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排序方式: 共有247条查询结果,搜索用时 15 毫秒
241.
Ching-Min Yeh Thomas Jarrett Yuan Gao Chun-Xia Zhao Andrew Whittaker Frank Sainsbury Alison L.White 《Particuology》2022,(5):145-152
Designer biosurfactants can be used to stabilise and functionalise interfaces.One particularly promising use is the stabilisation of oil-in-water emulsions,enab... 相似文献
242.
Spencer Napier Sebastian M. Marcuccio Heather Tye Mark Whittaker 《Tetrahedron letters》2008,49(24):3939-3942
Palladium catalysed Hiyama-type coupling of aryl disiloxanes or aryl silanols with aryl halides in the presence of stoichiometric silver(I) oxide and catalytic TBAF allows the rapid preparation of biaryls in moderate to high yield under mild thermal or microwave irradiation conditions. 相似文献
243.
Suzuki S Whittaker MR Wentrup-Byrne E Monteiro MJ Grøndahl L 《Langmuir : the ACS journal of surfaces and colloids》2008,24(22):13075-13083
Adsorption of well-defined fluorinated polymers onto clinically relevant poly(tetrafluoroethylene) (PTFE) substrates offers an attractive method for modifying the surface properties of chemically inert PTFE. Reversible addition-fragmentation chain transfer (RAFT) was successfully used for synthesis of the polymers in this study: the homopolymers poly(2,3,4,5,6-pentafluorostyrene) (PFS), poly(2,2,3,3-tetrafluoropropyl acrylate) (PTFPA), and poly(2,2,3,3-tetrafluoropropyl methacrylate) (PTFPMA) as well as their block copolymers with tert-butyl acrylate ( (t)BA). Water-soluble blocks were synthesized through the hydrolysis of the t-butyl side groups of P( (t)BA) to the corresponding carboxylic acid. Adsorption of selected polymers onto PTFE from a series of solvents (methyl ethyl ketone (MEK), dimethylformamide (DMF), fluorobenzene (FB), dichloromethane (DCM)) was investigated using X-ray photoelectron spectroscopy (XPS) and sessile water drop measurements. The three homopolymers studied all adsorbed irreversibly (i.e., were not removed by washing) from organic solvents at ambient temperature. PFS displayed the highest adsorption, and was attributed to strong hydrophobic interactions. From angle-resolved XPS it was concluded that PFS became impregnated into the PTFE substrate down to depths of 100 A when using FB as a solvent. The carboxylic acid-containing block copolymers adsorbed more effectively from DMF (a good solvent for the poly(acrylic acid) block) compared to MEK. The resulting modified PTFE substrates displayed high stability with respect to desorption in aqueous solution, yet conformational changes of the adsorbed polymer resulted in a switchable hydrophobic-hydrophilic surface (in air or water, respectively). These results highlight the success of a facile and simple approach to irreversibly adsorb functional polymers to a nonfunctional fluorinated surface. 相似文献
244.
Albert Badri Michael R. Whittaker Per B. Zetterlund 《Journal of polymer science. Part A, Polymer chemistry》2012,50(15):2981-2992
Graphene nanosheets possess a range of extraordinary physical and electrical properties with enormous potential for applications in microelectronics, photonic devices, and nanocomposite materials. However, single graphene platelets tend to undergo agglomeration due to strong π–π and Van der Waals interactions, which significantly compromises the final material properties. One of the strategies to overcome this problem, and to increase graphene compatibility with a receiving polymer host matrix, is to modify graphene (or graphene oxide (GO)) with polymer brushes. The research to date can be grouped into approaches involving grafting‐from and grafting‐to techniques, and further into approaches relying on covalent or noncovalent attachment of polymer chains to the suitably modified graphene/GO. The present Highlight article describes research efforts to date in this area, focusing on the use of controlled/living radical polymerization techniques. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
245.
Münnemann K Kölzer M Blakey I Whittaker AK Thurecht KJ 《Chemical communications (Cambridge, England)》2012,48(10):1583-1585
The first hyperpolarisation of polymers using parahydrogen induced polarisation (PHIP) is reported by hydrogenation of terminal alkyne groups in a biocompatible hyperbranched polymer. Signal enhancements of 1500-fold could be obtained depending on the structure of the polymer, thus opening new potential avenues for polymeric molecular imaging. 相似文献
246.
K. E. Whittaker L. Ciaffoni G. Hancock M. Islam R. Peverall G. A. D. Ritchie 《Applied physics. B, Lasers and optics》2012,109(3):423-432
Studies into the suitability of a novel, widely tunable telecom L-band (1563?C1613?nm) digital supermode distributed Bragg reflector (DS-DBR) laser for spectroscopy in the mid-IR are presented. Light from the DS-DBR laser was mixed with 1064?nm radiation in a periodically poled lithium niobate (PPLN) crystal to generate mid-IR light by quasi phase matching difference frequency generation (QPM-DFG). The resultant continuous wave radiation covered the range 3000?C3200?cm?1 with powers of up to 2.6???W. The use of such laser light for spectroscopic applications was illustrated by performing absorption experiments on both narrow-band and broad-band absorbers, namely methane (CH4) and methanethiol (CH3SH). Wavelength modulation spectroscopy (WMS) on CH4 demonstrated that the modulation characteristics of the DS-DBR laser observed in the near-IR were transposed to the mid-IR and yielded a sensitivity of 3.1×10?6?cm?1?Hz?1/2 over a 47?cm path length. In the CH3SH spectrum, the absorption feature at 3040?cm?1 was identified as a potential useful region for monitoring this biomarker in exhaled breath at reduced pressures. 相似文献
247.
Ao Chen Idriss Blakey Andrew K. Whittaker Hui Peng 《Journal of polymer science. Part A, Polymer chemistry》2016,54(23):3721-3732
The “breath figures” method provides an efficient and cost‐effective method to produce highly ordered honeycomb patterns in polymeric films at micrometer and sub‐micrometer dimensions. The size and regularity of the pores can be adjusted through a series of physical and chemical parameters. In this study, amphiphilic diblock copolymers, polystyrene‐block‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) with different lengths of P4VP, were synthesized through Reversible Addition‐Fragmentation Chain Transfer polymerization. The honeycomb‐patterned films were prepared from these well‐defined polymers through the dynamic breath figures method. A series of physical parameters including solution concentration, flow rate, humidity of the flow, and the humidity of the casting environment, were delicately adjusted to systematically investigate their effects on the morphology of the films. These studies identified four key factors which were found to influence the formation of the pattern. No obvious effect was found on the pore size by changing the length of P4VP block. The result provides clear direction on the fabrication of PS‐b‐P4VP honeycomb‐patterned films and more broadly contributes a deeper understanding of the processes involved in the formation of honeycomb patterns. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3721–3732 相似文献