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61.
A. Kuksis M. J. Mccarthy J. M. R. Beveridge 《Journal of the American Oil Chemists' Society》1964,41(3):201-205
Triglyceride gas chromatography was used for quantitative fractionation by carbon number of native and rearranged butter and coconut oils. Significant differences in the triglyceride type distributions between the corresponding native and chemically modified fats were found. Increased proportions of both short and long chain triglycerides occurred in the rearranged butterfat. In reconstituted coconut oil there was a shift towards the shorter chain length triglycerides. The natural and the rearranged triglyceride distributions of the two oils were shown to differ from the random distributions calculated for the corresponding fatty acid complements. The butterfat triglyceride compositions showed greater deviations from random than did the coconut oils. The modified oils approached random distributions more closely than did the native ones. In both cases the deviations from truly random populations appeared to be in the direction anticipated on the basis of chemical reactivity. 相似文献
62.
This study uses normal-phase HPLC with on-line positive ion electrospray mass spectrometry (ESI-MS) to obtain quantitative
compositional data on both synthetic and butterfat short-chain TAG. The product ion tandem MS of standards averaged 11.1 times
lower in abundance of the ion formed by cleavage of FA from the sn-2-position for the pairs of regioisomers in the TAG classes: L/L/S-L/S/L and L/S/S-S/L/S, where L denotes long and S short
acyl chain (C2−C6). The molar correction factors, determined for 42 regioisomeric pairs of short-chain TAG of 20 randomized mixture of standards,
differed by 1.4–80% as the ratios varied between 0.217 and 5.847. Butterfat TAG were resolved into four fractions on short
flash chromatography grade silica gel columns. Pairs of regioisomers in the TAG classes L/S/S-S/L/S with predominance of L/S/S
isomers and the sole regioisomers in the TAG classes L/L(M)/S were identified by tandem MS, where M denotes either 8∶0 or
10∶0 acyl chain. The total proportion of L/L(M)/S isomers was estimated at 34.7 and that of L/S/S-S/L/S at 1.0 mol%, including
a small proportion of S/S/S. In contrast to previous work, the present data indicate the presence of a small proportion of
butyric and caproic acids in the sn-1-position. The overall distribution of the FA in the short-chain TAG of butterfat, calculated from direct MS measurements,
was consistent with the results of indirect determinations based on stereospecific analyses of total butterfat. 相似文献
63.
A semiautomatic system is described for gas-chromatographic separation and recovery of triglycerides of uniform molecular
weight in milligram quantities. It employs an Aerograph Autoprep 700 (Wilkens Instrument and Research Inc.) equipped with
a stream splitter and a hydrogen flame ionization detector. The column is an aluminum or stainless steel tube (1/4 in. O.D.×2
ft) and contains silanized Chromosorb W (60–80 mesh) coated with 5% (w/w) JXR or SE-30. Five to ten milligrams of mixed triglyceride
are injected at a time and the temperature is programmed exponentially from 150 to 350C. With split ratios of 1∶5 to 1∶10
collections of 20 to 50 mg of each peak can be made with some 10 to 20 injections.
Presented in part before the Canadian Committee on Fats and Oils, Ottawa, Ontario, Canada, October 1964. 相似文献
64.
65.
Arnis Kuksis 《Journal of the American Oil Chemists' Society》1965,42(4):269-275
Available techniques are reviewed for gas-liquid chromatography of mono-, di- and triglycerides and their chemical modification
products. Major emphasis is placed upon optimum separation and quantitative estimation of the recorded peaks. Nonlinear rates
of temp programming are shown to be superior to linear rates for maximum resolution of complex glyceride mixtures. The use
of short columns improves the recoveries of the components but may not provide a sufficient number of theoretical plates for
all types of separations. The quantitative interpretation of the results is facilitated by the utilization of a flame ionization
detector which gives correct weight response for the combustible carbon content of these materials. 相似文献
66.
The lipid ester core aldehydes formed during a rapid oxidation (7.8 M tert-butyl hydroperoxide, 90 min at 37°C) of the triacylglycerols of purified corn and sunflower oils were isolated as dinitrophenylhydrazones
by preparative thin-layer chromatography and identified by reversed-phase high-performance liquid chromatography with on-line
electrospray ionization mass spectrometry and by reference to standards. A total of 113 species of triacylglycerol core aldehydes
were specifically identified, accounting for 32–53% of the 2,4-dinitrophenylhydrazine (DNPH)-reactive material of high molecular
weight representing 25–33% of the total oxidation products. The major core aldehyde species (50–60% of total triacylglycerol
core aldehydes) were the mono(9-oxo)nonanoyl- and mono(12-oxo)-9,10-epoxy dodecenoyl- or (12-oxo)-9-hydroxy-10,11-dodecenoyl-diacylglycerols.
A significant proportion of the total (9-oxo)nonanoyl and epoxidized (12-oxo)-9,10-dodecenoyl core aldehydes was found in
complex combinations with hydroperoxy or hydroxy fatty acyl groups (6–10% of total triacylglycerol core aldehydes). Identified
were also di(9-oxo)nonanoylmonoacylglycerols (0.5% of total) and tri(9-oxo)nonanoylglycerols (trace). The identification of
the oxoacylglycerols was consistent with the products anticipated from tert-butyl hydroperoxide oxidation of the major species of corn and sunflower oil triacylglycerols (mainly linoleoyl esters).
However, the anticipated (13-oxo)-9,11-tridecadienoyl aldehyde-containing acylglycerols were absent because of further oxidation
of the dienoic core aldehyde. A significant proportion of the unsaturated triacylglycerol core aldehydes contained tert-butyl groups linked to the unsaturated fatty chains via peroxide bridges (2–9%). The study demonstrates that rapid peroxidation with tert-butyl hydroperoxide consitutes an effective method for enriching natural oils and fats in triacylglycerol core aldehydes
for biochemical and metabolic testing. 相似文献
67.
