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81.
Laura Vera-Ramirez M. Carmen Ramirez-Tortosa Pedro Sanchez-Rovira Cesar L. Ramirez-Tortosa Sergio Granados-Principal Jose A. Lorente 《Critical reviews in food science and nutrition》2013,53(1):49-75
Breast cancer, which presents the highest global incidence of all female cancers, is caused by the interaction of genetic and environmental factors. Among the latter, diet has attracted considerable attention, as it is a modifiable risk factor and thus offers an opportunity to design preventive strategies. Nevertheless, only alcohol consumption has been unequivocally related to increased breast cancer risk. Despite the failure of observational studies in human populations to clearly define the nature of the relationship between specific nutrient exposures and breast cancer risk, in vivo and in vitro studies strongly suggest its existence. Moreover, studies at the molecular level have identified the putative action mechanism by which the nutritional constituents of specific foodstuffs may exert protective or enhancing effects with respect to breast cancer risk. The inadequate experimental design of some observational studies, or the occurrence of measurement errors and/or recall bias during data collection, or insufficient follow-up and subject characterization, may underlie these controversies. By improving the methods used to study the relationship between diet and breast cancer risk, and by applying new technologies linked to novel approaches such as “nutrigenomics,” it might be possible to derive effective recommendations for breast cancer prevention and thus improve anti-cancer treatment. 相似文献
82.
Reginaldo Almeida da Trindade Jorge Mancini‐Filho Anna Lúcia Casañas Haasis Villavicencio 《European Journal of Lipid Science and Technology》2009,111(11):1161-1168
The purpose of this study was to assess the efficacy of rosemary and oregano extracts in avoiding oxidative changes in beef burgers, and to evaluate the fatty acid profile of these products after electron beam exposition. Extracts, individually or in combination, were added to beef burgers and compared to synthetic antioxidants commonly used in food (butylated hydroxytoluene, butylated hydroxyanisole). The ground beef were submitted to electron beam irradiation at doses of 0, 3.5 and 7 kGy, and stored for 90 days. At regular time intervals, lipid oxidation and fatty acid composition were evaluated through measurement of thiobarbituric acid‐reactive substances (TBARS) and gas chromatography, respectively. The results indicate that, although the irradiation process triggers an increase in the lipid oxidation ratio expressed by TBARS values, great changes in the fatty acid profiles were not observed; instead, they continued to present characteristics very similar to that of non‐irradiated beef. Thus, as irradiation doses of up to 7 kGy for frozen meat can make foods safe from foodborne pathogens, natural antioxidants derived from spices are able to reduce and avoid lipid changes that may cause a deterioration of the sensory quality of these foods, and these natural extracts offer a good choice for replacing synthetic additives. 相似文献
83.
Antioxidative/Antimicrobial Effects and TBARS in Aerobically Refrigerated Beef as Related to Microbial Growth 总被引:2,自引:0,他引:2
Ground beef muscle-pretreated (PT) with 60 ppm chlortetracycline/0.2% potassium sorbate or nonpretreated (NPT)-was mixed with sodium lactate (3%), ascorbate (0.05%), tripolyphosphate (0.5%), citrate (0.5%), or water only and aerobically refrigerated for 0–18 days. More TBA-reactive substances (TBARS) were accumulated in PT than in NPT samples. Only lactate was antimicrobial and resulted in higher TBARS in the NPT. Ascorbate and citrate resulted in lower TBARS in both PT and NPT meat. TBARS correlated with 18:2 fatty acid losses only in microbially controlled (PT) samples. Ascorbate and citrate reduced overall off-odor scores in the PT and discoloration in both NPT and PT samples. 相似文献
84.
