全文获取类型
收费全文 | 205篇 |
免费 | 1篇 |
专业分类
化学 | 155篇 |
晶体学 | 3篇 |
数学 | 21篇 |
物理学 | 27篇 |
出版年
2016年 | 2篇 |
2013年 | 8篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 9篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1960年 | 1篇 |
排序方式: 共有206条查询结果,搜索用时 15 毫秒
1.
Tetsuji Kametani Hideo Lida Shinzo Kano Sadao Tanaka Keiichiro Fukumoto Shiroshi Shibuya Haruhiko Yagi 《Journal of heterocyclic chemistry》1967,4(1):85-92
Schotten-Baumann reaction of the amine (X) with 4-benzyloxy-3,4′-oxydiphenylacetyl chloride (XI) gave two amides, (XIIa) and (XIIb), which were cyclized to give the corresponding 3,4-dihydroisoquinolines, respectively. Methylation of the above 3,4-dihydro-isoquinolines, followed by hydrolysis, afforded the compounds having the same composition as berbamine (Ia) and oxyacanthine (Ib), whose structures are under examination. 相似文献
2.
The composition of nickel hexacyanoferrate(II) complexes depends on the ratios of sodium hexacyanoferrate(II) and nickel nitrate solutions mixed. The adsorption behavior of nickel hexacyanoferrate(II) is described; acid treatment of Ni2Fe(CN)6 accelerates the adsorption rate of cesium, but does not increase the adsorption capacity. The Ni—Cs exchange ratios of Ni2Fe(CN)6 are discussed. In concentrated salt solutions, the distribution coefficients of 59Fe, 60Co, 65Zn. 137Cs, 95Zr and 144Ce are determined together with those of 85Sr and 106Ru. A simple determination of 137Cs in sea water containing 59Fe, 60Co, 65Zn, 95Zr, 144Ce, 85Sr and 106Ru is described. 相似文献
3.
Sadao Arai Masanori Ishikura Kiyoshi Sato Takamichi Yamagishi 《Journal of heterocyclic chemistry》1995,32(3):1081-1083
The 16c-azonia[6]helicene salts, in which a carbon atom at the inner helix skeleton of [6]helicene is replaced by a quaternary nitrogen atom, have been synthesized by photo-induced intramolecular quater-nization of 2-[2-(1-chloronaphthyl)vinyl]benzo[h]quinolines in acetonitrile. 相似文献
4.
Masatoshi Sakae Masanori Katsurada Mayumi Watanabe Fumio Yoneda Sadao Nishigaki Toshimasa Ishida 《Journal of heterocyclic chemistry》1997,34(1):157-160
The reaction of 2-bromoethylamine 1 with methylisothiocyanate 2 under mild condition gave 2-methyl-amino-2-thiazoline 3 as the major product together with two kinds of byproducts, 3-(N-methylthiocar-bamoyl)-2-methyliminothiazolidine 4 and N,N′-dimethyl-N-(2-thiazolin-2-yl)thiourea 5. Thermal isomer-ization of 5 to 4 was observed. The structures of the byproducts were confirmed by X-ray crystallography. 相似文献
5.
Sadao Hayashi Toshihiro Hirai Sonoko Shimomichi Nobumasa Hojo 《Journal of polymer science. Part A, Polymer chemistry》1982,20(3):839-846
Polyiodide formed by complexation of poly(vinyl acetate) (PVAc) with iodine in the presence of iodide has been investigated by chemical analysis and resonance Raman spectrophotometry. When PVAc films were immersed in iodide-iodine aqueous solutions which had different ratios of iodide to iodine concentration [I?]/[I2], the complex films exhibited tremendous variations of swelling degree, despite the relatively small change in the amount of bound iodine. From a quantitative chemical analysis, the composition of polyiodide bound to PVAc was found to be 1.01 ± 0.035 in the molar ratio of iodide to iodine irrespective of the composition of the iodide-iodine aqueous solution ([I?]/[I2] = 2–500). The polyiodide formed in PVAc-iodine-iodide complex was therefore inferred to be (I3?)n. Resonance Raman spectra obtained on PVAc-iodine-iodide complexes were also identical to those of the benzamide-iodine complex, in which the polyiodide consists of (I3?)n, consistent with the result from chemical analysis. 相似文献
6.
