全文获取类型
收费全文 | 363篇 |
免费 | 7篇 |
专业分类
化学 | 285篇 |
力学 | 9篇 |
数学 | 10篇 |
物理学 | 66篇 |
出版年
2022年 | 2篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 13篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 16篇 |
2007年 | 12篇 |
2006年 | 13篇 |
2005年 | 18篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1979年 | 8篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1965年 | 1篇 |
1927年 | 2篇 |
排序方式: 共有370条查询结果,搜索用时 0 毫秒
1.
Masahiro Nakao Chikako Yamazaki Hiroshi Tominaga Takako Yamaguchi Yoshikazu Fujita 《Analytical sciences》2006,22(2):313-316
A simple and highly sensitive spectrophotometric method for the determination of anthracycline anticancer agents, such as Daunorubicin hydrochloride (DAU), was established by using aluminum(III) and Chromazurol S (CAS) in a nonionic surfactant micellar medium. In the case of determination of DAU, the apparent molar absorptivity was 1.3 x 10(5) dm3 mol(-1) cm(-1) at 615 nm. Beer's law was obeyed in the concentration range of 0.028 - 2.82 microg ml(-1) for DAU. Owing to no need for solvent extraction, this method could be applied to assays of DAU and related drugs in pharmaceutical preparations. 相似文献
2.
M. Tanaka Y. Minai T. Watanabe T. Tominaga 《Journal of Radioanalytical and Nuclear Chemistry》1992,164(4):255-264
Phthalocyanineiron(II) (FePc) and phthalocyaninato[(2-)bispyridine]iron(II) (FePc(py)2) synthesized in supercage of NaY, KY and RbY zeolite have been characterized by Mössbauer and ESR spectroscopy. The yield of formation of the pyridine adduct depends on the ionic radius of the alkali ions introduced into the supercage, but not on the number of iron ions trapped in the cages, suggesting that free space in the supercage was the most important factor for the formation of the FePc-py-adducts. 相似文献
3.
4.
Y. Yamada T. Kumagawa Y. T. Yamada T. Tominaga 《Journal of Radioanalytical and Nuclear Chemistry》1995,201(5):417-429
Mössbauer parameters of tin compounds, Sn(CH3)2H4–n (n=0, 1, 2, 3, 4), isolated in low temperature matrices were related to electronic properties at the tin nuclei obtained by molecular orbital calculations. Structures of novel species, Sn(CH3)2 and Sn(CH3)H, produced via photodissociation of matrix-isolated Sn(CH3)3H and Sn(CH3)2H2, respectively, were determined on the basis of molecular orbital calculations as compared with Mössbauer parameters. The correlations between Mössbauer quadrupole splitting and calculated electric field gradient using STO-3G or MINI-4 were found to depend on the valence of tin atoms because of poor allowance for basis sets in describing highly polar molecules. 相似文献
5.
A new hydroformylation of alkenes using carbon dioxide as a reactant is shown to take place in the presence of ruthenium cluster complexes and halide salts. Similar or even better yields of alcohols were formed as compared to the conventional hydroformylation with CO under the same reaction conditions. The reaction proceeded in three steps: CO2 is first converted to CO; then it is used as a reagent for hydroformylation to give aldehyde; subsequently, it is hydrogenated to alcohol. ESI-mass spectrometric analyses of the reaction solutions indicated formation of four kinds of ruthenium anionic complexes including tetra-, tri-, and mononuclear species. On the basis of experimental findings, possible roles of these complexes are discussed. 相似文献
6.
Mizooku Y Yoshikawa M Tsuneyoshi T Arakawa R 《Rapid communications in mass spectrometry : RCM》2003,17(16):1915-1918
(-)-Epigallocatechin gallate (EGCG) of catechins changes from non-colored at around neutral pH to yellow at higher pH region in aqueous solution. The pH-dependent oxidation of EGCG was analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). LC/MS/MS analysis of EGCG and its related compounds, (-)-epicatechin gallate (ECG) and (-)-epigallocatechin (EGC), successfully elucidated the structure relationship of EGCG solution involving the color change reaction at different pH conditions. The oxidation species produced at alkaline pH was detected at a different retention time from EGCG in the chromatograms of the EGCG sample. The oxidation species was found to correspond to M+14 (where M is the molecular weight of EGCG), which has two hydrogen atoms removed and addition of one oxygen atom to the gallyl moiety in the B-ring of EGCG. 相似文献
7.
Yoshinori Tominaga Hiroto Okuda Shinya Kohra Hisako Mazume 《Journal of heterocyclic chemistry》1991,28(5):1245-1255
Reaction of various types of enaminones, which are prepared by the condensation of 1,3-dicarbonyl compounds with aromatic amines, with carbon disulfide in the presence of sodium hydroxide as the base in dimethyl sulfoxide to give the corresponding enamino dithiocarboxylates, 1,3-thiazines and trithiones. Enamino dithiocarboxylates are cyclized under refluxing in diphenyl ether to give the fused quinoline derivatives. The reaction of 6-arylamino-1,3-dimethyluracils with excess carbon disulfide in the presence of sodium hydroxide and subsequent methylation with dimethyl sulfate gave directly the corresponding 1,3-dimethyl-5-methylthiopyrimido[4,5-b]quinoline-2,4(1H,3H)-diones. 相似文献
8.
H. Kagetsu N. Shioyasu N. Fukunishi M. K. Kubo Y. Sakai T. Tominaga K. Nishiyama K. Nagamine 《Hyperfine Interactions》1994,84(1):517-520
We have carried out SR experiments on [Co(NH3)6]Cl3 and [Co(ND3)6]Cl3. At 293 K, all the muons implanted into the complexes were in the diamagnetic state. The observed Gaussian-type muon spin relaxation function proved that the internal magnetic field was caused by nuclear dipole moments of the atoms in the complexes. In addition, another exponential-type muon spin relaxation function was observed in [Co(ND3)6]Cl3 below 50 K. 相似文献
9.
10.
Tsuneyoshi Tominaga 《Journal of fluorine chemistry》2004,125(1):67-71
Synthetic routes for α-trifluoromethylated carbonyl compounds based on the aldol reaction of silylenol ether and the palladium(0) catalyzed reaction using by 4,4,4-trifluorobutan-2-one are described. 相似文献