全文获取类型
收费全文 | 387篇 |
免费 | 42篇 |
专业分类
化学 | 374篇 |
晶体学 | 1篇 |
数学 | 1篇 |
物理学 | 53篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 17篇 |
2019年 | 12篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 21篇 |
2015年 | 26篇 |
2014年 | 20篇 |
2013年 | 22篇 |
2012年 | 12篇 |
2011年 | 25篇 |
2010年 | 18篇 |
2009年 | 9篇 |
2008年 | 17篇 |
2007年 | 16篇 |
2006年 | 14篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1979年 | 2篇 |
1977年 | 5篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1936年 | 2篇 |
排序方式: 共有429条查询结果,搜索用时 31 毫秒
21.
Martin Piesch Dr. Fabian Dielmann Stephan Reichl Prof. Dr. Manfred Scheer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(7):1518-1524
A systematic study on the reactivity of the triple-decker complex [(Cp’’’Co)2(μ,η4:η4-C7H8)] ( A ) (Cp’’’=1,2,4-tritertbutyl-cyclopentadienyl) towards sandwich complexes containing cyclo-P3, cyclo-P4, and cyclo-P5 ligands under mild conditions is presented. The heterobimetallic triple-decker sandwich complexes [(Cp*Fe)(Cp’’’Co)(μ,η5:η4-P5)] ( 1 ) and [(Cp’’’Co)(Cp’’’Ni)(μ,η3:η3-P3)] ( 3 ) (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) were synthesized and fully characterized. In solution, these complexes exhibit a unique fluxional behavior, which was investigated by variable temperature NMR spectroscopy. The dynamic processes can be blocked by coordination to {W(CO)5} fragments, leading to the complexes [(Cp*Fe)(Cp’’’Co)(μ3,η5:η4:η1-P5){W(CO)5}] ( 2 a ), [(Cp*Fe)(Cp’’’Co)(μ4,η5:η4:η1:η1-P5){(W(CO)5)2}] ( 2 b ), and [(Cp’’’Co)(Cp’’’Ni)(μ3,η3:η2:η1-P3){W(CO)5}] ( 4 ), respectively. The thermolysis of 3 leads to the tetrahedrane complex [(Cp’’’Ni)2(μ,η2:η2-P2)] ( 5 ). All compounds were fully characterized using single-crystal X-ray structure analysis, NMR spectroscopy, mass spectrometry, and elemental analysis. 相似文献
22.
Dr. Martin Piesch Dr. Amélie Nicolay Dr. Maria Haimerl Dr. Michael Seidl Dr. Gábor Balázs Prof. T. Don Tilley Prof. Dr. Manfred Scheer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202201144
The bridging MeCN ligand in the dicopper(I) complexes [(DPFN)Cu2(μ,η1 : η1-MeCN)][X]2 (X=weakly coordinating anion, NTf2 ( 1 a ), FAl[OC6F10(C6F5)]3 ( 1 b ), Al[OC(CF3)3]4 ( 1 c )) was replaced by white phosphorus (P4) or yellow arsenic (As4) to yield [(DPFN)Cu2(μ,η2 : η2-E4)][X]2 (E=P ( 2 a – c ), As ( 3 a – c )). The molecular structures in the solid state reveal novel coordination modes for E4 tetrahedra bonded to coinage metal ions. Experimental data and quantum chemical computations provide information concerning perturbations to the bonding in coordinated E4 tetrahedra. Reactions with N-heterocyclic carbenes (NHCs) led to replacement of the E4 tetrahedra with release of P4 or As4 and formation of [(DPFN)Cu2(μ,η1 : η1-MeNHC)][X]2 ( 4 a,b ) or to an opening of one E−E bond leading to an unusual E4 butterfly structural motif in [(DPFN)Cu2(μ,η1 : η1-E4DippNHC)][X]2 (E=P ( 5 a,b ), E=As ( 6 )). With a cyclic alkyl amino carbene (EtCAAC), cleavage of two As−As bonds was observed to give two isomers of [(DPFN)Cu2(μ,η2 : η2-As4EtCAAC)][X]2 ( 7 a,b ) with an unusual As4-triangle+1 unit. 相似文献
23.
24.
Bacteriochlorophyll (BChl) derivatives (with central Mg replaced by metal "M") ([M]-BChl with M = 2H, Mg, Zn, Pd, Cu) have been investigated for their photodynamic capacity and stability toward photodegradation in organic solvents and aqueous micellar solution. A protocol has been developed for screening new sensitizers. BChl and [Zn]-BChl are efficient sensitizers, but they are also quickly degraded by the reactive oxygen species (ROS) produced by autosensitization, as well as by hetero-sensitization with 17(4)-methyl-13(2)-demethoxycarbonyl-pheophorbide a (MPP). Photostable [Cu]-BChl is a poor sensitizer, whereas [Pd]-BChl and bacteriopheophytin a are not only very efficient sensitizers but are also very stable toward ROS. beta-Carotene is no efficient physical quencher of ROS in the system; rather, it acts as a photochemical quencher that competes with [M]-BChl and undergoes photooxygenation at high rates. Photolability seems to depend on the pigment oxidation potential and, in parallel, on the presence of central metals preferring coordination numbers higher than 4, whereas photodynamic capacity depends on long excited state life-times of the pigment or efficient intersystem crossing (or both). 相似文献
25.
26.
27.
Ohne Zusammenfassung 相似文献
28.
29.
30.