Antonella De Leonardis Alessandra Aretini Gabriele Alfano Vincenzo Macciola Giancarlo Ranalli 《European Food Research and Technology》2008,226(4):653-659
In this research, a phenol extract of high hydroxytyrosol (OLPE) content was obtained from olive leaves (Olea europaea L.), and subsequently tested under different contexts. The method used to obtain the OLPE basically involved two steps: the
use of strongly-acid aqueous steam, generated from 10% HCl (v/v) at 100°C, to directly hydrolyse the native complex phenols
from integral olive leaves, and OLPE recovery by liquid–liquid extraction with ethyl acetate. Hydrolysis time was 1 h. Finally,
the dried extract was dissolved in distilled water. The OLPE total phenols were determined by Folin–Ciocalteu’s method and
by HPLC analysis. Hydroxytyrosol was about 92% of the total phenols present in OLPE, and the yield was about 0.2% on fresh
leaves. OLPE showed antioxidant effects on different food lipids and did not inhibit lactic acid bacteria growth; however,
it showed cytotoxicity on NIH/3T3 fibroblasts and human umbilical vein endothelial cells at concentrations higher than 0.32 mM
(as hydroxytyrosol). 相似文献
85.
为提高牡丹籽油乳液的氧化稳定性,将叔丁基对苯二酚(TBHQ)与天然抗氧化剂(生育酚、抗坏血酸)进行复配,测定不同抗氧化剂对牡丹籽油乳液的抗氧化作用,并分析了不同复配抗氧化剂的相互作用机制。结果表明:在贮藏30 d时,添加和未添加抗氧化剂牡丹籽油乳液的粒径相较于0 d 均略有增加,200 mg/kg TBHQ与800 mg/kg抗坏血酸复配时乳液的Zeta电位绝对值最大,且抗氧化作用最强;TBHQ与抗坏血酸表现出较好的协同抗氧化作用,与生育酚表现出拮抗作用;TBHQ与生育酚之间拮抗作用的原因主要是TBHQ减少了生育酚在牡丹籽油乳液中油水界面的含量,而TBHQ与抗坏血酸之间协同作用主要是由于抗坏血酸增加了TBHQ在牡丹籽油乳液中油水界面的含量。综上,TBHQ与抗坏血酸复配能提高牡丹籽油乳液的氧化稳定性。 相似文献
86.
M. J. Abad A. Ares L. Barral J. Cano F. J. Díez S. García‐Garabal J. Lpez C. Ramírez 《应用聚合物科学杂志》2004,92(6):3910-3916
The properties of two polyethylenes [a high‐density polyethylene (HDPE) and a low‐density polyethylene (LDPE)] were studied after several extrusion cycles. To reduce the degradation effects during the reprocessing, a mixture of two stabilizers was added to the formulations. The predominant degradation mechanism was chain scission for the HDPE and chain branching and crosslinking for the LDPE. For both polyethylenes the FTIR spectra exhibited a growth in the number of carbonyl groups as a function of the number of extrusion cycles. Their tensile properties were degraded with the reprocessing but both polyethylenes maintained their nearly constant thermal behavior and crystallinity. The addition of a primary phenolic antioxidant and a secondary phosphite antioxidant preserved the melt behavior of virgin materials after the reprocessing and reduced the degradation effects. From the tensile tests, the efficiency of the antioxidants in the LDPE was very high and, after the reprocessing, the material retained the mechanical properties of virgin LDPE. The efficiency of the antioxidants for the HDPE was not significant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3910–3916, 2004 相似文献
87.
Ronald S Fletcher Tannis Slimmon Colette Y McAuley Laima S Kott 《Journal of the science of food and agriculture》2005,85(14):2429-2436
Selected high‐phenolic lines of spearmint were subjected to a constant 30 °C heat regimen for a period of 4 weeks to determine the effects of heat stress on soluble phenolics, phenols and rosmarinic acid biosynthesis and antioxidant capacity. Heat stress significantly reduced levels of total phenolic acids (71–87%) and soluble phenols (75–87%). This loss was concomitant with a loss of total antioxidant capacity of 21–60% after week 1 and up to 95% by week 4. High‐performance liquid chromatography profiling of heat‐stressed plants at 270 and 320 nm detected nearly a complete loss of rosmarinic acid in all seven chemotypes. High‐temperature drying of non‐heat‐stressed plants at 80 °C resulted in a similar loss of total antioxidant capacity and rosmarinic acid content an effect not observed in material that was subjected to low‐temperature drying first, followed by exposure to high temperature. This suggests that heat stress negatively regulates rosmarinic acid biosynthesis and causes a potential rapid biological breakdown of rosmarinic acid in tissues. 2,2‐Diphenyl‐1‐picrylhydrazyl radical assays of heat‐stressed and non‐stressed plants clearly show that rosmarinic acid is the major contributor to the antioxidant capacity in spearmint. Copyright © 2005 Society of Chemical Industry 相似文献
88.
