全文获取类型
收费全文 | 243篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
化学 | 170篇 |
晶体学 | 4篇 |
力学 | 2篇 |
数学 | 26篇 |
物理学 | 50篇 |
出版年
2021年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 7篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 12篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 1篇 |
1969年 | 3篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有252条查询结果,搜索用时 31 毫秒
161.
Weng Z Muratsugu S Ishiguro N Ohkoshi S Tada M 《Dalton transactions (Cambridge, England : 2003)》2011,40(10):2338-2347
Molecularly imprinted Ru-complex catalysts acting in water were prepared on a SiO(2) surface by molecular imprinting of a SiO(2)-supported Ru-complex using organic polymers as surface matrix overlayers. (R)-1-(o-fluorophenyl)ethanol, which is one of the hydrogenated products of o-fluoroacetophenone, was imprinted on the supported Ru-complex as a template, and an active Ru-complex with a shape-selective reaction space (molecularly imprinted cavity) was prepared inside the wall of the hydrophobic organic polymer matrix overlayers. Structures of the SiO(2)-supported and molecularly imprinted Ru catalysts were characterized by means of solid-state NMR, XPS, XRF, ICP, UV/vis, XAFS, TGA, and SEM. The molecularly imprinted Ru catalysts exhibited fine shape selectivity and enantioselectivity for the asymmetric transfer hydrogenation of o-fluoroacetophenone and its derivatives. 相似文献
162.
We have already developed a HCHO monitoring system which is called FP-30. In this experiment, we have developed a NO(2) detection tablet which can be used by the monitoring system. The detection tablet for the NO(2) was constructed with the sensing paper: porous cellulose paper that contains silica gel as an adsorbent, N-1-naphthylethylenediamine dihydrochloride (NED), and glycerin. The NO(2) in sample gas was blown over and adsorbed on the surface of the sensing paper. Then the NO(2) reacted with NED, producing a yellow compound. The coloring reaction took place on the surface of the sensing paper. The degree of color change of paper from white to yellow was monitored as a function of the intensity of the reflected light (lambda = 475 nm) of an LED. The detection limit was 0.01 ppm when the sampling time was 30 min, and the flow rate of sample gas was 250 ml/min. This sensing paper process was not interfered with by acetaldehyde, acetone, alcohols, hydrocarbons, carbon monoxide or carbon dioxide. The NO(2) concentrations in the rooms of a house or school were monitored using this monitoring system and the standard chemiluminescence method. The concentrations of NO(2) monitored by both methods were within 18% of the average. This highly sensitive, selective, and handy NO(2) gas monitoring system will be widely applicable and convenient for users who are not specialists in this field. 相似文献
163.
Bootstrapping Log Likelihood and EIC, an Extension of AIC 总被引:1,自引:0,他引:1
Makio Ishiguro Yosiyuki Sakamoto Genshiro Kitagawa 《Annals of the Institute of Statistical Mathematics》1997,49(3):411-434
Akaike (1973, 2nd International Symposium on Information Theory, 267-281,Akademiai Kiado, Budapest) proposed AIC as an estimate of the expected loglikelihood to evaluate the goodness of models fitted to a given set of data.The introduction of AIC has greatly widened the range of application ofstatistical methods. However, its limit lies in the point that it can beapplied only to the cases where the parameter estimation are performed bythe maximum likelihood method. The derivation of AIC is based on theassessment of the effect of data fluctuation through the asymptoticnormality of MLE. In this paper we propose a new information criterion EICwhich is constructed by employing the bootstrap method to simulate the datafluctuation. The new information criterion, EIC, is regarded as an extensionof AIC. The performance of EIC is demonstrated by some numerical examples. 相似文献
164.
Catalytic activation methods of nucleophile precursors recently developed in our research group were reviewed in this paper. These include (i) the catalytic double activation method of nucleophile precursors through enol formation and of electrophiles through coordination in alcohols; (ii) the double catalytic activation method by use of both catalytic amounts of chiral Lewis acid and external achiral amine; (iii) the catalytic activation method of nucleophile precursors with a chiral cationic Lewis acid in the presence of molecular sieves; and (iv) the single catalytic activation of nucleophile precursors through metal enolization in alcohol media. 相似文献
165.
