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101.
102.
Dynamic Photoswitching of Electron Energy Levels at Hybrid ZnO/Organic Photochromic Molecule Junctions
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Qiankun Wang Giovanni Ligorio Valentin Diez‐Cabanes David Cornil Björn Kobin Jana Hildebrandt Marco Vittorio Nardi Melanie Timpel Stefan Hecht Jérôme Cornil Emil J. W. List‐Kratochvil Norbert Koch 《Advanced functional materials》2018,28(28)
The functionality of interfaces in hybrid inorganic/organic (opto)electronic devices is determined by the alignment of the respective frontier energy levels at both sides of the heterojunctions. Controlling the interface electronic landscape is a key element for achieving favourable level alignment for energy and charge transfer processes. Here, it is shown that the electronic properties of polar ZnO surfaces can be reversibly modified using organic photochromic switches. By employing a range of surface characterization techniques combined with density functional theory calculations, it is demonstrated that self‐assembled monolayers (SAMs) of photochromic phosphonic acid diarylethenes (PA‐DAEs) can be employed to reversibly change the electronic properties of polar ZnO/SAM structures by light stimuli. The highest occupied molecular orbital level of PA‐DAE is raised by 0.7 eV and the lowest unoccupied one lowered by 0.9 eV, respectively, upon illumination by ultraviolet light and the levels shift back to their original position upon illumination by green light. The results thus provide a pathway to tailor hybrid interface electronic properties in a dynamic manner upon simple light illumination, which can be exploited to reversibly tune the electrical properties of photoswitchable (opto)electronic devices. 相似文献
103.
The dielectric behavior of different polar high polymers at ultra-high frequencies has been investigated by means of a dielectrometer, suitably modified to permit measurements at different temperatures. Experimental measurements were made at about 9 × 109 cps over the temperature range of ?150 to 200°C. for polyoxymethylene, polythiomethylene, poly(3,3′-chloromethyl)oxetane (Penton), polycarbonate of 4,4′-dioxydiphenyl-2,2′-propane (Makrolon), poly(vinyl alcohol), poly(vinyl acetate), poly(vinyl chloride), vinyl chloride–vinyl acetate copolymer, and two ABS plastics, type B (blend) and type G (graft). On comparing the dielectric behavior of the examined materials at ultra-high frequencies with the corresponding ones determined at low or at radiofrequencies, it is observed that, in the microwave region, all relaxation peaks, either connected with cooperative motions in main chain (primary processes) or with local motions in the backbone or in side chains (secondary processes), usually observed at lower frequencies, tend to disappear; the corresponding relaxation effects, however, manifest themselves through a progressive increase of losses with increasing temperature, which is particularly marked above the glass transition temperature Tg. The latter transition, in spite of the very high frequency, is easily distinguished, in most cases, by the sudden change of slope in the tan δ versus temperature curve which accompanies its onset. This is explained on the basis of the very wide distribution times of molecular relaxation processes in polymers and the increase in strength of the secondary relaxation effects, which is verified at Tg, as a consequence of the increased kinetic energy of macromolecules and of the larger free volume for orientation of side chains. Each case is discussed separately and the experimental results interpreted on the basis of the molecular structure and chain mobility of the examined polymers. 相似文献
104.
Silvia Pelegrini Andrea Adami Cristian Collini Paolo Conci Clodoaldo I. L. de Araújo Vittorio Guarnieri Saulo Güths André A. Pasa Leandro Lorenzelli 《Microsystem Technologies》2014,20(4-5):585-592
This work reports the development and the characterization of a microthermoelectric generator (μTEG) based on planar technology using electrochemically deposited constantan and copper thermocouples on a micro machined silicon substrate with a SiO2/Si3N4/SiO2 thermally insulating membrane to create a thermal gradient. The μTEG has been designed and optimized by finite element simulation in order to exploit the different thermal conductivity of silicon and membrane in order to obtain the maximum temperature difference on the planar surface between the hot and cold junctions of the thermocouples. The temperature difference was dependent on the nitrogen (N2) flow velocity applied to the upper part of the device. The fabricated thermoelectric generator presented maximum output voltage and power of 118 mV/cm2 and of 1.1 μW/cm2, respectively, for a device with 180 thermocouples, 3 kΩ of internal resistance, and under a N2 flow velocity of 6 m/s. The maximum efficiency (performance) was 2 × 10?3 μW/cm2 K2. 相似文献
105.
