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321.
Validation of the accuracy of the perturbation peak method for determination of multicomponent adsorption isotherm parameters in LC 总被引:1,自引:0,他引:1
The isotherm parameters were for the first time determined for a quaternary mixture. This was done by the perturbation peak (PP) method using racemic mixtures of methyl and ethyl mandelate enantiomers. One complication with the PP method is that the traditional blank injection technique makes all perturbation peaks, except one, vanish at moderately nonlinear concentration plateaus. Therefore, we devised a new injection technique that made all four peaks on a quaternary component concentration plateau detectable, thereby making the determination of multicomponent competitive isotherm parameters possible. The measured quaternary perturbation data fitted well to the bi-Langmuir isotherm model and excellent agreement was found between experimental and simulated single-component and multicomponent profiles, thus validating the method and the determined isotherm parameters. The method (i) is valuable for computer-assisted optimization of preparative chiral chromatography and (ii) opens the possibility of quantifying competitive drug-target interactions for chiral drugs directly on racemic mixtures, which today is impossible with any nonlabeled technique including surface plasmon resonance technology. 相似文献
322.
The purpose of this paper is to provide a utility eye-view of the European power-sector's CO2-compliance decision process under a tradable emissions scheme. The cost analysis indicates that, in the medium term, many utilities are likely to consider options based on traditional power technologies such as converting existing coal-fired capacity to burn gas, extending the lives of nuclear capacity, and replacing old coal-fired plants with more efficient gas- or even coal-fired units. The long-term economic potential of future options is highly uncertain, and utilities are likely to respond to this by maintaining flexibility in fuel choices and avoid large investments that lock them into a specific compliance method before more efficient and cleaner technologies have crystallized. Given the multitude of possible CO2-mitigation options, there is a strong case for emissions trading and for refraining from policies that build on mandatory fuel-requirements, higher rates of capital stock turnover and technology standards. 相似文献
323.
Lena Karlsson Thomas Thelin Björn Regnell Patrik Berander Claes Wohlin 《Empirical Software Engineering》2007,12(1):3-33
The process of selecting the right set of requirements for a product release is dependent on how well the organisation succeeds
in prioritising the requirements candidates. This paper describes two consecutive controlled experiments comparing different
requirements prioritisation techniques with the objective of understanding differences in time-consumption, ease of use and
accuracy. The first experiment evaluates Pair-wise comparisons and a variation of the Planning game. As the Planning game
turned out as superior, the second experiment was designed to compare the Planning game to Tool-supported pair-wise comparisons.
The results indicate that the manual pair-wise comparisons is the most time-consuming of the techniques, and also the least
easy to use. Tool-supported pair-wise comparisons is the fastest technique and it is as easy to use as the Planning game.
The techniques do not differ significantly regarding accuracy.
Editor: Daniel Berry 相似文献
324.
Patrik Fauser Jens Christian Tjell Hans Mosbaek Kim Pilegaard 《Petroleum Science and Technology》2013,31(9-10):991-1007
ABSTRACT A method for identifying and quantifying bitumen particles, generated from the wear of roadway asphalts, in aerosol and soil samples has been developed. Bitumen is found to be the only contributor to airborne particles containing organic molecules with molecular weights larger than 2000 g pr. mol. These are separated and identified using High Performance Gel Permeation Chromatography (HP-GPC) with fluorescence detection. As an additional detection method Infra Red spectrometry (IR) is employed for selected samples, The methods have been used on aerosol, soil and other samples. 相似文献
325.
Self-organized, free-standing TiO2 nanotube membrane for flow-through photocatalytic applications 总被引:2,自引:0,他引:2
In the present work we show a simple and robust fabrication process of a dense and free-standing membrane consisting of vertically oriented, both-side-open TiO2 nanotubes. This membrane structure allows direct, size-selective, flow-through photocatalytic reactions with a very high efficiency. 相似文献
326.
In this paper, we describe a new method for fabrication of nanoelectrospray emitters. The needles were pulled from fused silica capillary tubing, which was melted by means of a plasma, formed by electrical discharges between two pointed platinum electrodes. A key feature of the pulling device is a rotating configuration of the electrodes, which results in an even radial heating of the capillary. The construction of the setup is straightforward, and needles with a variety of shapes can be fabricated, including orifices of submicrometer dimensions. Pulled needles with long tapered tips and an orifice of 0.5 μm were utilized for electrospray ionization mass spectrometry (ESI-MS) of discrete sample volumes down to 275 pL. The picoliter-sized samples were transferred into the tip of the needle from a silicon microchip by aspiration. To avoid a rapid evaporation of the sample, all manipulations were performed under a cover of a fluorocarbon liquid. The limit of detection was measured to be ca. 20 attomole for insulin (chain B, oxidized). 相似文献
327.
Nanostructured titanium dioxide is one of the classic materials for photoelectrochemical water splitting. In the present work we dope TiO(2) nanotube anodes. For this, various low concentration bulk-Nb-doped TiO(2) nanotube layers were grown by self-organizing anodization of Ti-Nb alloys. At Nb-contents around 0.1 at%, and after an adequate heat-treatment, a strongly increased and stable photoelectrochemical water-splitting rate is obtained. 相似文献
328.
In the present work, we show that a porous alumina template can easily be filled with magnetic nanoparticles and then be sealed by a hot water treatment (by forming an aluminium oxyhydroxide (AlOOH) sealant layer). The porous layer then can be separated from the substrate by an etch to form free magnetic AlOOH nano-capsules. The process allows for a straightforward and highly defined size control of the magnetic units and can easily be scaled up. Furthermore, as AlOOH is biocompatible and has been used as a drug adjuvant for human use, the nanorod shaped capsules are highly promising for biomedical applications such as hyperthermal effects (heating in alternating magnetic fields). 相似文献
329.
330.
Svensson CP Mårtensson T Trägårdh J Larsson C Rask M Hessman D Samuelson L Ohlsson J 《Nanotechnology》2008,19(30):305201
Vertical light emitting diodes (LEDs) based on GaAs/InGaP core/shell nanowires, epitaxially grown on GaP and Si substrates, have been fabricated. The devices can be fabricated over large areas and can be precisely positioned on the substrates, by the use of standard lithography techniques, enabling applications such as on-chip optical communication. LED functionality was established on both kinds of substrate, and the devices were evaluated in terms of temperature-dependent photoluminescence and electroluminescence. 相似文献