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271.
Printed, organic diodes with a thin organic interfacial layer forming a Schottky barrier were fabricated and characterized. Experiments indicated that the thickness of the barrier layer is <10 nm. The interfacial layer reduces the reverse current of the diode by 2 orders of magnitude without significantly affecting the forward characteristics above 1 V. As a result, printed organic diodes with a rectification ratio of 5 orders of magnitude were fabricated. The diodes enable applications where low reverse currents are needed.  相似文献   
272.
ABSTRACT: The capability of an electronic nose, MGD-1, in the detection of aroma differences among 5 samples of strawberry ice cream of varying fat content (0,9, or 18% dairy or vegetable fat) was compared with the human nose. R-indices were determined to detect sensory differences. In addition, the headspace compositions of samples were determined with static headspace gas chromatography. The effect of the amount of fat on the aroma release could be detected with all three methods. The headspace of the nonfat sample was very different from the other samples, but samples containing 9 or 18% of fat were also differentiated. The type of fat did not significantly affect the aroma release. The MGD- 1's capability for detecting the aroma differences was fairly comparable with the sensory and the static headspace gas chromatographic method.  相似文献   
273.
Anthocyanins, the natural red and purple colorants of berries, fruits, vegetables, and tubers, improve carbohydrate metabolism and decrease the risk factors of metabolic disorders, but their industrial use is limited by their chemical instability. Acylation of the glycosyl moieties of anthocyanins, however, changes the chemical properties of anthocyanins and provides enhanced stability. Thus, acylated anthocyanins are more usable as natural colorants and bioactive components of innovative functional foods. Acylated anthocyanins are common in pigmented vegetables and tubers, the consumption of which has the potential to increase the intake of health-promoting anthocyanins as part of the daily diet. For the first time, this review presents the current findings on bioavailability, absorption, metabolism, and health effects of acylated anthocyanins with comparison to more extensively investigated nonacylated anthocyanins. The structural differences between nonacylated and acylated anthocyanins lead to enhanced color stability, altered absorption, bioavailability, in vivo stability, and colonic degradation. The impact of phenolic metabolites and their potential health effects regardless of the low bioavailability of the parent anthocyanins as such is discussed. Here, purple-fleshed potatoes are presented as a globally available, eco-friendly model food rich in acylated anthocyanins, which further highlights the industrial possibilities and nutritional relevance of acylated anthocyanins. This work supports the academic community and industry in food research and development by reviewing the current literature and highlighting gaps of knowledge.  相似文献   
274.
Rye bran is a high-fibre ingredient also containing starch and protein. The aim of this work was to investigate the effects of extrusion processing and bran particle size on the structural and mechanical properties of extruded rye bran. Native rye bran particle size of 750–1,250 μm was milled to produce feed material with three different average particle sizes (coarse, 440 μm; medium, 143 μm; fine, 28 μm). A co-rotating twin screw extruder was used for extrusion with various processing parameters. Extrusion processing did not have a significant (P?<?0.05) effect on soluble dietary fibre (SDF) content but the amount of insoluble dietary fibre (IDF) increased by 7.1–9.5 % in medium- and 11.3–12.3 % in fine-particle-sized rye bran extrudates as compared to the raw material prior to extrusion. Decreasing the particle size of rye bran to 28 μm resulted in lower amounts of IDF and total dietary fibre, but a higher amount of SDF after extrusion compared to coarse-particle-sized rye bran. Decreasing the particle size of rye bran to 28 μm gave more expanded (179–223 %), less hard (145–336 N), more crispy (2.7–7.2?×?10?4) and porous (79.2–83.9 %) extrudates compared to the coarse-particle-sized rye bran extrudates, which were less expanded (151–176 %), harder (210–433 N), less crispy (0.5–2.8?×?10?4) and less porous (64.4–65.1 %). Reduction of the particle size of rye bran significantly (P?<?0.05) increased the crispiness compared to the extrudates made of coarse-particle-sized rye bran. The results demonstrated that the structural and mechanical properties of rye bran extrudates can be improved without starch addition by reducing the particle size of bran.  相似文献   
275.
Deterioration in drinking water quality in distribution networks represents a problem in drinking water distribution. These can be an increase in microbial numbers, an elevated concentration of iron or increased turbidity, all of which affect taste, odor and color in the drinking water. We studied if pipe cleaning would improve the drinking water quality in pipelines. Cleaning was arranged by flushing the pipes with compressed air and water. The numbers of bacteria and the concentrations of iron and turbidity in drinking water were highest at 9 p.m., when the water consumption was highest. Soft deposits inside the pipeline were occasionally released to bulk water, increasing the concentrations of iron, bacteria, microbially available organic carbon and phosphorus in drinking water. The cleaning of the pipeline decreased the diurnal variation in drinking water quality. With respect to iron, only short-term positive effects were obtained. However, removing of the nutrient-rich soft deposits did decrease the microbial growth in the distribution system during summer when there were favorable warm temperatures for microbial growth. No Norwalk-like viruses or coliform bacteria were detected in the soft deposits, in contrast to the high numbers of heterotrophic bacteria.  相似文献   
276.
