol
ligand) in the basal plane of octahedron along with two imidazole nitrogen atoms at the apical positions. Strong intramolecular
H-bond exists between the uncoordinated carboxylic oxygen of the N-phthaloylglycinate ligand and the O–H of the methanol group. 相似文献
3.
Two series of 2-(N-aryl-2-oxo-2-arylethanehydrazonoyl)-6-methyl-4(3H)-pyrimidinones 11 (12) were prepared by coupling of diazotized anilines with 2-(aroylmethylene)-1,2-dihydro-6-methyl-4(3H)-pyrimidinones 2 (3). The spectral data of such compounds together with their 3-methyl analogs 13 (14) indicated that they exist predominantly in the hydrazone tautomeric form. 相似文献
4.
Awadallah Adel M. El-Halabi Nabil M. Ferwanah Abdel-Rahman S. Awad Boshra M. 《Transition Metal Chemistry》2004,29(3):280-283
3-Acetyl-1,2,4-triazole hydrazones (3b,c) and methylhydrazone (4d) were prepared by reacting triazoles (1b–d) with an excess of hydrazines at room temperature. Square planar nickel(II) complexes (8b,c) of (3b,c) were obtained from their reaction with Ni(OAc)2 in a 2:1 mol ratio in EtOH at room temperature. The spectral data suggest structures (8b,c) for the obtained complexes, which result from ring opening of the triazole ring followed by recyclization to give the 5-arylhydrazono-2,3-dihydro-4H-1,2,4-triazine ligand (7b,c). The reaction of triazole methylhydrazone (4d) with Ni(OAc)2 in EtOH resulted, however, in the formation of the starting triazole (1d). All new compounds were characterized by elemental analysis, i.r., 1H-n.m.r. 13C-n.m.r. and hrms. 相似文献
5.
Mostafa Mohsen M. El-Shazly Rafaat M. Rakha Tawfik H. Abdel-Rahman Mohamed H. 《Transition Metal Chemistry》2002,27(3):337-340
Tribochemical reactions of KBr, KI and CaI2 with [Cu(L)Cl2(EtOH)3/2(H2O)]1/2H2O (L = formylhydrazine) give novel CuI and CuII complexes, which have been characterized by elemental analyses, spectral (i.r., u.v.–vis., 1H-n.m.r.) and magnetic measurements. The i.r. spectra indicate that (L) behaves in a monodentate manner, coordinating via the azomethine nitrogen (C-N) group in the CuII complexes, but behaving as a bidentate ligand, via the carbonyl oxygen and NH2 groups in the CuI complexes. KI and CaI2 react with [Cu(L)Cl2(EtOH)3/2(H2O)]-1/2H2O in the solid state, accompanied by a colour change, substitution of the chloride by iodide ions, and reduction of CuII to CuI to give complexes with formulae [Cu(L)I(EtOH)1/2] and [Cu1.7(L)I1.7(EtOH)1/2]. On the other hand, the tribochemical reaction of KBr with [Cu(L)Cl2(EtOH)3/2(H2O)]1/2H2O is accompanied by a colour change; substitution of the chloride by bromide ions, but without reduction of CuII and yields a complex of formula [Cu(L)2Br2(EtOH)(H2O)]1/2EtOH. The spectral and magnetic results suggest a distorted octahedral geometry for the CuII complexes while a tetrahedral geometry around the CuI ion. The non-stoichiometric structure of [Cu1.7(L)I1.7(EtOH)1/2] is discussed. 相似文献
6.
Ayman M. Atta Ahmed A. Fadda Adel A.-H. Abdel-Rahman Husein S. Ismail Rasha R. Fouad 《Journal of Dispersion Science and Technology》2013,34(6):775-785
Water soluble nonionic amphiphilic block copolymers based on hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(propylene glycol) (PPG) were prepared. Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymers, PEG-PPG-PEG, were prepared in the normal condition. The chemical composition and molecular weights of the prepared copolymers were determined from 1H NMR and GPC techniques. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for water in crude-oil emulsions that were pronounced at different ratios of crude oil: water at 318 K and 333 K. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 100% based on demulsifier chemical compositions and concentrations. 相似文献
7.
