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51.
Lindholm-Sethson B Nyström J Geladi P Koeppe R Nelson A Whitehouse C 《Analytical and bioanalytical chemistry》2003,377(3):478-485
A novel concept of a membrane-based micro-array biosensor is presented. The methodology is based on a single lipid membrane interrogated with electrochemical impedance techniques followed by multivariate data analysis. A single membrane is designed so that relaxation processes with a range of time constants can be probed at different potentials. A range of other approaches cited in the literature is reviewed. 相似文献
52.
Crean CW Camier R Lawler M Stevenson C Davies RJ Boyle PH Kelly JM 《Organic & biomolecular chemistry》2004,2(24):3588-3601
Two 17-mer oligodeoxynucleotide-5'-linked-(6,7-diphenylpterin) conjugates, 2 and 3, were prepared as photosensitisers for targeting photooxidative damage to a 34-mer DNA oligodeoxynucleotide (ODN) fragment 1 representing the chimeric bcr-abl gene that is implicated in the pathogenesis of chronic myeloid leukaemia (CML). The base sequence in the 17-mer was 3'G G T A G T T A T T C C T T C T T5'. In the first of these ODN conjugates (2) the pterin was attached at its N3 atom, via a -(CH2)3OPO(OH)- linker, to the 5'-OH group of the ODN. Conjugate 2 was prepared from 2-amino-3-(3-hydroxypropyl)-6,7-diphenyl-4(3H)-pteridinone 10, using phosphoramidite methodology. Starting material 10 was prepared from 5-amino-7-methylthiofurazano[3,4-d]pyrimidine 4 via an unusual highly resonance stabilised cation 8, incorporating the rare 2H,6H-pyrimido[6,1-b][1,3]oxazine ring system. In the characterisation of 10 two pteridine phosphazenes, 15 and 29, were obtained, as well as new products containing two uncommon tricyclic ring systems, namely pyrimido[2,1-b]pteridine (20 and 24) and pyrimido[1,2-c]pteridine (27). In the second ODN conjugate the linker was -(CH2)5CONH(CH2)6OPO(OH)- and was attached to the 2-amino group of the pterin. In the preparation of 3, the N-hydroxysuccinimide ester 37 of 2-(5-carboxypentylamino)-6,7-diphenyl-4(3H)-pteridinone was condensed with the hexylamino-modified 17-mer. Excitation of 36 with near UV light in the presence of the single-stranded target 34-mer, 5'T G A C C A T C A A T A A G14 G A A G18 A A G21 C C C T T C A G C G G C C3' 1 caused oxidative damage at guanine bases, leading to alkali-labile sites which were monitored by polyacrylamide gel electrophoresis. Cleavage was observed at all guanine sites with a marked preference for cleavage at G14. In contrast, excitation of ODN-pteridine conjugate 2 in the presence of 1 caused oxidation of the latter predominantly at G18, with a smaller extent of cleavage at G15 and G14 (in the double-stranded portion) and G21. These results contrast with our previous observation of specific cleavage at G21 with ruthenium polypyridyl sensitisers, and suggest that a different mechanism, probably one involving Type 1 photochemical electron transfer, is operative. Much lower yields were found with the ODN-pteridine conjugate 3, perhaps as a consequence of the longer linker between the ODN and the pteridine in this case. 相似文献
53.
Rational maps, monopoles and skyrmions 总被引:1,自引:0,他引:1
We discuss the similarities between BPS monopoles and skyrmions, and point to an underlying connection in terms of rational maps between Riemann spheres. This involves the introduction of a new ansatz for Skyrme fields. We use this to construct good approximations to several known skyrmions, including all the minimal energy configurations up to baryon number nine, and some new solutions such as a baryon number seventeen Skyrme field with the truncated icosahedron structure of a buckyball.
The new approach is also used to understand the low-lying vibrational modes of skyrmions, which are required for quantization. Along the way we discover an interesting Morse function on the space of rational maps which may be of use in understanding the Sen forms on the monopole moduli spaces. 相似文献
54.
Gregory J. Barbante Conor F. Hogan Andrew B. Hughes 《Journal of Solid State Electrochemistry》2009,13(4):599-608
The solid state electrochemistry and solid state spectroelectrochemistry of two ruthenium complexes, ruthenium tris-(4,7-diphenyl-1,10-phenanthroline)
bis-hexafluorophosphate, [Ru(dpp)3](PF6)2, and ruthenium bis-(2,2′-bipyridine)(4,6-diphenyl-2,2′-bipyridine)bis-hexafluorophosphate, [Ru(bpy)2(dpb)](PF6)2, is described. Microparticles of the material are immobilised on ITO electrodes, and stable voltammetric signals are obtained
in contact with aqueous electrolyte solution. Spectral changes monitored during a slow cyclic voltammetric scan confirm the
exhaustive oxidation of the Ru2+ species to the Ru3+ form. The derivative of the absorbance signal monitored at a single wavelength during potential cycling is morphologically
identical to a cyclic voltammogram with no background current. This technique is shown to be useful when peaks of small magnitude
are obscured by capacitive background or when peaks close to the solvent limit are obscured by solvent electrolysis current.