The equilibrium sampling in silicone is increasingly applied to measure freely dissolved concentrations and chemical activities within bioaccumulation research of hydrophobic organic chemicals. Two equilibrium methods were applied to PCB-contaminated soil and sediment, and directly calibrated with respect to equilibrium partitioning concentrations in lipids (C(lipid,partitioning)): (i) Solid phase microextraction in the headspace above the sample (HS-SPME) required optimization for its application to PCBs, and it was calibrated above external partitioning standards in olive oil. (ii) Equilibrium sampling with internally coated glass jars with varying thicknesses of silicone (PDMS) resulted in proportionality between coating and analyte mass, which confirmed several validity criteria. C(lipid,partitioning) was here determined as product of PDMS concentration and PDMS to lipid partition ratio. The results of the two methods were in good agreement and thus validated each other. Finally, the coated glass jar method was applied to field sediment containing invertebrates, which lead to C(lipid,partitioning) that were about two times higher than measured lipid-normalized concentrations in the organisms. Temperature differences and animal lipid structure were discussed as possible reasons for this discrepancy. Both methods combine high analytical performance, reduced equilibration times and new calibration possibilities, which makes them suited for bioaccumulation research and environmental monitoring.  相似文献   
277.
The main objective of this study was to determine the level of surface contamination in fish processing factories and the presence of Listeria in the factory environment and products. Another objective was evaluation of the different hygiene-monitoring methods. Total aerobic heterotrophic and enterobacteria, yeast and mold samples were collected and ATP levels measured in 28 factories. The number of well or adequately washed and disinfected factories was small (2 of 28), in terms of total aerobic heterotrophic bacterial counts on the surfaces. Most surfaces contaminated with bacteria were heavily contaminated. Results of the ATP and the total bacteria contact agar slide methods were poorly correlated (r = 0.21) although 68% of the samples were categorized as good to moderate or unacceptable with both methods. The Listeria-positive surface samples usually contained increased numbers of total bacteria (70.9%). The contamination of products and raw fish together with Listeria spp. was 45% and with Listeria monocytogenes 12%. Cold smoked fish was the most contaminated, with 75% Listeria spp. and cold salted fish with 20% L. monocytogenes. Listeria innocua was found in the samples more than twice as often as L. monocytogenes.  相似文献   
278.
The study investigated the prevalence of five major Escherichia coli pathogroups in raw meats and beef intestines sold at the local markets in Ouagadougou, Burkina Faso. One hundred and twenty samples (36 beef, 36 beef intestine, 24 mutton and 24 chicken samples) were purchased from four markets between October 2008 and February 2009. Fifteen virulence genes specific for Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC) and enteroaggregative E. coli (EAEC) were examined using 16-plex PCR for mixed bacterial cultures derived from the samples. One or more diarrheagenic E. coli pathogroup was detected in 51 (43%) of all the 120 samples: in 16 (44%) beef, 19 (53%) beef intestine, 9 (38%) mutton and in 7 (29%) chicken samples. Thirty three (28%) samples were positive for stx(1) and/or stx(2) indicating presence of STEC. EPEC virulence markers (eae, escV and/or ent and/or bfp and/or EHEC-hlyA) were detected in 14 (12%) stx-negative samples. ETEC virulence markers (elt and/or estIb and/or estIa) were detected in 10 (8%) samples and EAEC virulence markers (pic or aggR) in 5 (4%) samples. No EIEC was detected. The results show that in Burkina Faso the microbiological quality of retail meat is alarmingly poor due to the common occurrence of diarrheagenic E. coli bacteria.  相似文献   
279.
Vertical distribution and activity contents of 210Pb and 210Po were investigated in forest soils of Scots pine-dominated (Pinus sylvestris L.) stands from seven different locations in Finland. The mean total inventory in the soil profile, up to 20 cm, of 210Pb was 4.0 kBq m− 2 (range 3.1-5.0 kBq m− 2) and 210Po 5.5 kBq m− 2 (range 4.0-7.4 kBq m− 2), the organic soil layer containing 45% of the total inventory of both nuclides. In both the organic and the mineral layers the 210Po/210Pb ratio was close to unity indicating a radioactive equilibrium between them. In the litter layer there was, however, a clear excess of 210Po suggesting that polonium is recycled via root uptake from the root zone to the ground surface. The activity concentration (Bq kg− 1) of 210Pb clearly correlated with organic matter and the Fe, Al and Mn concentrations in soil indicating that radioactive lead is associated both with humic substances and the oxides of iron, aluminium and manganese. Radioactive lead was also seen to follow the behavior of stable lead. No systematic correlation between polonium and soil properties was seen.  相似文献   
280.
A thermodynamic–kinetic model is presented for the simulation of phase change and solute redistribution during solidification of binary, one-solid-phase (fcc) copper alloys containing Ag, Al, Ni, P, Sn or Zn. Depending on the alloy composition, the cooling rate and the dendrite arm spacing, the model determines the phase fractions and compositions during solidification. In addition, it calculates important thermophysical material properties (enthalpy, specific heat, thermal conductivity, density and viscosity) from the liquid state down to room temperature. These data are important input data for other models, such as heat transfer and thermal stress models, whose reliability has become more and more dependent on the input data itself. The model is validated comparing calculated results with experimental data of literature.  相似文献   
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