全文获取类型
收费全文 | 169篇 |
免费 | 7篇 |
专业分类
化学 | 154篇 |
数学 | 11篇 |
物理学 | 11篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 11篇 |
2011年 | 9篇 |
2010年 | 15篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 7篇 |
2006年 | 9篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 15 毫秒
171.
Daniel Reker Dr. Michael Seet Max Pillong Dr. Christian P. Koch Dr. Petra Schneider Dr. Matthias C. Witschel Dr. Matthias Rottmann Céline Freymond Prof. Dr. Reto Brun Dr. Bernd Schweizer Dr. Boris Illarionov Prof. Dr. Adelbert Bacher Prof. Dr. Markus Fischer Prof.Dr. François Diederich Prof. Dr. Gisbert Schneider 《Angewandte Chemie (International ed. in English)》2014,53(27):7079-7084
The discovery of pyrrolopyrazines as potent antimalarial agents is presented, with the most effective compounds exhibiting EC50 values in the low nanomolar range against asexual blood stages of Plasmodium falciparum in human red blood cells, and Plasmodium berghei liver schizonts, with negligible HepG2 cytotoxicity. Their potential mode of action is uncovered by predicting macromolecular targets through avant‐garde computer modeling. The consensus prediction method suggested a functional resemblance between ligand binding sites in non‐homologous target proteins, linking the observed parasite elimination to IspD, an enzyme from the non‐mevalonate pathway of isoprenoid biosynthesis, and multi‐kinase inhibition. Further computational analysis suggested essential P. falciparum kinases as likely targets of our lead compound. The results obtained validate our methodology for ligand‐ and structure‐based target prediction, expand the bioinformatics toolbox for proteome mining, and provide unique access to deciphering polypharmacological effects of bioactive chemical agents. 相似文献
172.
Luan X Mariz R Gatti M Costabile C Poater A Cavallo L Linden A Dorta R 《Journal of the American Chemical Society》2008,130(21):6848-6858
A new class of easily accessible and stable imidazolin-2-ylidenes has been synthesized where the side chains are comprised of substituted naphthyl units. Introduction of the naphthyl groups generates C 2 -symmetric ( rac) and C s- symmetric ( meso) atropisomers, and interconversion between the isomers is studied in detail both experimentally and computationally. Complete characterization of the carbenes includes rare examples of crystallographically characterized saturated NHC structures. Steric properties of the ligands and an investigation of their stability are also presented. In catalysis, the new ligands show versatility comparable to the most widely used NHCs IMes/SIMes or IPr/SIPr. Excellent catalytic results are obtained when either the NHC salts (ring-opening alkylation of epoxides), NHC-modified palladium compounds (C-C and C-N cross-couplings), or NHC-ruthenium complexes (ring-closing metathesis, RCM) are employed. In several cases, this new ligand family provides catalytic systems of higher reactivity than that observed with previously reported NHC compounds. 相似文献
173.
Gerhard Bringmann Stefan Rüdenauer Torsten Bruhn Lauren Benson Reto Brun 《Tetrahedron》2008,64(23):5563-5568
The first total synthesis of the antimalarial naphthylisoquinoline alkaloid 5-epi-4′-O-demethylancistrobertsonine C (1a) and its—as yet unnatural—atropo-diastereomer, 1b, is described. The key step of the synthesis is the construction of the rotationally hindered and thus stereogenic biaryl axis, which was built up by a Suzuki reaction. The use of chiral ligands in the palladium-catalyzed cross-coupling permitted to increase the low internal asymmetric induction up to a diastereomeric ratio of 74:26. The assignment of the axial configurations of the atropo-diastereomers was achieved by 2D NMR experiments and corroborated by quantum chemical CD calculations. 相似文献
174.
Molecular sieving using nanofilters: past, present and future 总被引:2,自引:0,他引:2
Filtration of molecules by nanometer-sized structures is ubiquitous in our everyday life, but our understanding of such molecular filtration processes is far less than desired. Until recently, one of the main reasons was the lack of experimental methods that can help provide detailed, microscopic pictures of molecule-nanostructure interactions. Several innovations in experimental methods, such as nuclear track-etched membranes developed in the 70s, and more recent development of nanofluidic molecular filters, played pivotal roles in advancing our understanding. With the ability to make truly molecular-scale filters and pores with well-defined sizes, shapes, and surface properties, now we are well positioned to engineer better functionality in molecular sieving, separation and other membrane applications. Reviewing past theoretical developments (often scattered across different fields) and connecting them to the most recent advances in the field would be essential to get a full, unified view on this important engineering question. 相似文献
175.
Siegel JS Baldridge KK Linden A Dorta R 《Journal of the American Chemical Society》2006,128(33):10644-10645
[(COE)2M]+ fragments (M = Rh, Ir; COE = cyclooctene) react with corannulene to give eta6-bound complexes [(COE)2Rh(eta6-C20H10)]PF6 and [(COE)2Ir(eta6-C20H10)]PF6. Both compounds were characterized by X-ray diffraction studies, and binding in the solid state is compared with that of their aromatic analogues [(COE)2M(eta6-arene)]PF6 (aryl = benzene and phenanthrene). Solution NMR studies show that the [(COE)2Rh]+ fragment walks over the curved aromatic surface of corannulene, whereas the Ir analogue is not fluxional. Experimental as well as computational studies suggest that inter-ring movement of the Rh complex follows a hub migration mechanism. Initial reactivity studies indicate that the [(COE)2M]+ fragments can undergo chemical transformations, such as transfer dehydrogenation and substitution reactions, while still bound to corannulene. 相似文献
176.
Cinthia Piamonteze Uwe Flechsig Stefano Rusponi Jan Dreiser Jakoba Heidler Marcus Schmidt Reto Wetter Marco Calvi Thomas Schmidt Helena Pruchova Juraj Krempasky Christoph Quitmann Harald Brune Frithjof Nolting 《Journal of synchrotron radiation》2012,19(5):661-674
X‐Treme is a soft X‐ray beamline recently built in the Swiss Light Source at the Paul Scherrer Institut in collaboration with École Polytechnique Fédérale de Lausanne. The beamline is dedicated to polarization‐dependent X‐ray absorption spectroscopy at high magnetic fields and low temperature. The source is an elliptically polarizing undulator. The end‐station has a superconducting 7 T–2 T vector magnet, with sample temperature down to 2 K and is equipped with an in situ sample preparation system for surface science. The beamline commissioning measurements, which show a resolving power of 8000 and a maximum flux at the sample of 4.7 × 1012 photons s?1, are presented. Scientific examples showing X‐ray magnetic circular and X‐ray magnetic linear dichroism measurements are also presented. 相似文献