全文获取类型
收费全文 | 327篇 |
免费 | 26篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 123篇 |
金属工艺 | 9篇 |
机械仪表 | 8篇 |
建筑科学 | 9篇 |
能源动力 | 20篇 |
轻工业 | 57篇 |
无线电 | 27篇 |
一般工业技术 | 54篇 |
冶金工业 | 6篇 |
原子能技术 | 2篇 |
自动化技术 | 33篇 |
出版年
2023年 | 3篇 |
2022年 | 24篇 |
2021年 | 45篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 10篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 20篇 |
2012年 | 18篇 |
2011年 | 24篇 |
2010年 | 10篇 |
2009年 | 19篇 |
2008年 | 16篇 |
2007年 | 10篇 |
2006年 | 10篇 |
2005年 | 9篇 |
2004年 | 12篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1995年 | 2篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有353条查询结果,搜索用时 336 毫秒
71.
Mariusz Florek Piotr Domaradzki Leszek Drozd Piotr Skałecki Katarzyna Tajchman 《Sensing and Instrumentation for Food Quality and Safety》2017,11(3):1035-1044
The present investigation was designed to determine the meat nutritional profile of European beaver (Castor fiber L.). The proximate composition, energy value, amino acids composition, chemical scores for indispensable amino acids, fatty acids composition and mineral concentrations were determined. In 100 g of meat the content for moisture ranged from 75.42 to 77.32 g, for protein from 20.21 to 22.33 g, for fat from 0.66 to 2.44 and for ash from 1.12 to 1.24 g. The Nutritional Quality Index for muscle protein was 9. The indispensable amino acids (IAA) at the highest content were lysine and leucine (1.85 and 1.65 g 100 g?1). The average percentage of IAA was 45% and their chemical scores amounted to more than 100. The total percentages of trans-, saturated (SFA), mono, and polyunsaturated (PUFA) fatty acids were 2.25, 32.25, 18.83 and 49.08%. The ratio of PUFA/SFA and n-6/n-3 PUFA were 1.56 and 5.58. The cholesterol content averaged 55.10 mg 100 g?1. The muscle tissue of beavers contained favourable amount of minerals, particularly Fe and heme Fe (64.49 and 45.60 mg kg?1), Zn and Cu (45.07 and 0.98 mg kg?1), as well a low level of Na (461.9 mg kg?1). Summing up, beavers are a valuable nutritional meat source with a desirable chemical composition and a low calorific value and can constitute a healthy alternative food as advantageous for human health and coherent with diet recommendations. 相似文献
72.
Mariusz Ziejewski Kenton R. Kaufman A. W. Schwab E. H. Pryde 《Journal of the American Oil Chemists' Society》1984,61(10):1620-1626
A nonionic sunflower oil-aqueous ethanol microemulsion was formulated, characterized and evaluated as a fuel in a direct injection,
turbocharged, intercooled, 4-cylinder Allis-Chalmers diesel engine during a 200 hr EMA cycle laboratory screening endurance
test. Differences in engine operation between a baseline Phillips 2D reference fuel and the experimental fuel were observed.
The major problem experienced while operating with the microemulsion was an incomplete combustion process at low-load engine
operation. Significant lubricating oil dilution was observed initially, followed by an abnormal increase in the viscosity
of the lubricative oil. Heavier carbon residue on the piston lands, in the piston ring grooves and in the intake ports was
noted. In addition, premature injection-nozzle deterioration (sticking of the needle) was experienced. At present, the sunflower
oil-aqueous ethanol microemulsion studied cannot be recommended for long-term use in a direct-injection diesel engine, but
further modifications in formulation may produce acceptable sunflower oil microemulsions as alternative diesel fuels.
Presented at the AOCS meeting, Chicago, IL, May 1983. 相似文献
73.
74.
We propose a mixed-integer programming (MIP) formulation for a problem of optimal dimensioning of equipment of the fiber-to-the-home optical access network (FTTH-OAN). The optimization aims at minimizing capital expenditures (CAPEX) related to deployment of the FTTH-OAN, i.e., the cost of active equipment (OLTs and OLT cards), cost of passive equipment (optical splitters, cables, fibers, fibers terminations, splices, closures), cost of site preparations (building, cabinets), and cost of necessary labor (duct preparation and rollout of cables). The formulation has been implemented and validated. General results based on selected real-world scale numerical experiments are presented. 相似文献
75.
Telecommunication Systems - We propose a business/cost model for long-period changes of customer demands in FTTx networks. We show how to exploit this model in the formulation of a MIP optimization... 相似文献
76.
