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991.
992.
Alla Kipelova Marina Odnobokova Andrey Belyakov Rustam Kaibyshev 《Metallurgical and Materials Transactions A》2013,44(1):577-583
The microstructure and creep behavior of a 3 pct Co modified P911 steel and standard P911 steel were examined. It was shown that the nanoscale M23C6 carbides and MX carbonitrides in the 3 pct Co modified P911 steel are not susceptible to significant coarsening under creep conditions. Also, coarsening simulations of M23C6 particles were performed for both steels. The rates of lath and particle coarsening in the P911 + 3 pct Co steel are remarkably lower than those in the P911. Increased stability of a tempered martensite lath structure in the 3 pct Co modified P911 steel provides enhanced creep resistance at an exceptionally high temperature of 923 K (650 °C). 相似文献
993.
Sierra V Fernández-Suárez V Castro P Osoro K Vega-Naredo I García-Macía M Rodríguez-Colunga P Coto-Montes A Oliván M 《Journal of the science of food and agriculture》2012,92(13):2727-2740
BACKGROUND: The objective of this work was to study the post‐mortem evolution of potential biomarkers (µ‐calpain activity and proteolytic profile) of meat tenderisation in bovine longissimus dorsi (LD) muscle from several biotypes coming from two beef breeds (‘Asturiana de los Valles’ and ‘Asturiana de la Montaña’) and showing different levels of muscular hypertrophy (mh/mh, mh/+, + /+). RESULTS: LD samples were taken at 2, 12, 24 and 48 h and 3, 7, 14 and 21 days post‐mortem. The presence of muscular hypertrophy produced a faster rate of pH decline, faster exhaustion of µ‐calpain activity and earlier occurrence of proteolytic changes. Changes in the electrophoretic pattern of some peptides from sarcoplasmic (glyceraldehyde‐3‐phosphate dehydrogenase) and myofibrillar (troponin T and troponin I) muscle extracts within the first 24 h significantly correlated with meat toughness and allowed accurate discrimination of meat products into two groups: (1) fast tenderising meat, coming from mh‐biotypes, and (2) late tenderising meat, from normal (+/+) biotypes. CONCLUSION: Early monitoring (within 24 h after slaughter) of selected biomarkers in LD muscle allowed accurate prediction of ultimate meat toughness and could be used in the meat industry as a tool for early classification of beef into fast and late tenderising meat. Copyright © 2012 Society of Chemical Industry 相似文献
994.
Tavera-Quiroz MJ Urriza M Pinotti A Bertola N 《Journal of the science of food and agriculture》2012,92(7):1346-1353
BACKGROUND: As a result of consumers' health concerns and the trend towards healthier and low‐fat food products, research has been undertaken to reduce the amount of fat absorbed in fried foods. This work focused on studying the efficacy of sorbitol and glycerol as plasticizers of methylcellulose coatings used to reduce oil uptake during the frying process of potato chips RESULTS: Changes in color, mechanical properties, water activity and lipid oxidation during storage were monitored. Also, an explanation regarding the different performances between both methylcellulose coatings with and without plasticizer was attained and techniques from the field of packaging films such as dynamic mechanical analyzer (DMA) and Fourier transform infrared spectroscopy were applied to analyze the behavior of coatings submitted to the frying operation. The application of a methylcellulose coating was an adequate choice to reduce oil absorption in fried potato chips. The most effective formulation was 10 g L?1 methylcellulose with the addition of 7.5 g L?1 sorbitol. With the incorporation of this formulation, oil absorption was reduced by 30%. Neither the sorbitol concentration nor the presence of the MC coating affected the puncture maximum force and color parameters L and a*. The results of the sensory analysis indicated that the panelists could not distinguish between the coated and uncoated potato chips. CONCLUSION: Methylcellulose‐based coating plasticized with sorbitol could be an alternative for obtaining healthier potato chips. Copyright © 2011 Society of Chemical Industry 相似文献
995.