Taha M. Abdel-Rahman 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1737-1754
A novel method for the synthesis of 1,3,4-thiadiazole and 1,3,4-thiadiazine derivatives bearing a carbazole moiety is described. Carbazole was transformed into carbazole-9-thiocarbohydrazide in two steps. This compound was allowed to react with various electrophiles to yield 1,3,4-thiadiazole derivatives. The reaction with bifunctional electrophiles led to 1,3,4-thiadiazines. 2-(Carbazol-9-yl)-5,6-dihydro-4H-1,3,4-thiadiazin-5-one reacted with piperidine and formaldehyde to yield the 4-(piperidin-1-ylmethyl) derivative. The reaction with aromatic aldehydes led to the corresponding 6-arylidene derivatives, which were transformed into pyrimidino[4,5-e]-1,3,4-thiadiazines and pyrazolo[3,4-e]-1,3,4-thiadiazines by a reaction with guanidine, acetamidine, or phenylhydrazine, respectively. Structures of the products were confirmed by 1H NMR, 13C NMR, IR, and mass spectrometric measurements. Selected examples of products were screened for anticancer activity. 相似文献
8.
Fathy M. Abdelrazek Mohamed S. Farghaly Hussein E. Abdelrahman 《Journal of heterocyclic chemistry》2015,52(1):163-168
The xylidines 1a , 1b undergo condensation with ethyl cyanoacetate 2 and ethyl benzoyl acetate 15 to afford the cyano acetanilides 3a , 3b and the β‐diketones 16a , 16b , respectively. Compounds 3a , 3b react with hydrazine and phenyl hydrazine to afford the azine‐bis derivatives 5a , 5b and 7a , 7b , whereas 16a , 16b react with the same reagents to afford the pyrazolyl amine derivatives 17a , 17b and 18a , 18b , respectively. Compounds 3a , 3b react also with dimethylformamide dimethylacetal to afford the enaminonitriles 8a , 8b , whereas 16a , 16b react with the same reagent to afford only the enaminone 19b . The enaminonitriles 8a , 8b react with hydrazine and phenyl hydrazine to afford also the azine‐bis derivatives 11a , 11b and 14a , 14b , respectively. 相似文献
9.
Mousa Al-Noaimi Ismail I. Fasfous Firas F. Awwadi Deeb Taher Abdallah Alfayyoumi Obadah S. Abdel-Rahman 《Transition Metal Chemistry》2016,41(7):795-805
Five octahedral ruthenium(II) complexes with azoimine–quinoline (Azo) and α-diimine (L) ligands having the general formula [RuII(L)(Azo)Cl](PF6) (1–5) {Azo: PhN=NC(COMe)=NC9H6N, L = 4,4′-dimethoxy-2,2′-bipyridine (dmeb) (1), 4,4′-di-tertbutyl-2,2′-bipyridine (dtb) (2), 1,10-phenanthroline (phen) (3), 5-chlorophenanthroline (Clphen) (4), or 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) (5)} were prepared by stepwise addition of the tridentate azoimine (H2Azo) and α-diimine (L) pro-ligands to RuCl3 in refluxing EtOH. The tridentate azoimine–quinoline ligands coordinate to ruthenium via the Azo-N′, N′-imine and N″-quinolone nitrogen atoms. The spectroscopic properties (IR, UV/Vis, 1H, 13C and 19F NMR) and electrochemical behavior of complexes 1–5 and the X-ray crystal structures of complexes 2 and 3 are presented. The coordination of Ru(II) to these strong π-acceptor ligands (Azo and L) results in a large anodic shift for the Ru(III/II) couples of 1.63–1.72 V versus NHE. The electronic spectra in MeCN and IR spectra in CH2Cl2 for complex 3 in its oxidized 3 + and reduced 3 ? forms were investigated. The calculated absorption spectrum of 3 in MeCN was used to assign the UV–Vis absorption bands. 相似文献
10.
S. M. S. Atta N. M. Fawzy F. A. Ahmed A. H. Abdel-Rahman 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):863-875
4,7-Dimethoxy ( Ia ) and 4-methoxy ( Ib ) 6-hydroxybenzofuran-5-carbohydrazide were reacted with aryl or alkyl isothiocyanates to give the corresponding thiosemicarbazides ( IIa-h ). Cyclization of the substituted thiosemicarbazides with sodium hydroxide led to the formation of 1,3,4-triazol-2-yl-benzofuran derivatives ( IIIa-d ). Desulfurization of thiosemicarbazide by mercuric oxide gave 1,3,4-oxadiazolyl-benzofuran ( IVa-c ). Treatment of thiosemicarbazide with ethyl bromo-acetate or f -bromopropionic acid yielded 4-thiazolidin-2-yl-carbonyl-benzofuran ( Va-h ). The reaction of compounds IIb , e , f with sulphuric acid or phosphorus oxychloride gave 1,3,4-thiadiazol-2-yl-benzofuran ( VIa-d , VII ). 相似文献