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Nanang Rudianto Ariefta Hasna Tazkia Nikmawahda Takako Aboshi Tetsuya Murayama Keitaro Tawaraya Takuya Koseki Genta Katagi Yoshito Kakihara Yoshihito Shiono 《Tetrahedron》2019,75(10):1371-1377
Four novel compounds with γ-methylidene-spirobutanolide core, fusaspirols A-D, were isolated from the brown rice culture of Fusarium solani B-18. Their structures were established by extensive spectroscopic analyses of 1D/2D-NMR, HRESITOFMS, and chemical derivatization. The absolute configurations of secondary alcohols in fusaspirols A and D were determined using modified Mosher's ester method. Fusaspirol A and 4,9-di-O-acetylfusaspirol A activated a signaling pathway in osteoclastic differentiation of murine macrophage derived RAW264.7?cells. 相似文献
53.
Zhengguo Cai Yuushou Nakayama Takeshi Shiono 《Macromolecular rapid communications》2008,29(6):525-529
Polymerization of norbornene has been conducted with [t‐BuNSiMe2(3,6‐t‐Bu2Flu)]TiMe2 ( 1 ) in toluene at 20 °C using modified methylaluminoxane that contained 0.4 mol‐% of triisobutylaluminium (TIBA) (dMMAO(0.4)) or 1.8 mol‐% of TIBA (dMMAO(1.8)). The 1 ‐dMMAO(0.4) catalytic system undergoes a living polymerization of norbornene. The catalysis of norbornene and propylene with the 1 ‐dMMAO(1.8) catalytic system gives markedly different results because of differences in transfer times of the polymers from Ti to TIBA. The successive addition of norbornene and propylene before the complete consumption of the norbornene in the 1 ‐dMMAO(1.8) system gives monodisperse PNB‐block‐poly(propylene‐ran‐norbornene)‐block‐PP terminated with a Ti–PP bond, which is exchanged with TIBA. Hence the repeated addition of the same amount of norbornene and propylene realizes the catalytic synthesis of monodisperse block copolymer in this system.
54.
New nickel(II) diimine complexes bearing phenyl and sec‐phenethyl groups: synthesis,characterization and ethylene polymerization behaviour 下载免费PDF全文
Fuzhou Wang Jianchao Yuan Qingshan Li Ryo Tanaka Yuushou Nakayama Takeshi Shiono 《应用有机金属化学》2014,28(7):477-483
A series of nickel(II) catalysts containing phenyl and chiral sec‐phenethyl groups, {[(4‐R1‐2‐R2C6H2N?C)2Nap]NiBr2} (Nap: 1,8‐naphthdiyl, R1 = Me, R2 = Ph ( 3a ); R1 = Me, R2 = sec‐phenethyl ( 3b ); R1 = Cl, R2 = sec‐phenethyl ( 3c ); R1 = Me, R2 = Me ( 3d ) were synthesized and characterized. All organic compounds were fully characterized by FT‐IR and NMR spectroscopy and elemental analysis. The single crystal for X‐ray crystallography was isolated from 3a in CH2Cl2/n‐hexane under air; the crystal structure showed a binuclear complex 3a ′, in which each nickel atom was six‐coordinate. The two nickel atoms together with two bromine atoms form a planar four‐membered ring, with a bromine and H2O axial ligands. These complexes, activated by diethylaluminum chloride and chiral nickel pre‐catalysts rac‐ 3c , exhibited good activities (up to 2.85 × 106 g PE (mol Ni h bar)?1) for ethylene polymerization, and produced polyethylene products with a high degree of branching (up to 117 branched per 1000 carbons) at high temperature. The type and amount of branches of the polyethylenes obtained were determined by 1H and 13C NMR spectroscopy. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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56.
Dilip C. D. Nath Takeshi Shiono Tomiki Ikeda 《Journal of polymer science. Part A, Polymer chemistry》2002,40(17):3086-3092
The homopolymerization and copolymerization of 1,3‐butadiene and isoprene were achieved at 0 °C with cobalt dichloride in combination with methylaluminoxane and triphenylphosphine (Ph3P). For 1,3‐butadiene, highly cis‐specific and 1,2‐syndiospecific polymerization proceeded in the absence or presence of Ph3P, respectively, although the activity with Ph3P was much higher than that without Ph3P. Only a trace of the polymer was, however, obtained in isoprene polymerization when Ph3P had been added. For copolymerization, the polymer yield in the presence of Ph3P was about three times higher than that in its absence. Copolymerization in the presence of Ph3P was, therefore, investigated in more detail. Unimodal gel permeation chromatography elution curves with narrower polydispersity (weight‐average molecular weight/number‐average molecular weight ≈ 1.5) indicated that the propagation reaction proceeded by single‐site active species. Both the yield and molecular weight of the copolymer decreased with an increasing amount of isoprene in the feed, and this was followed by an increase in the isoprene content in the copolymer. The monomer reactivity ratios, r1 (1,3‐butadiene) and r2 (isoprene), were estimated to be 2.8 and 0.15, respectively. Although the 1,3‐butadiene content in the copolymer was strongly dependent on the comonomer composition in the feed, the ratio of 1,2‐inserted units to 1,4‐inserted units of 1,3‐butadiene was constant. Concerning the isoprene unit, the percentage of 1,2‐ and 3,4‐inserted units was increased at the expense of 1,4‐inserted units with an increasing isoprene content in the feed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3086–3092, 2002 相似文献
57.
