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131.
Takehiro YamagishiTakanori Kusano Babak KaboudinTsutomu Yokomatsu Chiseko SakumaShiroshi Shibuya 《Tetrahedron》2003,59(6):767-772
The diastereoselective synthesis of β-substituted α-hydroxyphosphinates was achieved by hydrophosphinylation of α-oxy aldehydes and α-amino aldehydes with ethyl allylphosphinate catalyzed by lithium phenoxide. 相似文献
132.
C F Tseng S Iwakami A Mikajiri M Shibuya F Hanaoka Y Ebizuka K Padmawinata U Sankawa 《Chemical & pharmaceutical bulletin》1992,40(2):396-400
N-trans- and N-cis-Feruloyltyramines were isolated as the inhibitors of in vitro prostaglandin (PG) synthesis from an Indonesian medicinal plant, Ipomoea aquatica (Convolvulaceae). In order to clarify structure activity relationships, cinnamoyl-beta-phenethylamines with possible combinations of naturally occurring cinnamic acids and beta-phenethylamines were synthesized and tested for their inhibitory activities against PG synthetase and arachidonate 5-lipoxygenase. The compounds containing catechol groups such as N-caffeoyl-beta-phenethylamine (CaP) showed higher inhibitory effects on PG synthetase. The catechol group was found to be essential for the inhibition of arachidonate 5-lipoxygenase. The investigation of concentration dependent effects on PG biosynthesis revealed that CaP enhanced PG biosynthesis at a lower concentration range, whereas it inhibited the reaction at a higher concentration. The effects of CaP on each reaction step were investigated with purified PG endoperoxide synthase and microsomal PG synthetase. CaP inhibited the cyclooxygenase reaction, while it enhanced the hydroperoxidase reaction. N-Acyldopamines which contain catechol and lipophylic group were synthesized from dopamine and fatty acids to test their inhibitory effects on arachidonate 5-lipoxygenase. N-Linoleoyldopamine was the most active compound and its IC50 value was 2.3 nM in our assay system, in which an IC50 value of AA 861, a specific inhibitor of 5-lipoxygenase, was 8 nM. 相似文献
133.
M. Fujioka S. Shibuya N. Kawamura A. Matsumoto Y. Kimura S. Hayashibe T. Ishimatsu R. Coussement M. Rots L. Hermans 《Hyperfine Interactions》1983,16(1-4):1017-1020
The time-integral angular distribution was measured as a function of an external magnetic field for -rays from the 398-keV 9/2 state of69Ge populated by bombarding a Zn single crystal with a natural -beam from a cyclotron. Clear resonances of dispersion as well as Lorentz types having a natural width (=4 s) were observed at Bres=9.14 kG corresponding to the first level-crossing resonance of the 9/2 state due to the combined collinear magnetic and electric interactions. The effects of non-collinearity were also demonstrated, and compared with theory. 相似文献
134.
Intramolecular cycloaddition of [1,1′-binaphthyl]-2,2′-bis(allylamine) Unlike the 1,1′-binaphthyl-2,2′-bis(allylether) the corresponding [1,1′-binaphthyl]-2,2′-bis(allylamine) (1) upon heating to 230° in mesitylene undergoes thermal decomposition only. However, when 1 is heated in a mixture of 2-methylaminoethanol and water, besides 3 the policyclic ketones 4 and 5 are formed in isolated yields of 28 and 10%, respectively (Scheme 1). Intermediates are the imines corresponding to 4 and 5 which are hydrolysed under the reaction conditions rather than decomposed. The imines are formed by a intramolecular Diels-Alder reaction, in which the double bond of one N-allylgroup reacts with the naphthalene ring of the second half of the molecule. The policyclic ketones 4 and 5 are characterized as acetates 6 and 7 , respectively, and as the acetylated reduced products 11 , and 12 and 13 , respectively. The constitutions of all compounds are derived from spectroscopic data, chiefly from the 1H-NMR. spectra. 相似文献
135.
