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81.
Adsorption of proteins on solid surfaces is widely studied because of its importance in various biotechnological, medical, and technical applications, e.g., biosensors, cardiovascular implants, and chromatography. Adsorption thermodynamics has been studied on the microbeads of N,N′‐diethylaminoethyl (DEAE) Dextran anion exchanger for the human serum albumin (HSA) at 25, 30, 35, 40, and 45°C. As a result, some thermodynamic parameters like Freundlich constants, thermodynamic equilibrium constant (KD), standard free energy changes (ΔGassoc), standard entropy changes (ΔSassoc), and standard enthalpy change (ΔHassoc) have been evaluated. Using the linear Van't Hoff plot, ΔHassoc value of the system for the interaction of bovine serum albumin (BSA)‐adsorbed crosslinked DEAE dextran microbeads was determined as 20.650 kJ/mol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3942–3947, 2006 相似文献
82.
New hydrogel microspheres based on crosslinked dextran containing N,N′‐diethylaminoethyl (DEAE) groups with different chemical structures have been used in adsorption–desorption studies. Bovine serum albumin (BSA) is frequently used in biophysical and biochemical studies. BSA has a well‐known primary structure that has been associated with binding of many different categories of small molecules. Both adsorption kinetics and equilibrium isotherms for the adsorption of BSA on crosslinked DEAE dextran have been determined experimentally. These were only slightly dependent on the initial concentration of BSA but were considerably affected by the pH of the medium. The results fitted the Freundlich–Langmuir isotherm model for pH 6.9. The adsorption capacity factor and the adsorption equilibrium constant were obtained and mathematical modeling of adsorption, adsorption rate constants, and maximum adsorption were determined. Swelling kinetics of crosslinked DEAE dextran and optimum ionic strength, pH, and mass of hydrogel were also investigated. Desorption studies were finally determined under optimum medium conditions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006 相似文献
83.
The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm(-2) and duration in the limits of 5-20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions. 相似文献
84.
Yesim Ozogul Mustafa Durmuş Esra Balıkcı Fatih Ozogul Deniz Ayas Hatice Yazgan 《International Journal of Food Science & Technology》2011,46(2):236-242
The effects of combination of freezing and the use of antioxidant technology on the quality of frozen sardine fillets were investigated in terms of sensory, biochemical [thiobarbituric acid (TBA), total volatile basic nitrogen (TVB‐N), peroxide value (PV) and free fatty acids (FFA)] and microbiological analyses [total viable count (TVC)]. Fish were filleted and divided into three groups. The first group was used as the control (C) without rosemary extract, the second group was treated with 1% rosemary extracts for 2 min (R1) and the third was treated with 2% rosemary extracts for 2 min (R2). All groups were frozen at ?18 °C over the storage period of 6 months. The results obtained from this study showed that the combination of antioxidant and frozen storage resulted in significant reduction of bacterial growth and stabilised the biochemical characteristics, especially for R2. However, the use of antioxidant at the level of 2% (R2) gave a bitter taste according to sensory assessment whereas the panellists mostly preferred R1. 相似文献
85.
BACKGROUND: A wide range of 1‐methylcyclopropene (1‐MCP) concentrations as well as various treatment durations have been studied in tomatoes by different researchers. However, little is known about interaction of 1‐MCP doses and maturity stages of tomatoes. Therefore the effects of different concentrations of 1‐MCP on storage and postharvest quality of ‘Zorro’ tomatoes harvested at mature green or pink maturity stages were investigated in a 2‐year trial study. RESULTS: Higher concentrations of 1‐MCP delayed and/or inhibited all parameters related to fruit ripening, such as lycopene, chlorophyll, surface color, polygalacturonase (PG) activity and soluble solids content/titratable acidity (SSC/TA), and these effects were greater in tomatoes harvested at the mature green stages. Lower concentrations of 1‐MCP slightly reduced the loss in general quality features compared with untreated tomatoes. CONCLUSION: The results suggest that 1‐MCP, especially at higher doses, is effective for delaying ripening of mature green tomatoes. Mature green fruits treated with 1000 nL L?1 1‐MCP were stored for 35 days without significant decreases in quality characteristics such as elasticity, surface color and SSC/TA with certain physiological processes (ethylene production, PG activity, lycopene synthesis). Copyright © 2011 Society of Chemical Industry 相似文献
86.
