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381.
Sergiy Kharchenko Andriy Drapailo Svitlana Shishkina Oleg Shishkin Maria Karavan Igor Smirnov 《Supramolecular chemistry》2013,25(10-12):864-872
A series of thiacalix[4]arenes bearing one, two or four chelating dibutylphopshinoylmethoxy groups have been synthesised and studied in the context of this paper. The synthesis consisted of precise Williamson alkylation of thiacalixarene tetrols with tosylate of dibutylhydroxymethyl phosphine oxide in the presence of alkali metal carbonates or sodium hydride. Stereochemical yield of the reaction (cone or 1,3-alternate conformer) depends on the nature of alkali metal. Small-sized ‘hard’ sodium cation organises the macrocyclic platform in the cone conformation, but larger and ‘soft’ potassium and cesium cations stabilise the macrocycle in the 1,3-alternate conformation. All synthesised compounds (except monophosphine monoxide) possess either moderate or high extraction ability towards pertechnetate ion. The cone-shaped thiacalix[4]arene tetraphosphine tetraoxide due to cooperative (macrocyclic) effect of eight oxygen atoms of the phosphinoylmetoxy-binding groups effectively extract spherical americium, europium cations due to cooperative (macrocyclic) effect of eight oxygen atoms of the phosphinoylmetoxy-binding groups. The extraction ability is very similar to that of calix[5]arene pentaphosphine pentaoxide existing in the cone conformation. 相似文献
382.
Yevgenii I. Boldyrev Natalya D. Ivanova Georgii V. Sokolsky Sergiy V. Ivanov Olga A. Stadnik 《Journal of Solid State Electrochemistry》2013,17(8):2213-2221
The application of nonstoichiometric chromium oxide-based thin film cathodes in lithium rechargeable and primary batteries operating at high rates has been demonstrated. Films of varying composition have been obtained by anionic Cr (VI) species electrodeposition on a 1X18N10Т grade stainless steel cathode from fluoride-containing electrolytes. The effect of film doping by Li+ ions during its electrosynthesis has been сonsidered. As-prepared films were studied by scanning and transmission electron microscopies, 3D optical profiler, thermogravimetric analysis, chemical analysis, and X-ray diffraction (XRD). The main phase components of the electrodeposited films regardless of Li+ in an electrolyte are Cr2O3, α-CrOOH, β-CrOOH, and metallic chromium as shown by XRD pattern refinement. The electrochemical reduction rate in a non-aqueous electrolyte (1 M LiClO4 in PC/DME) correlates with the chromium oxide-hydroxide component content of film. Primary CrO x -Li CR2325 mock-up cathode coating can be discharged in a pulsed mode at 10 Ω external resistance with 80–84 mA cm?2 current densities for 10–100 ms. Thin film cathodes electrodeposited in the presence of lithium ions become rechargeable when the lithium content of the film reaches 0.02 wt.%. Mock-ups of CR2325 coin battery with a thin film cathode doped with lithium ions can be discharged more than 40 times with 136 mAh g?1 specific capacity, 461 Wh kg?1 specific energy and 154 W kg?1 power density at 30 kΩ external resistance. The simplicity of thin film preparation makes this technology promising for thin film lithium batteries. 相似文献
383.
Motornov M Royter H Lupitskyy R Roiter Y Minko S 《Langmuir : the ACS journal of surfaces and colloids》2011,27(24):15305-15311
Monodisperse stimuli-responsive hydrogel capsules were synthesized in the 100-nm-diameter to 10-μm-diameter range from poly(4-vinylpyridine) (P4VP) and poly(ethyleneimine) (PEI) through a simple, efficient two-step cross-linking-precipitation template method under conditions of a good solvent. In this method, the core-shell particles were obtained by the deposition (heterocoagulation mechanism) of the cross-linked P4VP, PEI, or their mixtures on the surfaces of the template colloidal silica particles in nitromethane (for PEI) or a nitromethane-acetone mixture (for P4VP and P4VP-PEI mixtures) in the presence of cross-linker 1,4-diiodobutane. The cross-linked polymeric shell swollen in a good solvent stabilized the core-shell colloids. This mechanism provided the conditions for the synthesis of core-shell colloids in a submicrometer range of dimensions with an easily adjusted shell thickness (wall of the capsules) ranging from a few to hundreds of nanometers. The chemical composition of the shell was tuned by varying the ratio of co-cross-linked shell-forming polymers (P4VP and PEI). In the second step, the hollow capsules were obtained by etching the silica core in HF solutions. In this step, the colloidal stability of the hollow capsules was provided by ionized P4VP and PEI cross-linked shells. The hollow capsules demonstrate that the pH- and ionic-strength-triggered swelling and shrinking result in size-selective uptake and release properties. Cross-linked via quaternized functional groups, P4VP capsules undergo swelling and shrinking transitions at a physiologically relevant pH of around 6. The 200-nm-diameter hollow capsule with 25-nm-thick walls demonstrated a factor of 2 greater capacity to accommodate cargo molecules than the core-shell particles of the same dimensions because of an internal compartment and a combination of radial and a circumferential swelling modes in the capsules. 相似文献
384.
