全文获取类型
收费全文 | 207篇 |
免费 | 10篇 |
专业分类
化学 | 165篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 5篇 |
物理学 | 43篇 |
出版年
2023年 | 3篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 8篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 4篇 |
2006年 | 19篇 |
2005年 | 24篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 12篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 9篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有217条查询结果,搜索用时 62 毫秒
81.
82.
Tanabe Y Kajitani H Iwasaki M Ishii Y 《Dalton transactions (Cambridge, England : 2003)》2007,(41):4701-4707
The tetraruthenium complex [Cp*RuCl]4 (Cp* = eta(5)-C(5)Me(5)) reacts with Na(2)NCN to afford the anionic bis(cyanamido)-capped triruthenium complex [(Cp*Ru)3(micro(3)-NCN)(2)]- ((2-)), which undergoes single electron oxidation to form [(Cp*Ru)3(micro(3)-NCN)2] upon workup with 1 equiv. of [Cp(2)Fe](PF(6)) (Cp = eta(5)-C(5)H(5)). Treatment of (2-) with 1 equiv. of HCl at room temperature leads to the protonation of one of the Ru-Ru edges to give the hydrido-bridged complex [(Cp*Ru)3(micro-H)(micro-NCN)2], while the cationic side-on NCNH(2) complex [(Cp*Ru)3(micro-Cl)(micro(3)-NCN)(micro(3)-NCNH(2)-1kappaC,N:2kappaC:3kappaN)]Cl (5) is obtained by the reaction of (2-) with an excess amount of HCl at -78 degrees C. On the other hand, the reaction of (2-) with BR(3) (R = Et, Ph) results in the ligation of two BR(3) molecules to the terminal nitrogen atoms of the cyanamido ligands to yield the bis(borane) adduct (PPN)[(Cp*Ru)(3){(micro(4)-NCN)(BR(3))}(2)] (6, PPN = Ph(3)PNPPPh(3)). 6b (R = Et) slowly liberates one BEt(3) molecule in acetone to give the mono(borane) adduct (PPN)[(Cp*Ru)3(micro(3)-NCN){(micro(4)-NCN)(BEt(3))}] (7). (2-) is also shown to react with [AuCl(PPh(3))] or PhCOCl to afford the tetranuclear heterometallic complex [(Cp*Ru)3(micro(3)-NCN){(micro(4)-NCN)(AuPPh(3))}] (8) or the benzoylcyanamido complex [(Cp*Ru)3(micro(3)-NCN)(micro(3)-NCNCOPh)] in which the Au(PPh(3))+ or benzoyl fragment is bound to the terminal nitrogen atom of a cyanamido ligand. The molecular structures of PPN+(2-), 5.C(6)H(6), 7 and 8.C(6)H(6) have been determined by single-crystal X-ray analyses. 相似文献
83.
84.
Modulation of a Molecular π‐Electron System in a Purely Organic Conductor that Shows Hydrogen‐Bond‐Dynamics‐Based Switching of Conductivity and Magnetism 下载免费PDF全文
Dr. Akira Ueda Akari Hatakeyama Dr. Masaya Enomoto Prof. Dr. Reiji Kumai Prof. Dr. Youichi Murakami Prof. Dr. Hatsumi Mori 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):15020-15028
New important aspects of the hydrogen‐bond (H‐bond)‐dynamics‐based switching of electrical conductivity and magnetism in an H‐bonded, purely organic conductor crystal have been discovered by modulating its tetrathiafulvalene (TTF)‐based molecular π‐electron system by means of partial sulfur/selenium substitution. The prepared selenium analogue also showed a similar type of phase transition, induced by H‐bonded deuterium transfer followed by electron transfer between the H‐bonded TTF skeletons, and the resulting switching of the physical properties; however, subtle but critical differences due to sulfur/selenium substitution were detected in the electronic structure, phase transition nature, and switching function. A molecular‐level discussion based on the crystal structures shows that this chemical modification of the TTF skeleton influences not only its own π‐electronic structure and π–π interactions within the conducting layer, but also the H‐bond dynamics between the TTF π skeletons in the neighboring layers, which enables modulation of the interplay between the H‐bond and π electrons to cause such differences. 相似文献
85.
Mototada Kobayashi Toshifumi Hara Kenichi Shiota Yuichi Akahama Haruki Kawamura Youichi Murakami 《Molecular Crystals and Liquid Crystals》2013,570(1):611-616
Abstract X-ray diffraction and magnetic-susceptibility measurements have been carried out for single phase KxC70 (x=1, 3, 4, 6 and 9) compounds synthesized by heating stoichiometric amount of K9C70 and C70. The x-ray diffraction profiles show no structural transition down to 10K. The fairly large temperature-independent paramagnetic contribution was observed in x=3 and 4. The electrical resistivity has been measured for K evaporated C70 film with increasing K thickness. Two resistivity minima were observed at x=1 and 4. 相似文献
86.
87.
Phase-shifting interferometry with feedback control using heterodyne phase detection 总被引:1,自引:0,他引:1
Bitou Y 《Optics letters》2008,33(16):1777-1779
A phase-shifting interferometer with feedback control using heterodyne phase detection was developed. A composite heterodyne phase detection method for obtaining feedback signals was proposed. Interference fringe stabilization and accurate pi/2 phase shifts under micrometer-order vibrations were successfully demonstrated using a digital high-speed lock-in amplifier. 相似文献
88.
Mino T Sato Y Saito A Tanaka Y Saotome H Sakamoto M Fujita T 《The Journal of organic chemistry》2005,70(20):7979-7984
[Chemical reaction: See text] Chiral fluorous aminophosphine 4c bearing two fluorous ponytails was prepared from (S)-prolinol and applied to palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate (7) with a dialkyl malonate-BSA-LiOAc system with high enantioselectivities (up to 97% ee). Results indicated that the chiral fluorous palladium catalyst from ligand 4c was easily separated from the reaction mixture by simple solid/liquid separation and could be reused up to five times. 相似文献
89.
Youichi Ohno Katsuichi Kaneda Shozo Okada Kimiaki Hirama 《Journal of solid state chemistry》1984,54(2):170-178
The sulfur K and metal LIII absorption spectra of transition-metal trichalcogenides (TMTC's) were measured. The matrix element effect plays an important role in these spectra. It was considered that the structures up to 5 eV above the absorption edge reflect the chalcogen antibonding band, the metal nonbonding dz2 band, and the metal d bands, and that the higher energy structures are derived from the metal s and p bands. The chalcogen antibonding band arises from chalcogen pairing and the metal d, s, and p bands are the mixture bands with chalcogen p orbitals. Evidence that shows that the lowest conduction band of the group IV TMTC's is the chalcogen antibonding band is presented. The overlap of the metal d and metal s bands is promoted by increasing the atomic number of chalcogen atoms. 相似文献
90.