全文获取类型
收费全文 | 972篇 |
免费 | 194篇 |
国内免费 | 32篇 |
专业分类
化学 | 1124篇 |
晶体学 | 3篇 |
力学 | 1篇 |
综合类 | 1篇 |
物理学 | 69篇 |
出版年
2023年 | 7篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 32篇 |
2019年 | 29篇 |
2018年 | 22篇 |
2017年 | 22篇 |
2016年 | 60篇 |
2015年 | 63篇 |
2014年 | 66篇 |
2013年 | 92篇 |
2012年 | 75篇 |
2011年 | 71篇 |
2010年 | 52篇 |
2009年 | 74篇 |
2008年 | 66篇 |
2007年 | 65篇 |
2006年 | 56篇 |
2005年 | 71篇 |
2004年 | 46篇 |
2003年 | 52篇 |
2002年 | 25篇 |
2001年 | 21篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 25篇 |
1996年 | 18篇 |
1995年 | 26篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 2篇 |
排序方式: 共有1198条查询结果,搜索用时 15 毫秒
1.
Synthesis and Photophysical Properties of a Sc3N@C80‐Corrole Electron Donor–Acceptor Conjugate
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bin Liu Hongyun Fang Prof. Xiaofang Li Wenting Cai Lipiao Bao Marc Rudolf Fabian Plass Prof. Louzhen Fan Prof. Xing Lu Prof. Dirk M. Guldi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):746-752
Embedding endohdedral metallofullerenes (EMFs) into electron donor–acceptor systems is still a challenging task owing to their limited quantities and their still largely unexplored chemical properties. In this study, we have performed a 1,3‐dipolar cycloaddition reaction of a corrole‐based precursor with Sc3N@C80 to regioselectively form a [5,6]‐adduct ( 1 ). The successful attachment of the corrole moiety was confirmed by mass spectrometry. In the electronic ground state, absorption spectra suggest sizeable electronic communications between the electron acceptor and the electron donor. Moreover, the addition pattern occurring at a [5,6]‐bond junction is firmly proven by NMR spectroscopy and electrochemical investigations performed with 1 . In the electronically excited state, which is probed in photophysical assays with 1 , a fast electron‐transfer yields the radical ion pair state consisting of the one‐electron‐reduced Sc3N@C80 and of the one‐electron‐oxidized corrole upon its exclusive photoexcitation. As such, our results shed new light on the practical work utilizing EMFs as building blocks in photovoltaics. 相似文献
2.
Phenomena accompanying electrochemical doping of solid fullerene films with potassium were studied by sputter ion depth profiling
(XPS and SIMS). The potassium distribution was determined, and artifacts associated with possible damage of the layer composition
caused by ion impact were investigated and discussed. To compare the charge transfer while reductive doping is taking place
at fullerene/solution interface with doping from gas phase, model layers were prepared and doped by potassium under UHV conditions.
It was found that sputtering by Ar+ primary ions yields both accurate information on the alkaline metal distribution and on its concentration. Sputtering by
O+ ions led to an enrichment of potassium, apparently due to the reactivity of oxygen with the fullerene matrix. It is shown
that the reductive doping starts at the fullerene/solution interface. The concentration of potassium in the doped films was
found to be lower than expected from the charge transferred during the electrochemical reduction. Other phase transformations
such as hydrogenation are discussed.
Received March 4, 2002; accepted July 26, 2002 相似文献
3.
4.
V. P. Bubnov I. S. Krainskii E. E. Laukhina E. B. Yagubskii 《Russian Chemical Bulletin》1994,43(5):746-750
The effect of the parameters of the electric arc (helium pressure, current and voltage, clearance between electrodes) and of the peculiarities of the setup design (arrangement of electrodes, distance between the arc and the cooling surface, temperature of the soot condensation surface) on the yield of fullerenes has been studied. Conditions for producing soot with a C60 and C70 content up to 43% (toluene extract) have been found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 805–809, May, 1994.The authors are grateful to N. G. Spitsyna and A. V. Dubovitskii for the determination of the content of C60 and C70 fullerenes in the extract.The work was financially supported by the Russian Foundation for Basic Research (Project 93-03-18705). 相似文献
5.