Vladyslava B. Kovalska Mykhaylo Yu. Losytskyy Sergiy M. Yarmoluk Irit Lubitz Alexander B. Kotlyar 《Journal of fluorescence》2011,21(1):223-230
Two of earlier reported dsDNA sensitive cyanine dyes??monomethine Cyan 40 and meso-substituted trimethine Cyan 2 were studied for their ability to interact with non-canonical DNA conformations. These dyes were characterized by spectral-luminescent methods in the presence of G-quadruplex, triplex and dsDNA motifs. We have demonstrated that Cyan 2 binds strongly and preferentially to triple- and quadruple-stranded DNA forms that results in a strong enhancement of the dye fluorescence, as compared to dsDNA, while Cyan 40 form fluorescent complexes preferentially only with the triplex form. Highly fluorescent complexes of Cyan 2 with DNA triplexes and G-quadruplexes and Cyan 40 with DNA triplexes are very stable and do not dissociate during gel electrophoresis, leading to preferential staining of the above DNA forms in gels. The data presented point to the intercalation mechanism of the Cyan 2 binding to G4-DNA, while the complexes of Cyan 40 and Cyan 2 with triplex DNA are believed to be formed via groove binding mode. The Cyan dyes can provide a highly sensitive method for detection and quantification of non-canonical structures in genome. 相似文献
385.
Studies of Benzothiazole and Benzoselenazole Squaraines as Fluorescent Probes for Albumins Detection
Volkova KD Kovalska VB Losytskyy MY Bento A Reis LV Santos PF Almeida P Yarmoluk SM 《Journal of fluorescence》2008,18(5):877-882
Series of squaraine benzothiazole and benzoselenazole dyes were studied as possible fluorescent probes for the detection of
proteins, particularly albumins. It was shown that majority of the studied squaraines give significant fluorescent response
on the human serum albumin (HSA) and bovine serum albumin presence. For squaraine dyes with N-hexyl pendent groups (P-1, P-2, P-3, P-5) about 100−540-fold fluorescence intensity increase upon albumins addition was observed.
At the same time in presence of other proteins, namely insulin, avidin from hen egg white, immunoglobulin G (IgG), carbonic
anhydrase fluorescence enhancement values were considerably lower —up to 43 times in IgG presence. It was noted that generally,
squaraines with long N-hexyl pendent groups demonstrate higher emission increase values upon proteins addition comparing with their analogues with
short N-ethyl tails. It was shown that fluorescence intensity enhancement for benzothiazole squaraine dye P-3, relates linearly to
the HSA concentration over the wide range—from 0.2 to 500 μg/ml. Together with noticeable selectivity of this dye to albumins,
existence of wide dynamic range gives possibility to propose P-3 dye as probe for HSA quantification. 相似文献
386.
Yuri Roiter Volodymyr Samaryk Sergiy Varvarenko Natalya Nosova Igor Tarnavchyk Jürgen Pionteck Petra Pötschke Stanislav Voronov 《Macromolecular Symposia》2004,210(1):209-217
An approach to synthesize interfacial active peroxide graft copolymers, so called precompatibilizers, which are suitable for the universal compatibilization of one special polymer with a number of other polymers, has been presented. As example, this approach is illustrated by the reactive fusion of a random peroxide copolymer (VO) with polypropylene (PP) resulting in a VOgPP precompatibilizer. A mathematical model of the process of the VOgPP synthesis and the conduction of a full-factorial experiment have allowed both the optimization of the synthesis conditions and the prediction of its proceeding. During blending PP with other polymers VOgPP localizes across the blend interphases and initiates radical processes leading to the in situ formation of final compatibilizer macromolecules, which are efficient just for the blends where they are formed. The universality of the precompatibilizer concept is demonstrated in PP blends of the thermoplastic/thermoplastic type (with polystyrene and polyethylene) and of the thermoplastic/thermoset type (with unsaturated polyester resin). 相似文献
387.
Natalya Nosova Yuri Roiter Volodymyr Samaryk Sergiy Varvarenko Yuri Stetsyshyn Sergiy Minko Manfred Stamm Stanislav Voronov 《Macromolecular Symposia》2004,210(1):339-348
Method of polyolefin surface activation via covalent grafting of polyperoxide nanolayer by free radical mechanism has been presented. The features of such the nanolayer formation under the thermoprocessing conditions, i.e.: formation of 3D crosslinked network in polyperoxide bulk; and its grafting with complete coating of polyolefin surface, -- is considered. The method provides an availability of uniformly placed peroxide groups of one type over the polyolefin surface activated, which may further be utilized for the tailored modification of polymer surfaces using the “grafting to” and “grafting from” techniques in that time when it is necessary. 相似文献
388.
Leonid Ionov Manfred Stamm Sergiy Minko Frank Hoffmann Thomas Wolff 《Macromolecular Symposia》2004,210(1):229-235
Switchable binary polymer brushes grafted to Si-wafers were prepared from hydrophilic and hydrophobic polymer components. When exposed to solvents, either the hydrophobic or the hydrophilic component extends in to the liquid phase, depending on the polarity of the solvent. The hydrophilic component was poly-2-vinylpyridine; the hydrophobic component was made photocrosslinkable in that a polystyrene copolymer containing a photodimerizing chromophore was used. In this system surfaces differing in water contact angle between 60° and 100° can be produced by variation of the solvent. The chromophore was phenylindene, which forms crosslinks upon direct UV-irradiation. Therefore, the polystyrene component can be fixed in the extended or collapsed state. It will be shown that by irradiation through an appropriate mask, surfaces can be structured and the structures fixed. In both the systems structural patterns differing in surface properties were produced and fixed photochemically. 相似文献