全文获取类型
收费全文 | 897篇 |
免费 | 51篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 496篇 |
金属工艺 | 19篇 |
机械仪表 | 6篇 |
建筑科学 | 21篇 |
矿业工程 | 9篇 |
能源动力 | 32篇 |
轻工业 | 159篇 |
水利工程 | 6篇 |
石油天然气 | 1篇 |
无线电 | 16篇 |
一般工业技术 | 94篇 |
冶金工业 | 11篇 |
原子能技术 | 1篇 |
自动化技术 | 70篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 104篇 |
2021年 | 139篇 |
2020年 | 28篇 |
2019年 | 43篇 |
2018年 | 24篇 |
2017年 | 31篇 |
2016年 | 36篇 |
2015年 | 39篇 |
2014年 | 51篇 |
2013年 | 46篇 |
2012年 | 51篇 |
2011年 | 61篇 |
2010年 | 32篇 |
2009年 | 25篇 |
2008年 | 31篇 |
2007年 | 27篇 |
2006年 | 31篇 |
2005年 | 26篇 |
2004年 | 17篇 |
2003年 | 19篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有948条查询结果,搜索用时 15 毫秒
11.
Grażyna Budryn Dorota Żyżelewicz Ewa Nebesny Joanna Oracz Wiesława Krysiak 《Food research international (Ottawa, Ont.)》2013,50(1):149-160
This study investigated the influence of antioxidants of green tea aqueous extract (GTE) and green coffee aqueous extract (GCE) in concentrations of 0.25, 0.5 and 1 g·100 g? 1 on the nutritional properties of fine yeast pastry fried products such as donuts. Yeast donuts were made according to the traditional processing technology. In fried donuts physical properties (water activity, pH, hardness and color with the use of instrumental methods) as well as sensory properties were established. Moreover, quality of fat extracted from donuts (composition of fatty acids and peroxide value), content of acrylamide, composition of polyphenols and antioxidant activity were analyzed. Obtained extracts of GTE and GCE contained 26 and 41% of polyphenols, respectively, and the degree of polyphenol degradation during production of donuts was less when the dilution in dough was greater. Both tests indicated that the highest antioxidant activity had donuts with the highest analyzed addition of extract, however depending on the applied test or GTE or GCE had better antioxidant properties. Fatty acid composition was the most beneficial when the addition of GTE and GCE was on a level of 0.25 and 0.5 g·100 g? 1, respectively. In fried donuts relatively low amounts of acrylamide were obtained, amounting to 18–46 μg·kg? 1. Only the lowest addition of GTE and the highest addition of GCE caused an increase of acrylamide content in donuts, while all other levels of added extracts caused a decrease in the content of formed acrylamide. 相似文献
12.
Grażyna Budryn Ewa Nebesny Joanna Oracz 《International Journal of Food Properties》2013,16(2):290-302
The aim of this study was to determine the effect of different roasting conditions, including temperature, humidity, and roasting air velocity on acrylamide contents in roasted Robusta coffee. In addition, acrylamide concentrations were correlated with the degradation of coffee bean polyphenols and its antioxidant activity. In the process of roasting in a quarter-technological scale apparatus used temperatures ranged from 190 to 216°C. Dry or moist air at a velocity of 0.5 or 1 m s?1 was used. Beans were roasted to achieve optimal sensory properties. The increase of roasting air velocity regardless of its temperature resulted in the intensification of acrylamide formation. The increase of humidity of roasting air caused a reduction of acrylamide formation, but only at the highest used roasting temperature. However, the modification of roasting conditions to achieve a drop in acrylamide concentration resulted in increased degradation of polyphenols and/or deterioration of antioxidant activity. The optimal roasting parameters were: Temperature 203°C, dry air, and low velocity of roasting air. Under these conditions, the roasted beans were characterized by relatively low level of acrylamide and moderate degradation of polyphenols. 相似文献
13.
