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71.
Femke Danckaers Toon Huysmans Mattias Van Dael Pieter Verboven Bart Nicolaï Jan Sijbers 《Food and Bioprocess Technology》2017,10(11):2100-2112
A method to build a 3D statistical shape model of horticultural products is described. The framework consists of two parts. First, the surfaces of the horticultural products, which are extracted from X-ray CT scans, are registered to obtain meaningful correspondences between the surfaces. In the second part, a statistical shape model is built from these corresponded surfaces, which maps out the variability of the surfaces and allows to generate new, realistic surfaces. The proposed shape modelling method is applied to 30 Jonagold apples, 30 bell peppers, and 52 zucchini. The average geometric registration error between the original instance and the deformed reference instance is 0.015 ± 0.011 m m for the apple dataset, 0.106 ± 0.026 m m for the bell pepper dataset, and 0.027 ± 0.007 m m for the Zucchini dataset. All shape models are shown to be an excellent representation of their specific population, as they are compact and able to generalize to an unseen sample of the population. 相似文献
72.
Most simulations of colloidal suspensions treat the solvent implicitly or as a continuum. However as particle size decreases to the nanometer scale, this approximation fails and one needs to treat the solvent explicitly. Due to the large number of smaller solvent particles, such simulations are computationally challenging. Additionally, as the ratio of nanoparticle size to solvent size increases, commonly-used molecular dynamics algorithms for neighbor finding and parallel communication become inefficient. Here we present modified algorithms that enable fast single processor performance and reasonable parallel scalability for mixtures with a wide range of particle size ratios. The methods developed are applicable for any system with widely varying force distance cutoffs, independent of particle sizes and independent of the interaction potential. As a demonstration of the new algorithm's effectiveness, we present results for the pair correlation function and diffusion constant for mixtures where colloidal particles interact via integrated potentials. In these systems, with nanoparticles 20 times larger than the surrounding solvent particles, our parallel molecular dynamics code runs more than 100 times faster using the new algorithms. 相似文献
73.
The force transfer between concrete and reinforcement depends on the bond characteristics between the two materials. Bond influences crack widths and the deflections of RC members and also determines anchorage and splice lengths. Self-compacting concrete (SCC) is characterized by a smaller amount of coarse aggregates when compared to conventional vibrated concrete. To investigate whether this change in mix design has a significant influence on the bond behaviour, a series of beam tests (according to RILEM recommendation RC6) was performed. A total of 36 specimens were cast using 3 different concrete types: one conventional vibrated concrete (CVC) and two powder-type SCC’s. The bond stress—slip behaviour of reinforcing bars with diameters ranging from 12 to 40 mm has been recorded. From these tests, it can be concluded that the bond strength of SCC is even higher than it is for CVC for small bar diameters, but the difference becomes smaller for larger bar diameters. 相似文献
74.
Pieter Bauwens Ann Monté Wim Christiaens Jan Doutreloigne Jan Vanfleteren 《Displays》2009,30(2):71-76
One of the major problems with PM displays is that, depending on the used display material, only a limited number of lines can be multiplexed. We developed a new driving technology and display setup that takes care of that problem. We divided the display into several independent parts or modules. Each module acts as an individual display and has its own display driver. With the use of the new ultra-thin chip package (UTCP), these driver chips can be embedded into the (flexible) display itself. This paper explains the setup of the fully modular display and describes the basic structure of the display drivers and its components. 相似文献
75.
Pieter Hooijmans 《电子产品世界》2005,(18):58-62
未来消费电子产品的RF应用将向更高的载波频率方向发展.这种趋势已经初现端倪,新提议的IEEE-802.11a数字网络标准在5GHz频率工作,超宽带(UWB)的带宽要求则介于3GHz和10GHz之间.汽车防撞雷达的工作频率是25GHz,而多种IEEE 802.16WirelessMAN(无线城域网)标准、本地多点分布式服务(LMDS)网络和卫星返回通道所需的带宽位于25GHz到 35GHz之间(参见图1). 相似文献
76.
Eugne T. W. M. Schipper Alexander H. C. Roelofs Pieter Piet Anton L. German 《Polymer International》1994,33(1):79-86
In order to study the promoting effect of polycations on the cobalt(II)phthalocyanine-tetrasodiumsulphonate (CoPc(NaSO3)4)-catalysed autoxidation of thiols, it is imperative to know the molecular weight dependence of the polymer. Monodisperse oligomers can often supply a lot of information. To elecidate the mechanism of the promoting effect of 2,4-ionene, a poly(quaternary ammonium)salt, on the CoPc(NaSO3)4-catalysed autoxidation of 2-mercaptoethanol, a series of monodisperse 2,4-ionene oligomers were prepared. Trimeric 2,4-ionenes, containing two quaternary ammonium groups separated by four methylene groups, showed a high co-catalytic activity, and active Co-aggregates were detected with visible light spectroscopy. The spectroscopic behaviour was in close agreement with that of high molecular 2,4-ionene/CoPc(NaSO3)4 complexes. In order to achieve this aggregation several oligomeric ionenes have to act concertedly. If the distance between the ionic sites is short the trimer acts as a simple salt in stablizing the aggregates. With respect to the catalytic activity the optimum polycation/catalyst ratio, expressed as the N+/Co ratio, decreased with increasing chain lenght and reached a constant level of 50 at a 2,4-ionene nonamer. For the trimers and pentamers this ratio is affected by the type of end-group. All synthesized 2,4-ionene oligomers exhibited excellent co-catalytic properties at the optimum N+/Co ratio, with maximum turnover frequencies of 4600 mol thiol/(mol Co s), i.e. 50 times higher than those obtained for the polymer-free system. In the case of monodisperse 2,4-ionene pentamer with bromo end-groups, double Michaelis–Menten kinetics were observed, as also was exhibited by high molecular weight ionene. 相似文献
77.
