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161.
Salwa Bornaz Jacques Fanni Michel Parmentier 《Journal of the American Oil Chemists' Society》1995,72(10):1143-1148
Having demonstrated a partition of a hydrophobic medium (butter oil) under crossflow filtration and having tentatively explained
the phenomenon on stereochemical and saturation basis, the molecular partition was studied by tangential filtration. Under
specific hydrodynamic conditions, a filtration phenomenon was demonstrated. The solid fat content (SFC) at 20°C of the fractions
obtained was investigated accordingly. When the molecular partition takes place, an SFC divergency between the permeate and
the retentate is observed. The amplitude of the divergency depends on experimental conditions. 相似文献
162.
Hubert Maehr Gladys Zenchoff David L. Coffen 《Journal of the American Oil Chemists' Society》1994,71(5):463-467
Commercially available fish oils with n−3 fatty acid contents ranging from 29 to 34% were converted enzymically, with Amano
P lipase, to mixtures of glycerides with n−3 fatty acid contents ofca. 50%, in weight recovery yields of 23–50%, depending upon extraction procedures. Glyceride mixtures with n−3 fatty acid contents
above 70% were obtained in yields of 14–21%. The processes are based on the relative stability of the ester linkages that
involve n−3-fatty acyl groups and the regioselectivity of the enzyme toward acyl groups at the 1,3-positions of glycerol.
This paper was presented at the 82nd AOCS Annual Meeting, May 12–15, 1991. 相似文献
163.
The adsorption isotherms of several emulsifiers to fat and sugar crystals dispersed in oils have been determined. Further,
the influence of the emulsifiers on the interactions between the crystals has been estimated in sedimentation experiments,
where an increased sediment volume due to adsorption corresponds to an increased adhesion between the crystals andvice versa. Most of the emulsifiers examined adsorb weakly to fat crystals and form tight monolayers, resulting in increased adhesion
between the crystals at high concentrations. On the other hand, loosely packed layers are formed at low concentrations, and
a decreased adhesion is observed. Unsaturated monoglycerides and phospholipids cause a decrease in adhesion for all concentrations
examined.
The emulsifiers adsorb more strongly to sugar crystals than to fat crystals and form tightly packed monolayers with hydrocarbon
chains directed to the oil. The crystals are then stabilized sterically—the adhesion between them is weaker and the sediments
are more compact. At low concentrations, the opposite behavior often occurs. Monoglycerides interact in a specific way with
sugar and cause increased adhesion between the crystals for all concentrations examined. Phospholipids reduce the adhesion
between sugar crystals, resulting in much denser sediments. Saturated monoglycerides in amounts over the solubility limit
tend to precipitate as a network between fat or sugar crystals, which causes bulky sediments and results in better stability
against oiling out. 相似文献
164.
The influence of food emulsifiers on the viscoelastic properties (storage modulus and yield value) of fat and sugar dispersions
in vegetable oils has been investigated. It was found that almost all of the emulsifiers tested influence the rheology of
the dispersions. The magnitude and the direction of the rheological changes depend on both the type and the amount of emulsifier.
In most cases the changes are relatively small, especially for fat crystals. Generally speaking, the largest changes are caused
by lecithins and saturated monoglycerides. The magnitudes of colloidal forces and equilibrium distances between the particles
have been estimated from the rheological network model of van den Tempel [J. Colloid Sci. 16:284 (1964)] and from the correlation of the yield value to the interaction energy by Gillespie [J. Colloid Sci. 15:219 (1960)] and Tadros [Langmuir 6:28 (1990) andChemistry and Industry 7:210 (1985)]. The results indicate that van der Waals forces alone cannot be responsible for the interparticle interaction
in fat or sugar dispersions. The formation of water bridges is discussed as a probable source of interaction in both cases.
Furthermore, the validity of the network model for fat and sugar dispersions in oils is questionable. 相似文献
165.