Ohashi K Winarno H Mukai M Inoue M Prana MS Simanjuntak P Shibuya H 《Chemical & pharmaceutical bulletin》2003,51(3):343-345
Six fatty acids (1-6), two xanthines (7, 8), two flavonol glycosides (9, 10), one monoterpene glucoside (11), one lignan glycoside (12), and four flavanes (13-16) were clarified by a bioassay-guided separation as chemical constituents of Scurrula atropurpurea (Loranthaceae), a parasitic plant of the tea plant Thea sinensis (Theaceae). Among these constituents, it was found that the alkynic fatty acid octadeca-8,10,12-triynoic acid (6) exhibits a more potent inhibitory effect on cancer cell invasion in vitro than flavanes [(+)-catechin (13), (-)-epicatechin (14), (-)-epicatechin-3-O-gallate (15) and (-)-epigallocatechin-3-O-gallate (16)]. 相似文献
136.
The reaction of o-phenylenediamine with α-methylsulfinylcyclohexanone and α-methylsulfinylcyclopentanone in the presence of acetic acid afforded 1,2,3,4-tetrahydrophenazine and 2,3-dihydro-1H-cyclopenta[b]-quinoxaline, respectively. 3,4-Diaminotoluene and 3,4-diaminochlorobenzene were reacted with α-methyl-sulfinylacetophenone to give a mixture of the corresponding 6- and 7-substituted 2-phenylquinoxaline. Condensation of 3,4-diaminomethoxybenzene with α-methylsulfinylacetophenone gave 7-methoxy-2-phenylacetophenone, whereas, the same reaction between 3,4-diaminonitrobenzene and α-methylsulfinylacetophenone yielded 6-nitro-2-phenylquinoxaline. 相似文献
137.
Tetsuo MuranoYoko Yuasa Soichiro MuroyamaTsutomu Yokomatsu Shiroshi Shibuya 《Tetrahedron》2003,59(46):9059-9073
Lewis acid-mediated N-glycosylation of 2,3-dideoxyribofunanosides having a (diethoxyphosphorothioyl)difluoromethyl group at the 3α-position with silylated nucleobases was examined. The phosphorothioyldifluoromethyl was found to be an effective functional group for the diastereoselective synthesis of β-N1-pyrimidine-nucleotide analogues 26 and 28-30. However, the method was not useful for the diastereoselective synthesis of adenine nucleotide analogues. The nucleotide analogue 26 was transformed to the difluoromethylenephosphonate analogue 31 of thymidine-3′-phosphate by oxidation with m-CPBA, followed by aqueous work-up. 相似文献
138.
Abe I Sakano Y Sodeyama M Tanaka H Noguchi H Shibuya M Ebizuka Y 《Journal of the American Chemical Society》2004,126(22):6880-6881
Recombinant beta-amyrin synthase from Pisum sativum converted 24,30-bisnor-2,3-oxidosqualene into a 3:1:0.2 mixture of 29,30-bisnor-beta-amyrin, 29,30-bisnorgermanicol, and 29,30-bisnor-delta-amyrin. Further, enzyme reactions with [23-13C]- and [23,23-2H]-labeled isotopomers demonstrated that the cyclization did not proceed through formation of a lupanyl primary cation with a five-membered E-ring, but an electrophilic addition of the tetracyclic C-18 cation on to the terminal double bond directly generated a thermodynamically favored pentacyclic secondary cation with a less-strained six-membered E-ring. Interestingly, the formation of the three regioisomers suggested that the absence of the terminal methyl groups resulted in a structural perturbation in the folding conformation of the E-ring of the oleanyl cation at the active site of the enzyme. 相似文献
139.
The synthesis of 1,1-dimethylcarbapen-2-em derivative is described. The key step in the synthesis is an intramolecular aldol-type condensation reaction. 相似文献
140.
IR (4000-30 cm−1) and Raman (4000-0 cm−) spectra of [(CD3)3S]I have been observed, together with those of [(CH3)3S]I. By assuming a C3v molecular symmetry for the cations [(CH3)3S]+ and [(CD3)3S]+, all the active fundamentals of [(CD3)3s]+ have been assigned and normal coordinate calculations have been carried out by a symmetry force field for [(CH3)3S]+ and [(CD3)3S]+. The strength of the S---C and C---H bonds in the compound has been compared with that in dimethyl sulfide by using their valence stretching force constants. 相似文献