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81.
Federico Pazzagli Massimo Paci Pierluigi Magagnini Ugo Pedretti Carlo Corno Guglielmo Bertolini Carlo A. Veracini 《应用聚合物科学杂志》2000,77(1):141-150
The melt polycondensation of mixtures of sebacic acid (S), 4,4′‐diacetoxybiphenyl (B), and 4‐acetoxybenzoic acid (H), carried out for the synthesis of semiflexible liquid–crystalline copolyesters referred to as SBH 1 : 1 : x, has been studied with the aim of clarifying the effect of the reaction conditions on the microstructure and the thermal properties of the products. It has been shown that the segregation of a liquid–crystalline phase within the polymerizing mixture, coupled with the thermodynamic tendency of the two phases to undergo compositional differentiation as polymerization proceeds, is responsible for the formation of blocky, rather than ideally random, copolyesters with poor processibility, when the mole ratio of H to the other two monomers is higher than x ≈ 1.90. The results of this study have shown that this unwanted effect can be considerably limited by carrying out the polycondensation at a relatively high temperature from the very beginning, rather than by the standard technique involving progressive heating of the reaction mixture, thus allowing the production of SBH copolyesters with a higher degree of aromaticity. The results are discussed in terms of the relative rates of the condensation reactions, which are responsible for chain growth, and of the concurrent acidolysis and esterolysis reactions leading to copolyester sequence reorganization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 141–150, 2000 相似文献
82.
Magdi M. Mossoba John K. G. Kramer Hormoz Azizian Jana Kraft Pierluigi Delmonte Ali-Reza Fardin Kia Francisco J. Bueso Jeanne I. Rader Jung K. Lee 《Journal of the American Oil Chemists' Society》2012,89(3):419-429
Since trans fat labeling requirements became mandatory in the US and many other countries, there has been a need for rapid and accurate
analytical methodologies that can facilitate compliance with the various regulations. The determination of total trans fatty acids by mid-infrared (IR) spectroscopy is a widely used procedure that was standardized and validated as AOCS Official
Method Cd 14e-09 (negative second derivative infrared spectroscopic method for the rapid (5 min) determination of total isolated
trans fat) in 2009. The C–H out-of-plane deformation mid-IR band observed at 966 cm−1 is uniquely characteristic of isolated (non-conjugated) double bonds with trans configuration. AOCS Official Method Cd 14e-09, the most recent attenuated total reflection-Fourier transform IR (ATR-FTIR)
official method, entails the measurement of the height of the negative second derivative of the trans absorption band. In the present study, the performance of a novel, portable FTIR system equipped with a heated 9-bounce diamond
ATR crystal was evaluated and compared to that of a conventional benchtop single-bounce ATR-FTIR spectrometer. The introduction
of the 9-bounce diamond ATR crystal resulted in the lowering of the limit of quantification of trans fat, as a percentage of the total fat, from approximately 2 to 0.34%. The data collected from accurately weighed gravimetric
standards and 28 unknown test samples ranging in trans fat content from about 0.5 to 54%, as a percentage of the total fat, indicated that this IR official method and the use of
the new 9-bounce portable ATR-FTIR instrumentation could lead to a five-fold enhancement in sensitivity relative to single-bounce
systems. Implementing these changes would facilitate regulatory compliance and verification of fat and oil samples for trans fat content in the US and other countries, since all of the published regulations (e.g., “0 g trans fat per serving”) have levels of trans fat, as percentage of total fat, that exceed 0.34%. 相似文献
83.
Deepti Tikariha Birendra Kumar Namrata Singh Kallol K. Ghosh Pierluigi Quagliotto 《Journal of surfactants and detergents》2011,14(4):555-562
The micellization behavior of gemini surfactants i.e. alkanediyl-α,ω-bis(cetyldimethylammonium bromide) (C16-s-C16,2Br− where s = 3, 4, 10) in 10% (v/v) ethylene glycol solution was investigated by surface tension and conductometric measurements at
300 K. The critical micelle concentration, degree of micellar ionization, surface excess concentration, minimum surface area
per molecule of surfactant, surface pressure at the CMC and Gibbs energy of adsorption of the dimeric surfactants have also
been determined in the presence of different salts (NaCl, NaBr and NaI). The critical micelle concentration and degree of
micellar ionization values decrease significantly in the presence of sodium halides and follows the sequence NaCl < NaBr < NaI.