Aleksic I Popovic M Dimitrijevic R Andjelkovic U Vassilopoulou E Sinaniotis A Atanaskovic-Markovic M Lindner B Petersen A Papadopoulos NG Gavrovic-Jankulovic M 《Molecular nutrition & food research》2012,56(3):446-453
Scope Banana fruit has become an important cause of fruit allergy in the recent years. Among the five registered IUIS allergens, Mus a 1 and Mus a 2 have been characterized in detail. In this study, molecular characterization and evaluation of the allergenic properties of β‐1,3‐glucanase from banana (Musa acuminata), denoted as Mus a 5, were performed Methods and results The gene of Mus a 5 was cloned and sequenced. The obtained cDNA revealed a novel Mus a 5 isoform with an open reading frame encoding a protein of 340 amino acids comprising a putative signal peptide of 28 amino acid residues. By MALDI‐TOF analysis Mus a 5 isolated from banana fruit revealed a molecular mass of 33451±67 Da. Two Mus a 5 isoforms (pI 7.7 and 8.0) were detected by 2D immunoblot with an identical N‐terminal sequence. By mass fingerprint, 76 and 83% of the primary structure was confirmed for the two mature Mus a 5 isoforms, respectively. IgE reactivity to Mus a 5 was found in 74% of patients sensitized to banana fruit. Upregulation of basophil activation markers CD63 and CD203c was achieved with Mus a 5 in a concentration‐dependent manner Conclusion Mus a 5 is a functional allergen and a candidate for the component‐resolved allergy diagnosis of banana allergy. 相似文献
996.
997.
Taka T Baras MC Chaudhry Bet ZF 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2012,29(4):596-601
Chloramphenicol (CAP) is a broad spectrum antibiotic used in the treatment of human and animal diseases. However, CAP can exhibit toxic effects in certain susceptible individuals, causing bone marrow depression, including fatal aplastic anemia. As this condition is dose-independent, CAP has been banned for use in food-producing animals, including honeybees. In this study, a quick, simple and low-cost routine analytical method was developed for the screening and confirmation of chloramphenicol in honey by LC-MS/MS. Sample clean-up takes only two steps without SPE procedure and with recoveries >97%. Honey samples were selected from several producers in Brazil and diluted in a small amount of water. After fortification and addition of d (s)-chloramphenicol as internal standard, the samples were extracted with ethyl acetate. Complete validation of the method was performed on the basis of EU decision 2002/657. Within-laboratory CV reproducibility at the lowest concentration was <10%. An evaluation of two different methods to calculate the decision limit and detection capability gave 0.08 μg kg(-1) for CCα and 0.12 μg kg(-1) for CCβ. 相似文献
998.
Stefano SchirruSvetoslav Dimitrov Todorov Lorenzo FavaroNicoletta Pasqualina Mangia Marina BasagliaSergio Casella Roberta ComunianBernadette Dora Gombossy de Melo Franco Pietrino Deiana 《Food Control》2012,25(1):309-320
Goat breeding in Sardinia constitutes an important source of income for farming and shepherding activities. In this study 170 LAB strains were isolated from Sardinian goat’s milk and tested for bacteriocins production against several food-borne pathogenic microorganisms. Four isolates (SD1, SD2, SD3 and SD4) were selected for their effective inhibition on Listeria monocytogenes. The strains were classified as members of Enterococcus genus, according to their biochemical and physiological characteristics, and then genetically identified as Enterococcus faecium. In MRS broth at 37 °C, bacteriocins SD1 and SD2 were produced at much higher levels (51200 AU/ml) compared to bacteriocin SD3 (3200 AU/ml) and bacteriocin SD4 (800 AU/ml). Their peptides were inactivated by proteolytic enzymes, but not when treated with α-amylase, catalase and lipase. The four bacteriocins remained stable at pH from 2.0 to 12.0, after exposure to 100 °C for 120 min and were not affected by the presence of surfactants and salts (N-Laourylsarcosine, NaCl, SDS, Triton X-100, Tween 20, Tween 80 and urea). Their molecular size was determined to be approximately 5 kDa by tricine-SDS-PAGE.Since the strains exhibited a strong antimicrobial activity against 21 L. monocytogenes strains and 6 Salmonella spp. isolates, they should be considered as potential bio-preservatives cultures for fermented food productions. Moreover, due to their technological features, the four strains could be taken in account for using as adjunct NSLAB (non-starter lactic acid bacteria) rather than as starter culture. 相似文献
999.
Voltammetric investigations of iron(III)–chrysobactin complexes in aqueous solution at static mercury electrode, were performed. With cFe = (0.5–30) × 10?7 mol dm?3 and cCb = (0.5–100) × 10?7 mol dm?3 in pH range 6.7–10, reduction peaks with Ep ?0.64 to ?0.74 V (1) and Ep ?0.50 to ?0.62 V (2) vs. Ag/AgCl, were registered. These reduction processes were time dependent as well as solution composition (cFe, cCb and pH). Complexes are adsorbed at the mercury drop surface. Presumed stoichiometry of the detected complexes was FeIIICb3 (1) and FeIIICb2(OH)x (2). Their formation/dissociation processes were described. These investigations are of biological importance as well, since provide an insight into possible reduction mechanism in the bacterial cells that use chrysobactin to acquire the iron. 相似文献
1000.