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排序方式: 共有747条查询结果,搜索用时 203 毫秒
741.
Andersen KK Andersen SL Esberg J Knudsen H Mikkelsen R Uggerhøj UI Sona P Mangiarotti A Ketel TJ Ballestrero S;CERN NA 《Physical review letters》2012,108(7):071802
We report the first observation of a shoulder in the radiation spectrum from GeV electrons in a structured target consisting of two thin and closely spaced foils. The position of the shoulder depends on the target spacing and is directly connected to the finite formation length of a low-energy photon emitted by an ultrarelativistic electron. With the present setup it is possible to control the separation of the foils on a μm scale and hence measure interference effects caused by the macroscopic dimensions of the formation length. Several theoretical groups have predicted this effect using different methods. Our observations have a preference for the modified theory by Blankenbecler but disagree with the results of Baier and Katkov. 相似文献
742.
Application of Multi-Parametric Quadratic Programming to Simulation of Deflected Wires in a Wire Saw
Daniel Treyer Sebastian Gaulocher Stefan Niederberger Helge Rafael Alfons Ams 《PAMM》2017,17(1):779-780
In the wire sawing process, a silicon brick is fed into a moving wire web, thus deflecting the wires. By considering static deflections only, the wire displacement and the contact forces between wire and brick may be computed by minimizing the potential energy of the wire, which introduces a constrained quadratic optimization problem. In a time-domain simulation, the continuously changing contour inside the kerf requires the optimization problem to be solved recurringly. This work aims at reducing the optimization-related computational effort by applying multi-parametric quadratic programming. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
743.
744.
Dr. Conor T. Kelly Sean Dunne Dr. Irina A. Kühne Dr. Andrew Barker Dr. Kane Esien Dr. Solveig Felton Dr. Helge Müller-Bunz Dr. Yannick Ortin Prof. Grace G. Morgan 《Angewandte Chemie (International ed. in English)》2023,62(18):e202217388
Reversible proton-induced spin state switching of an FeIII complex in solution is observed at room temperature. A reversible magnetic response was detected in the complex, [FeIII(sal2323)]ClO4 ( 1 ), using Evans’ method 1H NMR spectroscopy which indicated cumulative switching from low-spin to high-spin upon addition of one and two equivalents of acid. Infrared spectroscopy suggests a coordination-induced spin state switching (CISSS) effect, whereby protonation displaces the metal-phenoxo donors. The analogous complex, [FeIII(4-NEt2-sal2323)]ClO4 ( 2 ), with a diethylamino group on the ligand, was used to combine the magnetic change with a colorimetric response. Comparison of the protonation responses of 1 and 2 reveals that the magnetic switching is caused by perturbation of the immediate coordination sphere of the complex. These complexes constitute a new class of analyte sensor which operate by magneto-modulation, and in the case of 2 , also yield a colorimetric response. 相似文献
745.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
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747.
Ria Thielhorn Isabelle Heing-Becker Nadja Hümpfer Jakob Rentsch Rainer Haag Kai Licha Helge Ewers 《Angewandte Chemie (International ed. in English)》2023,62(28):e202302318
Expansion microscopy (ExM) is a recently developed technique that allows for the resolution of structures below the diffraction limit by physically enlarging a hydrogel-embedded facsimile of the biological sample. The target structure is labeled and this label must be retained in a relative position true to the original, smaller state before expansion by linking it into the gel. However, gel formation and digestion lead to a significant loss in target-delivered label, resulting in weak signal. To overcome this problem, we have here developed an agent combining targeting, fluorescent labeling and gel linkage in a single small molecule. Similar approaches in the past have still suffered from significant loss of label. Here we show that this loss is due to insufficient surface grafting of fluorophores into the hydrogel and develop a solution by increasing the amount of target-bound monomers. Overall, we obtain a significant improvement in fluorescence signal retention and our new dye allows the resolution of nuclear pores as ring-like structures, similar to STED microscopy. We furthermore provide mechanistic insight into dye retention in ExM. 相似文献