全文获取类型
收费全文 | 72篇 |
免费 | 1篇 |
国内免费 | 13篇 |
专业分类
化学 | 82篇 |
晶体学 | 1篇 |
综合类 | 2篇 |
物理学 | 1篇 |
出版年
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 3篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1989年 | 2篇 |
排序方式: 共有86条查询结果,搜索用时 281 毫秒
11.
The mass spectra of a series of N-substituted cantharidinimides were examined. The feature of this series compounds is a sequential double hydrogen transfer from the oxabicycloheptane unit to either the carbonyl group of the succinimide unit or the nitrogen atom of the pyridyl or thiazolyl substituent through space. The ability of the N-substituent to accept a hydrogen atom possibly leads to the different fragmentation pathway. 相似文献
12.
13.
Hassan A. Swarup Nagaraju Chaithra Nagarakere C. Sandhya Shobith Rangappa 《合成通讯》2019,49(16):2106-2116
Novel and convenient methodology for the construction of N-substituted amide derivatives have been developed from nitriles and alcohols using propylphosphonic anhydride (T3P®). This methodology is an alternate approach to the synthesis of amides via Ritter reaction, which is one of the classical methods for the synthesis of N-substituted amides from nitriles and alcohols. In this approach, first T3P® activates the alcohol which is then attacked by nitrile to form N-substituted amides. This methodology can also apply for the synthesis of benzhydryl ether. This developed protocol is one of the novel applications of T3P®. 相似文献
14.
N—取代苯基—N‘—(2—甲基苯氧乙酰基)氨基脲的合成及鉴定 总被引:1,自引:0,他引:1
以无机碱作催化剂,用不同的N-取代三氯乙酰苯胺与2-甲基苯氧乙酰肼反应,合成了5种取代氨基脲,产率达82%以上。 相似文献
15.
Guo Zhang Xu Jian Hua Dong Kun Yuan Qiu 《Journal of polymer science. Part A, Polymer chemistry》1997,35(4):643-650
Several N-phenyl maleimides with different p-substituents have been synthesized from the maleic anhydride and relevant aromatic amine. In the presence of N,N-dimethyl-4-toluidine (DMT), the N-substituted phenyl maleimide (4-XPhMIs) could be polymerized under UV irradiation. It was observed that a new absorption appeared on the UV-Vis spectrum of the mixture solution of 4-XPhMI and DMT, which reveals the formation of charge-transfer complex in the ground state. It was found that the fluorescence of DMT was quenched by 4-XPhMI and the quenching constant of 4-XPhMI, obtained from the Stern–Volmer plot, increases with the electron-deficiency of ethylene double bond of 4-XPhMI. The dynamic quenching of the fluorescence of DMT by 4-XPhMI suggests the formation of exciplex in excited state between DMT and 4-XPhMI. The radicals formed in the systems have been detected by spin-trapping techniques and electron paramagnetic resonance (EPR) spectrometer. Based on all of these results, it has been proposed that the initiation process of the polymerization involves the formation of exciplex and the initial radicals were produced by proton-transfer in the exciplex from DMT to 4-XPhMI. © 1997 John Wiley & Sons, Inc. 相似文献
16.
17.
18.
Toru Doi Akira Akimoto Akikazu Matsumoto Takayuki Otsu 《Journal of polymer science. Part A, Polymer chemistry》1996,34(3):367-373
Radical copolymerization of N-methylmaleimide (MeMI) as well as other N-alkylmaleimides (RMI) and isobutene (IB) was carried out with 2,2′-azobis(isobutyronitrile) as an initiator at 60°C. The initial rate of the copolymerization (Rp) was dependent on the monomer composition and was maximum at the 40 mol % of MeMI in the feed. A solvent effect on the Rp and the monomer reactivity ratio was observed in this copolymerization system, i.e., copolymerization in chloroform produced a higher Rp and an alternating tendency compared with those in dioxane (rMeMI = 0.14, r1B = 0 in chloroform and rMeMI = 0.47, r1B = 0 in dioxane). The alternating copolymer of RMI and IB shows a high glass transition temperature (Tg) and excellent thermal stability, e.g., the Tg and the thermal decomposition temperature (Td) were 152 and 363°C, respectively, for the alternating copolymer of MeMI and IB. Both the Tg and Td increased as the concentration of the MeMI unit in the copolymers increased. Colorless transparent sheets were obtained from press molding the alternating copolymers. They showed excellent mechanical and optical properties. © 1996 John Wiley & Sons, Inc. 相似文献
19.
合成了N-(邻氯苯基)氨基乙酸铜(Ⅱ)和N-(邻甲基苯基)氨基乙酸铜(Ⅱ)的单晶体,测定了它们的晶体结构,并对其电子结构进行EHMO计算。N-(邻氯苯基)氨基乙酸铜(Ⅱ)属单斜晶系,空间群P2,/a.a=8.786(4),b=7.777(2),c=11.956(2)A,β=96.01(3)°,V=812.4A,Z=2,Dc=1.77g·cm~-;N-(邻甲基苯基)氨基乙酸铜(Ⅱ)属单斜晶系,空间群P2,/a,a=8.925(6),b=7.973(8),c=11.856(9)Aβ=96.23(6),V=838.6A,Z=2,Dc=1.55g·cm~(-?)。两配合物互为异质同晶。配合物中,铜原子为分子的对称中心,并与两个配位体的两个羧基氧和两个氨基氮原子形成四方形配位结构,平均Cu-O键长为1.902A,Cu-N为2.050A。量子化学计算表明,在配位键的形成中,铜原子的d轨道的作用均不大,但配体中苯环上取代基的性质对Cu-N键强度有一定影响。 相似文献
20.
Published data on the synthesis, structure, and chemical properties of N-substituted 2(3)-imino-2,3-dihydrofuran-3(2)-ones to 2002 are reviewed 相似文献