全文获取类型
收费全文 | 209篇 |
免费 | 55篇 |
国内免费 | 2篇 |
专业分类
化学 | 265篇 |
物理学 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 14篇 |
2015年 | 16篇 |
2014年 | 22篇 |
2013年 | 17篇 |
2012年 | 12篇 |
2011年 | 20篇 |
2010年 | 19篇 |
2009年 | 16篇 |
2008年 | 19篇 |
2007年 | 17篇 |
2006年 | 12篇 |
2005年 | 18篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有266条查询结果,搜索用时 15 毫秒
101.
Furuyama T Yonehara M Arimoto S Kobayashi M Matsumoto Y Uchiyama M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(33):10348-10356
We present full details of the unique reactivities of the newly developed dianion-type bulky zincate, dilithium tetra-tert-butylzincate (tBu(4)ZnLi(2)). With this reagent, halogen-zinc exchange reaction of variously functionalized haloaromatics and anionic polymerization of N-isopropylacrylamide (NIPAm)/styrene with excellent chemoselectivity were realized. Halogen-zinc exchange reaction followed by electrophilic trapping with propargyl bromide provided a convenient route to functionalized phenylallenes, particularly those with electrophilic functional groups (such as cyano, amide and halogens). Spectral and computational studies of the structure in the gas and liquid phases indicated extraordinary stabilization of this dianion-type zincate by its bulky ligands. 相似文献
102.
Concellón JM Rodríguez-Solla H Del Amo V 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(33):10184-10191
While the organometallic compounds derived from many metals have found a broad application in organic synthesis, the use of organomanganese compounds has only recently been developed due to the passivity exhibited by commercial Mn in the direct metalation of organic compounds. In this Concept article, we highlight the potential of manganese and its organometallic compounds in organic synthesis by illustration of the studies previously reported by others and our laboratory in this field. Based on the transformations reported herein, organomanganese compounds could become important tools in the future of the organic synthesis, due to their high selectivity. 相似文献
103.
(E)- and (Z)-configured alpha-lithioalkenyl sulfoximines, which are available through lithiation of the corresponding alkenyl sulfoximines, undergo a anionic cross-coupling reaction (ACCR) with organocuprates with formation of the corresponding alkenyl cuprates and sulfinamide. The alkenyl cuprates can be trapped by electrophiles. The ACCR presumably proceeds via the formation of a higher-order sulfoximine-substituted alkenyl cuprate, which undergoes a 1,2-metal-ate rearrangement whereby the sulfoximine group acts as the nucleofuge. The parent (E)- and (Z)-configured alkenyl sulfoximines suffer upon treatment with an organocuprate a deprotonation at the alpha-position with formation of the corresponding alpha-cuprioalkenyl sulfoximines. These derivatives also enter into a similar ACCR with organocuprates. The ACCR of sulfoximines substituted homoallylic alcohols allows a stereoselective access to enantio- and diastereopure substituted homoallylic alcohols. 相似文献
104.
105.
106.
107.
Xinli Leng Yan Lu Zhongping Wang Wei Li Xiaoqing Liu Li Wang 《Surface and interface analysis : SIA》2016,48(4):237-242
The metalation behaviors of 5,15‐diphenylporphyrin (2H‐DPP) on Pd(111) and Cu/Pd(111) have been investigated using scanning tunneling microscopy and density functional calculations. We show that 2H‐DPP molecules deposited on Pd(111) surface form Pd‐DPP with a proportion of about 75% already at room temperature (RT). This is in contrast to non‐metalation adsorption of 2H‐DPP on Cu–Pd alloy at RT. Annealing to 323 K facilitates the metalation of 2H‐DPP on Cu–Pd alloy island. The comparison of the results indicates that the metalation of 2H‐DPP calls for both enough surface free energy of approaching N? H bond and enough reactivity of breaking N? H bond. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
108.
Dr. Abraham B. Alemayehu Hugo Vazquez‐Lima Dr. Kevin J. Gagnon Prof. Dr. Abhik Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(20):6914-6920
The oxidative metalation method, involving the interaction of free‐base meso‐triarylcorroles and W(CO)6 in refluxing decalin, led to a set of three tungsten(VI) biscorroles, the first homoleptic sandwich compounds involving corroles. Single‐crystal X‐ray structures of two of the complexes revealed square‐antiprismatic coordination and strongly domed corroles with long W?N distances of 2.15–2.22 Å and a substantial displacement of ~1.17 Å of the metal relative to the mean N4 planes of the ligands. The structures correspond to approximate C2 symmetry and are thus chiral. DFT calculations strongly indicate that the enantiomers are configurationally stable and hence amenable to chiral resolution. Their other notable properties include a strongly blueshifted Soret band at (357±2) nm, a relatively intense π→W(d ) near‐IR feature at (781±3) nm, and a low electrochemical HOMO–LUMO gap of approximately 1.3 V. The results obtained herein suggest that metallobiscorroles may emerge as a new class of inherently chiral chromophores with novel optical and electrochemical properties. 相似文献
109.
Yushin Shibuya Prof. Dr. Atsunori Mori 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(31):6976-6987
Due to a wide range of applications in electronic materials, polythiophenes attract considerable attention in organic and polymer syntheses as well as in materials science. For the purpose of developing the practical synthetic protocol, this review focuses on the deprotonative pathway in the preparation of thiophene organometallic monomer, which was shown to be effective employing 2-halo-3-substituted thiophene as a monomer precursor. The thus metallated thiophene monomer was shown to undergo polymerization by nickel(II) complex catalysis, with which highly regioregular head-to-tail (HT)-type polythiophenes were obtained with controlled molecular weight and molecular weight distribution. Several polythiophene derivatives with modified thiophene-ring and side-chain structures were shown to be designed in order to achieve the designed functionality as materials. 相似文献
110.
Timothy E. Hurst Dr. Todd K. Macklin Dr. Maike Becker Eduard Hartmann Wolfgang Kügel Jean‐Christophe Parisienne‐La Salle Andrei S. Batsanov Dr. Todd B. Marder Prof. Dr. Victor Snieckus Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(27):8155-8161
Systematic studies are presented demonstrating the complementarity of directed ortho metalation (DoM) and Ir‐catalyzed strategies for the provision of borylated aromatics and their subsequent Suzuki–Miyaura coupling reactions. A new concept, the use of the TMS group, readily introduced by DoM, as a latent regiodirective moiety to overcome the otherwise problematic production of isomeric borylated product mixtures is presented. Additional electrophile‐induced ipso‐deborylation and DoM reactions of the Bpin products are described. 相似文献