全文获取类型
收费全文 | 278篇 |
免费 | 18篇 |
国内免费 | 2篇 |
专业分类
化学 | 232篇 |
晶体学 | 1篇 |
数学 | 3篇 |
物理学 | 62篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 10篇 |
2019年 | 14篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 18篇 |
2011年 | 28篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 17篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 11篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 4篇 |
1999年 | 2篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1966年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有298条查询结果,搜索用时 15 毫秒
71.
Masahiro Hayashi Shogo Tawada Yoshihiro Kubota Yoshihiro Sugi Jong Ho Kim 《Reaction Kinetics and Catalysis Letters》2004,83(2):329-335
Although extensive isomerization of 4,4'-diisopropylbiphenyl (4,4'-DIPB) occurred at 300oC over H-mordenite, high selectivity for 4,4'-DIPB among DIPB isomers was observed over silica-modified H-mordenite. This
is due to the prevention of the isomerization of 4,4'-DIPB by the deactivation of external acid sites.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
72.
N-Isobutylidenemethylamine reacted with dimethyl methoxymethylenemalonate to afford the N-alkylation product 3a exclusively. Exchanging the N-substituent of the Schiff's base from methyl to t-butyl altered the course of the reaction, allowing Michael addition to take place predominantly. The Michael adduct 4c on reaction with hydrazinoalkanols 6a,b, 6c,d and 6e gave tetrahydropyrazolo[5,1-b]oxazoles 9a,b , tetrahydro-pyrazolo[5,1-b][1,3]oxazines 9c,d and hexahydropyrazolo[5,1-b][1,3]oxazepine 9e , respectively. 相似文献
73.
Haruyuki Okamura Shogo Toda Masahiro Tsunooka Masamitsu Shirai 《Journal of polymer science. Part A, Polymer chemistry》2002,40(17):3055-3062
Photocrosslinkable systems with thermally cleavable properties based on blends of poly(vinyl phenol) (PVP) and diepoxides were investigated. Thermally cleavable diepoxides as crosslinkers were prepared and characterized. As a thermally cleavable linkage, a tertiary ester moiety was incorporated into the crosslinker molecule. PVP/crosslinker blended films containing photoacid generators (PAGs) became insoluble in solvents after UV irradiation and subsequent post‐exposure‐bake (PEB) treatment. With a rise in the PEB temperature, the insoluble fraction of the irradiated films increased, passed through a maximum value, decreased, and increased again at elevated baking temperatures. The insolubilization profiles of the irradiated films were complicated and strongly dependent on the type of PAG used, the structure of the crosslinkers, and the PVP/crosslinker ratio. A mechanism for the thermal degradation was studied with Fourier transform infrared spectroscopy. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3055–3062, 2002 相似文献
74.
It was found that a degree of the binding of alkylphenols to N-alkylacrylamide gel increased transitionally to induce the volume phase transition of gel. Binding isotherms of nonylphenol (n-Ph), propylphenol (p-Ph), ethylphenol (e-Ph), methylphenol (m-Ph), and phenol (Ph) to N-isopropylacrylamide (NIPA), N,N-diethylacrylamide (DEA), N,N-dimethylacrylamide (DMA), and acrylamide (AM) gels were examined. Two types of binding, the site binding at beta < 1 and the multimolecular binding at beta > 1, were observed, where beta was a degree of binding to a monomeric unit of the chain. The former binding was analyzed with the Hill equation applicable to the cooperative binding and the latter binding with the Brunauer-Emmett-Teller (BET) equation applicable to the multilayer adsorption. The binding constant, K, and the Hill coefficient, N, decreased and increased, respectively, in the order of DEA, NIPA, and DMA gels in the case where the binding alkylphenol was the same. The K value increased in the order of Ph, m-Ph, e-Ph, p-Ph, and n-Ph that bound to the same type of gel. The N value was found to change little with the type of binding alkylphenol. The complexes of N-alkylamide with alkylphenol were condensed to form the ordered nanostructures that were observed as broad scattering peaks in small-angle X-ray scattering experiments. The fluorescence excimer emission was observed for the phenol-binding DMA gel, which corresponded to the condensed state of phenol. 相似文献
75.
76.
Shogo Ihara Takashi Soma Daigo Yano Shunichi Aikawa Yasuhiko Yoshida 《Journal of heterocyclic chemistry》2011,48(3):577-581
The cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a , 1b , 1c , 1d , 1e , 1f , with dimethyl acetylenedicarboxylate 2 , trimethyl ethylenetricarboxylate 4 , or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a , 3b , 3c , 3d , 3e , 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b , 5c , 5d , 5e , 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a , 7b , 7c , 7d , 7e , 7f (32–59%), respectively. In these reactions, 1a , 1b , 1c , 1d , 1e , 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2 , 4, and 6 to give annulation products 3 , 5 , and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011). 相似文献
77.
Makoto Ohki Haruo Sakurai Shogo Kozaki 《International Journal of Infrared and Millimeter Waves》1997,18(10):2031-2045
This paper is described for T-matrix analysis of the electromagnetic wave diffraction from a Fourier grating that the boundary
value problem is treated by applying the extended boundary condition. The rigorous form of the expression of matrix elements
is presented in the term of Bessel functions of the first kind. The error of power conservation versus the truncated number
has been examined for mode number. Diffraction efficiencies versus groove depth and wavelength for a second or third harmonic
wave of Fourier grating have been discussed. Numerical results are in good agreement with those obtained from other method
and experimental values. Reasonable numerical results are presented for a groove depth per period of the Fourier grating less
than 0.25. 相似文献
78.
79.
Shogo Kuriyama Shenglan Wei Takeru Kato Yoshiaki Nishibayashi 《Molecules (Basel, Switzerland)》2022,27(7)
A series of manganese complexes bearing an anionic pyrrole-based PNP-type pincer ligand and an anionic benzene-based PCP-type pincer ligand is synthesized and characterized. The reactivity of these complexes toward ammonia formation and silylamine formation from dinitrogen under mild conditions is evaluated to produce only stoichiometric amounts of ammonia and silylamine, probably because the manganese pincer complexes are unstable under reducing conditions. 相似文献
80.
Kazuhira Miwa Shinobu Aoyagi Takahiro Sasamori Shogo Morisako Hiroshi Ueno Yutaka Matsuo Hideki Yorimitsu 《Molecules (Basel, Switzerland)》2022,27(2)
The reduction of fullerene (C60) with sodium dispersion in the presence of an excess amount of dipropyl sulfate was found to yield highly propylated fullerene, C60(nC3H7)n (max. n = 24), and C60(nC3H7)20 was predominantly generated as determined by mass spectroscopy. 相似文献