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51.
Electrical energy metering: Some challenges of the European Directive on Measuring Instruments (MID)
Andrea Bernieri Giovanni Betta Luigi Ferrigno Marco Laracca Rosario Schiano Lo Moriello 《Measurement》2013
The introduction of static electric energy meter together with voltage and current distortions in the electric networks are revolutionizing the measurement of the electrical energy. Several questions and studies are proposed in the scientific literature concerning with metrological and reliability aspects of the actual electrical energy measurement. The European Directive on Measuring Instruments (MID) represents a different spin on setting the performance and safety requirements for those meters. The International Organization of Legal Metrology (OIML) has published the document D11 discussing recommendations for legislation to meet the MID. An OIML technical committee is drafting the recommendation (IR46) that would give regulatory bodies an easily-adoptable set of requirements and tests to meet the requirements of the MID. With the introduction of the MID directive, the actual discussion involves aspects as the metrological characterization of the meters. The paper proposes an analysis of the test settings imposed by the actual MID-harmonized standards, regarding the electric energy metering. The aim is to check the presence of degree of freedom in the test settings that could compromise both result reliability and the compliance/non-compliance of a given apparatus. 相似文献
52.
Nicolette Pegels Isabel González Irene Martín María Rojas Teresa García Rosario Martín 《Food Control》2011,22(8):1189-1196
A TaqMan real-time polymerase chain reaction (PCR) method was developed for specific detection of bovine, ovine and caprine processed animal protein (PAP) in industrial feedstuffs. The method uses species-specific primers and probes targeting short mitochondrial D-loop sequences, and a positive amplification control based on 18S rRNA gene. The applicability of the real-time PCR protocol was assessed through analysis of 126 industrial feed samples that were manufactured to reproduce rendering processes of commercial feeds destined for farmed animals. The assay successfully classified samples as positive or negative according to the ruminant composition, enabling qualitative detection of banned material in feeds at levels as low as 0.1%. Although the method provides quantitative potential, results suggest that the real quantitative capability of the assay is limited by the existing variability in terms of composition and processing treatments of the feeds, which affect the amount and quality of amplifiable DNA. 相似文献
53.
Juan M. Rodríguez Patino Ana Lucero Caro M. Rosario Rodríguez Niño Alan R. Mackie A. Patrick Gunning Victor J. Morris 《Food chemistry》2007,102(2):532-541
This contribution is concerned with phospholipid films in relation to food dispersions such as emulsions and foams. Structural, morphological and surface rheological characteristics of dipalmitoyl phosphatidylcholine (DPPC) and dioleoyl phosphatidylcholine (DOPC) monolayers were determined at the air–water interface at 20 °C and at pH 5, 7, and 9, by means of surface pressure (π)–area (A) isotherms coupled with Brewster angle microscopy (BAM), atomic force microscopy (AFM) and surface dilatational and shear rheometry. From the π–A isotherms it was deduced that DPPC monolayers show structural polymorphism at the air–water interface. DOPC monolayers formed a liquid-expanded (LE) structure under all experimental conditions, a consequence of the weak molecular interactions due to the double bond in the hydrocarbon chain. Electrostatic interactions between film-forming components influence the monolayer structure. BAM and AFM images corroborate, at a microscopic and at nanoscopic level respectively, the structural polymorphism deduced from the π–A isotherm for DPPC monolayers as a function of surface pressure and the pH of the aqueous phase. However, the homogeneous morphology of DOPC monolayers at a microscopic level, as observed by BAM, shows structural heterogeneity at a nanoscopic level when observed by AFM. The relative monolayer thickness increases with surface pressure and is a maximum at the collapse point, especially for DPPC monolayers. The results confirm that the interfacial rheological characteristic measured under dilatation and shear conditions are very dependent on the structural characteristics and morphology of the phospholipids (DPPC and DOPC) monolayers. 相似文献
54.
Sage and rosemary essential oils versus BHT for the inhibition of lipid oxidative reactions in liver pâté 总被引:1,自引:0,他引:1
The antioxidant effect of two plant essential oils (sage and rosemary essential oils) and one synthetic antioxidant (BHT) on refrigerated stored liver pâté (4 °C/90 days) was evaluated. Pâtés with no added antioxidants were used as controls. Liver pâtés were analysed for the amount of polyunsaturated fatty acids (PUFA), thiobarbituric acid reactive substances (TBA-RS) numbers, and lipid-derived volatiles at days 0, 30, 60 and 90 of refrigerated storage. The amount of PUFA gradually decreased during refrigerated storage of porcine liver pâtés with this decrease being significantly greater (P<0.05) in control and BHT pâtés than in those with added essential oils. Consistently, the increase of TBA-RS numbers during refrigerated storage of liver pâtés was significantly higher in control pâtés than in the treated counterparts. At days 60 and 90, TBA-RS numbers in treated pâtés were significantly smaller (P<0.05) than in the control counterparts. Headspace solid-phase microextraction (HS-SPME) successfully isolated recognized indicators of lipid decomposition (i.e. hexanal, nonanal, hexan-1-ol, oct-1-en-3-ol, deca-(E,Z)-2,4-dienal) from liver pâtés whereas some other volatiles analysed are typical contributors to the overall off-flavour of oxidized liver (i.e. hept-(Z)-4-enal, non-(E)-2-enal, nona-(E,E)-2,4-dienal). The addition of antioxidants significantly (P<0.05) reduced the total amount of lipid-derived volatiles isolated from liver pâtés HS. Plant essential oils inhibited oxidative deterioration of liver pâtés to a higher extent than BHT did. 相似文献
55.
