全文获取类型
收费全文 | 707篇 |
免费 | 56篇 |
国内免费 | 4篇 |
专业分类
化学 | 567篇 |
晶体学 | 1篇 |
力学 | 24篇 |
数学 | 70篇 |
物理学 | 105篇 |
出版年
2024年 | 1篇 |
2023年 | 12篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 30篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 33篇 |
2015年 | 35篇 |
2014年 | 34篇 |
2013年 | 42篇 |
2012年 | 83篇 |
2011年 | 85篇 |
2010年 | 42篇 |
2009年 | 35篇 |
2008年 | 47篇 |
2007年 | 48篇 |
2006年 | 36篇 |
2005年 | 37篇 |
2004年 | 32篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1890年 | 2篇 |
排序方式: 共有767条查询结果,搜索用时 656 毫秒
741.
Clarisse D Pelotier B Piva O Fache F 《Chemical communications (Cambridge, England)》2012,48(1):157-159
Prins cyclization between a homoallylic alcohol and an aldehyde, promoted by trimethylsilyl halide, afforded 4-halo-tetrahydropyrans with good to excellent yields. Thanks to the absence of the solvent and metal, the THP thus obtained have been implicated without purification in several other reactions, in a sequential way, affording in particular new indole derivatives. 相似文献
742.
R Miranda-Castro D Marchal B Limoges F Mavré 《Chemical communications (Cambridge, England)》2012,48(70):8772-8774
A simple and fast electrochemical nucleic acid assay based on a target recycling strategy and the release of a double-stranded DNA intercalating redox probe upon digestion of a specific duplex by exonuclease III is demonstrated. 相似文献
743.
Capelot M Montarnal D Tournilhac F Leibler L 《Journal of the American Chemical Society》2012,134(18):7664-7667
Catalytic control of bond exchange reactions enables healing of cross-linked polymer materials under a wide range of conditions. The healing capability at high temperatures is demonstrated for epoxy-acid and epoxy-anhydride thermoset networks in the presence of transesterification catalysts. At lower temperatures, the exchange reactions are very sluggish, and the materials have properties of classical epoxy thermosets. Studies of model molecules confirmed that the healing kinetics is controlled by the transesterification reaction rate. The possibility of varying the catalyst concentration brings control and flexibility of welding and assembling of epoxy thermosets that do not exist for thermoplastics. 相似文献
744.
745.
David Hill George Melvin Damien Mondragon 《Journal of Pure and Applied Algebra》2012,216(5):1052-1079
A new class of algebras has been introduced by Khovanov and Lauda and independently by Rouquier. These algebras categorify one-half of the Quantum group associated to arbitrary Cartan data. In this paper, we use the combinatorics of Lyndon words to construct the irreducible representations of those algebras associated to Cartan data of finite type. This completes the classification of simple modules for the quiver Hecke algebra initiated by Kleshchev and Ram. 相似文献
746.
Schwemmer T Baumgartner J Faivre D Börner HG 《Journal of the American Chemical Society》2012,134(4):2385-2391
The peptide-mediated functionalization of inorganic particle surfaces is demonstrated on gadolinium oxide (GdO) particles, revealing specific means to functionalize nano- or microparticles. Phage display screening is exploited to select 12mer peptides, which exhibit sequence-specific adhesion onto surfaces of GdO particles. These peptide adhesion domains are exploited to effectively decorate GdO particles with fluorescently labeled poly(ethylene oxide) (PEO), proving to result in a stable surface modification as shown by significant reduction of protein adsorption by 80%, compared to nonfunctionalized particles. Peptide adhesion and stability of the noncovalent coating are investigated by adsorption/elution experiments and Langmuir isotherms. Fluorescence microscopy, contact angle, and energy dispersive X-ray (EDX) measurements confirmed the sequence specificity of the interactions by comparing adhesion sequences with scrambled peptide sequences. Noncovalent, but specific modification of inorganic particle surfaces represents a generic strategy to modulate functionality and function of nano- or microparticle surfaces. 相似文献
747.
748.
A reflection-based optical implementation of two simultaneous scale-invariant fractional Fourier transforms (FRTs) is used to develop a novel compact speckle photographic system. The system allows the independent determination of both surface tilting and in-plane translational motion from two sequential mixed domain images captured using a single camera. 相似文献
749.
Ignatova M Voccia S Gilbert B Markova N Cossement D Gouttebaron R Jérôme R Jérôme C 《Langmuir : the ACS journal of surfaces and colloids》2006,22(1):255-262
A two-step "grafting from" method has been successfully carried out, which is based on the electrografting of polyacrylate chains containing an initiator for the atom transfer radical polymerization (ATRP) of 2-(tert-butylamino)ethyl methacrylate (TBAEMA) or copolymerization of TBAEMA with either monomethyl ether of poly(ethylene oxide) methacrylate (PEOMA) or acrylic acid (AA) or styrene. The chemisorption of this type of polymer brushes onto stainless steel surfaces has potential in orthopaedic surgery. These films have been characterized by ATR-FTIR, Raman spectroscopy, atomic force microscopy (AFM), and measurement of contact angles of water. The polymer formed in solution by ATRP and that one detached on purpose from the surface have been analyzed by size exclusion chromathography (SEC) and (1)H NMR spectroscopy. The strong adherence of the films onto stainless steel has been assessed by peeling tests. AFM analysis has shown that addition of hydrophilic comonomers to the grafted chains decreases the surface roughness. According to dynamic quartz crystal microbalance experiments, proteins (e.g., fibrinogen) are more effectively repelled whenever copolymer brushes contain neutral hydrophilic (PEOMA) co-units rather than negatively charged groups (PAA salt). Moreover, a 2- to 3-fold decrease in the fibrinogen adsorption is observed when TBAEMA is copolymerized with either PEOMA or AA rather than homopolymerized or copolymerized with styrene. Compared to the bare stainless steel surface, brushes of polyTBAEMA, poly(TBAEMA-co-PEOMA) and poly(TBAEMA-co-AA) decrease the bacteria adhesion by 3 to 4 orders of magnitude as revealed by Gram-positive bacteria S. aureus adhesion tests. 相似文献
750.
Redshaw C Rowan MA Homden DM Dale SH Elsegood MR Matsui S Matsuura S 《Chemical communications (Cambridge, England)》2006,(31):3329-3331
Vanadyl complexes of C or N-capped tripodal ligands, possessing distorted tetrahedral geometry at vanadium, serve as extremely active, thermally robust pro-catalysts for ethylene homo- and ethylene/propylene copolymerisation, whereas pseudo-octahedral pro-catalysts produce far lower activities. 相似文献