全文获取类型
收费全文 | 1293篇 |
免费 | 107篇 |
专业分类
电工技术 | 4篇 |
综合类 | 4篇 |
化学工业 | 332篇 |
金属工艺 | 4篇 |
机械仪表 | 18篇 |
建筑科学 | 57篇 |
矿业工程 | 4篇 |
能源动力 | 17篇 |
轻工业 | 171篇 |
水利工程 | 20篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 87篇 |
一般工业技术 | 182篇 |
冶金工业 | 345篇 |
原子能技术 | 1篇 |
自动化技术 | 151篇 |
出版年
2023年 | 15篇 |
2022年 | 56篇 |
2021年 | 73篇 |
2020年 | 28篇 |
2019年 | 35篇 |
2018年 | 37篇 |
2017年 | 31篇 |
2016年 | 56篇 |
2015年 | 42篇 |
2014年 | 55篇 |
2013年 | 67篇 |
2012年 | 66篇 |
2011年 | 111篇 |
2010年 | 92篇 |
2009年 | 74篇 |
2008年 | 70篇 |
2007年 | 84篇 |
2006年 | 48篇 |
2005年 | 52篇 |
2004年 | 50篇 |
2003年 | 27篇 |
2002年 | 26篇 |
2001年 | 20篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 12篇 |
1997年 | 18篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1964年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有1400条查询结果,搜索用时 531 毫秒
971.
High hydrostatic pressure was applied to hydrated soybeans (100–700 MPa, 25 °C) and soymilk (400–750 MPa; 25 and 75 °C) to assess its effect on isoflavone content, profile and water-extractability. Neither pressure level nor initial treatment temperature affected soymilk isoflavone content. However, combined pressure and mild thermal treatment modified the isoflavone distribution. At 75 °C, the isoflavone profile shifted from malonylglucosides toward β-glucosides, which was correlated to the effect of adiabatic heating. When pressure was applied to the hydrated soybeans, the soymilk isoflavone concentration varied between 4.32 and 6.06 μmol/g. The content of protein decreased and fat increased in soymilks prepared from pressurized soybeans with increasing pressure level. 相似文献
972.
Absalome A Monde Françoise Michel Marie‐Annette Carbonneau Georges Tiahou Marie‐Hélène Vernet Sabrina Eymard‐Duvernay Stephanie Badiou Benjamin Adon Eugène Konan Daniel Sess Jean Paul Cristol 《Journal of the science of food and agriculture》2009,89(15):2535-2540
BACKGROUND: Fatty acid, tocopherol, tocotrienol and carotene contents were assessed in four oil palm species from the National Centre of Agronomical Research of Côte d'Ivoire, two of which were the basal Lamé (HP1) and Deli (HP2) collections and two of which resulted from crossings between HP1 and HP2 varieties of Eleais guineensis, HP3 and HP4 being identified as the first and second cycle selection, respectively. RESULTS: Palm oil species were characterized by the richness in polyunsaturated fatty acids composition (48–60%) compared to saturated fatty acids (40–52%), especially the first variety, which was from the base collection, and the two hybrids ensuing from crossing. Total carotene content of those varieties was higher and accounted for 832–3575 µg g?1, and the β‐carotene level (580–2390 µg g?1) was predominant. Total vitamin E content was 864–1124 µg g?1, with a notable higher content of tocotrienols, especially γ‐and α‐tocotrienol, ranging from 400 to 515 µg g?1 and from 238 to 350 µg g?1, respectively. CONCLUSION: Crossing seemed to be useful in improving the performance and analytical characteristics of the base collection materials. Copyright © 2009 Society of Chemical Industry 相似文献
973.
