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排序方式: 共有169条查询结果,搜索用时 265 毫秒
161.
Kise N Ohya K Arimoto K Yamashita Y Hirano Y Ono T Ueda N 《The Journal of organic chemistry》2004,69(22):7710-7719
The electroreduction of aromatic beta- and gamma-imino esters prepared from beta-alanine and GABA in the presence of chlorotrimethylsilane and subsequent N-alkoxycarbonylation of the resulting five- and six-membered cyclized amines gave mixed ketals of N-alkoxycarbonyl-2-arylpyrrolidin-3-ones and 2-arylpiperidin-3-ones, respectively. The best result of the electroreductive intramolecular coupling was achieved using Bu(4)NClO(4) as a supporting electrolyte and a Pb cathode in THF. Acid hydrolysis of the mixed ketals afforded N-alkoxycarbonyl-2-arylpyrrolidin-3-ones and 2-arylpiperidin-3-ones in good yields. The reduction of these ketones with NaBH(4) in methanol afforded the corresponding N-alkoxycarbonyl-cis-2-arylpyrrolidin-3-ols and cis-2-arylpiperidin-3-ols diastereospecifically. 相似文献
162.
Jun-ichi Yoshida Shinji Yano Tadahiro Ozawa Nariyoshi Kawabata 《Tetrahedron letters》1984,25(26):2817-2820
2,2-Dibromo-1,3-diketones reacted with copper powder and olefin to give 4,5-dihydrofuran derivatives in a highly regioselective fashion. 相似文献
163.
Jun'ichi Katakawa Tadahiro Tetsumi Tadamasa Terai Masaaki Katai Ken-ichi Sakaguchi Mamoru Sato 《Journal of chemical crystallography》2000,30(2):139-141
The crystal and molecular structure of a grayanotoxin derivative, iso-grayanotoxin II, is presented. The crystal is orthorhombic, space group
. The molecule is based on a tetracyclic structure consisting of two five-membered, one six-membered, and one seven-membered rings with various conformations. 相似文献
164.
165.
Akira Matsumoto Tadahiro Kiguchi Hiroyuki Aota 《Macromolecular rapid communications》2000,21(17):1201-1204
The free‐radical crosslinking polymerization of diallyl adipate (DAA) was carried out in the presence of poly(benzyl methacrylate) (poly(BzMA)) as a chemically inactive polymer in order to clarify the topological bonding formation between linear polymer and prepolymer before gelation; we found by chance that even at an early stage of the polymerization, the topological bonding was formed between ultra‐high molecular weight poly(BzMA) and poly(DAA) prepolymer. 相似文献
166.
Kyoji Kaeriyama Seiichi Kouyama Mitsutoshi Sekita Tadahiro Nakayama Yasuhisa Tsukahara 《Macromolecular rapid communications》1999,20(2):50-54
Poly(alkoxycarbonylphenylene)s with long alkoxy groups were prepared by dehalogenative polycondensation of alkyl dichlorobenzoates with nickel bromide/zinc/triphenylphosphine catalyst. The poly(alkoxycarbonyl‐p‐phenylene)s and poly(alkyloxycarbonyl‐m‐phenylene)s are liquid crystalline, although the latter are composed wholly of kinked repeating units. While poly(hexyloxycarbonylphenylene)s exhibit only thermotropic liquid crystalline behavior, poly(dodecyloxycarbonylphenylene)s and poly(hexadecyloxycarbonylphenylene)s show amphotropism. 相似文献
167.
Tadahiro Kato Toshifumi Hirukawa Takaaki Suzuki Masaharu Tanaka Masahiro Hoshikawa Makoto Yagi Motoyuki Tanaka Shin‐suke Takagi Naoko Saito 《Helvetica chimica acta》2001,84(1):47-68
Based on the putative biogenesis of trinervitane‐ and kempane‐type diterpenes (Scheme 1), a biogenetic‐type transformation was simulated by cyclization of 7,16‐secotrinervita‐7,11,15‐triene‐2α,3α,17‐triol ( 23 ) and of its 17‐chloro derivative 30 . The requisite substrates were prepared from geranylgeranoic acid chloride 6 (Schemes 2, 4, and 5). Treatment of 30 with AgClO4 at −20° provided the trinervitantrienediols 32 and 33 in 68 and 5% yields, while kempadienediol 35 was obtained in 50% yield by the same reagent at +20° (Scheme 7). The structures of the cyclization products were elaborated from detailed inspection of NMR spectra including H,H COSY, C,H COSY, and NOESY (Tables 1 and 2). The conformation of 30 and its plausible cyclization intermediate was discussed with the help of physical evidence, including X‐ray crystallographic analysis. 相似文献
168.
169.
Dr. Haruno Murayama Dr. Qi-An Huang Dr. Eiji Yamamoto Prof. Dr. Makoto Tokunaga Dr. Tamao Ishida Dr. Mitsutaka Okumura Dr. Tetsuo Honma Dr. Tadahiro Fujitani Dr. Atsuko Isogai 《Chemical record (New York, N.Y.)》2023,23(11):e202300148
Heterogeneous noble metal catalysts exhibit various functions. Although their redox functions have been extensively studied, we focused on their soft Lewis acid functions. Supported Au, Pt, and Pd catalysts electrophilically attack the π-electrons of soft bases such as alkynes, alkenes, and aromatic compounds to perform addition and substitution reactions. Hydroamination, intramolecular cyclization of alkynyl carboxylic acids, isomerization of allylic esters, vinyl exchange reactions, Wacker oxidation, and oxidative homocoupling of aromatics are introduced based on a discussion of the active species and reaction mechanisms. Furthermore, the adsorption of sulfur compounds, which are soft bases, onto the supported AuNPs is discussed. The adsorption and removal of 1,3-dimethyltrisulfane (DMTS), which is the compound responsible for the stale odor of “hine-ka” in alcoholic beverages, particularly Japanese sake, is described. 相似文献