全文获取类型
收费全文 | 350篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
化学 | 299篇 |
晶体学 | 2篇 |
力学 | 4篇 |
数学 | 21篇 |
物理学 | 38篇 |
出版年
2023年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 14篇 |
2012年 | 11篇 |
2011年 | 38篇 |
2010年 | 21篇 |
2009年 | 13篇 |
2008年 | 26篇 |
2007年 | 24篇 |
2006年 | 21篇 |
2005年 | 20篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 19篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1928年 | 2篇 |
1927年 | 1篇 |
排序方式: 共有364条查询结果,搜索用时 296 毫秒
71.
72.
Analysis of water-soluble vitamins by micellar electrokinetic capillary chromatography 总被引:1,自引:0,他引:1
Seven water-soluble vitamins were determined simultaneously by micellar electrokinetic capillary chromatography with UV detection. All these compounds were separated from each other within ca. 22 min by using a carrier containing sodium dodecyl sulphate as the surfactant. On-column detection at 254 nm with ethyl p-aminobenzoate as the internal standard allowed sensitive, accurate and reproducible determination of these compounds. Five principal constituents of a vitamin injection were determined with relative standard deviations of less than 2.1%. 相似文献
73.
ZnS-Zn nanocables and ZnS nanotubes have been synthesized by a thermochemical process in a simple and safe way. The as-prepared nanocables consist of a single crystal Zn core with a diameter of 20 nm and a polycrystalline ZnS sheath with a thickness of 8 nm. The evaporation of the Zn core leads to the formation of ZnS nanotubes. 相似文献
74.
75.
76.
Katsuhiro Shirono Kosei Iwase Hiroshi Okazaki Masaru Yamazawa Kazuhiro Shikakume Natsuo Fukumoto Masashi Murakami Masaaki Yanagisawa Takahisa Tsugoshi 《Accreditation and quality assurance》2013,18(3):161-174
Methods of utilizing the Youden plot obtained from interlaboratory comparison tests are proposed. The Youden plot is a powerful tool for visually evaluating between- or within-laboratory errors. However, there are no generally applicable methods to indicate the anomalies in the between- and the within-laboratory errors in qualitative terms. An evaluation frame was therefore developed in this study as an indication method. Moreover, the Youden plot is considered to be useful for visually assessing the comprehensive performance of laboratories using two types of results. Although the confidence ellipse has been proposed in ISO 13528:2005 for this purpose, robust determination of the parameters has not yet been implemented. In the present study, robust determination of one of the parameters, the correlation coefficient, was developed. Our proposals were analytically validated using two types of statistical models. In addition, the properties were evaluated through computational simulations. From the results obtained, it can be concluded that our proposals are practically applicable to actual interlaboratory comparison tests. 相似文献
77.
Toshiyuki Yokoi Syusaku Sato Yoichiro Ara Daling Lu Yoshihiro Kubota Takashi Tatsumi 《Adsorption》2010,16(6):577-586
Chiral mesoporous silica (CMS) has been successfully synthesized in the presence of basic amino acids; the use of basic amino
acids in combination with the chiral anionic surfactant is advantageous for the formation of CMS in terms of uniformity in
the twisted morphology. We first demonstrate that thus obtained chiral mesoporous silicas can be used for the enantioselective
separation of racemic compounds; the helical rod-shaped CMS is found to be capable of asymmetric separation of racemic N-trifluoroacetylalanine ethyl ester (CF3CO-Ala-OEt). The left handedness-rich CMS shows asymmetric preferential adsorption of the L isomer and vice versa. 相似文献
78.
Iron-catalyzed synthesis of glycine derivatives via carbon-nitrogen bond cleavage using diazoacetate
Treatment of tertiary amines with diazoacetate in the presence of a catalytic amount of an iron salt, FeCl(3), in ethanol gave glycine derivatives. In this reaction, a carbon-nitrogen single bond of the amine was cleaved. 相似文献
79.
The synthesis of unsymmetric functionalized pentacenes from 1,4-anthraquinones and functionalized isobenzofurans, which were prepared by transformation via C-H bond activation, was successfully accomplished. Examples of the synthesis of pentacenes with functional groups at the 5-position are still rare. These obtained functionalized pentacenes are highly soluble in hexane, toluene, and THF. 相似文献
80.
Masaki Oba Yoichiro Maruyama Katsuaki Akaoka Masabumi Miyabe Ikuo Wakaida 《Applied Physics A: Materials Science & Processing》2010,101(3):545-549
Emission characteristics of gadolinium (Gd) oxide are studied, using ns and fs laser pulses for ablation in double-pulse laser
induced breakdown spectroscopy (LIBS). In the current conditions of pulse energy and signal detection timing, emission intensity
enhancement in the reheating mode is 25-fold, but little effect can be observed in a pre-pulse mode. It is shown that the
optimum focus position of the ablation pulse is about 5 mm apart from the sample surface in the reheating mode. Although little
emission can be observed in the single-pulse configuration with fs ablation pulses, the intense emission can be observed in
the reheating mode in the double-pulse configuration. 相似文献