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71.
Oxidative decomposition of cholesterol in fish products 总被引:2,自引:0,他引:2
Toshiaki Ohshima Nan Li Chiaki Koizumi 《Journal of the American Oil Chemists' Society》1993,70(6):595-600
Cholesterol oxides in fish products popular in Japan, including salted and dried, boiled and dried and smoked products, were
qualitatively and quantitatively determined as trimethylsilyl ether derivatives by gas-liquid chromatography and mass spectrometry.
The level of total cholesterol oxides ranged widely between 8.3 ppm in boiled and dried shrimp and 188.0 ppm in boiled and
dried anchovy. 7β-Hydroxycholesterol and 7-ketocholesterol were the most prominent oxidative decomposition products of cholesterol.
The levels of epimeric epoxides, cholestane triol and 25-hydroxycholesterol were relatively low. To elucidate a mechanism
of cholesterol oxidation proceeding during fish processing and subsequent preservation, four model systems, consisting of
a mixture of purified cod liver triglycerides plus cholesterol, of a mixture of authentic triolein plus cholesterol, of triolein
alone and of cholesterol alone, were stored separately at 25°C in dry air for up to 104 d. The residual fatty acids of the
triglycerides, and the cholesterol oxides produced, were recovered and determined. Oxygen uptake remained almost unchanged
for the mixture of triolein plus cholesterol. No detectable amount of cholesterol oxides was produced, and the fatty acid
content of the residual oleic acid, measured by an internal standard, remained almost unchanged. For the mixture of cod liver
triglycerides plus cholesterol, a remarkable increase in oxygen uptake was observed. A continuous increase in the amount of
cholesterol oxides was observed, accompanied by a remarkable concurrent decrease in polyunsaturated fatty acid residues, as
well as of the oleic acid naturally present. These results strongly suggest that cholesterol oxidation in fish products proceeds
in conjunction with oxidative decomposition of the coexisting polyunsaturated fatty acids of fish oils. 相似文献
72.
Marcel S. F. Lie Ken Jie C. C. Lam Mohammed Khysar Pasha 《Journal of the American Oil Chemists' Society》1996,73(5):557-562
13C nuclear magnetic resonance (NMR) spectroscopic analysis of the whole oil (triacylglycerols) ofBiota orientalis seeds confirms the presence of oleate [18:1(9Z)], linoleate [18:2(9Z, 12Z)], linolenate [18:3((9Z, 12Z, 15Z)], 20:3 (5Z,
11Z, 14Z), 20:4(5Z, 11Z, 14Z, 17Z), and saturated fatty acids in the acyl groups by comparing the observed carbon shifts with
previously established shift data for model triacylglycerols. This technique shows that the saturated, 20:3 and 20:4 fatty
acids are distributed mainly in the α-acyl positions, whereas oleate, linoleate, and linolenate are randomly acylated to the
α- and β-positions of the glycerol “backbone”. Stereospecific hydrolysis of theBiota oil with pancreatic lipase, followed by chromatographic analysis of fatty esters, reveals the presence of trace amounts of 16:0(0.7%),
18:0(0.5%), 20:3 (0.4%), and 20:4 (1.3%) in the β-position of the glycerol “backbone”, which are undetectable by13C NMR technique on the whole oil. Semiquantitative assessment of the13C NMR signal intensities gives the relative percentages of the fatty acid distribution as: saturated 16:0, 18:0 (12.0% α-acyl),
oleate (7.7% α-acyl 8.7% β-acyl), total linoleate and linolenate (31.7% α-acyl; 24.2% βacyl), total 20:3 and 20:4 (15.7% α-acyl).
The13C NMR spectroscopic analysis of carrot seed oil identifies the presence of saturated (18:0), 18:1(6Z), 18:1(9Z), and 18:2(9Z,
12Z). The saturated fatty acid is found in the α-acyl positions. Semi-quantitative assessment of the signal intensities gives
the relative percentages of the fatty acids as: 18:0 (4.5% α-acyl), 18:1(6Z) (49.6% α-acyl; 19.7% β-acyl), oleate (6.5% α-acyl;
8.6% β-acyl) and linoleate (5.2% α-acyl; 6.9% β-acyl). 相似文献
73.
