全文获取类型
收费全文 | 256篇 |
免费 | 16篇 |
专业分类
电工技术 | 7篇 |
综合类 | 2篇 |
化学工业 | 96篇 |
机械仪表 | 5篇 |
建筑科学 | 9篇 |
矿业工程 | 3篇 |
能源动力 | 3篇 |
轻工业 | 48篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 11篇 |
一般工业技术 | 35篇 |
冶金工业 | 13篇 |
原子能技术 | 3篇 |
自动化技术 | 30篇 |
出版年
2023年 | 4篇 |
2022年 | 11篇 |
2021年 | 20篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 23篇 |
2012年 | 30篇 |
2011年 | 20篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1982年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有272条查询结果,搜索用时 15 毫秒
121.
Michael Hinze Martin Kunkel Andreas Steinbrecher Tatjana Stykel 《International Journal of Numerical Modelling》2012,25(4):362-377
We consider model order reduction of integrated circuits with semiconductor devices. Such circuits are modeled using modified nodal analysis by differential‐algebraic equations coupled with the nonlinear drift‐diffusion equations. A spatial discretization of these equations with a mixed finite element method yields a high dimensional nonlinear system of differential‐algebraic equations. Balancing‐related model reduction is used to reduce the dimension of the decoupled linear network equations, whereas the semidiscretized semiconductor model is reduced using proper orthogonal decomposition. Because the computational complexity of the reduced‐order model through the nonlinearity of the drift‐diffusion equations still depends on the number of variables of the full model, we apply the discrete empirical interpolation method to further reduce the computational complexity. We provide numerical comparisons that demonstrate the performance of the presented model reduction approach. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
122.
Vladimir M. Tomović Marija R. Jokanović Ljiljana S. Petrović Mila S. Tomović Tatjana A. Tasić Predrag M. Ikonić Zdravko M. Šumić Branislav V. Šojić Snežana B. Škaljac Milena M. Šošo 《Meat science》2013
Effects of rapid chilling of carcasses (at − 31 °C in the first 3 h of chilling, and then at 2–4 °C) and earlier deboning (8 h post-mortem), compared to rapid (till 24 h post-mortem) and conventional chilling (at 2–4 °C, till 24 h post-mortem), on quality characteristics of pork M. semimebranosus and cooked ham were investigated. Quality measurements included pH value, colour (CIEL*a*b* values) and total aerobic count of M. semimebranosus, as well as sensory (colour, juiciness, texture, and flavour), physical (pH value, colour – CIEL*a*b* values and texture – Warner–Bratzler shear and penetration forces) and chemical (protein, total fat, and moisture content) characteristics of cooked ham. The cooked ham was manufactured from pieces of M. semimebranosus with ultimate lightness (CIEL* value) lower than 50. Rapid chilling and earlier deboning significantly increased quantity of M. semimebranosus desirable for cooked ham manufacturing. Earlier start of pork fabrication did not affect important quality characteristics of cooked ham. 相似文献
123.
Christine Hoelzl Siegfried Knasmüller Karl‐Heinz Wagner Leonilla Elbling Wolfgang Huber Nina Kager Franziska Ferk Veronika Ehrlich Armen Nersesyan Oliver Neubauer Aurélien Desmarchelier Maricel Marin‐Kuan Thierry Delatour Clotilde Verguet Claudine Bezençon Amélie Besson Dominik Grathwohl Tatjana Simic Michael Kundi Benoît Schilter Christophe Cavin 《Molecular nutrition & food research》2010,54(12):1722-1733
Scope: Coffee is among the most frequently consumed beverages. Its consumption is inversely associated to the incidence of diseases related to reactive oxygen species; the phenomenon may be due to its antioxidant properties. Our primary objective was to investigate the impact of consumption of a coffee containing high levels of chlorogenic acids on the oxidation of proteins, DNA and membrane lipids; additionally, other redox biomarkers were monitored in an intervention trial. Methods and results: The treatment group (n=36) consumed instant coffee co‐extracted from green and roasted beans, whereas the control consumed water (800 mL/P/day, 5 days). A global statistical analysis of four main biomarkers selected as primary outcomes showed that the overall changes are significant. 8‐Isoprostaglandin F2α in urine declined by 15.3%, 3‐nitrotyrosine was decreased by 16.1%, DNA migration due to oxidized purines and pyrimidines was (not significantly) reduced in lymphocytes by 12.5 and 14.1%. Other markers such as the total antioxidant capacity were moderately increased; e.g. LDL and malondialdehyde were shifted towards a non‐significant reduction. Conclusion: The oxidation of DNA, lipids and proteins associated with the incidence of various diseases and the protection against their oxidative damage may be indicative for beneficial health effects of coffee. 相似文献
124.
