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21.
Conductance data are reported for Ph4AsPic, Ph4PPic, Ph4SbPic, Hex4NPic, Bu4PPic, Et4NSbCl6 in propylene carbonate at 25°C in the concentration range 1×10–4 to 15×10–4 M. The data were analyzed by the Justice modification of the Fuoss-Hsia equation and all salts studied were found to be associated and to form solvent separated ion pairs. Application of the Barthel-Bjerrum model of ion association permitted calculation of the non coulombic portion of the potentials of mean force, W±. Ionic limiting equivalent conductances of six ions were calculated using known values of R4N+, and Pic– ions. Walden products of ions in propylene carbonate were examined in the light of modern ion mobility theories, including Boyd-Zwanzig, Hubbard-Onsager, and Hubbard-Kayser models of ion solvent interactions. 相似文献
22.
Liliane Bokobza Mostafa Rahmani Colette Belin Jean‐Luc Bruneel Nour‐Eddine El Bounia 《Journal of Polymer Science.Polymer Physics》2008,46(18):1939-1951
The reinforcement of a styrene‐butadiene rubber (SBR) by single fillers—carbon black (CB) or multiwall carbon nanotubes (MWNTs)—or by mixtures of CB and MWNTs, is investigated. The morphologies, mechanical and electrical properties of the composites, are analyzed. A significant improvement in the tensile properties is observed for samples containing a dual phase. Using atomic force (AFM) and transmission electron (TEM) microscopies, we demonstrate that the double loading improves the dispersion of the nanotubes in SBR. Electrical measurements show lower resistivity and a lower percolation threshhold for composites containing blends of fillers, which provides further evidence of better dispersion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 46: 1939–1951, 2008 相似文献
23.
Jong Seol Yuk Colette McDonagh Brian D. MacCraith 《Analytical and bioanalytical chemistry》2010,398(5):1947-1954
The technique of surface plasmon-coupled emission (SPCE) involves the coupling of light which is emitted from a fluorophore
into the surface plasmon of an adjacent thin metal film, giving rise to highly directional emission. We have combined the
advantages of SPCE with the high light collection efficiency of supercritical angle fluorescence by carrying out an immunoassay
on a paraboloid array biochip in the absence of the conventional SPCE spacer layer normally used to minimize metal quenching
of the fluorescence. In this work, we have successfully demonstrated an SPCE-based assay by utilizing the protein assay layer
as the spacer layer. A novel 3 × 3 injection molded polymer biochip with paraboloid elements was used. The paraboloid elements
served to enhance the light collection efficiency while the top surface was coated with a gold layer to use excitation of
surface plasmons and detection of SPCE emission. Theoretical modeling of the gold-protein layer structure showed that the
surface plasmon resonance angles were located in the detection range of the paraboloid biochip. The polarization dependence
of SPCE emission was also demonstrated. Finally, a human IgG sandwich immunoassay was carried out which exhibited a limit
of detection of ~10 ng/ml using 3σ. The results demonstrate the potential of the SPCE-based paraboloid array biochip as a novel platform for high-throughput
analysis of biomolecular interactions. 相似文献
24.
R.J. Holmes C. McDonagh S. Mohr P.R. Fielden 《Journal of Physics and Chemistry of Solids》2011,72(6):626-629
Component binding within microfluidic devices is a problem that has long been seeking a solution. In this investigation, the use of microwave radiation to seal PMMA components has been investigated using polyaniline as an absorber that is capable of inducting interfacial bonding. Straight microchannels were machined into PMMA using a Datron CAT3DM6 CNC machine with widths and depths across a range of 100-1000 μm. Prototype fluidic devices were prepared with channel patterns utilizing varying feature sizes, bends and flow profiling to demonstrate the application of the technique to real microfluidic devices. Experimental data illustrated the successful bonding of channels in the range stated previously and bonding (tensile) strength was assessed via pull tests on bonded PMMA using an Engstrom Zwick 100 tensile testing system (Engstrom Ltd, US). Coherent, defect free seals were attained with breakage tests requiring an excess of 1 kN force. 相似文献
25.
Colette Besombes Baya Berka-Zougali Karim Allaf 《Journal of chromatography. A》2010,1217(44):6807-6815
Détente Instantanée contrôlée (DIC), French for Instant Controlled Pressure Drop, was performed on laboratory apparatus as well as on a pilot plant for proving its feasibility, and identifying the optimized processing conditions and recognizing the energy consumption and the quantity of water used for such an operation. GC–MS and SPME analysis of the extracts and residue material were carried out to assess the extracts and solid residues. The lavandin essential oils obtained by using the new DIC extraction process was studied, modeled and quantitatively and qualitatively compared to the conventional hydrodistillation method. The most important differences between the two essential oils were reflected in the yields, with 4.25 as against 2.3 g EO/100 g of raw matter, and in the extraction time, with 480 s as against some hours for respectively the DIC and the hydrodistillation operations. These differences have been previewed through the fundamental analysis. They can normally explain the great decreasing of energy consumption to be 662 kWh/t of raw material. The amount of water to be added was about 42 kg water/t of raw material. 相似文献
26.
