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排序方式: 共有224条查询结果,搜索用时 15 毫秒
91.
Yin Ruixing Li Rongshan Lin Weixiong Yang Dezhai Pan Shangling 《European Journal of Lipid Science and Technology》2006,108(7):561-568
There are 56 nationalities in China. Han is the largest and Zhuang the second largest. Geographically and linguistically, Zhuang can be classified into 43 ethnic subgroups, in which Hei Yi (meaning black‐worship and black‐dressing) Zhuang is proved to be the most conservative group according to its unique culture and custom. Information on the genetic influence on the lipid profile is limited in this population. To obtain some of this information, a cross‐sectional survey of hyperlipidemia was carried out in 500 people of Hei Yi Zhuang and 500 people of Han in the same area. The genotypes and alleles of the microsomal triacylglycerol transfer protein (MTP –493 G/T) were also determined, by polymerase chain reaction combined with an allele‐specific oligonucleotide hybridization method, and then confirmed by direct sequencing. The frequencies of the G and T alleles were 0.74 and 0.26, respectively, in Hei Yi Zhuang, and 0.73 and 0.27 (p >0.05) in Han. The frequencies of the GG, GT and TT genotypes were 0.58, 0.33 and 0.09, respectively, in Hei Yi Zhuang, and 0.56, 0.34 and 0.09 (p >0.05) in Han. In the combined population of both Hei Yi Zhuang and Han, the levels of total cholesterol, triacylglycerol, low‐density lipoprotein cholesterol, and apolipoprotein B in the TT genotype were significantly higher than those in the GT (p <0.05 to <0.01) or GG genotypes (p <0.05 to <0.01), but there were no significant differences in their values between the GG and GT genotypes (p >0.05). The levels of high‐density lipoprotein cholesterol and apolipoprotein A1 were not significantly different among the three genotypes (p >0.05). 相似文献
92.
Electrospray and matrix assisted laser desorption ionization generate abundant molecular ion species from all known lipids that have long chain fatty acyl groups esterified or amidated to many different polar headgroup features. Molecular ion species include both positive ions from proton addition [M+H](+) and negative ions from proton abstraction [M-H](-) as well as positive ions from alkali metal attachment and negative ions from acetate or chloride attachment. Collisional activation of both MALDI and ESI behave very similarly in that generated molecular species yield product ions that reveal many structural features of the fatty acyl lipids that can be detected in tandem mass spectrometric experiments. For many lipid species, collision induced dissociation of the positive [M+H](+) reveals information about the polar headgroup, while collision induced dissociation of the negative [M-H](-) provides information about the fatty acyl chain. The mechanisms of formation of many of these lipid product ions have been studied in detail and many established pathways are reviewed here. Specific examples of mass spectrometric behavior of several molecular species are presented, including fatty acids, triacylglycerol, phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidylglycerol, ceramide, and sphingomeylin. 相似文献
93.
Huiling Mu Henrik Sillen Carl-Erik Hiy 《Journal of the American Oil Chemists' Society》2000,77(10):1049-1060
Atmospheric pressure chemical ionization liquid chromatography/mass spectrometry was used in the identification of diacylglycerol
and triacylglycerol (TAG) molecular species in a sample of a structured lipid. In the study of acylglycerol standards, the
most distinctive differences between the diacylglycerol and TAG molecules were found to be the molecular ion and the relative
intensity of monoacylglycerol fragment ions. All saturated TAG ranging from tricaproin to tristearin, and unsaturated TAG
including triolein, trilinolein, and trilinolenin, had ammonium adduct molecular ions [M+NH4]+. Protonated molecular ions were also produced for TAG containing unsaturated fatty acids and the intensity increased with
increasing unsaturation. Diacylglycerol fragment ions were also formed for TAG. The ammonium adduct molecular ion was the
base peak for TAG containing polyunsaturated fatty acids, whereas the diacylglycerol fragment ion was the base peak for TAG
containing saturated and monounsaturated medium- and long-chain fatty acids; the relative intensities of the ammonium adduct
molecular ions were between 14 and 58%. The most abundant ion for diacylglycerols, however, was the molecular ion [M−17]+, and the relative intensity of the monoacylglycerol fragment ion was also higher than that for TAG. These distinctive differences
between the diacylglycerol and TAG spectra were utilized for rapid identification of the acylglycerols in the sample of a
structured lipid. 相似文献
94.
J. -P. Kurvinen O. Sjövall H. Kallio 《Journal of the American Oil Chemists' Society》2002,79(1):13-22
Triacylglycerol (TAG) molecular weight distribution and regioisomeric structure of selected molecular weight species in human
milk and in 32 human milk substitutes was determined. Negative ion chemical ionization mass spectrometry was used to determine
the molecular weight distribution and collisionally induced dissociation tandem mass spectrometry applied to identify the
sn-2 and sn-1/3 positions of fatty acids in TAG. The main molecular weight species of human milk TAG in decreasing order of abundance
were 52∶2, 52∶3, 52∶1, 54∶3, 50∶2, 50∶1, 54∶4, 48∶1, 54∶2, 48∶2, 46∶1, 52∶4, and 50∶3 (acyl carbon number/number of double
bonds), constituting 83 mol% of total TAG molecular species. In human milk substitutes, the proportion of the corresponding
molecular weight species varied from 33 to 87 mol%. The main TAG regioisomers within the molecular weight species 52∶2, 52∶3,
and 50∶1 in human milk were 18∶1-16∶0-18∶1 (83 mol%), 18∶1-16∶0-18∶2 (83 mol%), and 18∶1-16∶0-16∶0 (80 mol%), respectively.
