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631.
632.
Karina Knudsmark Jessing Stephen O. Duke Nina Cedergreeen 《Journal of chemical ecology》2014,40(2):100-117
Artemisia annua L. (annual wormwood, Asteraceae) and its secondary metabolite artemisinin, a unique sesquiterpene lactone with an endoperoxide bridge, has gained much attention due to its antimalarial properties. Artemisinin has a complex structure that requires a significant amount of energy for the plant to synthesize. So, what are the benefits to A. annua of producing this unique compound, and what is the ecological role of artemisinin? This review addresses these questions, discussing evidence of the potential utility of artemisinin in protecting the plant from insects and other herbivores, as well as pathogens and competing plant species. Abiotic factors affecting the artemisinin production, as well as mechanisms of artemisinin release to the surroundings also are discussed, and new data are provided on the toxicity of artemisinin towards soil and aquatic organisms. The antifungal and antibacterial effects reported are not very pronounced. Several studies have reported that extracts of A. annua have insecticidal effects, though few studies have proven that artemisinin could be the single compound responsible for the observed effects. However, the pathogen(s) or insect(s) that may have provided the selection pressure for the evolution of artemisinin synthesis may not have been represented in the research thus far conducted. The relatively high level of phytotoxicity of artemisinin in soil indicates that plant/plant allelopathy could be a beneficial function of artemisinin to the producing plant. The release routes of artemisinin (movement from roots and wash off from leaf surfaces) from A. annua to the soil support the rationale for allelopathy. 相似文献
633.
Thais Regina Ferreira de Melo Rafael Consolin Chelucci Maria Elisa Lopes Pires Luiz Antonio Dutra Karina Pereira Barbieri Priscila Longhin Bosquesi Gustavo Henrique Goulart Trossini Man Chin Chung Jean Leandro dos Santos 《International journal of molecular sciences》2014,15(4):5821-5837
A series of anti-inflammatory derivatives containing an N-acyl hydrazone subunit (4a–e) were synthesized and characterized. Docking studies were performed that suggest that compounds 4a–e bind to cyclooxygenase (COX)-1 and COX-2 isoforms, but with higher affinity for COX-2. The compounds display similar anti-inflammatory activities in vivo, although compound 4c is the most effective compound for inhibiting rat paw edema, with a reduction in the extent of inflammation of 35.9% and 52.8% at 2 and 4 h, respectively. The anti-inflammatory activity of N-acyl hydrazone derivatives was inferior to their respective parent drugs, except for compound 4c after 5 h. Ulcerogenic studies revealed that compounds 4a–e are less gastrotoxic than the respective parent drug. Compounds 4b–e demonstrated mucosal damage comparable to celecoxib. The in vivo analgesic activities of the compounds are higher than the respective parent drug for compounds 4a–b and 4d–e. Compound 4a was more active than dipyrone in reducing acetic-acid-induced abdominal constrictions. Our results indicate that compounds 4a–e are anti-inflammatory and analgesic compounds with reduced gastrotoxicity compared to their respective parent non-steroidal anti-inflammatory drugs. 相似文献
634.
Catherine M. Santos Karina Milagros Cui Farid Ahmed Maria Celeste R. Tria Regina Aileen May V. Vergara Al Christopher de Leon Rigoberto C. Advincula Debora F. Rodrigues 《大分子材料与工程》2012,297(8):807-813
A PVK/MWNT nanocomposite coating on stainless steel is developed and tested for antimicrobial and anticorrosion properties. The coating is prepared via electrochemical deposition onto SS surfaces and is monitored using cyclic voltammetry. High‐resolution XPS measurements of the C 1s and N 1s regions are used to estimate the film composition. AFM shows a homogeneous thin film of several µm thickness with well‐defined globular domains. The bactericidal functionality of the electrodeposited film is demonstrated by its antibacterial activity against Escherichia coli, even with low MWNT loading (≈6%). The excellent anticorrosion property of the coating is demonstrated after 7 d of exposure to NaCl (0.5 M ) solution.
635.
Total antioxidant activity (TAA), total phenolic compounds (TPC), and physicochemical characteristics of ready-to-drink orange juice and nectar from the most consumed brands available in Brazil were evaluated. TPC ranged from 18.7 to 54.2 mg of gallic acid/100 mL, and TAA varied from 57.88 to 349.32 μmol TEAC/100 mL ready-to-drink orange juice and nectar. The ascorbic acid content was the only physicochemical parameter that showed strong variation among packages and brands. Correlation of TPC with TAA showed that the higher the level of TPC the higher the TAA. Correlation of ascorbic acid content with TAA is higher for ready-to-drink orange juice than nectar. The same was found for the correlation of ascorbic acid content with TPC. The results confirm the contribution of the TPC to TAA. 相似文献
636.
Karina Huerta-Vera Enrique Flores-Andrade Juan Antonio Pérez-Sato Victorino Morales-Ramos Luz Alicia Pascual-Pineda Adriana Contreras-Oliva 《Food and Bioprocess Technology》2017,10(6):1053-1062
The aim of this study was to use the process of osmotic dehydration to enrich banana slices with Lactobacillus rhamnosus encapsulated in a double emulsion. The effect of a pulsed vacuum and the concentration of the osmotic solution on the impregnation of the microorganism and on mass transfer during osmotic dehydration of the fruit were assessed. The kinetics of the water loss (WL), solid gain (SG) and water activity (aw) were obtained using an aqueous solution with 40, 50 and 60% sucrose with emulsion and a vacuum pulse of 50 mbar for 10 and 20 min at the beginning of the osmotic process. The high concentrations of sucrose in the osmotic solution, combined with the application of a pulsed vacuum, produced an increase in the rates of WL and SG of the osmodehydrated banana, as well as a reduction of its aw. L. rhamnosus survived at levels above 107 CFU/g in the hypertonic solution and in the osmodehydrated bananas. Scanning electron microscopy (SEM) showed that the encapsulated probiotic adheres to the banana’s surface, which demonstrates that double emulsions can be used to impregnate probiotics in vegetal tissues. 相似文献
637.