Propylene polymerizations were conducted by [t-BuNSiMe2(3,6-t-Bu2Flu)]TiMe2 using dried modified methyaluminoxane as a cocatalyst in heptane, chlorobenzene (CB), and a mixture of heptane/CB (1:1 in
volume) at 0°C. Postpolymerizations testified that the propylene polymerization proceeded in a living manner regardless of
the solvent used. The heptane system gave highly syndiotactic crystalline polypropylene (PP), whereas the CB and heptane/CB
mixture systems gave amorphous PP. After the first polymerization in heptane had been completed, the same amounts of propylene
and CB were added for the second polymerization. This procedure gave the syndiotactic-atactic stereoblock PP with a melting
point of 119°C.
The text was submitted by the authors in English. 相似文献
58.
Abdou Tchoukoua Turibio Kuiate Tabopda Shota Uesugi Ken‐ichi Kimura Eunsang Kwon Hiroyuki Momma Bonaventure Tchaleu Ngadjui Takuya Koseki Yoshihito Shiono 《Magnetic resonance in chemistry : MRC》2016,54(11):893-896
Phytochemical investigation of the roots of Albizia chevalieri led to the isolation of two new 5‐deoxyflavan‐3,4‐diol glucosides from roots of A. chevalieri, Chevalieriflavanosides A and B. Their structures were established by 2D NMR techniques, UV, IR, CD, and mass spectrometry. Cytotoxicity of the two compounds was evaluated against acute promyelocytic leukemia HL60 cells. The antibacterial activities of 1 and 2 also were evaluated against Pseudomonas aeruginosa and Staphylococcus aureus using the agar diffusion test. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
59.
Yuushou Nakayama Yuuichi Sogo Zhengguo Cai Takeshi Shiono 《Journal of polymer science. Part A, Polymer chemistry》2013,51(5):1223-1229
A series of titanium complexes with ansa‐(fluorenyl)(cyclododecylamido) ligands, Me2Si(η3‐R)(N‐c‐C12H23)TiMe2 [R = fluorenyl ( 5 ), 2,7‐tBu2fluorenyl ( 6 ), 3,6‐tBu2fluorenyl ( 7 )], was synthesized. The crystal structure of complex 6 revealed η3‐coordination of the fluorenyl moiety to the metal. Upon activation with trialkylaluminum‐free modified methylaluminoxane, complexes 5 – 7 as well as the corresponding tBu amide complexes, Me2Si(η3‐R)(NtBu)TiMe2 [R = fluorenyl ( 2 ), 2,7‐tBu2fluorenyl ( 3 ), 3,6‐tBu2fluorenyl ( 4 )], were adopted as the catalysts for the copolymerization of ethylene (E) and isobutylene (IB). Among these complexes, complex 6 was found to achieve the highest IB incorporation to produce alternating E‐IB copolymers. Complex 6 system also achieved copolymerization of E and limonene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
60.
Mitsuhiro Okada Yuushou Nakayama Tomiki Ikeda Takeshi Shiono 《Macromolecular rapid communications》2006,27(17):1418-1423
Summary: A novel nickel complex ligated with 2‐(2,6‐diisopropylanilino)‐1,4‐naphthoquinone ( 1 ) was synthesized. The molecular structure of 1 determined by X‐ray analysis was a square‐planar geometry. Complex 1 conducted ethylene polymerization at 40 °C in a low activity to give linear polyethylene. On the other hand, 1 activated with 4 eq. of B(C6F5)3 was highly active for ethylene polymerization and gave a polymer possessing short chain branches of methyl, ethyl and propyl groups formed by a chain walking mechanism, as well as long chain branches, of which the content was almost the same as the total content of short chain branches. These results suggest that the macromonomer formed via β‐hydride elimination should have effectively copolymerized with ethylene to give the long chain branches in the B(C6F5)3‐activated system.