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991.
为解决传统植脂奶油所用部分氢化植物油中饱和脂肪酸与反式脂肪酸带来的健康问题,以椰子油-葵花籽油混合油(质量比1∶ 1)为基料油,β-环糊精和大豆卵磷脂为复合乳化剂,采用物理复配法制备植脂奶油,采用单因素试验研究了水分含量、β-环糊精和大豆卵磷脂添加量对植脂奶油持油性、持水性和稳定性的影响,并通过响应面法优化了制备工艺条件。结果表明:植脂奶油最优制备工艺条件为β-环糊精添加量6.0%、大豆卵磷脂添加量1.1%、水分含量38.0%,在此条件下植脂奶油的持油性和持水性分别达到98.9%和93.8%;对植脂奶油的稳定性分析也进一步说明了持油性、持水性与稳定性之间的正向关系。综上,以β-环糊精和大豆卵磷脂为复合乳化剂,采用物理复配法制备的椰子油-葵花籽油基植脂奶油是一种潜在的营养健康植脂奶油。 相似文献
992.
993.
阿布来提·阿布都热西提 《食品科学》2009,30(4):96-98
对从向日葵舌状花中提取的天然黄色色素在不同环境条件下进行稳定性研究。结果表明,该色素水溶性好,黄色素的最大吸收波长在390nm,具有较好的耐热性、耐光性和耐氧化还原性,食品添加剂和Na+、Ca2+、Zn2+,Cu2+ 等金属离子对这种色素具有护色作用。它是一种价廉易得,使用方便的天然植物色素和良好的食品添加剂及着色剂。 相似文献
994.
High-performance size-exclusion chromatographic studies on polar components formed in sunflower oil used for frying 总被引:1,自引:0,他引:1
R. Arroyo C. Cuesta C. Garrido-Polonio S. López-Varela F. J. Sánchez-Muniz 《Journal of the American Oil Chemists' Society》1992,69(6):557-563
Thermoxidative and hydrolytic alterations of a sunflower oil used in sixty repeated and discontinuous deep-fat fryings of
potatoes were evaluated by column and high-performance size-exclusion (HPSE) chromatography. Successive fryings of potatoes
in sunflower oil, without turnover of fresh oil during the performance of fryings, increased the level of total polar components
in the oil from 3.75% to 27.28% (w/w). Triglyceride polymers, triglyceride dimers, oxidized triglycerides and diglycerides
increased after sixty fryings 89.8, 21.8, 4.9 and 1.7 times, respectively. These increases were well correlated with the number
of fryings. However, there was not significant correlation between levels of free fatty acids and the number of fryings. Polar
compounds were highly (r=0.9691) and significantly (P<0.01) correlated with triglyceride polymers and also highly (r=0.9969 and r=0.9738) and significantly (P<0.01) with triglyceride dimers and oxidized triglycerides, respectively. Nevertheless polar compounds were not significantly
correlated with free fatty acids. Data suggest that an intensive thermoxidative rather than a hydrolytic process takes place
in experimental deep-fat frying of potatoes. 相似文献
995.
Enzymatic interesterification of tallow-sunflower oil mixtures 总被引:2,自引:0,他引:2
Thomas A. Foglia Kimberly Petruso Stephen H. Feairheller 《Journal of the American Oil Chemists' Society》1993,70(3):281-285
In an effort to improve the physical and/or thermal characteristics of solid fats, the enzymatic interesterification of tallow
and butterfat with high-oleic sunflower oil and soybean oil was investigated. The two simultaneously occurring reactions,
interesterification and hydrolysis, were followed by high-performance liquid chromatography of altered glycerides and by gas-liquid
chromatography of liberated free fatty acids. The enzymes used in these studies were immobilized lipases that included either
a 1,3-acyl-selective lipase or acis-9-C18-selective lipase. The degree of hydrolysis of the fat/oil mixtures was dependent upon the initial water content of the reaction
medium. The extent of the interesterification reaction was dependent on the amount of enzyme employed but not on the reaction
temperature over the range of 50–70°C. Changes in melting characteristics of the interesterified glyceride mixtures were followed
by differential scanning calorimetry of the residual mixed glycerides after removal of free fatty acids. Interesterification
of the glyceride mixes with the two types of enzymes allowed for either a decrease or increase in the solid fat content of
the initial glyceride mix. 相似文献
996.
