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201.
Tanaka M Norimine Y Fujita T Suemune H Sakai K 《The Journal of organic chemistry》1996,61(20):6952-6957
7-Substituted norbornadienes were stereoselectively converted into the meso-3,5-bis(acetoxymethyl)cyclopentenes by a three-step sequence of ozonolysis, reduction, and acetylation. Rhizopus delemar lipase (RDL)-catalyzed asymmetric hydrolysis of meso-3,5-bis(acetoxymethyl)cyclopentenes afforded the monoalcohols of high enantiomeric purities (>95% ee) in good yields (64-95%). The obtained monoalcohols 11 and 14 could be applied for the synthesis of antiviral carbocyclic nucleosides (-)-carbovir and (-)-BCA. 相似文献
202.
Treatment of thiacalix[8]arene (3.8H) with KH in THF, followed by recrystallization from methanol, affords an adduct of [K4(3.4H)].8MeOH as a pale yellow crystal (4), which shows highly-extensive coordination that gives rise to a zeolitic structure. An adduct of 4 gives apohost [K4(3.4H)] with the loss of methanol, which can adsorb such gaseous organic guest molecules as methanol and benzene. After binding methanol as the guest molecule, the apohost is converted back to the original structure of 4. 相似文献
203.
The direct reductive amination (DRA) of carbonyl compounds with amines has been achieved using homogenous iridium catalyst and gaseous hydrogen. It appeared that the cationic iridium catalyst, [Ir(cod)2]BF4, without any other ligands was sufficient for the reaction. For the DRA of the ketone substrates, an ionic liquid, [Bmim]BF4, was found to be superior to the other organic solvent used. Especially, the counter anion of the ionic liquid has a significant influence on the selectivity, and at the same time, a high reaction temperature was found to be crucial for the excellent selectivity. 相似文献
204.
Reaction of ethyl isocyanoacetate with α,β-unsaturated carbonyl compounds was promoted by a stoichiometric amount of ZnCl2 or a catalytic amount of CuCl/Et3N (1:1) to give 5-alkenyl-4-carboethoxyoxazolines (3) in moderate yields. The oxazolines (3) were converted by palladium catalyst to 2-formamino-2,4-alkadienoic acid ethyl esters (5). 相似文献
205.
Yamamoto M Yamamoto F Luong TT Williams T Kominato Y Yamamoto F 《Electrophoresis》2003,24(14):2295-2307
206.
Yoshimori Omote Yasuomi Takizawa Shunichi Mochida Yoshihiko Tsuda Noboru Sugiyama 《Journal of heterocyclic chemistry》1977,14(8):1361-1363
The oxidative coupling of indole with three naphthols, 2-naphthol, 2,3-dihydroxynaphthalene and 2,7-dihydroxynaphthalene gave 1,1-bis(3′-indolyl)-2(1H)naphthalenone, 1,1-bis(3′-indolyl)-3-hydroxy-2(1H)naphthalenone and 1,1-bis(3′-indolyl)-7-hydroxy-2(1H)naphthalenone, respectively. The coupling of indole with protocatechuic aldehyde gave bis-(3-indolyl)-(3′,4′-di-hydroxyphenyl)methane and that of indole with homocatechol gave 3-(2′-methyl-3′,4′-di-hydroxyphenyl)indole. 相似文献
207.
Hiroharu Suzuki Yoshihiko Koyama Yoshihiko Moro-Oka Tsuneo Ikawa 《Tetrahedron letters》1979,20(16):1415-1418
A novel synthetic method for silyl enol ethers from allyl alcohols was developed using ruthenium hydride catalyst. 相似文献
208.
Tatsushi Murae Akihiko Sugie Yoshihiko Moriyama Takahiko Tsuyuki Takeyoshi Takahashi 《Journal of mass spectrometry : JMS》1974,8(1):297-301
The mass spectra of several bitter principles isolated from Picrasma ailanthoides Planchon (= P. quassioides Bennett) have been measured and characteristic fragmentation patterns useful for structure elucidation shown. The mass spectra of some related compounds are also described. 相似文献
209.
The ruthenium-catalyzed one-pot double allylation/cycloisomerization of 1,3-diketones and methyl acetoacetate gave exo-methylenecyclopentanes in moderate to good yields with high isomer selectivity. The double allylation step effectively proceeded in the presence of a Ru(II) precatalyst, [Cp*RuCl(cod)], in 1,2-dichloroethane at 90 degrees C. The subsequent cycloisomerization was carried out upon addition of triethylsilane as a hydride source without purification of a 1,6-diene intermediate. Detailed inspections of the reaction by (1)H NMR spectroscopy disclosed that triethylsilyl methyl ether plays an important role for the conversion of a ruthenium(IV) allyl complex formed in the double allylation step into a ruthenium(II) species required for the cycloisomerization. 相似文献
210.
[reaction: see text] The chiral palladium complex generated in situ from [Pd(eta(3)-allyl)Cl](2) and (R)-BINAP is a good catalyst for the catalytic asymmetric allylation of 1,3-diketones. The reaction provided chiral 2,2-dialkyl-1,3-diketones with 64-89% ee in high yields (13 examples). Enantiomeric excesses are strongly affected by the gamma-substituent of the allylic substrates. A variety of unsymmetrical 1,3-diketones were alkylated with cinnamyl acetate in good enantioselectivities via use of the BINAP-palladium catalyst (77-89% ee). 相似文献