Agata Skwarek Mariusz Pluska Andrzej Czerwinski Krzysztof Witek 《Materials Science and Engineering: B》2012,177(15):1286-1291
This paper describes variations in whisker growth on the surface of tin-rich, lead-free alloys soldered on a Cu layer depending on the laminate used for the printed circuit board, which can be either glass-epoxy or paper-phenol. The structure of the glass-epoxy laminate surface is characterized by spatial nonuniformity caused by the regular structure formed by regions of glass fibers and resin in the top layer of the laminate. The higher value of thermal expansion of the resin than of the glass fiber means that the area of the resin expands more than that of the glass fiber. This causes local compressive stress in the solder layer and as a result promotes whisker growth in the area of the alloy soldered on the Cu layer over the glass fiber. This effect does not occur on the surface of an alloy soldered on Cu layer over a paper-phenol laminate. 相似文献
77.
Wood adhesives derived from hyperbranched polyglycerol cross-linked with hexamethoxymethyl melamines
Mariusz ?. Mamiński Ma?gorzata Czarzasta Pawe? Parzuchowski 《International Journal of Adhesion and Adhesives》2011,31(7):704-707
Wood adhesive system based on hyperbranched polyglycerol cross-linked with hexamethoxymethyl melamines was described. The obtained results showed that it was possible to develop polyglycerol-based interior-grade adhesive exhibiting dry shear strengths of the joints exceeding that of the solid wood. Gelling times of the studied formulations were comparable to those of the industrial thermosetting systems (60–80 s at 100 °C). It was also found that wet shear strengths depended on functionality and F/Me molar ratio in the cross-linking resin. 相似文献
78.
Mariusz Szymczak Edward Kołakowski Katarzyna Felisiak 《International Journal of Food Science & Technology》2012,47(2):282-289
Salt concentrations of brine above 10% are still commonly used in fish marinating process. The study has showed an increasing salt concentrations affect to adversely all the properties of marinated herring meat. Increase in salt concentration from 5% to 15% resulted in significantly (P < 0.05) decrease content of water, non‐protein nitrogen and products of protein hydrolysis. Consequently, weight yield of marinated fresh herring decreased from 83% to 74%. The most palatable marinades contained 2–3% NaCl in meat only. The higher salt concentrations applied significantly (P < 0.05) worsened the taste, texture and colour of marinated herring. Texture profile analyses (TPA), free hydroxyproline content and colour analyses (L*a*b) confirmed the negative influence of high salt concentration on the marinades quality. Frozen and thawed herring tissue showed greater sensitivity to salt. Namely, marinades from frozen fish contained by 0.3 more salt (P < 0.05), and the weight yield was by 2.3–10.3 percent point lower than from the fresh herring. Meat from frozen herring when matured has significantly (P < 0.05) lower sensory value, lower content of protein hydrolysis products, free hydroxyproline and higher parameter b* value of than the fresh one. 相似文献
79.
This paper describes a hybrid tabu search algorithm dedicated to a job shop problem with a no-wait constraint with a makespan criterion. The proposed here algorithm complexity is that the superior algorithm based on the tabu search technique selects parameters controlling the work of a certain constructional algorithm. This approach limits the checked solutions only to a group of solutions being able to be generated by the structural algorithm in question. It bears serious consequences both positive, for example it limits the research scope for a small fraction of relatively extremely well quality of acceptable solutions, and negative that is the lack of possibility of finding the optimal solution. In this paper numerical researches of the proposed algorithm are conducted as well as a comparative analysis with reference to the literature algorithms of the algorithm in question is made. 相似文献
80.
Violeta T. Pardio Maria D. Mariezcurrena Krzysztof N. Waliszewski Victor Sánchez Mariusz K. Janczur 《International Journal of Food Science & Technology》2009,44(12):2417-2423
The effects on the aroma compositions of ethanol extracts obtained by traditional and enzyme‐assisted methods from seven killing conditions used in vanilla pod curing were studied. Two procedures of vanilla pod killing consisted of either freezing pods at ?10 °C for 24 h or immersing pods in 80 °C water for 10 s each of three times with 30 s intervals resulted in the highest vanillin values in terms percentage of dry weight of the bean (2.84 and 2.96), 4‐hydroxybenzaldehyde (0.18 and 0.20), vanillyl alcohol (0.56 and 0.57) and vanillic acid (0.18 and 0.19 respectively) when traditional vanilla ethanol extraction was used. When this extract was aged for 3 months it showed improvement in flavour compounds. Enzyme‐assisted vanilla ethanol extraction showed a higher content of flavour compounds than traditional extract, for example vanillin 4.38% and 2.96% respectively. Only vanillic acid levels were improved after ageing of the enzyme‐assisted extracts. 相似文献