Andrei Mocan Dan Cristian Vodnar Laurian Vlase Ovidiu Cri?an Ana-Maria Gheldiu Gianina Cri?an 《International journal of molecular sciences》2015,16(9):21109-21127
Aerial parts of Veronica species are used in Romanian traditional medicine for the treatment of various conditions like kidney diseases, cough, and catarrh, and are known for their wound-healing properties. In the present study, the phenolic and sterolic content and the antioxidant and antimicrobial activities of three Veronica species (Plantaginaceae), V. officinalis L., V. teucrium L. and V. orchidea Crantz, were studied. The identification and quantification of several phenolic compounds and phytosterols were performed using LC/MS techniques and the main components were p-coumaric acid, ferulic acid, luteoline, hispidulin and β-sitosterol. More than that, hispidulin, eupatorin and eupatilin were detected for the first time in the Veronica genus. Nevertheless, representatives of the Veronica genus were never investigated in terms of their phytosterol content. The antioxidant potential investigated by Trolox equivelents antioxidant capacity (TEAC) and EPR spectroscopy revealed that V. officinalis and V. orchidea extracts presented similar antioxidant capacities, whilst the values registered for V. teucrium extract are lower. Regarding the antimicrobial activity of the investigated species, Staphylococcus aureus, Listeria monocytogenes and Listeria ivanovii were the most sensitive strains with MIC values between 3.9 and 15.62 mg/mL. The results obtained by this study may serve to promote better use of representatives from the genus Veronica as antioxidant and antimicrobial agents. 相似文献
89.
Chunhua Luo Warren Grigsby Neil Edmonds Allan Easteal Jafar Al‐Hakkak 《应用聚合物科学杂志》2010,117(1):352-360
Reported is the preparation of various condensed tannin stearates and the associated chemical characterization and thermal properties of these products. Stearate esters of condensed tannins from both quebracho and pine bark extracts were prepared in generally high, isolated yields from reaction with stearic acid chloride. Tannin esterification was confirmed by both Fourier transform infrared and nuclear magnetic resonance (NMR), and the average degree of stearate substitution was calculated from 1H‐NMR analysis. Product degree of substitution (DS) was observed to proportionately increase with higher stearic acid chloride ratio with maximum DS values of 4.0 and 5.1 achieved for quebracho and pine tannins, respectively. Thermal analysis revealed that tannin stearate products have increased thermal stability with a degradation onset at significantly higher temperature for those samples possessing relatively greater DS. Analysis using differential scanning calorimetry revealed isolated products to consist of multiple components which exhibit interesting melt behaviors, a likely result from their work up on isolation. However, multiple melt features of the individual components in products were lost on heating to give single, broad melt endotherms due to coalescence of sample components. Furthermore, tannin stearate samples with high DS show relatively greater endothermic melting at higher temperature than those samples with lower DS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
90.
Development of an HPLC method for measurements of the stability of Irganox-type polymer antioxidants in fatty food simulants 总被引:1,自引:0,他引:1
A reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed to measure the stability of four
Irganox-type polymer antioxidants (Irganox 245, Irganox 1035, Irganox 1098 and Irganox 3114) in an olive oil food simulant
and isooctane, which has been proposed as an alternative fatty food simulant. The tests of stability in olive oil were carried
out under three different conditions, i.e. 40°C for 10 days, 100°C for 1 h and 175°C for 1 h. The exposure conditions for
isooctane were 60°C for 3 h. Results showed that for all additives tested no instability phenomena in olive oil or isooctane
simulants were observed under the exposure conditions applied. The analytical methodology developed could eventually be used
for stability testing and migration studies of other similarly structured antioxidants in fatty food simulants.
Received: 11 September 1997 相似文献