Jolanta Gawałek Ewa Domian Antoni Ryniecki Sławomir Bakier 《International Journal of Food Science & Technology》2017,52(9):1933-1941
A semi‐industrial spray drying process of chokeberry juice concentrate using maltodextrin was analysed. The influence of the content and dextrose equivalent (DE) of maltodextrin, inlet air temperature and rotary disc atomiser speed was studied on the physicochemical properties of the obtained powders. The size and structure of the powder particles, bulk density, moisture content, flowability, yield and total polyphenol content were analysed. An increase in carrier content from 50% to 70% caused a 4.9% increase in total polyphenol retention, better flowability (Hausner ratio decrease of 0.17) and greater yield of the powder (60%). An increase in the drying temperature (150–170 °C) caused larger particle size and improved powder flowability but also resulted in greater loss of total polyphenols. A decrease in rotary atomiser speed (11 000–15 000 rpm) had a moderate influence on particle size and improvement in flowability but had no effect on polyphenol retention. Changes in the DE (8–22) of maltodextrin as a carrier indicated a moderate growing dependence on particle size and worse flowability. 相似文献
14.
The objective of this study was to evaluate the potential of double wall material combinations, using legume protein (soy protein isolate and pea protein isolate) in combination with wheat dextrin soluble fiber or trehalose, as alternative materials for microencapsulation of flaxseed oil by spray drying. The obtained preparations, with oil content of 35%, were fine and difficult flowing powders, regardless of their composition. The 1% addition of silica to the powders significantly reduced their cohesiveness and improved their flowability. The efficiency of microencapsulation, calculated based on oil fat content, ranged from 62 to 98% and was higher in the powders with trehalose and in the powders containing soy protein. Effective protection against oxidation of microencapsulated oil was achieved in the protein-trehalose matrix, especially in the case of the vacuum-packed powders with pea protein during storage at refrigeration temperature. Replacing trehalose with soluble fiber enabled formation of powders less susceptible to caking under conditions of increased humidity, but it resulted in decreased microencapsulation efficiency. The combination of pea protein/carbohydrate resulted in the formation of microcapsules with porous structure, especially in the system with soluble fiber. With time, the structure of the primary emulsions and those reconstituted from powders containing pea protein changed from liquid to greasy and paste-like. 相似文献
15.
Katarzyna E. Sartowska Agnieszka Korwin‐Kossakowska Ewa Polawska Paulina Lipinska Grazyna Sender 《International Journal of Food Science & Technology》2014,49(12):2635-2642
The objective of the study was to evaluate the impact of birds’ sex on the carcass composition and meat (breast muscle) nutritional value in Japanese quails in a large‐scale four‐generation study. Standard poultry feed was used, based on maize, soya bean meal and wheat. Four generations of quails were housed up to the age of 17 weeks each. Then samples of breast muscle were collected after dissection and analysed for basic nutrient content and for fatty acids composition. Results were analysed by GLM procedure in SAS, and significance of differences between birds of different sex was estimated by Duncan's test. Dissection revealed marked differences between birds’ of different sex in case of relative organ weight. Results of meat analyses showed no differences in the basic composition. Fatty acids analyses showed a more advantageous profile in female meat. 相似文献
16.
Dorota Żyżelewicz Wiesława Krysiak Ewa Nebesny Grażyna Budryn 《European Food Research and Technology》2014,238(4):549-563
Cocoa beans of Forastero variety from Togo were subjected to roasting under either constant or variable process parameters. The variable process parameters were roasting air flow rate, temperature and relative humidity. The color of roasted cocoa beans was determined by pigment extraction under various conditions followed by either their spectrophotometric assays or CIE L*a*b measurements. Also the Maillard compounds index and total polyphenols content correlated with progress of the browning of beans were determined. It was found that an increase in the roasting air relative humidity stimulated formation of brown pigments, while elevated temperature caused worsening of color parameters of roasted cocoa beans. The most suitable method of color characterization of roasted cocoa beans was found to be pigments extraction combined with either separation of their fractions or CIE L*a*b measurements. These assays revealed that cocoa beans roasted under variable roasting air flow rate were characterized by improved color parameters. The relatively simple and inexpensive CIE L*a*b measurements ensured fast analysis of color parameters, while total polyphenols in roasted cocoa beans were quickly estimated by using F–C reagent. Furthermore, quantification of melanoid pigments in roasted cocoa beans can be based on determination of the index of nonenzymatic browning products content, which is relatively simple and inexpensive. 相似文献
17.