S.?Marmesat M.?Mancha M.?V.?Ruiz-Méndez M.?C.?DobarganesEmail author 《Journal of the American Oil Chemists' Society》2005,82(7):505-510
High-oleic, high-palmitic sunflower oil (HOHPSO) is a seed oil from a new mutant sunflower line characterized by increased
levels of both oleic acid (>50%) and palmitic acid (>25%) and a high oxidative stability. In this study, its performance at
frying temperature was compared with that of palm olein in thermoxidative assays (4 h, 180°C). Also, industrial discontinuous
frying of almonds, peanuts, and sunflower seeds (200 kg of each product) was carried out to define both the performance of
HOHPSO and the main changes undergone by the foods. The evaluation of polar compounds and their distribution in the main groups,
i.e., polymers, oxidized monomers, and DAG, as well as changes in tocopherols and oxidative stability, demonstrated the excellent
behavior of HOHPSO during thermoxidation and frying. The increase in polar compounds and the loss of tocopherols and stability
were much lower for HOHPSO than for palm olein under identical heating conditions. Only 1.3% polar compounds were formed during
industrial discontiuous frying for 4 h and the oil stability increased, probably due to the formation of antioxidant compounds.
As for the foods, the FA composition of the surface oil was clearly different from that corresponding to the internal oil,
the former denoting the presence of HOHPSO in high concentration, particularly in fried sunflower seeds. Changes in oil stability
of the foods attributable to the frying process clearly demonstrate the interest in using a highly stable oil such as HOHPSO
to protect the surface against oxidation during food storage. 相似文献
997.
将小米种子排列成模板,通过在模板内对Al2O3浆料进行离心成形来制备孔径均匀的Al2O3泡沫陶瓷。观察了浆料固相含量对Al2O3生坯密度均匀性的影响,研究了植物种子特性对Al2O3生坯干燥和焙烧行为的影响,测量烧结产物的密度、收缩率、孔隙率和压缩强度,并通过体式显微镜和扫描电镜观察Al2O3泡沫陶瓷的宏观结构和显微组织。研究结果表明,小米和Al2O3生坯具有较好的收缩匹配性,干燥后可以保持生坯形状完整。在较高的固相含量(50%,体积分数)下,离心时的物质分离现象被抑制,孔壁具有较高的生坯相对密度(63.8%)。1500℃烧结2h后,Al2O3泡沫陶瓷具有致密的孔壁和较高的烧结相对密度(98.9%),其孔隙度为66.5%,抗压强度为5.26MPa。 相似文献
998.
