全文获取类型
收费全文 | 678篇 |
免费 | 52篇 |
国内免费 | 3篇 |
专业分类
化学 | 606篇 |
晶体学 | 14篇 |
力学 | 5篇 |
数学 | 16篇 |
物理学 | 92篇 |
出版年
2023年 | 7篇 |
2022年 | 2篇 |
2021年 | 19篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 23篇 |
2017年 | 7篇 |
2016年 | 27篇 |
2015年 | 38篇 |
2014年 | 20篇 |
2013年 | 21篇 |
2012年 | 58篇 |
2011年 | 62篇 |
2010年 | 23篇 |
2009年 | 17篇 |
2008年 | 34篇 |
2007年 | 39篇 |
2006年 | 26篇 |
2005年 | 43篇 |
2004年 | 39篇 |
2003年 | 26篇 |
2002年 | 20篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1997年 | 5篇 |
1995年 | 3篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 15篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有733条查询结果,搜索用时 15 毫秒
71.
The synthesis and characterization of two coordination polymers, {Cu(I)[Mo(V)(bdt)(3)]·0.5Et(2)O}(n) (1·0.5Et(2)O, bdt: o-benzenedithiolato) and {Ag(I)[Mo(V)(bdt)(3)]}(n) (2), composed of redox-active [Mo(V)(bdt)(3)](-) metalloligand with Cu(I) and Ag(I) ions are reported. The complexation reactions of [Mo(V)(bdt)(3)](-) with Cu(II)(ClO(4))(2) or Ag(I)ClO(4) commonly lead to the formation of one-dimensional (1-D) coordination polymers. The presence of Cu(I) in 1·0.5Et(2)O strongly indicates that the Cu(II) ion is reduced during the complexation reaction with [Mo(V)(bdt)(3)](-), which acts as an electron donor. The total dimensionalities of the assembled structures of 1·0.5Et(2)O and 2 are significantly different and related to the type of additional metal ions, Cu(I) and Ag(I). In contrast to the isolated 1-D chain structure of 1·0.5Et(2)O, complex 2 has a three-dimensional (3-D) assembled structure constructed from additional π-π stacking interactions between adjacent [Mo(V)(bdt)(3)](-) moieties. These structural differences influence the solubility of the complexes in organic solvents; complex 1·0.5Et(2)O is soluble as origomeric species in highly polar solvents, while 2 is insoluble in organic solvents and water. Coordination polymers 1·0.5Et(2)O and 2 were investigated by UV-vis spectroscopy in the solid state, and that in solution together with their electrochemical properties were also investigated for 1 because of its higher solubility in polar organic solvents. Complex 1·0.5Et(2)O dissolved in CH(3)CN demonstrates concentration-dependent UV-vis spectra supporting the presence of coordinative interactions between [Mo(V)(bdt)(3)](-) moieties and Cu(I) ions to create the origomeric species even in solutions, an observation that is supported also by electrochemical experiments. 相似文献
72.
1-Phenylcyclopentadiene fused with two homoadamantene units at the 2,3- and 4,5-positions (4) was deprotonated with KH to lead to the quantitative formation of the corresponding cyclopentadienyl (Cp) anion 3(-). This anion was oxidized by AgCl to afford an orange crystalline solid consisting of Cp radical 3(?) and cyclopentadiene 4. The ESR spectrum in hexane exhibited approximately 15 lines, demonstrating that the two homoadamantene frameworks were equivalent and that the C1-C2(Ph)-C3 moiety of the five-membered ring formed a symmetrical allyl-like radical in agreement with the prediction by DFT calculation. The reaction of the Cp radical 3(?) with an oxygen molecule in the presence of Ag(+)SbF(6)(-) afforded the SbF(6)(-) salt of a phenylpyrylium ion annelated with two homoadamantene frameworks (8(+)SbF(6)(-)). 相似文献
73.
Matsutani R Inoue K Wada N Kojima K 《Chemical communications (Cambridge, England)》2011,47(20):5840-5842
The amount of polyynes produced by Nd:YAG laser (355, 532, and 1064 nm) ablation of fullerene and graphite pellet targets was the largest for 1064 nm ablation, contrary to the powder target in the previous report. This result is believed to come from the difference in the main polyyne-production area in liquids in the optical cell, depending on the pellet and powder targets. 相似文献
74.
Statistical Inference for Stochastic Processes - In this paper, we consider the problem of estimating the lead–lag parameter between two stochastic processes driven by fractional Brownian... 相似文献
75.
76.
Kohei Tamao 《Angewandte Chemie (International ed. in English)》2007,46(40):7538-7539
77.
Nanosized gold clusters were developed in a gold-doped soda-lime silicate glass after X-ray irradiation followed by annealing, which provided an alternative way of forming metallic nanoclusters in glass to ion implantation. The formation of gold nanoclusters can be controlled by irradiation time or annealing time. 相似文献
78.
79.
80.