6.
We describe the topology, structure, and stability of giant fullerenes exhibiting various symmetries (I, I
h
, D
2h
, T). Our results demonstrate that it is possible to create two new families of nested chiral icosahedral (I) fullerenes namely C260@C560@C980@C1520@, ...,and C140@C380@C740@C1220@ ..., which exhibit interlayer separations of ca. 3.4 Å. These chiral fullerenes are thought to possess metalliclike conduction properties. We discuss in detail the transformation of polyhedral graphitic particles into quasispherical nested giant fullerenes by reorganization of carbon atoms, which result in the formation of additional pentagonal and heptagonal carbon rings. These spherical structures are metastable and we believe they could be formed under extreme conditions, such as those produced by high-energy electron irradiation. There is circumstantial experimental evidence for the presence of heptagonal rings within these spherical fullerenes. 相似文献
7.
8.
Atsushi Ikeda Tsukasa HatanoToshifumi Konishi Jun-ichi KikuchiSeiji Shinkai 《Tetrahedron》2003,59(19):3537-3540
In a light-to-photocurrent conversion system based on a C60-porphyrin bilayer prepared by electrostatic alternate adsorption, porphyrin units in a porphyrin polymer have been isolated by cyclodextrin utilizing the host-guest interaction. In this system, a high quantum yield was achieved by suppression of self-quenching of porphyrin units. 相似文献
9.
Dzhemilev U. M. Ibragimov A. G. Khafizova L. O. Khalilov L. M. Vasil"ev Yu. V. Tomilov Yu. V. 《Russian Chemical Bulletin》2001,50(2):297-299
1-Ethyl-2,3-fullerenoaluminacyclopropanes (EtAl)n(2-C60) were synthesized by the reaction of fullerene C60 with an excess of EtAlCl2 in the presence of Mg and using Cp2TiCl2 as the catalyst in a THF--toluene solution at 20 °C. Deuterolysis of fullerenoaluminacyclopropanes afforded a mixture of deuteriofullerenes C60Dm, where m = 6--12. 相似文献
10.
Imahori H Fujimoto A Kang S Hotta H Yoshida K Umeyama T Matano Y Isoda S Isosomppi M Tkachenko NV Lemmetyinen H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(24):7265-7275
Novel gold nanoparticles modified with a mixed self-assembled monolayer of porphyrin alkanethiol and short-chain alkanethiol were prepared (first step) to examine the size and shape effects of surface holes (host) on porphyrin-modified gold nanoparticles. The porphyrin-modified gold nanoparticles with a size of about 10 nm incorporated C60 molecules (guest) into the large, bucket-shaped holes, leading to the formation of a supramolecular complex of porphyrin-C60 composites (second step). Large composite clusters with a size of 200-400 nm were grown from the supramolecular complex of porphyrin-C60 composites in mixed solvents (third step) and deposited electrophoretically onto nanostructured SnO2 electrodes (fourth step). Differences in the porphyrin:C60 ratio were found to affect the structures and photoelectrochemical properties of the composite clusters in mixed solvents as well as on the SnO2 electrodes. The photoelectrochemical performance of a photoelectrochemical device consisting of SnO2 electrodes modified with the porphyrin-C60 composites was enhanced relative to a reference system with small, wedged-shaped surface holes on the gold nanoparticle. Time-resolved transient absorption spectroscopy with fluorescence lifetime measurements suggest the occurrence of ultrafast electron transfer from the porphyrin excited singlet states to C60 or the formation of a partial charge-transfer state in the composite clusters of supramolecular complexes formed between porphyrin and C60 leading to efficient photocurrent generation in the system. Elucidation of the relationship between host-guest interactions and photoelectrochemical function in the present system will provide valuable information on the design of molecular devices and machines including molecular photovoltaics. 相似文献