Stephanie A. Vogelmann Michael Seitter Ulrike Singer Markus J. Brandt Christian Hertel 《International journal of food microbiology》2009,130(3):205-212
The adaptability of lactic acid bacteria (LAB) and yeasts to sourdoughs prepared from cereals, pseudocereals and cassava was investigated using PCR-DGGE and bacteriological culture combined with rRNA gene sequence analysis. Sourdoughs were prepared either from flours of the cereals wheat, rye, oat, barley, rice, maize, and millet, or from the pseudocereals amaranth, quinoa, and buckwheat, or from cassava, using a starter consisting of various species of LAB and yeasts. Doughs were propagated until a stable microbiota was established. The dominant LAB and yeast species were Lactobacillus fermentum, Lactobacillus helveticus, Lactobacillus paralimentarius, Lactobacillus plantarum, Lactobacillus pontis, Lactobacillus spicheri, Issatchenkia orientalis and Saccharomyces cerevisiae. The proportion of the species within the microbiota varied. L. paralimentarius dominated in the pseudocereal sourdoughs, L. fermentum, L. plantarum and L. spicheri in the cassava sourdough, and L. fermentum, L. helveticus and L. pontis in the cereal sourdoughs. S. cerevisiae constituted the dominating yeast, except for quinoa sourdough, where I. orientalis also reached similar counts, and buckwheat and oat sourdoughs, where no yeasts could be detected. To assess the usefulness of competitive LAB and yeasts as starters, the fermentations were repeated using flours from rice, maize, millet and the pseudocereals, and by starting the dough fermentation with selected dominant strains. At the end of fermentation, most of starter strains belonged to the dominating microbiota. For the rice, millet and quinoa sourdoughs the species composition was similar to that of the prior fermentation, whereas in the other sourdoughs, the composition differed. 相似文献
974.
Comparative life‐cycle cost analysis of pedestrian bridges made from different materials. Considerable maintenance costs may accrue during the life time of infrastructure objects. Therefore, the choice of construction options should not only be made based on purchase price, but also taking into account expected follow‐up costs. Against this background, a study conducted with Deutsche Bahn AG and Peter Maier Leichtbau GmbH analyzed which construction material promises the best overall cost‐effectiveness for pedestrian bridges. Cost‐effectiveness was evaluated based on a life‐cycle‐cost analysis. This study investigated pedestrian bridges built of conventional construction materials wood, steel and reinforced concrete, as well as bridges made of aluminium alloy. An annuity was chosen to be the comparison value for life‐cycle costs. For coping with uncertainties in cost determination and forecasting, diverse sensitivity analyses were used to verify their effects on the final results. Aluminium alloy came out to be the most cost‐effective option for the bridge system investigated within this study. 相似文献
975.
Pinto Patricio X. Al-Abed Souhail R. Holder Christopher D. Warner Richard McKernan John Fulton Stephanie Somerville Eric 《Mine Water and the Environment》2018,37(1):31-41
Mine Water and the Environment - The exposure of readily soluble components of overburden materials from surface coal mining to air and water results in mineral oxidation and carbonate mineral... 相似文献
976.
Mariana Wolff de Carvalho Nathalia Darminia Aceval Arriola Stephanie Silva Pinto Silvani Verruck Carlise Beddin Fritzen‐Freire Elane Schwinden Prudêncio Renata Dias de Mello Castanho Amboni 《International Journal of Dairy Technology》2019,72(1):57-64
In this study, yoghurt samples were fortified with 0.25% and 0.5% freeze‐dried stevia extract (FSE). The control and stevia‐fortified yoghurts were evaluated and compared for the viability of the starter cultures, physicochemical properties, total phenolic content (TPC) and antioxidant activity throughout 30 days of storage. In addition, TPC and antioxidant activity were evaluated during in vitro gastrointestinal digestion. The results showed that the yoghurt matrix preserved the TPC, antioxidant capacity and total solids during storage, while the acidity, synaeresis and counts of the starter cultures of the final product were not significantly affected. However, addition of 0.5% FSE exerted a buffering effect on the system. After simulated digestion, the values of TPC and antioxidant activity of the fortified yoghurts increased in relation to the undigested fractions. These findings showed the feasibility of employing FSE as a functional ingredient in the manufacture of yoghurts with potential antioxidant properties. 相似文献
977.
