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521.
Coculture-inducible bacteriocin activity of Lactobacillus plantarum strain J23 isolated from grape must 总被引:1,自引:0,他引:1
Rojo-Bezares B Sáenz Y Navarro L Zarazaga M Ruiz-Larrea F Torres C 《Food microbiology》2007,24(5):482-491
Detection and characterization of bacteriocin production by Lactobacillus plantarum strain J23, recovered from a grape must sample in Spain, have been carried out. Bacteriocin activity was degraded by proteolytic enzymes (trypsin, alfa-chymotrypsin, papaine, protease, proteinase K and acid proteases), and it was stable at high temperatures (121 degrees C, 20min), in a wide range of pH (1-12), and after treatment with organic solvents. L. plantarum J23 showed antimicrobial activity against Oenococcus oeni, and a range of Lactobacillus and Pediococcus species. Bacteriocin production was detected in liquid media only when J23 was cocultivated with some inducing bacteria, and induction took place when intact cells or 55 degrees C heated cells of the inducer were cocultivated with J23, but not with their autoclaved cells. Bacteriocin activity of J23 was not induced by high initial J23 inocula, and it was detected in cocultures during the exponential phase. The presence of ethanol or acidic pH in the media reduced bacteriocin production in the cocultures of J23 with the inducing bacteria. The presence of plantaricin-related plnEF and plnJ genes was detected by PCR and sequencing. Nevertheless, negative results were obtained for plnA, plnK, plNC8, plS and plW genes. 相似文献
522.
M. Carmen Collado Yolanda Moreno José M. Cobo Manuel Hernández 《European Food Research and Technology》2006,222(1-2):112-117
The aim of this study was to evaluate the presence of Bifidobacterium animalis subsp. lactis in commercial dairy products using different molecular techniques. We analyzed the microbiological composition of 13 commercial
fermented milks available in the Spanish market. Thirteen strains of genus Bifidobacterium were isolated from these products and were identified by genus-specific PCR, by fluorescence in situ hybridization (FISH),
by multiplex PCR and amplified ribosomal DNA restriction analysis (ARDRA). The same sets of strains were typed by randomly
amplified polymorphic DNA (RAPD) analysis and by amplified fragment length polymorphism technique (AFLP). All strains were
identified as B. animalis subsp. lactis using ARDRA and multiplex PCR techniques. Similarity between strains was evaluated based on RAPD and AFLP profiles. The isolated
strains showed similar profiles by using these techniques, revealing the reduced genetic variability existing among commercial
strains, and all these profiles were reproducible in repeated analysis. ARDRA and multiplex PCR are techniques that allow
differentiation of the bifidobacteria at genus and species level, but do not indicate if they are different strains, for which
reason the RAPD technique is very useful. All bifidobacteria isolated from commercial fermented milks in Spain belong to the
same species B. animalis subsp. lactis. Our results demonstrate the necessity to control the presence of bifidobacteria in commercial fermented milks, not only
at species level but also at strain level. Multiplex PCR and RAPDs are the most suitable, rapid and precise techniques to
identify all bifidobacteria contained in fermented milk products at genus-, species-, and strain levels. 相似文献
523.
Anna Lagunas ;Albert G. Castano ;Juan M. Artes ;Yolanda Vida ;Daniel Collado ;Ezequiel Perez-lnestrosa ;Pau Gorostiza ;Silvia Claros ;Jose A. Andrades ;Josep Samitier 《Nano Research》2014,7(3):399-409
Cell adhesion processes are governed by the nanoscale arrangement of the extracellular matrix (ECM), being more affected by local rather than global concentrations of cell adhesive ligands. In many cell-based studies, grafting of dendrimers on surfaces has shown the benefits of the local increase in concentration provided by the dendritic configuration, although the lack of any reported surface characterization has limited any direct correlation between dendrimer disposition and cell response. In order to establish a proper correlation, some control over dendrimer surface deposition is desirable. Here, dendrimer nanopatterning has been employed to address arginine-glycine-aspartic acid (RGD) density effects on cell adhesion. Nanopatterned surfaces were fully characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), showing that tunable distributions of cell adhesive ligands on the surface are obtained as a function of the initial dendrimer bulk concentration. Cell experiments showed a clear correlation with dendrimer surface layout: Substrates presenting regions of high local ligand density resulted in a higher percentage of adhered cells and a higher degree of maturation of focal adhesions (FAs). Therefore, dendrimer nano- patterning is presented as a suitable and controlled approach to address the effect of local ligand density on cell response. Moreover, due to the easy modification of dendrimer peripheral groups, dendrimer nanopatterning can be further extended to other ECM ligands having density effects on cells. 相似文献
524.