We experimentally demonstrate for the first time a very compact plasmonic hetero-oligomer structure where the multiple radiant and subradiant modes can be tailored independently. Unlike previous approaches based on collective excitations in complex plasmonic systems, we show precise engineering of resonances leading to simultaneous spectral overlap of multiple plasmonic modes with opposite radiative character. This asymmetric behavior combined with inherent spatial features of the structure leads to directional double Fano resonances as shown with numerical analysis. A model based on temporal coupled mode theory is also provided to describe the double Fano behavior. 相似文献
87.
Hatice Kalkan Yıldırım Burçak İşçi Ahmet Altındişli 《Journal of the Institute of Brewing》2015,121(4):636-641
The aim of the study was to investigate the quality of blended wines produced from Vitis vinifera L. Cabernet Sauvignon, Merlot and Sauvignon blanc grapes. Wines were processed according to accepted conventional methods for white and red wines. Blended wines were produced with different ranges (25, 50, 75 and 100%) of Cabernet Sauvignon, Merlot and Sauvignon blanc wines. Produced wines were evaluated for total phenols (mg/L), total tartaric esters (mg/L caffeic acid), total flavonols (mg/L quercetin), chemometric parameters such as D280%, D420%, D520%, D620%, dA%, CD%, T, CI%, R%, Y% and B%, CIELAB parameters, protein, total and volatile acidity. Analyses on an n‐dimensional scale demonstrated the relationships among the wines of different grape origins and different blending ratios. On the basis of these differences, two main groups were plotted using principal component analysis and cluster analysis. The results demonstrate the possibilities of optimizing wines on the basis of defined parameters. Copyright © 2015 The Institute of Brewing & Distilling 相似文献
88.
Burçak Işçi Hatice Kalkan Yildirim Ahmet Altindisli 《Journal of the Institute of Brewing》2014,120(3):238-243
The quality of wine depends on many factors. One of the most important is the selection of appropriate and defined grape varieties. The analysis of phenolic compounds, amino acids, trace elements and isotopes of wines, used for the identification of grapes varieties, is not sufficient and requires a lengthy analysis period. The development of molecular techniques such as restriction fragment length polymorphism, random amplified polymorphic DNA and microsatellites provides opportunities for the differentiation of grape varieties. In this regard, the use of DNA extracted from must and wine appears to be a good marker for the identification of grape varieties used in wine production. In this study, DNA was extracted from grape, leaf, must and wine samples of Vitis vinifera L. cv. Cabernet Sauvignon, Merlot and Sauvignon Blanc origin and examined using different extraction methods. Of the DNA extraction methods tested, the method using absorption at 260/280 nm (with values of 0.19 and 1.92) was considered the method of choice. Copyright © 2014 The Institute of Brewing & Distilling 相似文献
89.
Ersel Ozkazanc Sibel Zor Hatice Ozkazanc Ufuk Abaci 《Polymer Engineering and Science》2011,51(4):617-623
Electrical and morphological properties of Polyaniline (PANI) filled with various mass fractions of manganese chloride (MnCl2) synthesized in aqueous hydrochloric acid (HCl) medium using ammonium persulphate as an oxidant were investigated. The sample morphology was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Significant changes were observed in the morphology of the samples depending on the filler level. The direct current (dc) and alternating current (ac) electrical properties were investigated as a function of temperature. The dc conductivity decreased 72% with 10% filler level whereas ac conductivity has shown a 120% increase with 6% filler level at room temperature. It is shown that the alternating charge transport mechanism of the unfilled and filled polyaniline samples is consistent with correlated barrier hopping (CBH) model. Imaginary (M″) parts of electric modulus exhibited temperature‐dependent dielectric relaxation behavior for both filled and unfilled PANI samples. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers. 相似文献
90.
In this study, the pure polystyrenes (PS) with different molecular weights (3.5 × 105 and 5.0 × 105) have been modified by the chemical modification with succinic anhydride (SA), maleic anhydride (MA), and phthalic anhydride
(PhA). The modified polystyrenes (MPS) have been mixed with the pure PS with the molecular weight of 2.3 × 105 in weight % ratio 90:10, 80:20, and 70:30. Young’s modulus of obtained composites has been measured mechanically by the tensile
test and ultrasonic method at frequency of 5 MHz. Further, the values of Young’s modulus measured by both methods have been
compared with each other. From the results, a significant difference has not been found between the values of Young’s modulus
of both methods. As a result it can be stated that measuring the Young’s modulus of these materials by the ultrasonic methods
is more sensitive and economical than the mechanical methods. 相似文献