Daniela Aiello Flaviano Testa Rosario Aiello Luca Malfatti Tongjit Kidchob Plinio Innocenzi Iolinda Aiello Tonino Martino Mauro Ghedini Massimo La Deda 《Inorganic chemistry communications》2009,12(3):237-239
A luminescent zinc complex was successfully incorporated to mesostructured porous titania films through a grafting process. The resulting films show an intense blue-emission increasing with functionalization time. The emission quantum yield of these newly synthesized films was quantitatively and accurately determined by measurements carried by an integrating sphere. 相似文献
56.
Roque Calvo Rosario Domingo Miguel A. Sebastián 《International Journal of Flexible Manufacturing Systems》2007,19(3):247-263
Manufacturing flexibility is becoming a fundamental production objective, along with cost, quality, and delivery time. Current
production systems face quick changes in market conditions and they need to adapt in this environment. The supply chain and
industrial globalization give an important role for assembly systems. Placed at the end of the value chain, assembly systems
must face those quick changes successfully to reach the expected performance. The key performance indicators are normally
based on cost, quality, and delivery time objectives. Reducing costs and improving quality are almost universal goals. Delivery
time is typically determined by customer demand in the supply chain, planning from make-to-stock to make-to-order, and aspiring
to reach a just-in-time manufacturing system. In this context, flexibility could be the differential advantage to tackle uncertainty.
Closely related to the rest of production objectives and the overall performance of the system, flexibility must be integrated
in the system for successful decision-making in operations. This work presents this approach of flexibility. A brief review
of flexibility concepts and measurements in the literature precedes an introduction to flexibility, defined based on the function
of utility. This function represents the expectations of system performance. This approach allows the formulation of the taxonomy
of operational flexibility in agreement with the classical types identified in former works. Next, an integer model is programmed
to simulate the basic behavior of task planning in a make-to-order assembly system. This first application illustrates flexibility
quantification based on utility evolution. The use of common industrial parameters to quantify operational flexibility will
finally facilitate an integrated interpretation of system performance trends. 相似文献
57.
58.
Poly(acrylonitrile-co-butadiene-co-styrene) (ABS), an engineering plastic, was combined with carbon black (CB) to increase
its conductivity. The ABS/CB composites were prepared using two different methods: dissolution of ABS in Butan-2-one and manual
mixing of the constituent materials. These fabrication methods led to different microstructures, which led to vastly different
electrical properties. The microstructures were acquired using scanning electron microscopy (SEM) and optical microscopy,
while the electrical conductivity was obtained using impedance spectroscopy. The percolation threshold of the composites fabricated
using the manual mixing method was found to be much lower (0.0054 vol.% CB) than that of the composites fabricated using the
dissolution method (2.7 vol.% CB). 相似文献
59.
For the most compelling applications of threshold cryptosystems, security against chosen cipher text attack is a requirement.
However, prior to the results presented here, there appeared to be no practical threshold cryptosystems in the literature
that were provably chosen ciphertext secure, even in the idealized random oracle model. The contribution of this paper is
to present two very practical threshold cryptosystems, and to prove that they are secure against chosen ciphertext attack
in the random oracle model. Not only are these protocols computationally very efficient, but they are also non-interactive,
which means they can be easily run over an asynchronous communication network.
Received November 2000 and revised September 2001 Online publication 11 March 2002 相似文献
60.
Free fatty acids (FFA) and lipid and protein oxidation changes were studied throughout maturation process of a raw goat milk cheese with protected designation of origin. Cheeses were analyzed at 4 different times of maturation, at 1, 30, 60, and 90 d. All FFA significantly increased during maturation and the relative increase was higher for long-chain than medium- or short-chain FFA. At the end of maturation, oleic (C18:1 n9), butyric (C4:0), and palmitic (C16:0) acids were the most abundant. The higher levels of short-chain fatty acids (SCFA) regarding total FFA obtained at the end of Ibores cheese ripening compared with other raw goat milk cheeses, highlight the notable role of SCFA on the flavor of this cheese owing to their low-odor thresholds. Lipid oxidation values significantly increased during maturation process but low levels of malondialdehyde were reported; however, protein oxidation did not significantly change during ripening. 相似文献