In human milk substitutes, the corresponding proportions varied in a wide range of 0–82 mol%, 0–100 mol%, and 0–73 mol%, respectively.
Although TAG structures in some human milk substitutes closely resembled those in human milk, the great variation among samples
leads to the conclusion that it is still possible to improve the TAG composition in human milk substitutes by applying novel
methods to synthesize structured TAG. 相似文献
95.
Bart G. Muuse F. Petrus Cuperus Johannes T. P. Derksen 《Journal of the American Oil Chemists' Society》1994,71(3):313-317
Dimorphotheca pluvialis is increasingly recognized as an interesting industrial new oilseed crop because it contains up to 60% of the unusual fatty
acid dimorphecolic acid (9-hydroxy,10t,12t-18∶2) (DA) for which new applications are being developed. In this paper, the yield, composition and quality are evaluated
for dimorphotheca oils (DMO) which were recovered by pressing, conventional solvent extraction and supercritical carbon dioxide
extraction (SCE). Mechanical pressing of the seeds required high temperatures and resulted in an oil recovery of only 40%,
whereas the extraction protocols yielded more than 95%. Oil recovery by pressing of winged seed was even more difficult than
that of unwinged seeds; hence, solvent extraction of winged seeds was preferred. The dark-colored DMO, recovered by expelling
or by extraction with organic solvents, needed further refining to remove pigments and gums, whereas the light yellow-colored
SCE DMO did not require further refining. SCE oil had a low phospholipid content (11 mg P/kg). Pressed oil (95 mg P/kg) and
hexaneor pentane-extracted DMO (200 mgP/kg) had much higher phospholipid contents. Peroxide andp-anisidine values were low for freshly recovered oils, but increased after storage, especially in the SCE oil, due to the
low concentration of natural antioxidants in SCE DMO, such as tocopherols. The DA content of the oils recovered by the various
techniques showed only minor differences, except that supercritical carbon dioxide had slightly decreased solubilizing power
for tri- and di-dimorphecolin as compared to hexane and pentane. 相似文献
96.
More than 95% of polyunsaturated acid (PUFA) was converted to triacylglycerol by immobilized lipase fromCandida antarctica orRhizomucor miehei. The esterification was carried out at 50–60°C with shaking and dehydration for 24 h. The substrates consisted of glycerol
and free fatty acid or ethyl esters of the fatty acid at a 1∶3 molar ratio. The docosahexaenoic acid (DHA) or eicosapentaenoic
acid (EPA) in the substrate polymerized during the reaction, and they required 5–10% more than the stoichiometric amount to
compensate for the PUFA loss. On the contrary, ethyl esters of DHA and EPA were not polymerized. Pure tridocosahexaenoyl,
trieicosapentaenoly and triarachidonoyl glycerol were isolated after passing the product through a basic aluminum oxide column.
Industrial feasibility of this process was discussed for the ethyl ester as substrate.
Portions of this article were presented at the annual meeting of the Japan Society for Bioscience, Biotechnology, and Agrochemistry
and at the annual meeting of The Japan Oil Chemists' Society held in Kyoto, Japan, March 31, 1991, and in Hamamatsu, Japan,
October 4, 1991, respectively. 相似文献
97.
98.
Denis R. Body 《Journal of the science of food and agriculture》1985,36(8):679-684
Lipid analysis was carried out on orange roughy (Hoplostethus atlanticus) roe oil. Various chromatographic analytical techniques were compared and it was shown, although total orange roughy oil was rich in wax esters, that roe oil contained triacylglycerol and phospholipids as the principal components. The fatty acid content of the individual lipids (except wax esters) had 16:0, 18:1, 20:1, 20:5 and 22:6 as their major constituents. 相似文献
99.
A potential revolution in FA therapies is on the horizon. In recent years, the full magnitude of various FA treatments and
their overall importance to health has become increasingly apparent. Fetal and infant nutrition studies have clearly shown
that FA status at birth can have life-long health implications affecting eye and brain function, insulin resistance, and blood
pressure control. As well, nutrition studies have identified dietary imbalances and deficiencies that have the potential to
alter the health of future generations severely and to promote progression of age-related degenerative disorders.
Mixtures of naturally occurring FA have shown promise as therapeutic agents for a diverse range of health conditions including
atopic eczema, rheumatoid arthritis, cardiovascular disease, and neurological problems. Through the 1990s, the creation of
technologies to concentrate and formulate pharmacologically active individual FA components as well as tailored combinations
propelled development of this new drug category. However, high production costs and government regulatory encumbrance limited
the expansion of this emerging pharmaceutical sector. Fortunately, many countries are now creating regulatory frameworks that
are better suited for product evaluation and control of the manufacturing FA products than historical drug models, and hence
expansion in this area is now anticipated. 相似文献
100.
Coconut is the largest oilseed. In the present investigation, various lipid classes, such as triacylglycerol, free fatty acid,
diacylglycerol, and their fatty acid compositions were determined from three regions of germinating coconut at three stages
of germination. In this process, triacylglycerol was hydrolyzed and resynthesized in the haustorium tissue. Cooperative participation
of various tissues, such as endosperm, haustorium, and embryo, was therefore involved in the process of germination of coconut. 相似文献