Robert L. Wolff Laurent G. Deluc Anne M. Marpeau 《Journal of the American Oil Chemists' Society》1996,73(6):765-771
The seed oils from twenty-five Conifer species (from four families—Pinaceae, Cupressaceae, Taxodiaceae, and Taxaceae) have
been analyzed, and their fatty acid compositions were established by capillary gas-liquid chromatography on two columns with
different polarities. The oil content of the seeds varied from less than 1% up to 50%. Conifer seed oils were characterized
by the presence of several Δ5-unsaturated polymethylene-interrupted polyunsaturated fatty acids (Δ5-acids) with either 18
(cis-5,cis-9, 18∶2,cis-5,cis-9,cis-12 18∶3, andcis-5,cis-9,cis-12,cis-15 18∶4 acids) or 20 carbon atoms (cis-5,cis-11 20∶2,cis-5,cis-11,cis-14, 20∶3, andcis-5,cis-11,cis-14,cis-17 20∶4 acids). Pinaceae seed oils contained 17–31% of Δ5-acids, mainly with 18 carbon atoms. The 20-carbon acids present
were structurally derived from 20∶1n-9 and 20∶2n-6 acids. Pinaceae seed oils were practically devoid of 18∶3n-3 acid and did
not contain either Δ5-18∶4 or Δ5-20∶4 acids. Several Pinaceae seeds had a Δ5-acid content higher than 50 mg/g of seed. The
only Taxaceae seed oil studied (Taxus baccata) had a fatty acid composition related to those of Pinaceae seed oils. Cupressaceae seed oils differed from Pinaceae seed
oils by the absence of Δ5-acids with 18 carbon atoms and high concentrations in 18∶3n-3 acid and in Δ5-acids with 20 carbon
atoms (Δ5-20∶3 and Δ5-20∶4 acids). Δ5-18∶4 Acid was present in minute amounts. The highest level of Δ5-20∶4 acid was found
inJuniperus communis seed oil, but the best source of Δ5-acids among Cupressaceae wasThuja occidentalis. Taxodiaceae seed oils had more heterogeneous fatty acid compositions, but the distribution of Δ5-acids resembled that found
in Cupressaceae seed oils. Except forSciadopytis verticillata, other Taxodiaceae species are not interesting sources of Δ5-acids. The distribution profile of Δ5-acids among different
Conifer families appeared to be linked to the occurrence of 18∶3n-3 acid in the seed oils. 相似文献
999.
We assessed the anti-Listerial activities of crude n-hexane and aqueous extracts of Garcinia kola seeds against a panel of 42 Listeria isolates previously isolated from wastewater effluents in the Eastern Cape Province of South Africa and belonging to Listeria monocytogenes, Listeria grayi and Listeria ivanovii species. The n-hexane fraction was active against 45% of the test bacteria with zones of inhibition ranging between 8-17 mm, while the aqueous fraction was active against 29% with zones of inhibition ranging between 8-11 mm. The minimum inhibitory concentrations (MIC) were within the ranges of 0.079-0.625 mg/mL for the n-hexane extract and 10 to >10 mg/mL for the aqueous extract. The rate of kill experiment carried out for the n-hexane extract only, revealed complete elimination of the initial bacterial population for L. grayi (LAL 15) at 3× and 4× MIC after 90 and 60 min; L. monocytogenes (LAL 8) at 3× and 4× MIC after 60 and 15 min; L. ivanovii (LEL 18) at 3× and 4× MIC after 120 and 15 min; L. ivanovii (LEL 30) at 2, 3 and 4× MIC values after 105, 90 and 15 min exposure time respectively. The rate of kill activities were time- and concentration-dependant and the extract proved to be bactericidal as it achieved a more than 3log(10) decrease in viable cell counts after 2 h exposure time for all of the four test organisms at 3× and 4× MIC values. The results therefore show the potential presence of anti-Listerial compounds in Garcinia kola seeds that can be exploited in effective anti-Listerial chemotherapy. 相似文献
1000.
变浓度合成ZSM-5分子筛膜的成膜机理研究 总被引:1,自引:0,他引:1
在平均孔径为2 μm多孔α-Al2O3陶瓷管外表面,采用不同方法合成了ZSM-5分子筛膜.通过对ZSM-5分子筛膜SEM的研究,提出了变浓度下ZSM-5分子筛膜的成膜机理.变浓度晶化法合成分子筛膜,预涂在载体表面的纳米晶种粒子形成凝胶层,此层晶种诱发更多新的晶核生成;在浓晶化液中,发生固相机理和液相机理作用,晶核会逐渐长大;在稀晶化液中,是液相机理起作用,载体表面晶粒的部分溶解,晶粒表面的修饰和再生长,膜内晶粒的形貌更加完整,有效地减少了晶化液的用量和合成次数,膜层薄,膜质量好.最后对不同方法合成的ZSM-5分子筛膜进行了XRD表征,并且对膜性能进行了比较. 相似文献