The free energy, enthalpy and entropy of micellization of dimeric surfactants in 10% (v/v) ethylene glycol solution were determined
using the temperature dependence of the critical micelle concentration. The standard free energy of micellization was found
to be negative in all the cases. 相似文献
84.
Hormoz Azizian Magdi M. Mossoba Ali Reza Fardin‐Kia Pierluigi Delmonte Sanjeewa R. Karunathilaka John K. G. Kramer 《Lipids》2015,50(7):705-718
A new, rapid Fourier transform near infrared (FT‐NIR) spectroscopic procedure is described to screen for the authenticity of extra virgin olive oils (EVOO) and to determine the kind and amount of an adulterant in EVOO. To screen EVOO, a partial least squares (PLS1) calibration model was developed to estimate a newly created FT‐NIR index based mainly on the relative intensities of two unique carbonyl overtone absorptions in the FT‐NIR spectra of EVOO and other mixtures attributed to volatile (5280 cm?1) and non‐volatile (5180 cm?1) components. Spectra were also used to predict the fatty acid (FA) composition of EVOO or samples spiked with an adulterant using previously developed PLS1 calibration models. Some adulterated mixtures could be identified provided the FA profile was sufficiently different from those of EVOO. To identify the type and determine the quantity of an adulterant, gravimetric mixtures were prepared by spiking EVOO with different concentrations of each adulterant. Based on FT‐NIR spectra, four PLS1 calibration models were developed for four specific groups of adulterants, each with a characteristic FA composition. Using these different PLS1 calibration models for prediction, plots of predicted vs. gravimetric concentrations of an adulterant in EVOO yielded linear regression functions with four unique sets of slopes, one for each group of adulterants. Four corresponding slope rules were defined that allowed for the determination of the nature and concentration of an adulterant in EVOO products by applying these four calibration models. The standard addition technique was used for confirmation. 相似文献
85.
This paper is centred on one of the main results of the ELeGI project, namely its software architecture for the delivery of
personalised formal-learning experiences. The architecture has been designed and developed: (1) taking into account a general
model for the personalisation of learning experiences, allowing us to obtain a solution that is flexible with respect to the
pedagogies, and (2) on top of service oriented grid technologies, allowing us to obtain several advantages in the process
of creation and delivery of personalised learning experience like, for instance, ubiquitous and seamless access to heterogeneous
learning resources distributed over the network. In order to validate our result, the first prototype of the ELeGI architecture
has been deployed on a virtual organisation consisting of three geographically distributed nodes. Each node of the VO provides
services and learning resources that have been adopted in the creation and delivery of a personalised learning experience
about the Torricelli’s law and based on the virtual scientific experiment model. The case of study has been successfully executed
and has given us a proof of our assumptions related to the added value of the service oriented grid mainly in terms of: (1)
capabilities to access educational resources distributed over the network, that is relevant in achieving the personalisation
of learning experiences, and (2) high level of dynamicity and adaptiveness in the creation and delivery processes of a personalised
learning experience.
相似文献
Pierluigi RitrovatoEmail: |
86.
The proposed research is aimed to define some BIPV (building integrated photovoltaics) paradigms for the refurbishment of historical contexts, by defining strategic criteria related to linguistic-architectural and technological-constructive aspects of solar systems (including case-studies in specific application contexts). This research could, once perfected and shared, be used within operative tools (guidelines, case studies, etc.) really applicable to common scale, e.g., in today's post-earthquake reconstruction in L'Aquila, for defining possible solar implementation possibilities in sensitive areas according to an innovative and sustainable method of intervention. 相似文献
87.
Luca Lietti Soraia T. Brandao Pierluigi Villa Stefano Rossini 《Catalysis Letters》1996,36(3-4):151-157
The reactivity of lanthanum titanate catalysts is investigated in the oxidative coupling of methane (OCM) under lean-oxygen conditions. The catalyst performances are influenced by the catalyst preparation method and by the amounts of the alkali dopant. A transient method was also used to study the mobility of lattice oxygen species under OCM reaction conditions. It is found that (i) in the absence of gas phase oxygen the sample does not possess lattice oxygen species which participate in the reaction; (ii) the alkali doping does not appreciably modify the mobility of lattice oxygen; and (iii) the role of the alkali promoter in the reaction is that of modifying the surface acid/base and oxidizing properties. 相似文献
88.