The technique effectively widens the electrochemical window available for voltammetric measurements. After suitable correction
of the signal, the value of the voltammetric peak height (I
p) as well as peak potential (E
p) may be obtained from the derivative absorbance signal. Chronospectrometry is demonstrated to provide the equivalent to a
chronocoulometric response, but is closer to the ideal simulated response. A facile method for simulating time or potential-dependant
spectroelectrochemical responses using commercial electrochemical simulation software is described. Absorbance transients
monitored during the electrolysis of solid particles of [Ru(dpp)3](PF6)2 show best agreement with simulated data at very short and very long timescales. This observation, in conjunction with the
observations from the potential scan experiments, suggests that the absorbance, charge, or current vs. time behaviour of the
system can be adequately described by a semi-infinite diffusional model at short experimental timescales and by a finite diffusional
model at sufficiently long timescales.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Dedicated to the 80th birthday of Keith B. Oldham. 相似文献
55.
Conor J. Twomey Shaw H. Chen Thomas N. Blanton Ansgar Schmid Kenneth L. Marshall 《Journal of Polymer Science.Polymer Physics》1994,32(10):1687-1695
In view of the residual crystallinity in PEO found to limit the solubility of some Nd3+-compounds, amorphous PEO (aPEO) was synthesized for exploration as an alternative host. Complexation, solubility limit, morphology, and response to moisture absorption in the doped systems were investigated using FTIR, DSC, TGA, and WAXD techniques. Representing a perturbation to the structural regularity present in PEO, aPEO was found to present lower solubilities for dopants (Nd(act)3 and Nd(acac)3, both characterized by a weak Nd3+–ether oxygen interaction. On the other hand, no difference in solubility was observed for dopant Nd(NO3)3, characterized by a strong Nd3+–ether oxygen interaction. Laser interferometry was employed to assess film homogeneity of the Nd(NO3)3-doped systems across a 20-mm diameter, and the measured peak-to-valley distortion values were observed to be encouraging for practical applications. © 1994 John Wiley & Sons, Inc. 相似文献
56.
Colin?FitzpatrickEmail author Conor?O’Donoghue Elfed?Lewis Ian?Grout 《Optical Review》2003,10(4):330-334
A fabrication process for distributed multi-point fibre optic sensors based on cladding luminescence is presented. Fibres which have had their cladding removed are coated using a rig which pneumatically dispenses an epoxy phosphor mixture whilst the syringe is being moved axially along the length of the rotating fibre. The new coatings have uniform thickness on the fibre both radially and axially as well as having the same dopant density throughout the coating. A cross-sectional micrograph of a coated fibre is shown as well as the thickness distribution along the fibre. 相似文献
57.
By exploiting its ability to play sounds, a mobile phone with suitable software installed can serve the basic functions of a potentiostat in controlling an applied potential to oxidise ECL-active molecules, while the resultant photonic signal is monitored using the camera in video mode. In combination with paper microfluidic sensors this opens significant new possibilities for low-cost, instrument-free sensing. 相似文献
58.
59.
Dr. Chinmay Y. Majmudar Dr. Jonas W. Højfeldt Carl J. Arevang Dr. William C. Pomerantz Jessica K. Gagnon Pamela J. Schultz Laura C. Cesa Conor H. Doss Dr. Steven P. Rowe Victor Vásquez Prof. Dr. Giselle Tamayo‐Castillo Prof. Dr. Tomasz Cierpicki Prof. Dr. Charles L. Brooks III Prof. Dr. David H. Sherman Prof. Dr. Anna K. Mapp 《Angewandte Chemie (International ed. in English)》2012,51(45):11258-11262
60.
Conor J. Twomey Shaw H. Chen Tom Blanton Ansgar Schmid Kenneth L. Marshall 《Journal of Polymer Science.Polymer Physics》1993,31(6):647-654
Samples of poly(ethylene oxide), PEO, doped with neodymium acetate, Nd (Act)3, were prepared and found to be microphase separated. At an EO/Nd (Act)3 molar ratio no less than 4, wide-angle x-ray diffraction (WAXD) patterns and small-angle x-ray scattering (SAXS) data suggest that bulk Nd (Act)3 and ionic clusters are both absent. It is inferred from differential scanning calorimetry (DSC) thermograms that in the presence of PEO, Nd (Act)3 forms an amorphous phase which is different from the amorphous phase formed by Nd (Act)3 alone. The tighter binding of CH3COO- to Nd3+, in comparison to Cl-, appears to be responsible for the lack of true dissolution of Nd (Act)3 in PEO, a behavior clearly distinct from a number of polymer-metal salt complexes reported in the literature. © 1993 John Wiley & Sons, Inc. 相似文献