Vladimir N. lgnatov Claudio Carraro Vittorio Tartari Roberto Pippa Francesco Pilati Corrado Berti Maurizio Toselli Maurizio Fiorini 《Polymer》1996,37(26):5883-5887
Reactive blending of commercial poly(ethylene terephthalate) (PET) and bisphenol A polycarbonate (PC), with catalysts added in the form of powder dispersed on the polymers just before melt mixing, was performed in a Brabender Plasticord 2000 apparatus at 275°C. Catalytic activity of the catalysts freshly added to polymers was found to be much higher as compared with that of the residues of the same type of catalysts remaining in PET after its synthesis. Furthermore, the catalytic activity appeared to be strongly dependent on the structure of the ligand that influences the catalyst solubility in the polymer melt. N.m.r. spectroscopy, selective degradation of PC fragments, solubility tests in methylene chloride and d.s.c. measurements made it possible to range the catalysts studied according to their catalytic activity. 相似文献
106.
In this article, the linear theory of thermoelasticity for solids with double porosity is considered. The fundamental solutions for the systems of steady vibrations (including quasi-static case) and equilibrium equations are constructed by means of elementary functions; the basic properties of such solutions are also established. 相似文献
107.
Titania solar cells are a new type of photovoltaic device invented by Professor Michael Grätzel at Ecole Polytechnique Federale de Lausanne (Switzerland). Titania solar cells convert sunlight directly into electricity through a process similar to photosynthesis. It has performance advantages over other solar cells, which include the ability to perform well in low light and shade, and to perform consistently well over a wide range of temperatures. Titania solar cells can be fabricated to be either transparent or opaque in appearance. The simple materials, construction technique and processing equipment make Titania modules attractive for affordable power generation. Applications of such a module include many consumer and professional products, including vertically mounted solar tiles used as integrated building materials and, in future, used as power generating windows. 相似文献
108.
In the present paper, in the context of the linear theory of heat-flux dependent thermoelasticity for micropolar porous media, we derive a uniqueness theorem with no positive definiteness assumption on the elastic constitutive coefficients. Moreover, we prove, under non homogeneous initial conditions, a reciprocal relation and a variational principle. These generalize previous results about inhomogeneous and anisotropic micropolar thermoelastic materials. 相似文献
109.
This paper presents an Application-specific Run-Time managEment (ARTE) framework to tackle the problem of managing computational resources in an application specific multi-core system. The ARTE framework run-time goal is to minimize applications’ response times while meeting the applications’ computational demands and fitting within the available power budget. 相似文献
110.
McCrae Robert R.; Costa Paul T.; de Lima Margarida Pedroso; Sim?es António; Ostendorf Fritz; Angleitner Alois; Maru?i? Iris; Bratko Denis; Caprara Gian Vittorio; Barbaranelli Claudio; Chae Joon-Ho; Piedmont Ralph L. 《Canadian Metallurgical Quarterly》1999,35(2):466
Both cross-sectional and longitudinal studies in the United States have shown consistent changes between college age and middle adulthood. There appear to be declines in 3 of the 5 major factors of personality-Neuroticism, Extraversion, and Openness-and increases in Agreeableness and Conscientiousness. To examine cross-cultural generalizability of these findings, translations of the Revised NEO Personality Inventory were administered to samples in Germany, Italy, Portugal, Croatia, and South Korea (N?=?7,363). Similar patterns of age differences were seen in each country, for both men and women. Common trends were also seen for the more specific traits that define the major factors. Because these nations differ substantially in culture and recent history, results suggest the hypothesis that these are universal maturational changes in adult personality. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献