Effects of various roasting conditions on antioxidant properties of five Theobroma cacao L. varieties were investigated. The cocoa beans were roasted at four different temperatures (110–150°C) and three different air humidities (0.3–5.0%). The raw cocoa beans were characterized by high antioxidant activities. The antioxidant properties of the roasted cocoa beans varied markedly among the analyzed cultivars and geographical regions and were affected by roasting conditions. Generally, cocoa beans of the cv. Forastero from Brazil exhibited higher total phenolic content, free radical scavenging activity, and metal chelating ability than samples of the other analyzed cocoa varieties. Roasting at 110°C caused negligible changes in total phenolics content and antioxidant activity of cocoa beans, while almost all samples tended to have lower antioxidant potential when roasting temperature increased. The air humidity used in roasting did not affect the total phenolics content and antioxidant activity for lowest roasting temperature (110°C). Moreover, the obtained results revealed that thermal processing at the higher temperatures and elevated air humidity resulted in the higher antioxidant capacities. It was also found that the ferrous ion chelating activity of cocoa beans increased with the roasting temperature (in the range from 110 to 150°C), with the exception of cv. Trinitario from Papua New Guinea. The data showed that roasting at lower temperatures with humid air are more favorable in terms of preserving the bioactivity of roasted cocoa beans. 相似文献
18.
19.
A multiresidue method for the analysis of over 140 multiclass pesticides in fruiting vegetables, based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation procedure followed by gas chromatography-tandem mass spectrometry (GC-MS/MS), was established. In the validation study, the overall recoveries from spiked samples were 102?±?7, 95?±?7, and 95?±?7 % with RSD values of 7?±?3, 7?±?4, and 7?±?3 % at the spiking levels of 0.01, 0.05, and 0.5 mg kg?1, respectively, demonstrating fitness for purpose of the method. The limit of quantification (LOQ) was 0.01 mg kg?1 for more than 90 % of the target compounds. The analysis of over 300 samples of tomatoes, sweet peppers, and cucumbers was carried out in 2006–2014. Of these samples, 52 % contained pesticide residues but the results of the assessment of dietary exposure supported the conclusion that the presence of pesticide residues was unlikely to have a negative effect on the health of consumers. Although some of the pesticides detected in years 2006–2009 are no longer approved in the European Union member countries (namely endosulfan, oxadixyl, procymidone, propargite, and tolylfluanid), the consumer dietary exposure was low and did not exceed 12 % of the acceptable daily intake (ADI) considering both adults’ and children’s diet. Regarding short-term exposure (acute), in only one case of procymidone in sweet pepper, the acute reference dose (ARfD) for children was exceeded by 139.6 % of the ARfD. 相似文献
20.
Time dependence of bioactive compounds and antioxidant capacity during germination of different cultivars of broccoli and radish seeds 总被引:2,自引:0,他引:2
Cristina Martinez-Villaluenga Elena Peñas Ewa Ciska Mariusz K. Piskula Halina Kozlowska Concepción Vidal-Valverde Juana Frias 《Food chemistry》2010
Optimisation of the germination process of different cultivars of broccoli (Brassica oleracea var. italica cv. Lucky, cv. Tiburon and cv. Belstar) and radish (Raphanus sativus cv. Rebel and cv. Bolide) seeds in relation to the content of glucosinolates (GLS), vitamin C and total antioxidant capacity was carried out in order to maximise the health-promoting properties of Brassica sprouts. The content of total and individual GLS varied between species, among cultivars, and germination time. Glucoraphanin in broccoli and glucoraphenin in radish were the predominant GLS in raw seeds (61–77 and 63–129 μmol/g DM, respectively) and, although their content decreased during germination, they were maintained in rather large proportions in sprouts. Vitamin C was not detected in raw seeds and its content increased sharply in broccoli and radish sprouts (162–350 and 84–113 mg/100 g DM, respectively). Raw brassica seeds are an excellent source of antioxidant capacity (64–90 and 103–162 μmol Trolox/g DM in broccoli and radish, respectively) and germination led to a sharp increase. Germination of broccoli cv. Belstar and radish cv. Rebel for 4 days provided the largest glucoraphanin and glucoraphenin content, respectively, and also brought about large amounts of vitamin C and antioxidant capacity. 相似文献