全文获取类型
收费全文 | 159篇 |
免费 | 7篇 |
专业分类
化学 | 142篇 |
力学 | 1篇 |
数学 | 9篇 |
物理学 | 14篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1958年 | 1篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
81.
Wenzhi Hu Kiyoshi Hasebe Kazuhiko Tanaka James S. Fritz Soichi Inoue Masashi Ozeki 《Analytical and bioanalytical chemistry》2001,370(4):399-402
A new ion chromatographic (IC) system, in which n-tetradecylphosphocholine (TDPC, a phosphobetaine type of zwitterionic surfactant) was used as the stationary phase, pure water as the mobile phase, and conductivity as the method of detection, has been developed for the determination of inorganic acids. Five model acids, HCl, HNO3, HClO4, H2SO4, and H3PO4, were separated to baseline and eluted in the order H3PO4 > HCl > HNO3 > H2SO4 > HClO4. When peak areas were plotted against the concentrations of the acids in samples, linear calibration curves were obtained. Ultimate determination limits were approximately 1 mmol L–1, but the discrimination of the method between solutions of different concentration was better than 10 μmol L–1 for those model analytes. Salts of divalent cations could also be separated, but they were eluted faster than the acids. No separation was observed for the salts of monovalent cations. This newly proposed approach is applicable to the simultaneous determination of the inorganic acids (produced by reactions of NOx, SOx, and HCl with water) in aerosols. 相似文献
82.
Kishi R Fujii H Kishimoto S Murata Y Ito S Okuno K Shigeta Y Nakano M 《The journal of physical chemistry. A》2012,116(17):4371-4380
We develop novel calculation and analysis methods for the dynamic first hyperpolarizabilities β [the second-order nonlinear optical (NLO) properties at the molecular level] in the second-harmonic generation based on the quantum master equation method combined with the ab initio molecular orbital (MO) configuration interaction method. As examples, we have evaluated off-resonant dynamic β values of donor (NH(2))- and/or acceptor (NO(2))-substituted benzenes using these methods, which are shown to reproduce those by the conventional summation-over-states method well. The spatial contributions of electrons to the dynamic β of these systems are also analyzed using the dynamic β density and its partition into the MO contributions. The present results demonstrate the advantage of these methods in unraveling the mechanism of dynamic NLO properties and in building the structure-dynamic NLO property relationships of real molecules. 相似文献
83.
84.
85.
86.
A highly enantioselective cyclization of prochiral unsaturated aldehydes has been accomplished with a chiral zinc reagent derived from dimethylzinc and ()-(+)-1,1′-bi-2-naphthol. 相似文献
87.
Masami Sawada Yoshio Takai Chang Chong Terukiyo Hanafusa Soichi Misumi Yuho Tsuno 《Tetrahedron letters》1985,26(41):5065-5068
Substituent effect on the reverse Menschutkin reaction of 1-methylpyridinium cations with iodide anion can be described in terms of the LArSR equation with ?=3.60 which provides evidence against very late transition state of the nitrogen-to-iodine transmethylation. 相似文献
88.
89.
90.