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951.
We devise a methodology to predict failures in wind turbine drive‐train components and quantify its utility. The methodology consists of two main steps. The first step is the set up of a predictive model for shutdown events, which is able to raise an alarm in advance of the fault‐induced shutdown. The model is trained on data for shutdown events retrieved from the alarm log of an offshore wind farm. Here, it is assumed that the timely prediction of low‐severity events, typically caused by abnormal component operation, allows for an intervention that can prevent premature component failures. The prediction models are based on statistical classification using only supervisory control and data acquisition (SCADA) data. In the second step, the shutdown prediction model is combined with a cost model to provide an estimate of the benefits associated with implementing the predictive maintenance system. This is achieved by computing the maximum net utility attainable as a function of the model performance and efficiency of intervention carried out by the user. Results show that the system can be expected to be cost‐effective under specific conditions. A discussion about potential improvements of the approach is provided, along with suggestions for further research in this area. 相似文献
952.
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954.
Stefano Santoro Claudio Santi Michela Sabatini Lorenzo Testaferri Marcello Tiecco 《Advanced Synthesis \u0026amp; Catalysis》2008,350(18):2881-2884
The first general and efficient diphenyl diselenide‐catalyzed dihydroxylation of double bonds is presented. Hydrogen peroxide can be used as the oxidizing agent, affording generally good yields and high diasteroselectivity. 相似文献
955.
Influence of chemical composition of olive oil on the development of volatile compounds during frying 总被引:1,自引:1,他引:0
Giuseppe Procida Angelo Cichelli Dario Compagnone Rubén M. Maggio Lorenzo Cerretani Michele Del Carlo 《European Food Research and Technology》2009,230(2):217-229
In this study, 15 virgin olive oils from an industrial oil plant in the Abruzzo region were analyzed in terms of the volatile
compounds responsible for the characteristic odor and olfactory perception of virgin olive oils and its modification upon
frying (up to 60 min of heat treatment). Dynamic headspace–gas chromatography–mass spectrometry analysis was used to evaluate
the volatile profile before and after each frying step and examine correlations with qualitative characteristic of oil (fatty
acid composition, total phenolic compound content, tocopherols and pigments). The chemometric approach (genetic algorithms–partial
least squares/multiple linear regression) developed for this study is a novel model for data treatment to select important
variables in olive oil composition and understand their influence on spoilage during frying. An inverse correlation between
oleic acid content and formation of toxic volatiles such as acrolein and crotonal during frying was demonstrated. Moreover,
it was also observed that pigments such as chlorophylls, pheophytins, and carotenoids may prevent the formation of some aldehydes
during frying. 相似文献
956.
Mar Vilanova Zlatina Genisheva Lorenzo Bescansa Antón Masa José M. Oliveira 《Journal of the Institute of Brewing》2009,115(1):35-40
Wine aroma is formed by volatile compounds of different chemical natures and origins. Betanzos is the most northern viticole geographic area from Galicia (NW Spain). The aromatic profiles of wines produced from two white varieties (Blanco lexítimo and Agudelo) and one red variety (Serradelo) from Betanzos, harvested in 2006 and 2007, have been established by gas chromatography (GC/FID). A total of 35 varietal and fermentative aroma compounds were identified and quantified in free volatile form, which include terpenols, C13‐norisoprenoids, alcohols, esters, volatile fatty acids and volatile phenols. To ascertain the compounds with major impact odours, the Odour Activity Value (OAV) was calculated. Twelve compounds showed concentrations above their perception threshold (OAV>1). The results obtained suggest that ethyl octanoate (apple), isoamyl acetate (banana), ethyl hexanoate (fruity) and β‐damascenone (floral) were the most powerful odorants for the white wines Blanco lexítimo and Agudelo from Betanzos. Ethyl octanoate and β‐damascenone (fruity and floral aroma respectively) were the most odorant for the red wine Serradelo. 相似文献
957.