The long chain triglycerides of bovine milk fat were isolated by thin layer chromatography, and their chemical structure determined
by combined thin layer and gas liquid chromatography, and a stereospecific analysis of a molecular distillate of butteroil
of comparable composition. The milk fat fraction (39% of total) contained C8–C20 fatty acids which were distributed among the glycerides of 40–56 acyl carbon atoms in a manner not unlike that found for
the same acids in the short chain triglycerides. Although individual triglycerides were not identified, the specific distribution
of the fatty acids could best be accounted for by assuming a common pool of long chain 1,2-diglyceride precursors from which
the bulk of both short and long chain triglycerides are synthesized by a stereospecific introduction of C4–C18 fatty acids in position 3 of sn-glycerol. This hypothesis is compatible with the results of stereospecific analyses of the
short and long chain fractions and of the total butteroil. It is supported by the nonrandom distributions demonstrated for
the molecular weights of the milk fat triglycerides of different degrees of saturation.
Presented in part at the AOCS meeting, Philadelphia, October, 1966. 相似文献
68.
The effect of low α-linolenic acid diet on glycerophospholipid molecular species in guinea pig brain
The changes in guinea pig brain (cerebrum) glycerophospholipid molecular species resulting from a low α-linolenic acid (ALA)
diet are described. Two groups of six guinea pigs were raised from birth to 16 wk of age on either an n-3 deficient diet containing
0.01 g ALA/100 g diet or n-3 sufficient diet containing 0.71 g AlA/100 g diet. Molecular species of diradyl glycerophosphoethanolamine.
(GroPEtn), glycerophosphocholine, glycerophosphoserine, and glycerophosphoinositol were analyzed by high-performance liquid
chromatography with on-line electrospray ionization mass spectrometry (HPLC/ESI/MS). Alkenylacyl GroPEtn species were determined
by comparing spectra before and after mild acid treatment while diacyl- and alkylacyl species were distinguished by HPLC/
ESI/MS. The proportions of phospholipid classes and of the diradyl GroPEtn subclasses were not altered by diet changes. The
main polyunsaturated molecular species of diradyl GroPEtn subclasses and of phosphatidylcholine and phosphatidylserine (PtdSer)
contained 16∶0, 18∶0, or 18∶1 in combination with docosahexaenoic acid (DHA, 22∶6n-3), docosapentaenoic (DPA, 22∶5n-6), or
arachidonic acid (ARA, 20∶4n-6). A significant proportion of DPA containing species were present in both diet groups, but
in n-3 fatty acid deficiency, the proportion of DPA increased and DHA was primarily replaced by DPA. The combined value of
main DHA and DPA containing species in the n-3 deficient group ranged from 91-111% when compared with the n-3 sufficient group,
indicating a nearly quantitative replacement. The n-3 fatty acid deficiency did not lower the content of ARA containing molecular
species of PtdSer of the guinea pig brain as reported previously for the rat brain. The molecular species of phosphatidylinositol
were not altered by n-3 fatty acid deficiency. The present data show that the main consequence of a low ALA diet is the preferential
replacement of DHA-containing molecular species by DPA-containing molecular species in alkenylacyl- and diacyl GroPEtn and
PtdSer of guinea pig brain. 相似文献
69.
The triglycerides of bovine milk fat globules were isolated and separated into short, medium and long chain lengths by thin-layer
chromatography. The molecular weight distribution and the fatty acid composition of the component triglycerides was then separately
determined by gas chromatography following argentation-thin-layer and preparative gas chromatography. Some 38 triglyceride
types (28% of total), of which there could be up to 6 isomers, were specifically identified and quantitatively estimated.
The quantitative estimates for the rest of the milk fat triglycerides were limited to much more complex glyceride groups.
The results confirm the earlier claim that butyric and caproic acids occur in milk fat almost exclusively in combination with
medium and long chain fatty acids.
Presented in part at the AOCS Meeting, Philadelphia, October, 1966. 相似文献
70.
Kuksis A. Myher J. J. Marai L. Little J. A. McArthur R. G. Roncari D. A. K. 《Lipids》1986,21(6):371-377
The bulk of the plasma plant sterol in phytosterolemia occurs in the esterified form and is carried mostly in the low and
high density lipoproteins. We have determined the fatty acid composition of the individual plasma steryl esters from a newly
discovered subject with phytosterolemia and xanthomatosis. For this purpose the intact steryl esters were subject to high
temperature gas liquid chromatography (GLC) on a polar capillary column, which separated the major esters on the basis of
molecular weight and degree of unsaturation of the fatty acids. The saturated and unsaturated sterols esterified to saturated,
monoenoic, dienoic and tetraenoic fatty acids were identified by GLC analysis of the sterol moieties of the corresponding
AgNO3-TLC fractions of the steryl esters. The GLC results were confirmed by reversed phase high performance liquid chromatography
combined with mass spectrometry via direct liquid inlet interface. It was found that, in general, each fatty acid was esterified
to the same complement of sterols, and that the esterified sterols possessed a composition comparable to that of the free
plasma sterols, which was comprised of about 75% cholesterol, 6% campesterol, 4% 22,23-dihydrobrassicasterol and 15% β-sitosterol.
The fatty acid composition of the steryl esters differed from that of the 2-position of the plasma phosphatidylcholines, which
contained significantly less palmitic and oleic and more linoleic acid. On the basis of these results and a review of the
literature it is suggested that the plasma cholesteryl and plant steryl esters in phytosterolemia originate from both synthesis
in plasma via the lecithin-cholesterol acyltransferase and synthesis in tissues via the acylCoA-cholesterol acyltransferase. 相似文献