N-Carbamoylimidazoles dissociate in solution to yield imidazole and an isocyanate that may be reacted with another aryl amine to form an unsymmetrical biaryl urea. This paper investigates the reaction kinetics and the influence of electron withdrawing/donating substituents on the reaction of N-carbamoylimidazoles with aniline. The overall reaction mechanism involves two zwitterionic intermediates, formed during dissociation and upon reaction of the liberated isocyanate with aniline. The rate limiting step for the reaction is a base catalysed proton transfer from the second zwitterionic intermediate. Although electron withdrawing substituents on the aryl group hinder dissociation, they significantly increase reaction rates compared to compounds bearing electron donating substituents. The imidazole liberated upon dissociation catalyses the rate determining step so that reactions of dissociated N-carbamoylimidazoles proceed more rapidly than those involving only isocyanates. In addition, the imidazole eliminates the need for anhydrous reaction conditions. The N-carbamoylimidazole methodology was demonstrated by preparing sorafenib, a biaryl urea kinase inhibitor, in good yield and excellent purity. 相似文献
27.
28.
We report on an 888 nm pumped passively mode-locked TEM(00)Nd:YVO(4) oscillator providing 56 W of average power at a repetition rate of 110 MHz with 33 ps pulse duration, further amplified to 111 W in a 52% optical efficiency single-pass amplifier stage, maintaining beam quality at M(2)=1.05. Frequency doubling in a LiB(3)O(5) crystal generated up to 87 W at 532 nm, while a third harmonic power of 35 W was achieved in a nonoptimized tripling configuration, corresponding to 80% and 33% conversion efficiency. 相似文献
29.
A Ruthenium(II)–Copper(II) Dyad for the Photocatalytic Oxygenation of Organic Substrates Mediated by Dioxygen Activation
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Dr. Wissam Iali Dr. Pierre‐Henri Lanoe Dr. Stéphane Torelli Dr. Damien Jouvenot Prof. Frédérique Loiseau Colette Lebrun Dr. Olivier Hamelin Dr. Stéphane Ménage 《Angewandte Chemie (International ed. in English)》2015,54(29):8415-8419
Dioxygen activation by copper complexes is a valuable method to achieve oxidation reactions for sustainable chemistry. The development of a catalytic system requires regeneration of the CuI active redox state from CuII. This is usually achieved using extra reducers that can compete with the CuII(O2) oxidizing species, causing a loss of efficiency. An alternative would consist of using a photosensitizer to control the reduction process. Association of a RuII photosensitizing subunit with a CuII pre‐catalytic moiety assembled within a unique entity is shown to fulfill these requirements. In presence of a sacrificial electron donor and light, electron transfer occurs from the RuII center to CuII. In presence of dioxygen, this dyad proved to be efficient for sulfide, phosphine, and alkene catalytic oxygenation. Mechanistic investigations gave evidence about a predominant 3O2 activation pathway by the CuI moiety. 相似文献
30.
Colette J. Whitfield Andrew T. Turley Dr. Eimer M. Tuite Prof. Bernard A. Connolly Dr. Andrew R. Pike 《Angewandte Chemie (International ed. in English)》2015,54(31):8971-8974
A polymerase chain reaction (PCR) derived method for preparing long DNA, consisting of multiple repeat units of one to ten base pairs, is described. Two seeding oligodeoxynucleotides, so‐called oligoseeds, which encode the repeat unit and produce a duplex with 5′‐overhangs, are extended using a thermostable archaeal DNA polymerase. Multiple rounds of heat–cool extension cycles, akin to PCR, rapidly elongate the oligoseed. Twenty cycles produced long DNA with uniformly repeating sequences to over 20 kilobases (kb) in length. The polynucleotides prepared include [A]n/[T]n, [AG]n/[TC]n, [A2G]n/[T2C]n, [A3G]n/[T3C]n, [A4G]n/[T4C]n, [A9G]n/[T9C]n, [GATC]n/[CTAG]n, and [ACTGATCAGC]n/[TGACTAGTCG]n, indicating that the method is extremely flexible with regard to the repeat length and base sequence of the initial oligoseeds. DNA of this length (20 kb≈7 μm) with strictly defined base reiterations should find use in nanomaterial applications. 相似文献