全文获取类型
收费全文 | 76篇 |
免费 | 1篇 |
专业分类
化学 | 65篇 |
数学 | 4篇 |
物理学 | 8篇 |
出版年
2019年 | 1篇 |
2013年 | 7篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1996年 | 2篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有77条查询结果,搜索用时 15 毫秒
1.
2.
Minimal contracted Gaussian basis sets are presented for Ga through Cd. Characteristically these Gaussian-based minimal sets give far better d orbital energies than those by minimal STO basis sets. These new basis sets were tested on Br2 for which a new benchmark calculation was also performed. The test result is satisfactory in that these basis sets produce good general agreement with the near Hartree–Fock calculation with respect to the molecular spectroscopic constants. 相似文献
3.
4.
New ring-opening reaction of thiazoline-azetidinones 1 to dithioazetidinones 2 was achieved with 2-benzothiazolyl disulfide in aqueous acidic media and its potentiality for the preparation of a variety of cephalosporins 3 from various thiazoline-azetidinones 1 is demonstrated. 相似文献
5.
Katsuya Maeyama Kenji Yamashita Shugo Maeda Noriyuki Yonezawa Shunichi Aikawa Yasuhiko Yoshida 《合成通讯》2013,43(23):4158-4170
Optically active aromatic ether ketone macrocycles containing 2,2′-dimethoxy-1,1′-binaphthyl-6,6′-diyl moieties were synthesized through electrophilic aromatic substitution reaction and stepwise nucleophilic aromatic substitution reactions. Structures of the resulting macrocycles were confirmed by NMR and matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass measurements. 相似文献
6.
A novel α-phenylselenenylation of carbonyl compounds has been performed by electrolysis of a solution of ketones, diphenyl diselenide, tetraethylammonium bromide, and magnesium bromide in polar solvents (MeOH, AcOH, MeCN). The electrolysis enables us to prepare the desired seleno-carbonyl compounds without employing strong bases and the activated selenenyl reagents PhSeX. 相似文献
7.
It is demonstrated that the first-order relativistic correction term to the Schrödinger hamiltonian for the hydrogen-like atom, cannot be used safely even for small values of atomic number, Z, in the variational calculation. A modified form of the operator R is proposed so that one may incorporate it into the variational treatment of molecular systems. 相似文献
8.
d1-Theaspirane (1) was prepared by the selenium-mediated electrochemical oxidation of α-dihydroionol (3), via a novel selenium-mediated spiroannelation. 相似文献
9.
Maeyama T Yagi I Murota Y Fujii A Mikami N 《The journal of physical chemistry. A》2006,110(51):13712-13716
Vibrational spectra of microsolvated benzonitrile radical anions (C6H5CN- -S; S = H2O and CH3OH) were measured by probing the electron detachment efficiency in the 3 microm region, representing resonance bands of autodetachment via OH stretching vibrations of the solvent molecules. The hydrogen-bonded OH band for both the cluster anions exhibited a large shift to the lower energy side with approximately 300 cm-1 compared to those for the corresponding neutral clusters. The solvent molecules are bound collinearly to the edge of the CN group of the benzonitrile anion in the cluster structures optimized with the density functional theory, in which the simulated vibrational energies are in good agreement with the observed band positions. Natural population analyses were performed for a qualitative implication in changes of solvent orientation upon electron attachment. Asymmetric band shapes depending on the vibrational modes are discussed with respect to dynamics of the autodetachment process from a theoretical aspect incorporated with density functional calculations. 相似文献
10.
Y. Maeyama 《Historia Mathematica》1989,16(4)
A new method which shows, simply and accurately, the planetary position as a geometrical point in the orbit as a function of time is presented. By comparison with the historical hypotheses of planetary motion, it is thus visually recognizable how such hypotheses, especially those propagated in the 17th century, approached the Keplerian motion geometrically by means of observations. The reason why such a mathematically accurate hypothesis as that presented here was not developed previously, say in the 17th century, was due mainly to the inaccurate values for the solar parallax involved in the observations of that time. 相似文献