Monitoring of fatty acid composition in virgin olive oil by Fourier transformed infrared spectroscopy coupled with partial least squares 总被引:1,自引:0,他引:1
Rubén M. Maggio Teodoro S. Kaufman Michele Del Carlo Lorenzo Cerretani Alessandra Bendini Angelo Cichelli Dario Compagnone 《Food chemistry》2009
A rapid Fourier transformed infrared (FTIR) attenuated total reflectance (ATR) spectroscopic method was applied to the determination of fatty acid (FA) profile and peroxide value (PV) of virgin olive oil. Calibration models were constructed using partial least squares (PLS) regression. A FA calibration model was constructed in the spectral range from 3033 to 700 cm−1. Oleic acid (62.0–80.0%), linoleic acid (5.3–15.0%), saturated fatty acids (SFA, 12.6–19.7%), mono-unsaturated fatty acids (MUFA, 64.4–81.0%) and poly-unsaturated fatty acids (PUFA, 6.0–15.9%) were considered for chemometric analysis. PV (5.7–15.7 meq O2 kg−1) was calibrated using the signal of the full spectral range 4000–700 cm−1 with first derivative pre-treatment. The LODs of the FTIR-chemometric methods were: 3.0% for oleic acid, 0.5% for linoleic acid, 1.3% for SFA, 3.0% for MUFA, 0.3% for PUFA and 1.0 meq O2 kg−1 for PV. Analytical methods were evaluated by use of validation samples (n = 25 for all the FA related parameters and n = 10 for PV) with nearly quantitative recovery rates (98–103%). The proposed method provided results comparable to official procedures, with the advantages of being less expensive and more rapid. 相似文献
958.
Emma Chiavaro Carlo Barnaba Elena Vittadini Maria Teresa Rodriguez-Estrada Lorenzo Cerretani Alessandra Bendini 《Food chemistry》2009
The effect of microwave heating of commercial categories of olive oil for human consumption (extra virgin olive oil [EVOo], olive–pomace oil [Po] and olive oil [Oo]) on DSC thermal properties was evaluated at different times of microwave treatment. 相似文献
959.
Lorenzo Cerretani Maria-José Motilva Maria-Paz Romero Alessandra Bendini Giovanni Lercker 《European Food Research and Technology》2008,226(6):1251-1258
The aim of this study was to characterise the pigment profile (chlorophylls and carotenoids) of monovarietal virgin olive
oils from six Italian olive cultivars (Ghiacciolo, Giarraffa, Sant’Agatese, Biancolilla, Nocellara del Belice and Gentile di Larino), from three Italian olive-growing regions (Emilia-Romagna, Sicily and Molise). The results show that the qualitative study
of the pigment chlorophyll and carotenoid fractions of virgin olive oils demonstrated a common pattern that did not depend
on the olive cultivar or growing region. Besides these, mutatoxanthin was only detected in oils from the Nocellara del Belice and Gentile di Larino cultivars, and pheophorbide a was only detected in oils from the Ghiacciolo and Sant’Agatese cultivars. However, significant quantitative differences were observed in the composition of the pigment fractions. The principal
component discriminate analysis showed that the first two discriminate functions of the statistical analysis explained 78.9%
of the total variance. The plot of discriminate functions showed an effect of the olive cultivar and growing area on the chlorophyll
and carotenoid contents of the virgin olive oils. The results of this study are a contribution to the pigment characterization
of the Italian monovarietal olive oils, which should be completed with more samples obtained from different crop seasons and
different growing areas. 相似文献
960.
Aurora Rizzi Lorenzo Brusetti Stefania Arioli Kaare M. Nielsen Isabella Tamagnini Alberto Tamburini Claudia Sorlini Daniele Daffonchio 《European Food Research and Technology》2008,227(6):1699-1709
The presence and the transforming capacity of feed-derived DNA in milk obtained from eight lactating goats fed on maize E176
silage were evaluated. The presence of single- and multi-copy maize genes was monitored by real-time PCR and conventional
PCR. Chromosomal and plastid DNA extracted directly from maize flour and silage were readily amplifiable by conventional PCR,
however, only chloroplast-specific gene fragments of 199 and 532 bp were detected in about 60 and 20%, respectively, of the
milk samples analysed. Quantification by real time PCR yielded 9.5 (±6.7) × 102 plant gene copies/mL of milk sediment. In contrast, all milk samples were negative for the chromosomally located maize zein gene or the E176 specific cry1Ab transgene. The minimum concentration of plant DNA required for detection was 0.01 ng/mL raw milk for the chloroplast-specific
fragment and 1 ng/mL for the cry1Ab transgene. The detection limit was determined by spiking milk samples with plant DNA prior to DNA extraction. The transformation
capability of DNA in milk was evaluated after constructing a marker rescue system in Acinetobacter
baylyi strain BD413 based on recombinational repair of the bla
TEM gene. Two systems were developed that allowed the plant marker gene to recombine with the bacterial chromosome [A. baylyi BD413 (pUC-bla)] or plasmids [A. baylyi BD413 (pBBR1MCS-2Φ)]. The two systems showed the same efficiency of transformation, yielding 10−5 transformants per recipient cell (t/r) using plasmid pUC18 or a 1,873 bp fragment as donor DNA, and 3.5 × 10−11 t/r using DNA isolated from flour (E176). No transformants were detected when exposing the recipient bacterium to DNA extracted
from maize (E176) silage or from milk obtained from goats feed maize (E176). 相似文献