S. Hendrich C. K. Lii R. Myers J. Dupont 《Journal of the American Oil Chemists' Society》1993,70(8):797-802
Three generations of CBA/2 and C57B1/6 mice were reared on semipurified diets containing either 17.2% beef tallow and 3.5%
corn oil or 8.6% beef tallow, 8.6% crudeCuphea oil and 3.5% corn oil. TheCuphea oil contained 76% decanoic acid; therefore, health effects of long-term feeding of moderate amounts of medium-chain triacylglycerols
were evaluated. The reproductive performance of both strains of mice varied little with diet but, compared with the F1 generation,
survival of F2 and F3 pups was diminished. At several time points during 13 wk,Cuphea feeding suppressed body weights and food intakes of males of three generations of both strains. But during long-term feeding
of males (5–12 mon),Cuphea did not suppress body weight or food intake. Mice of both strains developed fatty livers. Mice of the CBA/2 strain had hepatic
nodular hyperplasia.Cuphea oil feeding caused no specific pathological changes. Although medium-chain triacylglycerols have been reported to be hypocholesterolemic,
the substitution ofCuphea for half of the dietary beef tallow did not suppress serum cholesterol concentrations in males aged 4–13 mon. The effects
of long-term substitution of medium-chain triacylglycerols for beef tallow do not differ from feeding the beef tallow diet.
Long-term and multigenerational feeding of crudeCuphea oil does not cause any specific toxic effect in mice. 相似文献
166.
Justine Moucoucou Christian Villaume Hwei-Ming Bau Jean-Pierre Nicolas Luc Mjean 《Journal of the science of food and agriculture》1992,60(3):361-368
Seven groups of 12 Wistar rats were fed during two experimental periods. During the first period of 4 weeks, rats were fed diets containing 100 g kg?1 of casein or soya-protein. In the case of casein, diets contained casein, casein + 3.5 g kg?1 of sodium carrageenan and casein + 3.5 g kg?1 of sodium carrageenan + 1 g kg?1 of DL-methionine. In the case of soya protein, diets contained soya protein, soya protein + 6.2 g kg?1 of sodium carrageenan, soya protein + 6.2 g kg?1 of sodium carrageenan + 1 g kg?1 of DL-methionine and soya protein + 1 g kg?1 of DL-methionine. During the second period of 8 weeks, all rats were fed laboratory pellets containing 170 g kg?1 of standard protein mixture. Methionine supplementation of heated soya bean meal containing carrageenan prevented the decrease of growth observed with unsupplemented diet. Methionine supplementation of casein improved protein efficiency ratio and had no effect on long-term growth of rats because carrageenan did not cause growth retardation. At the end of second period, carrageenan ingested during the first period had no effect on plasma cholesterol. When carrageenans added to casein were ingested during the first period, plasma triglycerides were significantly lower after the second period. It would seem that carrageenans induce protein malnutrition by a lack of methionine when they are present in low protein diets with low methionine content, and that a sufficient content of methionine in diets prevents the carrageenan effect. 相似文献
167.
Carbohydrate foods that breakdown rapidly during digestion are known to have the highest glycemic index (GI) values. It is known that lipid-starch complexes can form in foods; however how this may enhance the resistance of starch to enzyme hydrolysis is unknown. The aim of this study was to examine the effect of adding different fats to a carbohydrate rich food on the digestibility of starch in-vitro. Three sets of carbohydrate-lipid emulsion (CLE) batters in the form of pancakes were prepared as 1) low fat (20.3% mass as fat), 2) medium fat (32.7% mass as fat) and 3) high fat (45.1% mass as fat). For each set of CLE a control (containing no added fat), saturated fat (butter), polyunsaturated fat (sunflower oil), monounsaturated fat (olive oil) and medium chain triglyceride saturated fat (MCT oil) was prepared. The CLEs were digested in-vitro and sugars released measured. The results indicated that increasing the concentrations of fat in the CLE augmented sugar release (p < 0.001). The results also showed that there were differences between the different types of fats in the CLE (p < 0.001). The primary differences existed between the control and all the other CLEs, as well as between the MCT CLE and all other CLEs. Correlation analysis showed an inverse relationship between the amount of remnants remaining after digestion and the sugars released from the CLE (p = 0.004 and p = 0.014). This research indicates that adding fat to a carbohydrate food will increase the digestibility of starch and release of sugars from the food which may impact on glycemic response. 相似文献
168.
中链甘油三酯在动物体内的代谢及应用研究 总被引:3,自引:0,他引:3
中链甘油三酯(MCT)是由6~12个碳原子的脂肪酸组成的甘油三酯,它们在体内具有消化、吸收、转运、代谢快的特点.MCT能迅速提供能量,但同时也产生大量的酮体,进入血液,使血液中酮体水平升高.MCT用于仔猪的饲养效果不一致,但用于母猪和鸡的饲养中有明显的正效果.如何消除MCT在肝细胞内氧化产生的大量酮体带来的不利影响,以及寻找一种简便的饲喂方法,都有待今后进一步的研究. 相似文献
169.
170.