José Luis García‐Dorado Pedro M. Santiago del Río Javier Ramos David Muelas Victor Moreno Jorge E. López de Vergara Javier Aracil 《International Journal of Network Management》2014,24(3):181-199
Voice over IP (VoIP) is increasingly replacing the old public switched telephone network (PSTN) technology. In this new scenario, there are several challenges for VoIP providers. First, VoIP requires a detailed monitoring of both users' quality of service (QoS) and experience (QoE) to a greater extent than in traditional PSTNs. Second, such a monitoring process must be able to track VoIP traffic in high‐speed networks, nowadays typically of multi‐Gb/s rates. Third, recent government directives require that providers retain information from their users' calls. Similarly, the convergence of data and voice services allows operators to provide new services such as full‐data retention, in which users' calls can be recorded for either quality assessment (call centers, QoE) or security purposes (lawful interception). This implies a significant investment in infrastructure, especially in large‐scale networks which require multiple points of measurement and redundancy. This paper proposes a novel methodology, architecture and system to fulfill such challenges, called VoIPCallMon, as well as the data structures and necessary hardware‐tuning knowledge for its development. As distinguishing features, VoIPCallMon provides very high performance, being able to process VoIP traffic on‐the‐fly at high bitrates, novel services and significant cost reduction by using commodity hardware with minimal interference with operational VoIP networks. The performance evaluation shows that the system copes with the VoIP load of real‐world operators. We further evaluated the system performance at a fully saturated 10 Gb/s link and no packet loss was reported, therefore demonstrating the potential of commodity hardware solutions. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
525.
Luis Javier R. Barron Yolanda Redondo Mikel Aramburu Pilar Gil Francisco J. Prez-Elortondo Marta Albisu Ana I. Njera Mertxe de Renobales Estrella Fernndez-García 《International Dairy Journal》2007,17(12):1401-1414
The volatile composition and sensory properties of industrially produced Idiazabal cheeses made from ewes’ raw milk (RM) or pasteurised milk (PM) and with addition of different starter cultures were compared. Cheeses were analysed at 90 and 180 d of ripening. Acids were the major volatile compounds in RM cheeses. Methyl ketones were the major volatile compounds in PM cheeses at 90 ripening days. However, the content of acids strongly increased with ripening whereas the content of ketones decreased in PM cheeses. The concentration of esters was higher in RM cheeses than in PM cheeses. No differences were found in the content of alcohols. Most aldehydes, hydrocarbons, terpenes and furans identified were minor volatile compounds in both RM and PM cheeses. In RM cheeses, characteristic sensory attributes for the aroma of Idiazabal cheese were present at 3 months, whereas in PM cheeses those desirable sensory attributes did not appear until 6 months of ripening. 相似文献
526.