Fumio Yoneda Ryosuke Koga Sadao Nishigaki Shinobu Fukazawa 《Journal of heterocyclic chemistry》1982,19(4):949-951
Treatment of 6-amino-1,3-dimethyl-5-nitrosouracil (Ia) with dimethyl acetylenedicarboxylate (DMAD) in dimethylformamide (DMF) afforded 6,7-bis(dimethoxycarbonyl)-1,3-dimethyllumazine (II). Similarly, the reaction of 6-amino-1,3-dimethyl-5-phenylazouracil with DMAD gave also II. Hydrolysis of II with hydrochloric acid gave 1,3-dimethyllumazine-6-carboxylic acid (III). III was chlorinated with thionyl chloride and then aminated with ethanolic ammonia to give rise to 6-carbamoyl-1,3-dimethyllumazine (V). V was alternatively synthesized by the treatment of Ia with propiolamide in DMF. 相似文献
7.
Haruhiko Aoi Michihiro Ishimori Sadao Yoshikawa Teiji Tsuruta 《Journal of organometallic chemistry》1975,85(2):241-248
An optically active Co(I)(salen) type complex, lithium N,N′-bis(salicylaldehyde)-1(R), 2(R)-1,2-trans-cyclohexanediiminatocobalt(I), was prepared by reducing the CoII complex, N,N′-bis(salicylaldehyde)-1(R),2(R)-1,2-trans-cyclohexanediiminatocobalt(II), with LiAlH4. The structure of the CoI complex was determined on the basis of the structure of the corresponding CoII complex and was confirmed by usual physicochemical methods. Furthermore, characteristics of the absorption and circular dichroism(CD) spectra of the CoI complex were compared with those of the reported structure of Na+[Co(I)(salen)]?. Highly asymmetric selectivity was found in a resolution reaction of DL-propylene oxide by use of the above optically active lithium cobalt(I) complex as a catalyst. 相似文献
8.
Stainless-steel tubes having inside diameters of 1.5 mm and 1.8 mm were packed with polystyrene gels of particle diameter 10 ± 2 μm. Two 50 cm × 1.8 mm I.D. packed columns, connected in series, were calibrated and molecular-weight averages of polystyrene NBS 706 were measured, the results coinciding with the data of the National Bureau of Standards. The peak widths of polystyrenes of narrow molecular-weight distributions in both semi-micro column (four 25 cm × 1.5 mm I.D.) and conventional column (two 50 cm × 8 mm I.D.; packed by the manufacturer) systems were determined at different mobile-phase velocities, and the minimum peak width in the latter system was obtained at the velocity of 0.2 mm/sec, which was higher than that for the semi-micro system. The interstitial volume was higher and the inner volume was lower for the semi-micro column system (1.8 mm I.D.) than those for the conventional one, which means that semi-micro columns were packed less densely, resulting in a steep calibration curve. The peak height of a solute was proportional to the cell length of an ultraviolet detector if the sample load was proportional to the cross-sectional areas of columns having the same column efficiency. Although conventional size-exclusion chromatography has many advantages in respect of velocity, calibration curtve and sample peak height, semi-micro size-exclusion chromatography still holds some merits such as low consumption of gels and of mobile-phase solvents. 相似文献
9.
Tetsuo Kusumoto Ken-Ichi Sato Kumiko Ogino Tamejiro Hiyama Sadao Takehara Masashi Osawa 《Liquid crystals》2013,40(3):727-732
Abstract New chiral dopants β-hydroxy ketones 1, 1,3-diols 2, 1,3-dioxanes 3 and 1,3-dioxan-2-ones 4 were designed and synthesized. Reaction of (R)-1,2-epoxyoctane with carbanions derived from 2-(4-substituted phenyl)-1,3-dithianes followed by hydrolysis of the resulting hydroxy dithianes afforded 1. Reduction of 1 gave the diols 2, which yielded 3 upon acetalization and 4 upon carbonation. The syn isomers of 2, 3, and 4 exhibited larger spontaneous polarizations, when applied as chiral dopants, than the anti isomers or hydroxy ketones 1. 相似文献
10.
A previously proposed model describing the trapping site of the interstitial atomic hydrogen in borate glasses is analyzed. In this model the atomic hydrogen is stabilized at the centers of oxygen polygons belonging to B–O ring structures in the glass network by van der Waals forces. The previously reported atomic hydrogen isothermal decay experimental data are discussed in the light of this microscopic model. A coupled differential equation system of the observed decay kinetics was solved numerically using the Runge Kutta method. The experimental untrapping activation energy of 0.7×10−19 J is in good agreement with the calculated results of dispersion interaction between the stabilized atomic hydrogen and the neighboring oxygen atoms at the vertices of hexagonal ring structures. 相似文献