A comparative nutritive study was made to show that the extent of purification markedly influences the nutritive characteristics
of rice bran oil. The coefficient of digestibility was 93.8% when rice bran oil that had been purified by degumming, deacidifying,
bleaching and deodorizing was fed to rats; whereas it was 94.8% when extremely pure rice bran oil, which was achieved by including
an additional dewaxing step, was used. Rice bran oil without deodorization, but purified by other treatments, showed a 96.2%
coefficient of digestibility, which is somewhat lower than that of groundnut oil. However, after a feeding experiment over
three months, the highly purified rice bran oil showed better results than the other two purified samples of rice bran oil,
and was sometimes better than groundnut oil in terms of total lipid, triglyceride and especially in cholesterol content in
serum, liver and heart tissues. 相似文献
74.
Junichi Matsumoto Kazuo Erami Hiroshi Ogawa Mikiharu Doi Taro Kishida Kiyoshi Ebihara 《Journal of food science》2005,70(7):s467-s474
The hypocholesterolemic effects of smoke‐dried bonito undigested fractions remaining after microbial proteases treatment (SDBR), SDBR undigested fractions remaining after pepsin treatment (P‐SDBR), SDBR undigested fractions remaining after alcalase treatment (A‐SDBR), and defatted A‐SDBR (A‐SDBR/DF) were studied in 6‐month‐old, ovariectomized rats. Casein was used as the control. Smoke‐dried bonito, Katsuobushi, is a traditional Japanese food. SDBR, P‐SDBR, and A‐SDBR contain mainly 2 components: bonito oil and protease‐undigested proteins. In comparison with casein, SDBR, P‐SDBR, and A‐SDBR decreased plasma cholesterol concentration and increased fecal bile acid excretion and fecal output, whereas A‐SDBR/DF increased fecal bile acid excretion and fecal output, but did not decrease plasma cholesterol concentration. In addition, SDBR, P‐SDBR, and A‐SDBR, when compared with casein, decreased plasma triglyceride (TG) concentration and increased hepatic total lipid concentration, free cholesterol, and TG concentrations and CYP7A1 mRNA levels. Yet, these effects were not observed in rats fed A‐SDBR/DF. These results suggest that the hypocholesterolemic effect of SDBR, P‐SDBR, and A‐SDBR is mediated by an increase in bile acid excretion through a combination of promoted secretion of bile acids by bonito oil and binding of bile acids to resistant proteins. The hypotriglyceridemic effect may be mediated by reduced hepatic TG synthesis and secretion due to the intake of bonito oil. 相似文献
75.
Shanyu Wang Mengyue Hu Ling Zhao Qi Liu Rong Cao 《International Journal of Food Science & Technology》2022,57(7):4234-4244
Herein, the effect of three common cooking methods (boiling, baking and microwaving) on lipids and volatile compounds in shrimp (Penaeus vannamei) was assessed. The results revealed that contents of phospholipid, triglyceride, cholesterol and free fatty acids in the cooked shrimp significantly declined when compared to the raw shrimp. And these decreases occurred especially in the boiling and microwaving treatment. Among free fatty acids, the contents of palmitic acid (C16:0), oleic acid (C18:1n9c) and linoleic acid (C18:2n6c) also decreased greatly in the boiled and microwaved shrimp, while EPA and DHA enhanced in each cooked group (P < 0.05). Furthermore, microwaved samples exhibited higher levels of oxidation parameters, such as acid value (AV) and thiobarbituric acid-reactive substances (TBARS). For volatile compounds, a total of 31 volatile compounds were detected by GC-IMS, and these contents increased after cooking. Aliphatic volatile compounds, including 1-octen-3-one, pentane-1-ol, 1-propanol, octanal, heptanal, pentanal and hexanal, were main flavour contributors in cooked shrimp, with higher contents observed in microwaved shrimp. In addition, the correlation analysis showed that linoleic acid was a substrate for 15 volatile compounds of cooked shrimp meat. These results indicate that microwave cooking exerts more influences on lipid profiles in shrimp and consequently caused more volatile compounds. 相似文献
76.