Escherichia coli of poultry food origin as reservoir of sulphonamide resistance genes and integrons 总被引:1,自引:0,他引:1
Soufi L Sáenz Y Vinué L Abbassi MS Ruiz E Zarazaga M Ben Hassen A Hammami S Torres C 《International journal of food microbiology》2011,144(3):497-502
The antimicrobial resistance phenotype and genotype, the flanking regions of sulphonamide resistance genes and the integrons were analyzed in 166 Escherichia coli isolates recovered from poultry meat in Tunisia. High percentages of resistance were detected to ampicillin, streptomycin, nalidixic acid, sulphonamide and tetracycline (66-95%), and lower percentages to gentamicin, amoxicillin-clavulanic acid and cefoxitin (1-4%). The blaTEM, tet(A)/tet(B), aph(3′)-Ia, aac(6′)-Ib-cr, aac(3)-II and cmlA genes were identified in 92, 82, 29, 2, 2 and 7 isolates, respectively. Class 1 and/or class 2 integrons were detected in 52% of E. coli isolates and five different gene cassette arrangements were identified in the variable regions of class 1 integrons, which included antimicrobial resistance determinants. Sixty-eight isolates contained the sul1 gene and 37 of them presented this gene into a class 1 integron structure. The sul3 gene was detected associated with non-classic class 1 integrons in 4 out of 46 sul3-positive isolates. The sul2 gene was detected in 66 isolates, 51 of them were linked to strA/B genes in seven different genetic structures. Seventy-three-per-cent of integron-positive isolates presented resistance to at least five different antimicrobial families versus 38.7% of integron-negative isolates. Our study highlights the role of commensal E. coli isolates from poultry meat as an important reservoir for sulphonamide resistance genes and integrons carrying antimicrobial resistance genes. 相似文献
527.
Belén Suárez Ángel L. Álvarez Yolanda Diñeiro García Gloria del Barrio Anna Picinelli Lobo Francisco Parra 《Food chemistry》2010
Methanolic and acetonic extracts of apple pomace were evaluated for phenolic profiles, antioxidant properties and antiviral effect against herpes simplex virus type 1 (HSV-1) and 2 (HSV-2). Acetone extraction yielded the higher amounts of phenolic compounds. The extraction method influenced the phenolic composition although antioxidant activity correlated weakly with phenols concentration. Among the polyphenols analysed, quercetin glycosides were the most important family, followed by dihydrochalcones. Apple pomace extracts were able to inhibit both HSV-1 and HSV-2 replication in Vero cells by more than 50%, at non-cytotoxic concentrations. Selectivity indexes (SI) ranged from 9.5 to 12.2. 相似文献
528.
Leuconostc mesenteroides B-512F and L. mesenteroides B-742 were cultivated in clarified cashew apple juice to produce prebiotic oligosaccharides. Yeast extract (20 g/L); K2HPO4 (g/L) and sucrose (50 g/L) were added to the juice to promote the microbial growth and dextransucrase production. Initial pH was adjusted to 6.5 with H3PO4. Fermentations were carried out at 30 °C and 150 rpm for 24 h. The prebiotic effect of the fermented cashew apple juice, containing oligosaccharides, was evaluated through the Lactobacillus johnsonii B-2178 growth. L. johnsonii was incubated for 48 h using fermented cashew apple juice as substrate. Lactobacillus growth was compared to the microbial growth in non-fermented juice and in MRS broth. L. johnsonii growth in the fermented cashew apple juice was threefolds the observed growth in the non-fermented juice. 相似文献
529.
530.
Rivelino Flores‐Farías Fernando Martínez‐Bustos Yolanda Salinas‐Moreno Yoon Kil Chang Jsus Gonzlez Hernndez Elvira Ríos 《Journal of the science of food and agriculture》2000,80(6):657-664
Three commercial nixtamalised Mexican maize flours (CNMFs) designated HI‐A, HI‐B and HI‐C were evaluated in this work. For each brand, four samples corresponding to four consecutive months of production were evaluated. Tortillas prepared by the traditional process of nixtamalisation were used as the control. The maize flours and their respective tortillas showed variations between samples in their physical, chemical and rheological parameters. The three commercial maize flours incorporated additives and preservatives. The moisture content, colour, pH, subjective water absorption capacity, water solubility index, water absorption index and swelling capacity of flours showed strong differences between the three CNMFs with respect to the chemical analysis. Important differences in the protein, calcium and amylose contents were observed. Tortillas from CNMFs had a blander maize flavour, less desirable texture and staled more rapidly than traditional tortillas. Some modifications are required in the current Official Mexican Quality Standard, principally in the appropriate selection of additives and levels used in the preparation of CNMFs. © 2000 Society of Chemical Industry 相似文献