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101.
Paul Blomstedt Romain Gauriot Niina Viitala Tapani Reinikainen Jukka Corander 《Journal of Chemometrics》2014,28(1):52-59
Statistical comparison of oil samples is an integral part of oil spill identification, which deals with the process of linking an oil spill with its source of origin. In current practice, a frequentist hypothesis test is often used to evaluate evidence in support of a match between a spill and a source sample. As frequentist tests are only able to evaluate evidence against a hypothesis but not in support of it, we argue that this leads to unsound statistical reasoning. Moreover, currently only verbal conclusions on a very coarse scale can be made about the match between two samples, whereas a finer quantitative assessment would often be preferred. To address these issues, we propose a Bayesian predictive approach for evaluating the similarity between the chemical compositions of two oil samples. We derive the underlying statistical model from some basic assumptions on modeling assays in analytical chemistry, and to further facilitate and improve numerical evaluations, we develop analytical expressions for the key elements of Bayesian inference for this model. The approach is illustrated with both simulated and real data and is shown to have appealing properties in comparison with both standard frequentist and Bayesian approaches. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
102.
Abstract Aliphatic polyesters, such as poly(lactic acids), need high molecular weight for acceptable mechanical properties. This can be achieved through ring-opening polymerization of lactides. The lactide route is, however, relatively complicated, and alternative polymerization routes are of interest. In this paper we report the properties of a polymer made by a two-step process: first a condensation polymerization of lactic acid and then an increase of the molecular weight with diisocyanate. The end product is then a thermoplastic poly(ester-urethane). The hydroxylterminated prepolymer was made with condensation polymerization of L–lactic acid and a small amount of 1,4-butanediol. The polymerization was performed in the melt under nitrogen and reduced pressure. The preparation of poly(ester-urethane) was done in the melt using aliphatic diisocyanates as the chain extenders reacting with the end groups of the prepolymer. The polymer samples were carefully characterized, including preliminary degradation studies. The results indicate that this route to convert lactic acid into thermoplastic biodegradable polymer has high potential. Lactic acid is converted into a mechanically attractive polymer with high yield, which could make the polymer suitable for high volume applications. The mechanical properties of the poly(ester-urethane) are comparable with those of poly(lactides). Capillary rheometer measurements indicate that the polymer is processible both by injection molding and extrusion. 相似文献
103.
Fabio Terzi Jonathan Pelliciari Chiara Zanardi Laura Pigani Antti Viinikanoja Jukka Lukkari Renato Seeber 《Analytical and bioanalytical chemistry》2013,405(11):3579-3586
A gold electrode partially coated by graphene multilayer is developed and tested with respect to high concentrations of hydrogen peroxide. The effective use of conventional electrode materials for the determination of such an analyte by anodic oxidation or cathodic reduction is prevented by the occurrence of adsorptions fouling the electrode surface. This prevents reliable and repeatable voltammetric curves for being recorded and serious problems arise in quantitative analysis via amperometry. The gold–graphene electrode is shown to be effective in quantitative evaluation, by cathodic reduction, of hydrogen peroxide at concentration levels that are of interest in an industrial. Acid, neutral, and basic pH values have been tested through correct adjustment of a Britton Robinson buffer. The experiments have been performed both by cyclic voltammetry and with amperometry at constant potential in unstirred solution. The latter technique has been employed in drawing a calibration linear plot. In particular, the performances of the developed electrode system have been compared with those of both pure gold and pure graphene electrode materials. The bi-component electrode was more sensitive; co-catalytic action by the combination of the two components is hypothesised. The system is stable over many potential cycles, as checked by surface-enhanced Raman spectra recorded over time. 相似文献
104.
105.
We study a 2D model of the orientation distribution of fibres in a paper machine headbox. The goal is to control the orientation
of fibres at the outlet by shape variations. The mathematical formulation leads to an optimization problem with control in
coefficients of a linear convection-diffusion equation as the state problem. Existence of solutions both to the state and
the optimization problem is analyzed and sensitivity analysis is performed. Further, discretization is done and a numerical
example is shown.
This research was supported by the Charles University Grant Agency under Contract 6/2005/R, MSM 0021620839 (MŠMT ČR), and
the Academy of Finland, Grant #204741. 相似文献
106.
Ge, Rusjan, and Zweifel introduced a binary tree which represents all the periodic windows in the chaotic regime of iterated one-dimensional unimodal maps. We consider the scaling behavior in a modified tree which takes into account the self-similarity of the window structure. A nonuniversal geometric convergence of the associated superstable parameter values towards a Misiurewicz point is observed for almost all binary sequences with periodic tails. For these sequences the window period grows arithmetically down the binary tree. There are an infinite number of exceptional sequences, however, for which the growth of the window period is faster. Numerical studies with a quadratic maximum suggest more rapid than geometric scaling of the superstable parameter values for such sequences. 相似文献
107.