77.
Ying Li Zhen Kang Songtao Li Tian Kong Xiaohong Liu Changhao Sun 《Molecular nutrition & food research》2010,54(11):1609-1617
Ursolic acid (UA) is a pentacyclic triterpenic acid with many biological functions naturally existing in many kinds of food. To investigate whether UA can accelerate lipolysis, primary‐cultured rat adipocytes were treated with UA, and glycerol release in the culture medium was measured. UA stimulated lipolysis significantly. Furthermore, the lipolytic effect of UA was inhibited by the protein kinase A (PKA) specific inhibitor H89, suggesting that UA exerted its lipolytic function through the cAMP‐dependent PKA pathway. Downstream targets of the PKA pathway, hormone‐sensitive lipase (HSL) and perilipin A were checked, UA enhanced lipolysis by promoting the translocation of HSL from the cytosol to the lipid droplets and inhibiting the expression of perilipin A. Additionally, adipose triglyceride lipase (ATGL), a novel rate‐limiting lipase in the lipolytic catabolism, was upregulated by UA. UA‐induced expression of ATGL could not be blocked by H89, suggesting that ATGL upregulation is not regulated by the PKA pathway. These findings suggest that UA significantly stimulates lipolysis by translocating HSL, decreasing perilipin A expression by the PKA pathway, and up‐regulating ATGL in primary cultured adipocytes. Thus, UA is a promising candidate for the treatment of obesity. 相似文献
78.
Tommaso Gomes Debora Delcuratolo Vito Michele Paradiso 《European Food Research and Technology》2008,226(6):1409-1414
The aim of the research was to evaluate the pro-oxidant action of oxidized triglyceride oliogopolymers, a class of oxidation
compounds present in refined vegetable oils. Silica gel column chromatography was used to obtain the polar compounds from
a thermally oxidized oil and preparative gel permeation chromatography to separate and collect the oxidized triglyceride oligopolymers.
A purified oil that was practically free of oxidation and hydrolytic degradation products, pigments and anti-oxidants was
prepared in the laboratory to evaluate pro-oxidant activity without interferences. Addition of percent amounts of oxidized
triglyceride oligopolymers of 0.25 to 1.0% to both the purified and unpurified oils clearly evidenced the pro-oxidant activity
of this class of compounds. 相似文献
79.
Antonietta Baiano Tommaso Gomes & Francesco Caponio 《International Journal of Food Science & Technology》2005,40(8):829-834
The hydrolytic and oxidative degradation of olive oil and extra‐virgin olive oil, used as covering liquids in canned dried tomatoes, was studied during storage by means of conventional (acidity, peroxide value, p‐anisidine value) and non conventional (polar compounds) analyses. The effects of the addition of spices were also considered. The hydrolysis and oxidation of olive oil increased faster and was higher than that of extra‐virgin olive oil in terms of absolute values but some other indices, such as percentage of oligopolymers and percentage of oxidized triglycerides, increased faster in extra‐virgin olive oil than in olive oil. The antioxidant effect given by a higher concentration of polyphenols in the extra‐virgin olive oil was shown by a reduced amount of secondary oxidation. However, olive oil and extra‐virgin olive oils showed similar behaviour in terms of peroxide formation. 相似文献
80.
有关用油脂的脂肪酸组成推算其甘三酯组份的假说很多,但用之比较有效的仅有两种,即Vander Wal的2—随机1.3—随机假说与Tsuda的1随机2随机3随机假说,前者以甘三酯2位脂肪酸分布为基础,而后者是以甘三酯“立体专一分析”数据为基础,因此后者更比较符合天然油脂的实际。本文综合介绍了有关甘三酯“立体专一分析”的函义、反应机制、操作程序以及对研究甘三酯组份的重要性。 相似文献