Extrusion modifies some physicochemical properties of milk protein concentrate for improved performance in high‐protein nutrition bars
下载免费PDF全文
![点击此处可从《Journal of the science of food and agriculture》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Justin C Banach Stephanie Clark Buddhi P Lamsal 《Journal of the science of food and agriculture》2018,98(1):391-399
BACKGROUND
Extruded and ground milk protein concentrate powders, specifically those with 800 g kg–1 protein (i.e. MPC80), imparted softness, cohesion and textural stability to high‐protein nutrition (HPN) bars. The present study evaluated some physicochemical properties of extruded and conventionally produced (i.e. spray‐dried) MPC80 to explain these improvements. Protein chemical changes and aggregations within MPC80‐formulated HPN bars during storage were characterized.RESULTS
Extruded MPC80 powders had broader particle size distribution (P < 0.05) and smaller volume‐weighted mean diameter (P < 0.05) than the spray‐dried control. Loose, tapped and particle densities increased (P < 0.05) and correspondingly occluded and interstitial air volumes decreased (P < 0.05) after extruding and milling MPC80. Extrusion decreased water holding capacity (P < 0.05) and solubility (P < 0.05), yet improved the wettability (P < 0.05) of MPC80. MPC80 free sulfhydryl (P < 0.05) and free amine (P < 0.05) concentrations decreased after extrusion. Sulfhydryl and amine concentrations changed (P < 0.05) and disulfide‐linked and, more prominently, Maillard‐induced aggregates developed during HPN bar storage.CONCLUSION
Extrusion and milling together changed the physicochemical properties of MPC80. Chemical changes and protein aggregations occurred in HPN bars prepared with either type of MPC80. Thus, the physicochemical properties of the formulating powder require consideration for desired HPN bar texture and stability. © 2017 Society of Chemical Industry 相似文献978.
Joshua Derenski Erik Porse Hannah Gustafson Dan Cheng Stephanie Pincetl 《Energy Efficiency》2018,11(2):485-497
School buildings are significant energy consumers. They are important targets for energy efficiency improvements, which can reduce energy spending and meet energy policy goals for state and federal governments. In the US, few studies have quantified electricity and natural gas consumption patterns in schools. Such information vitally supports energy planning and benchmarking. We present an analysis of high-detail electricity and natural gas consumption for schools in Los Angeles County over an extended period of time. Using a robust database of monthly account-level consumption, we examine electricity and natural gas consumption trends for hundreds of schools in relation to key structural and categorical characteristics, including size, geography, and school type. Results show that school energy use varies greatly across socio-demographic, structural, and climate factors. Correlations between electricity and natural gas consumption are time dependent and seasonally distinct. The analysis provides a useful case study with benchmarks for US public schools and demonstrates challenges with devising large-scale studies of school energy use. We conclude with a discussion of policy implications. 相似文献
979.
Ofelia D. Giron Jessabelle E. Basa Katherine Stephanie E. Distor Kristin Glori N. Pusing 《The International journal of environmental studies》2017,74(2):230-239
Soil physico-chemical parameters and total mercury concentrations were measured in soil and rice plant samples collected over a cropping period grown in areas near mine tailings ponds in two Philippine small-scale mining (SSM) communities. Step-wise regression analysis relating environmental parameters to Hg uptake showed that pH has a highly significant effect on Hg content in the samples (p < 0.001) while temperature, contrary to previous studies, had no significant effect. The mean total Hg concentrations appeared to be significantly lower in rice plant parts sampled in control sites than in the contaminated sites in both SSM communities: 0.020 and 2.832 mg/kg, respectively in Aroroy, Masbate and 0.004 and 0.016 mg/kg, respectively in Fidelisan, Sagada. Harvested rice grains from the Masbate sampling sites further revealed total Hg concentration at 0.1331 mg/kg, exceeding the maximum permissible limit of 0.02 mg/kg Hg contamination. The study shows that Hg use in SSM activities and the cumulative effects of prolonged exposure to the metal through regular consumption of the village-cultivated rice may put the local residents at risk of health problems related to mercury. 相似文献
980.
Hansen AK Galante M McCarren D Sears S Scime EE 《The Review of scientific instruments》2010,81(10):10D701
Recent laser upgrades on the Hot Helicon Experiment at West Virginia University have enabled multiplexed simultaneous measurements of the ion velocity distribution function at a single location, expanding our capabilities in laser-induced fluorescence diagnostics. The laser output is split into two beams, each modulated with an optical chopper and injected perpendicular and parallel to the magnetic field. Light from the crossing point of the beams is transported to a narrow-band photomultiplier tube filtered at the fluorescence wavelength and monitored by two lock-in amplifiers, each referenced to one of the two chopper frequencies. 相似文献