Perez Carrillo A Bonada J Patynen J Valimaki V 《The Journal of the Acoustical Society of America》2011,130(2):1020-1029
This work presents a method for measuring and computing violin-body directional frequency responses, which are used for violin sound synthesis. The approach is based on a frame-weighted deconvolution of excitation and response signals. The excitation, consisting of bowed glissandi, is measured with piezoelectric transducers built into the bridge. Radiation responses are recorded in an anechoic chamber with multiple microphones placed at different angles around the violin. The proposed deconvolution algorithm computes impulse responses that, when convolved with any source signal (captured with the same transducer), produce a highly realistic violin sound very similar to that of a microphone recording. The use of motion sensors allows for tracking violin movements. Combining this information with the directional responses and using a dynamic convolution algorithm, helps to improve the listening experience by incorporating the violinist motion effect in stereo. 相似文献
108.
Anni Karppinen Arja-Helena Vesterinen Tapio Saarinen Pirjo Pietikäinen Jukka Seppälä 《Cellulose (London, England)》2011,18(6):1381-1390
Using two cationic methacrylate polymers: poly([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide) (PDMQ) and poly[(stearyl
methacrylate)-stat-([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide)] (PSMA13Q), we modified microfibrillated cellulose (MFC) water suspensions.
The aim was to affect the flocculation and rheological behavior of the MFC suspension. PDMQ is a strongly cationic polymer
while PSMA13Q, also a cationic polymer, contains hydrophobic segments. We studied the MFC/polymer suspension rheological properties
with a rotational rheometer in oscillatory and flow measurements. To observe structural changes in suspensions at different
shear rates, we measured flow curves with transparent outer geometry and photographed the sample with a digital camera. The
oscillatory measurements showed that a small amount of the cationic PDMQ in the MFC suspension strengthened the gel, whereas
a small amount of amphiphilic PSMA13Q weakened it. Increased amounts of either polymer increased the gel strength. PSMA13Q
also changed the rheological character of the MFC suspension turning it more fluid-like. When we photographed the flow curve
measurement, we saw a clear change in the floc structure. This floc structure rupture coincided with a transient region in
the flow curve. 相似文献
109.
Jukka Antikainen Mikael von und zu Fraunberg Joni Orava Juha E. Jaaskelainen Markku Hauta-Kasari 《Optical Review》2011,18(6):458-461
It has been noticed that spectral information can be used for analyzing and separating different biological tissues. However,
most of the studies for spectral image acquisitions are mainly done in vitro. Usually the main restrictions for in vivo measurements are the size or the weight of the spectral camera. If the camera weights too much, the surgery microscope cannot
be stabilized. If the size of the camera is too big, it will disturb the surgeon or even risk the safety of the patient. The
main goal of this study was to develop an independent spectral imaging device which can be used for collecting spectral information
from the neurosurgeries without any previously described restrictions. Size of the imaging system is small enough not to disturb
the surgeon during the surgery. The developed spectral imaging system is used for collecting a spectral database which can
be used for the future imaging systems. 相似文献
110.
Two different in situ-polymerization techniques were studied, emulsion polymerization and combined emulsion/suspension polymerization, with styrene and methyl methacrylate in the presence of different multiwalled carbon nanotubes (MWCNTs). Molar masses and molar mass distributions were determined by size exclusion chromatography, and particle size of the emulsions by dynamic light scattering and rotation rheometry. The compatibility of the MWCNTs and monomer affected polymerization and therefore the molar masses. The MWCNTs stabilized the emulsions, and molar mass distributions narrowed with higher amounts of MWCNTs. In emulsion polymerization of styrene, MWCNTs increased the molar mass. The increase of molar mass was based on the compatible molecular structures of MWCNTs and styrene, so that individual nanotubes were covered by monomer clouds when initiator arrived. In combined emulsion/suspension polymerization of styrene, MWCNTs reacted with the initiator and there was less initiator to polymerize the monomer. There is probably a critical surface area of MWCNTs, for which more initiator is consumed in the reaction with MWCNTs than in polymerization of the monomer. In emulsion polymerization of MMA, monomer clouds around MWCNTs do not form due to incompatible molecular structures, and nanotubes do not enhance polymerization of MMA. In combined polymerization, the initiator is reacting with the nanotubes and the tube is acting as a carrier for initiator, and molar masses are higher. 相似文献