Victor A. Feodorov Tatjana. N. Plushnikova Andrey V. Chivanov Margarita V.Chemerkina Roman A. Kirillov. 《材料研究与应用》2005,(3):147-148
The purpose of this work was research into influence of ultra-violet radiation on size of run of regional and screw dislocations in beams of dislocation sockets, formed at indentation surface of alkali-halide crystals. In experiments it was used crystals NaCl, with the quantitative maintenance of impurity 10-2 -10-3weight%, the wave length of UV-radiation λ=250 nanometers, the sizes of samples 10mm× 20mm× 2mm,temperature of samples was constant T=290 K.It is established that indentation and the simultaneous irradiation of samples a ultraviolet is increases size of run of head dispositions in dislocation sockets..It is marked, that influence UV-radiation nonequivalence for various times of an exposition. At small times (till 5 minutes) the size of run grows. The length of beams increases on ~ 50 %. At the further increase in time of influence of a ultraviolet the length of beams is reduced till the sizes corresponding stressing without an irradiation (Figs. 1, 2, 3). The effect is observed on dislocation beams of regional and screw orientations and most expressed at small loadings (in our experiments-10 grams) (Fig. 3).Observable effects are explained from positions dislocation-exciton interactions. At UV-radiation exciton cooperates with the charged step on a disposition, causing movement of a step along a disposition on one internuclear distance. Due to this interaction overcoming by a disposition of a grid of stoppers is facilitated.Big times of endurance cause a relaxation of pressure directly in a print that provides convertible movement of dispositions in area of a print and as consequence, reduction of length of beams of dislocation sockets. 相似文献
125.
126.
Jochen Jung Tatjana Jaufmann Uwe Hener Andreas Münch Mirjam Kreck Helmut Dietrich Armin Mosandl 《European Food Research and Technology》2006,223(6):811-820
The determination of glycerol and 2,3-butanediol by photometric or enzymatic methods is well established. This paper reports on the direct assessment of glycerol and stereoselective analysis of 2,3-butanediol isomers in wine using capillary GC without any derivatisation. A “model wine” and commercially available wines, as well as wines of definite origin were investigated. The contents of glycerol and 2,3-butanediol and the ratio of (R,R)- and meso-2,3-butanediol were determined. Capillary GC has proved to be a reliable alternative in glycerol assessment from wine, thus a GC-IRMS method for authenticity assessment of glycerol was developed.δ13CV‐PDB and δ18OV‐SMOW multi-element IRMS-analysis of glycerol, an important by-product of wine fermentation, is reported. For that reason glycerol, extracted from a self-prepared “model wine”, from wines of definite origin, as well as commercially available wines, was investigated. Furthermore, the 18O/16O and 13C/12C isotope ratios of commercial glycerols from different origins were determined. In addition fermentation experiments with beet and cane sugar, and with grape juices were carried out. In order to check the influence of water on the oxygen isotope ratios, water from different places in Germany was used in the fermentation experiments with cane and beet sugar. 相似文献
127.
128.
Tasić Tatjana Ljiljana Petrović Predrag Ikonić Vera Lazić Marija Jokanović Natalija Džinić Vladimir Tomović Ljubiša Šarić 《Packaging Technology and Science》2014,27(2):129-139
The objective of this study was to examine the quality characteristics of packaging materials and packaging units, and the viability and acceptability of the colour and sensorial properties of fresh pork meat during storage in low oxygen and high carbon dioxide modified atmosphere packaging up to 16 days at two temperatures (0°C and 4°C), as well as the sensorial properties of cooked meat. Packaging materials had good mechanical and barrier properties and were suitable for packaging in selected atmosphere. The concentration of oxygen during the whole storage period was less than 0.5% at both temperatures. The proportion of red colour (a*) was successfully maintained although the colour was slightly darker (L*) and the sensory value was lower when evaluated at the end of the storage period. Based on the obtained results and discussion, it can be concluded that samples packaged in a modified atmosphere with 40% CO2 and 60% N2 can be stored at 0°C for 15 days and at 4°C for 10 days. Samples had a good sensory quality until the 16th day, with the best results achieved on the 7th day. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
129.
130.
Karin Stana-Kleinschek Volker Ribitsch Tatjana Kreze Lidija Fras 《Materials Research Innovations》2002,6(1):13-18
The reactivity and adsorption properties of cellulose fibres are critical for successful treatment because behavior during
the finishing process is determined by both structure and surface properties. The fine structure of natural cellulose fibres
i.e. cotton, is different from the regular viscose, modal and new types of regenerated cellulose fibres i.e. lyocell, which
are clarified by different hydrophilic/hydrophobic character of fibres and different adsorption properties. Tensiometry, seldom
used in fibre characterization was used to obtain the differences in the adsorption properties of different cellulose fibres.
The surface tension, contact angle and adsorption were measured, and then compared with various methods for determining water
adsorption. Currently some additional methods especially sensitive to surface properties (electrokinetic properties of fibres)
are being applied in order to characterize the adsorption character and reactivity of the fibre surfaces. The streaming potential
was measured due to the fact that the interaction properties are strongly influenced by electric charges on the surface, and
from these values the zeta potential (ζ) was calculated as a function of the pH and the surfactant concentration in the liquid
phase. As with the results of fibre reactivity and adsorption properties obtained by conventional methods, the electrokinetic
character of the materials and their adsorption ability determined using the tensiometry also show the same phenomena. The
natural fibres have the smaller hydrophilic character and they are less reactive than the regenerated ones, so the ζmax of cotton is the highest and the contact angle ϕ the greatest [1, 2, 3]
Electronic Publication 相似文献