Allergy-preventive flavonoids from Xanthorrhoea hastilis 总被引:1,自引:0,他引:1
Allergy-preventive activity was demonstrated for an extract of resins from Xanthorrhoea hastilis R. BR. in a search for allergy-preventive substances from natural sources. By bioassay-directed fractionation of this plant extract, a new flavanone, 3',5'-dihydroxy-7,4'-dimethoxyflavanone (1), and two new chalcones, 3,5,2'-trihydroxy-4,4'-dimethoxychalcone (2) and 5,2'-dihydroxy-3,4,4'-trimethoxychalcone (3), were isolated together with five known compounds, 5'-hydroxy-7,3',4'-trimethoxyflavanone (4), 3'-hydroxy-7,4'-dimethoxyflavanone (5), liquiritigenin 7-methyl ether (6), 4,2'-dihydroxy-4'-methoxychalcone (7) and sakuranetin (8). The structures of 1, 2 and 3 were elucidated by spectroscopic methods. All of these compounds showed allergy-preventive effects. 相似文献
166.
Visualization of the Heterogeneity of Cerium Oxidation States in Single Pt/Ce2Zr2Ox Catalyst Particles by Nano‐XAFS
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Nozomu Ishiguro Prof. Dr. Tomoya Uruga Dr. Oki Sekizawa Dr. Takuya Tsuji Dr. Motohiro Suzuki Dr. Naomi Kawamura Dr. Masaichiro Mizumaki Dr. Kiyofumi Nitta Prof. Dr. Toshihiko Yokoyama Prof. Dr. Mizuki Tada 《Chemphyschem》2014,15(8):1563-1568
The cerium oxidation states in single catalyst particles of Pt/Ce2Zr2Ox (x=7 to 8) were investigated by spatially resolved nano X‐ray absorption fine structure (nano‐XAFS) using an X‐ray nanobeam. Differences in the distribution of the Ce oxidation states between Pt/Ce2Zr2Ox single particles of different oxygen compositions x were visualized in the obtained two‐dimensional X‐ray fluorescent (XRF) mapping images and the Ce LIII‐edge nano X‐ray absorption near‐edge structure (nano‐XANES) spectra. 相似文献
167.
168.
Kazuo Ishiguro 《Mathematische Zeitschrift》1961,76(1):288-294
Ohne Zusammenfassung 相似文献
169.
Mathematische Zeitschrift - 相似文献
170.
S Saito K Kuroda Y Hayashi Y Sasaki Y Nagamura K Nishida I Ishiguro 《Chemical & pharmaceutical bulletin》1991,39(9):2333-2339
Glycyrrhetic acid glycosides (1-7) having beta(1----2)-linked disaccharides such as 2-O-beta-D-glucopyranosyl-beta-D-galactopyranose, 2-O-beta-D-galactopyranosyl-beta-D-galactopyranose, 2-O-beta-D-glucuronopyranosyl-beta-D-galactopyranose, 2-O-beta-D-glucopyranosyl-beta-D-glucuronopyranose, 2-O-beta-D-galactopyranosyl-beta-D-glucuronopyranose, 2-O-beta-D-galactopyranosyl-beta-D-glucopyranose, 2-O-beta-D-glucuronopyranosyl-beta-D-glucopyranose, respectively, were synthesized by stepwise construction; from glycyrrhetic acid monoglycosides to the diglycosides. The cytoprotective activities of the glycosides 1-7 and 2-O-(beta-D-glucopyranosyl)-beta-D-glucopyranosyl-11-oxoolean-12-e n-30-oate (8) were compared with natural occurring glycyrrhizin (9). Among these glycosides 1-8, glycosides 3 and 7 having beta-D-glucuronopyranose (glcUA) as the only terminal sugar component were more effective materials against hepatic injury than glycyrrhizin 9. 相似文献