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711.
A novel and efficient method to access phenolic glycosides has been established by using copper-mediated coupling reaction of aryl boronic acids with hemiacetals. The reaction enjoyed a wide range of substrate scope, and many phenolic glycosides can be synthesized in good yields. 相似文献
712.
Rajshekhar Ghosh 《Journal of organometallic chemistry》2005,690(5):1282-1293
The insertion of phenyl isocyanate into titanium isopropoxide leads to the formation of a dimeric complex [Ti(OiPr)2(μ-OiPr){C6H5N(OiPr)CO}]2 (1) which has been structurally characterized. Reaction of titanium isopropoxide with two and more than 2 equiv. of phenyl isocyanate is complicated by competitive, reversible insertion between the titanium carbamate and titanium isopropoxide. The ligand formed by insertion of phenyl isocyanate into the titanium carbamate has been structurally characterized in its protonated form C6H5N{C(OiPr)O}C(O)N(H)C6H5 (3aH). Insertion into the carbamate is kinetically favored whereas insertion into isopropoxide gives the thermodynamically favored product. 相似文献
713.
Iodine/MeOH: a novel and efficient reagent system for thiocyanation of aromatics and heteroaromatics
Indoles, pyrroles, oxindoles and aromatic amino compounds undergo smooth thiocyanation with ammonium thiocyanate in the presence of molecular iodine in methanol under mild conditions to afford the corresponding 3-indolyl, 2-pyrrolyl and 4-aryl thiocyanates, respectively, in excellent yields with high selectivity. The reactions proceed rapidly at room temperature without heating or the use of strong Lewis acids. 相似文献
714.
Dadkhoda?GhazanfariEmail author Fariba?Najafizadeh Fereshteh?Khosravi 《Monatshefte für Chemie / Chemical Monthly》2004,135(11):1409-1413
Summary. 4-Aminoperoxybenzoic acid supported on silica gel in presence of air was found to be a selective and convenient oxidant for the oxidation of methylene groups in aryl ketones to convert them to -diketones. 相似文献
715.
C Picherit 《Tetrahedron letters》2004,45(12):2579-2583
Depending on the amount of acid used, treating aryl-dialkyl triazenes of general structure 3 with triflic acid resulted in the formation of either the corresponding arenediazonium triflates 4 or aryl triflates 8 apparently by two different pathways, the latter conversion being favoured at high acid concentration. 相似文献
716.
Bernadette S Creaven John F Gallagher John McGinley Brian A Murray Giuseppe S Whelan 《Tetrahedron》2004,60(1):137-143
Nolte's bis(o-xylylenyl)diphenylglycoluril molecular clips, in which the phenyls act as conformational ‘locks’ of the receptor site, have been modified with p-methoxy substituents on the phenyls. While this change does not have a major effect on the complexation of guests such as resorcinol (m-dihydroxybenzene) in chloroform solution, it allows for new binding geometries in the solid state. The crystal structure of new host 1,6:3,4-bis(1,2-xylylene)tetrahydro-3a,6a-bis(4-methoxyphenyl)-imidazo[4,5-d]imidazole-2,5(1H,3H)-dione (11) complexed with 4-phenylphenol (4-PP) has been determined as its toluene solvate [(11):2(4-PP):0.5(C7H8)]. Molecules of 11 aggregate in 1-D chains through polymeric self-inclusion via C-H?π(aromatic) interactions: 2-D sheets form via aryl stacking of the 1-D chains and the 3-D structure consists of alternating sheets of 11 in between which sheets of (4-PP):0.5(C7H8) reside. 相似文献
717.
A series of new aryloxymethylquinoxalines, benzo[b]- and naphtho[2,1-b]furylquinoxalines, possessing potential biological activity, was prepared, characterized by IR and NMR spectroscopy and their electron ionization (EI) mass spectra studied in detail. The aryloxymethylquinoxalines were obtained by reacting halogenomethylquinoxalines with bifunctional O-nucleophiles. The benzo[b]furylquinoxalines and naphtho[2,1-b]furylquinoxalines were prepared via two routes, which differed in the order of the two cyclization steps involved in the syntheses. The composition of the ions obtained by EI mass spectrometry were determined by accurate mass measurements and the fragmentation pathways clarified by B/E linked scans and collision induced dissociation. The mass spectrometric behaviour of the compounds studied as to the possible loss of OH radicals proved to be very characteristic. 相似文献
718.
《印度化学会志》2021,98(3):100012
Catalytic oxidation of organic substrates has wide applications in chemical industries due to which huge extensive research work is continuously going on throughout the world. Present study reports efficacious use of Trans (Cl)-2,2′-bipyridinedicarbonyldichlororuthenium(II) complex catalyzed oxidation of internal and terminal olefins, aryl hydrocarbons and alcohols. CH2Cl2–C2H5OH (6:4) was suitable solvent system for these oxidation reactions. The normal pressure oxidation reaction has been carried out at 1 atm. Pressure of oxygen and at 300C. The high pressure oxidation reaction was done at 4.48 × 103 KNm3 pressure of oxygen and at 600C. No diminished catalytic activity was observed while checking the recyclability of catalyst up to 6–8 catalytic runs. Catalytic activity was also investigated using tert-butyl hydroperoxide as oxidant inspite of di-oxygen. Effect of different parameters on the rate of oxidation was also studied i.e. extra ligand, temperature, solvents, acids and bases. Kinetic studies have been done and on the basis of kinetics, the mechanism is proposed. 相似文献
719.
The coupling reaction of aryl chlorides with arylboronic acids was successfully performed in isopropanol (IPA) by using [NiCl(Ph2PCH2CH2OH)2(H2O)]Cl (5), a cationic Ni(II)-complex, as a precatalyst in the absence of a reducing agent. The coupling reaction proceeded smoothly under mild conditions to provide biaryls in satisfactory to excellent yields, and formation of the undesired dechlorination products of aryl chlorides was completely prevented. 相似文献
720.
Arylselenylations of methylbenzenes, methoxybenzenes and thiophene were smoothly achieved with selenenium ions generated by comproportionation of 1:1 mixtures of p-toluenesulfonic acid salts of seleninic acids and the corresponding diselenides. A series of p-toluenesulfonic salts of seleninic acids were prepared by hydrogen peroxide oxidation of the corresponding diselenides in the presence of p-toluenesulfonic acid. Novel 2-(organylseleno)thiophenes were obtained by heating the protonated seleninic acids with a 50-fold excess of thiophene in glacial acetic acid. 相似文献