Alexandru I. Petrisor Sandra Szyjka Tomohiro Kawaguchi Pieter T. Visscher Robert Sean Norman Alan W. Decho 《International journal of molecular sciences》2014,15(1):850-877
Microspatial arrangements of sulfate-reducing microorganisms (SRM) in surface microbial mats (~1.5 mm) forming open marine stromatolites were investigated. Previous research revealed three different mat types associated with these stromatolites, each with a unique petrographic signature. Here we focused on comparing “non-lithifying” (Type-1) and “lithifying” (Type-2) mats. Our results revealed three major trends: (1) Molecular typing using the dsrA probe revealed a shift in the SRM community composition between Type-1 and Type-2 mats. Fluorescence in-situ hybridization (FISH) coupled to confocal scanning-laser microscopy (CSLM)-based image analyses, and 35SO4
2−-silver foil patterns showed that SRM were present in surfaces of both mat types, but in significantly (p < 0.05) higher abundances in Type-2 mats. Over 85% of SRM cells in the top 0.5 mm of Type-2 mats were contained in a dense 130 μm thick horizontal layer comprised of clusters of varying sizes; (2) Microspatial mapping revealed that locations of SRM and CaCO3 precipitation were significantly correlated (p < 0.05); (3) Extracts from Type-2 mats contained acylhomoserine-lactones (C4-, C6-, oxo-C6 C7-, C8-, C10-, C12-, C14-AHLs) involved in cell-cell communication. Similar AHLs were produced by SRM mat-isolates. These trends suggest that development of a microspatially-organized SRM community is closely-associated with the hallmark transition of stromatolite surface mats from a non-lithifying to a lithifying state. 相似文献
78.
Pulsed electric fields (PEF) nonthermally induce cell membrane permeabilization and thereby improve dehydration and extraction efficiencies in food plant materials. Effects of electrical field strength and number of pulses on plant tissue integrity have been studied extensively. Two previous studies on the effect of pulse frequency, however, did not provide a clear view: one study suggested no effect of frequency, while the other found a greater impact on tissue integrity at lower frequency. This study establishes the effect of pulse frequency on integrity of onion tissues. Changes in electrical characteristics, ion leakage, texture parameters, and percent weight loss were quantified for a wide range of pulse frequencies under conditions of fixed field strength and pulse number. Optical microscopy and viable-cell staining provided direct visualization of effects on individual cells. The key finding is that lower frequencies (f < 1 Hz) cause more damage to tissue integrity than higher frequencies (f = 1 to 5000 Hz). Intriguingly, the optical microscopy observations demonstrate that the speed of intracellular convective motion (that is, cytoplasmic streaming) following PEF application is strongly correlated with PEF frequency. We provide the first in situ visualization of the intracellular consequence of PEF at different frequencies in a plant tissue. We hypothesize that cytoplasmic streaming plays a significant role in moving conductive ionic species from permeabilized cells to the intercellular space between plant cells, making subsequent pulses more efficacious at sufficiently low frequencies. The results suggest that decreasing the pulse frequency in PEF may minimize the number of pulses needed to achieve a desired amount of permeabilization, thus lowering the total energy consumption. Practical Application: PEF cause pores to be formed in plant cell membranes, thereby improve moisture removal and potential extraction of desirable components. This study used in situ microscopic evaluation of onion cells, as they were pulsed with electric fields at different frequencies, to determine whether frequency was an important parameter. We illustrate that membranes were more effectively broken at lower frequencies as compared to higher frequencies. Application of this information will allow for improved design of PEF systems for more energy efficient dehydration or extraction of plant tissues. 相似文献
79.
Aarts HJ Vos P Larsson JT van Hoek AH Huehn S Weijers T Grønlund HA Malorny B 《International journal of food microbiology》2011,145(Z1):S68-S78
A proof of principle of a multi-target assay for genotyping Salmonella has been developed targeting 62 genomic marker sequences of Salmonella related to pathogenicity. The assay is based on multiplex ligation detection reaction (LDR) followed by customized ArrayTube? microarray detection. The feasibility of the developed assay was verified in a method comparison study with conventional PCR using 16 Salmonella 'test' strains comprising eight serovars. Subsequently, the feasibility of the LDR microarray assay was also tested by analyzing 41 strains belonging to 23 serovars. With the exception of four serovars each serovar was characterized by a unique virulence associated gene repertoire. The LDR microarray platform proved to be a convenient, rapid and easy to use tool with potential in tracing a Salmonella contamination in the food chain, for outbreak studies, and to provide data for risk assessors that support bio-traceability models. 相似文献
80.
Thus far most studies of operational energy use of buildings fail to take a longitudinal view, or in other words, do not take into account how operational energy use changes during the lifetime of a building. However, such a view is important when predicting the impact of climate change, or for long term energy accounting purposes. This article presents an approach to deliver a longitudinal prediction of operational energy use. The work is based on the review of deterioration in thermal performance, building maintenance effects, and future climate change. The key issues are to estimate the service life expectancy and thermal performance degradation of building components while building maintenance and changing weather conditions are considered at the same time. Two examples are presented to demonstrate the application of the deterministic and stochastic approaches, respectively. The work concludes that longitudinal prediction of operational energy use is feasible, but the prediction will depend largely on the availability of extensive and reliable monitoring data. This premise is not met in most current buildings. 相似文献