Carlsen Charlotte U. Rasmussen Karina T. Kjeldsen Kamilla K. Westergaard Pernille Skibsted Leif H. 《European Food Research and Technology》2003,217(3):195-200
Protein fractions from pork (longissimus dorsi), isolated in search of the factor in meat enhancing non-heme iron absorption, have been analysed for their effect on radical formation and oxidation processes. In heat-treated minced meat samples with the protein fractions incorporated, the water-soluble proteins showed a prooxidative effect on lipid oxidation compared to the salt-soluble and the insoluble proteins, which did not influence oxidation in the meat system relative to control samples. The level of secondary oxidation products in meat samples with water-soluble proteins added was, however, not as high as would be expected from the ability of this protein fraction to initiate oxidation as measured by spin-trapping ESR-spectroscopy in meat emulsions and by oxygen depletion rates in a lipid model system with the protein fraction added. In agreement with this observation, the water-soluble protein fraction was found, in addition to being prooxidative, also to have the highest antioxidative potential of the three protein fractions as measured by spin probing ESR-spectroscopy (Fremy's salt method). The prooxidative activity of the water-soluble proteins was assigned to myoglobin and hemoglobin derivatives (detected spectrophotometrically), emphasising the role of iron-catalysis in oxidative deterioration of meat products. 相似文献
638.
Cristian Tello-Ireland Roberto Lemus-Mondaca Antonio Vega-Gálvez Jessica López Karina Di Scala 《LWT》2011,44(10):2112-2118
Effect of air temperature on drying kinetics, functional properties, phycobiliproteins (PE and PC), colour, antioxidant capacity, total phenolic content, texture and agar yield during drying of algae Gracilaria chilensis were studied. Drying curves were satisfactorily simulated with the Weibull model at 40, 50, 60 and 70 °C. Both, Rehydration Ratio and Water Holding Capacity decreased with increasing temperature. Low drying temperatures showed higher PE and PC concentration than higher temperatures (e.g. 60 and 70 °C). In particular, dehydration at 50 °C presented the higher values of these two pigments. The three chromatic coordinates (L1, a1 and b1) were influenced by the treatments showing the highest ?E value at 50 °C. Antioxidant activity as well as texture were notably influenced by increasing drying temperatures. At 70 °C, a maximum agar yield of 40 g/100 g was obtained. Results indicated that agar yield and quality of dried algae showed opposite behaviours leading to a compromise decision on operating conditions involved in the overall process. According to these results, optimization of the process based on economical aspects of the final dried product is required. 相似文献
639.
Laura Fariña Karina Medina Maia Urruty Eduardo Boido Eduardo Dellacassa Francisco Carrau 《Food chemistry》2012
Although redox state is a well-known key process parameter in microbial activity, its impact on wine volatile aroma compounds produced during fermentation has not been studied in detail. In this study we report the effect of reductive and microaerobic conditions on wine aroma compound production using different initial amounts of yeast assimilable nitrogen (YAN: 180 and 400 mg N/l) in a simil grape must defined medium and two S. cerevisiae strains commonly used in wine-making. In batch fermentation culture conditions, reductive conditions were obtained using flasks plugged with Muller valves filled with sulphuric acid; while microaerobic conditions were attained with defined cotton plugs. It was found that significant differences in redox potential were obtained using the different plugs, and with variation of over 100 mV during the main fermentation period. 相似文献
640.
Changes in Structure, Rheology, and Water Mobility of Apple Tissue Induced by Osmotic Dehydration with Glucose or Trehalose 总被引:5,自引:0,他引:5
Sebastián Vicente Andrea B. Nieto Karina Hodara María A. Castro Stella M. Alzamora 《Food and Bioprocess Technology》2012,5(8):3075-3089
The impact of osmotic dehydration to water activity (a w) at 0.97 or 0.94 with glucose or trehalose solutions on structure (optical and transmission electronic microscopy observations), rheological properties (small-scale dynamic oscillatory and creep/recovery measurements and large-scale compression force-deformation testing) and water mobility (1H-NMR spectra) of parenchymatous apple tissue was investigated. In general, the nature and the concentration of sugar employed significantly affected the material properties and the structure of apple tissue. A dramatic loss in rigidity (E d); an increase in deformation at rupture (?? R R ), creep compliances (J 0, J 1, and J 2), and fluidity (1/?? 0) and a decrease in storage (G??) and loss (G??) moduli, true rupture stress (?? R R ), and proton transverse relaxation times (T 2i) were induced by osmotic treatments. ?? R R , C 1, and T 2i parameters allowed to discriminate between the sugars used as osmotic agents while the different a w levels for each sugar resulted in changes in ?? R R , W, and T 2i values. Loss of turgor due to plasmolysis or rupture of membranes and desorganization/degradation of walls allowed explaining, at least partially, the changes in material parameters. 相似文献