Since the mid 1990s, Phytophthora ramorum has been responsible for the widespread mortality of tanoaks, as well as several oak species throughout California and Oregon
forests. However, not all trees die, even in areas with high disease pressure, suggesting that some trees may be resistant
to the pathogen. In this study, the chemical basis of host resistance was investigated. Three field experiments were carried
out in California between December 2004 and September 2005. The levels of nine phenolic compounds (gallic acid, catechin,
tyrosol, a tyrosol derivative, ellagic acid, and four ellagic acid derivatives) extracted from the phloem of trees that had
been either artificially inoculated with P. ramorum or trees putatively infected with P. ramorum (based on canker symptoms) were quantified by high-performance liquid chromatography (HPLC). Significant differences in phenolic
profiles were found between phloem sampled from the active margins of cankers, healthy phloem from asymptomatic trees, and
phloem sampled 60 cm away from canker sites, although the magnitude and direction of the responses was not consistent across
all experiments. Concentrations of gallic acid, tyrosol, and ellagic acid showed the greatest differences in these different
tissues, but varied considerably across treatments. Gallic acid and tyrosol were tested in in vitro bioassays and showed strong dose-dependent inhibitory effects against P. ramorum, P. cinnamomi, P. citricola, and P. citrophthora. These results suggest that phloem chemistry varies in response to pathogen infection in California coast live oak populations
and that changes in phloem chemistry may be related to apparently resistant phenotypes observed in the field.
Frances S. Ockels and Alieta Eyles contributed equally to the paper 相似文献
89.
Pierluigi Paris Leonardo MareschiMaurizio Sabatti Andrea PisanelliAlfredo Ecosse Fabrizio NardinGiuseppe Scarascia-Mugnozza 《Biomass & bioenergy》2011,35(4):1524-1532
Short rotation forest (SRF) plantations of hybrid poplars are attractive for Italian farmers due to the availability of public grants and the potential for producing wood chips for energy production. Growth and dendromass yield of new clones for SRF were evaluated after two biennial rotations within a network of experimental fields established in 2003 on three sites of low (Bigarello), medium (Vinovo) and high soil quality (Mira), across northern Italy. Soil preparation, planting density (5900 trees ha−1), weed control, tree water status and mechanical harvesting were homogeneous across the sites. Nitrogen fertilization was applied only in Mira (300 kg N ha−1).In all sites, survival was high for almost all clones, and stem density increased dramatically, with a decrease of stem dimensions, after the first coppicing. In Bigarello, with limiting soil conditions, there was no significant difference among clone biennial yields, which varied from 10.3 (first rotation) to 14.2 (second rotation) Mg ha−1 in dry matter (dm). In the medium and high quality sites of Vinovo and Mira, there was a significant difference in clone yields, with the new clones performing better than control clones (I-214 and Lux). In Mira, mean biennial yield increased from 30.2 to 40.3 Mg dm ha−1 from the first to second cycle.Preliminary results of new clones on medium and high soil quality need to be further confirmed throughout further coppicing cycles; on a marginal soil, even by using the new clones, poplar SRF is not an advisable option. 相似文献
90.
This work investigates the behaviour of planar solid oxide fuel cells (SOFCs) fed by two different fuel mixtures that simulate biogases coming from anaerobic digestion. The fuel mixtures are namely bio-methane and bio-hydrogen. The first composition is the conventional one, where a biological process of fermentation is carried out to produce a gas that contains a mixture of methane and carbon dioxide with traces of H2S and other organic sulphur compounds. The second mixture is representative of a biogas produced through a novel routine: a particular pre-treatment of the bacteria inoculum (generally clostridia bacteria) is performed in order to inhibit the methanogenic step in the fermentation process, such that bio-hydrogen is produced as the only effluent of the digester (a mixture of H2/CO2, with no traces of methane). 相似文献