全文获取类型
收费全文 | 557篇 |
免费 | 31篇 |
专业分类
电工技术 | 25篇 |
化学工业 | 93篇 |
金属工艺 | 15篇 |
机械仪表 | 13篇 |
建筑科学 | 33篇 |
能源动力 | 9篇 |
轻工业 | 85篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 121篇 |
一般工业技术 | 83篇 |
冶金工业 | 68篇 |
原子能技术 | 4篇 |
自动化技术 | 36篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 13篇 |
2019年 | 9篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 31篇 |
2012年 | 27篇 |
2011年 | 25篇 |
2010年 | 20篇 |
2009年 | 29篇 |
2008年 | 36篇 |
2007年 | 23篇 |
2006年 | 24篇 |
2005年 | 21篇 |
2004年 | 26篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 12篇 |
2000年 | 16篇 |
1999年 | 20篇 |
1998年 | 29篇 |
1997年 | 20篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有588条查询结果,搜索用时 15 毫秒
81.
K.M.G.M.M. Kariyawasam R.K.C. Jeewanthi N.-K. Lee H.-D. Paik 《Journal of dairy science》2019,102(5):3887-3893
This study aimed to evaluate the potential of Weissella cibaria D30 as an adjunct culture in cottage cheese, including an assessment of antioxidant, antilisterial, and compositional parameters. Cottage cheese samples were manufactured using a commercial starter culture and probiotic strains Lactobacillus rhamnosus GG (GG) or W. cibaria D30 (W) and without probiotic (control). Samples were stored at 4 ± 1°C for 28 d. Bacterial cell counts (log cfu/g) of control, GG, and W samples were counted at 0, 7, 14, 21, and 28 d. Counts of W. cibaria D30 in the W samples remained at 6.85 log cfu/g after 28 d. Total solids, fat, protein, ash, and pH were measured and no significant differences were observed in compositional parameters or pH after 28 d of storage in all cheeses except those inoculated to Listeria monocytogenes. To measure the antilisterial effect, Listeria monocytogenes was inoculated into the cottage cheese samples and bacterial cell counts were obtained at 0, 6, 12, 24, 48, 72, 96, 120, and 144 h. Listeria monocytogenes counts were less than the analytical limit of detection (<10 cfu/g) in the inoculated GG and W samples, whereas the counts of L. monocytogenes in the inoculated control sample remained at 3.0 log cfu/g after 144 h. We used the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activity assays to assess antioxidant activity: GG and W samples exhibited significant increases in antioxidant activity compared with the control sample. These results indicate that W. cibaria D30 has potential as an adjunct culture in the dairy industry. 相似文献
82.
Ji-Young Hong Na-Kyoung Lee Sung-Hun Yi Sang-Pil Hong Hyun-Dong Paik 《Journal of dairy science》2019,102(12):10845-10849
The aim of this study was to analyze the β-glucan contents, physicochemical features, and microbial communities in milk kefir prepared using Saccharomyces cerevisiae KU200284 isolated from cucumber jangajji, a fermented vegetable commonly eaten in Korean. Three types of milk kefir were manufactured, with (1) activated kefir grain, (2) activated kefir grain with commercial S. cerevisiae BOF, and (3) activated kefir grain with S. cerevisiae KU200284. β-Glucan contents of milk kefir using kefir grain and kefir grain with S. cerevisiae strains BOF and KU200284 were 8.29, 8.59, and 8.57%, respectively. The pH, titratable acidity, viscosity, Brix level, and alcohol contents of milk kefir using kefir grain with S. cerevisiae strains were acceptable compared with milk kefir using only kefir grain. In milk kefir produced using kefir grains and S. cerevisiae strains, 16S rRNA reads showed representative strains of Lactobacillus kefiranofaciens (>72% relative abundance) and Acetobacter fabarum (>16% relative abundance). In particular, milk kefir using kefir grain with S. cerevisiae KU200284 had the highest relative abundance of L. kefiranofaciens. In addition, the internal transcribed sequence (ITS) rRNA reads in tested milk kefir showed representative strains of Kluyveromyces marxianus (>52% relative abundance) and Saccharomyces cerevisiae (>16% relative abundance). In contrast, milk kefir using S. cerevisiae strains had higher relative abundance of S. cerevisiae (>37%). The β-glucan production, physicochemical properties, and microbial community profiling indicate that S. cerevisiae KU200284 could be used in functional dairy products as a starter culture. 相似文献
83.
Jang Hye Ji Kim Jong Ha Lee Hyun-Sook Paik Hyun-Dong 《Food science and biotechnology》2022,31(6):731-737
Food Science and Biotechnology - The objective of this study was to develop a non-fermented probiotic milk that maintains its physicochemical properties, microbial properties, antioxidant activity,... 相似文献
84.
85.
Seo-Yeong Yeo Tae-Hyeong Kwon Chang-Sun Park Chang-Il Kim Ji-Sun Yun Young-Hun Jeong Youn-Woo Hong Jeong-Ho Cho Jong-Hoo Paik 《Journal of Electroceramics》2018,41(1-4):1-8
The main objective of our work is to increase transmittance in the mid infrared region by removing impurities through the pre-heating treatment of zinc sulfide (ZnS) produced by hydrothermal synthesis. The pre-heating treatment proceeded at 450 to 600 °C for 2 h under vacuum atmosphere (10?2 Torr). It was confirmed that the particle size increased as the pre-heating temperature increased. Additionally, all ZnS nano powders had a sphalerite (cubic) structure unaffected by pre-heating treatment. The ZnS nano powders were sintered by hot-press sintering method. As the pre-heating temperature increased, transmittance was improved due to the decreasing of porosity, increase of particle size, and the removal of impurities (carbon and sulfate). However, when the pre-heating treatment temperature was 600 °C, the transmittance slightly decreased due to the formation of a hexagonal phase. The ZnS ceramic with pre-heating treatment at 550 °C showed the highest transmittance (71.6%) and density (99.9%). 相似文献
86.
HyukSu Han Ju Won Paik MinJi Ham Kang Min Kim Jin Kuen Park Young Kyu Jeong 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(33)
Transition metal (TM)‐based carbon hybrids have numerous applications in the field of regenerative electrochemical energy. The synergetic effects of high conductivity of carbon supports and abundant catalytic active sites in TMs make these hybrids promising oxygen evolution reaction (OER) electrocatalysts. However, strategies for modulating the catalytic active species in the above hybrids are limited despite being highly sought after. Furthermore, the exact roles of chemical species in the hybrids (e.g., N, C, or TM) mainly responsible for this high OER performance remain unknown. Herein, an innovative approach based on atomic layer deposition is developed to tune the true active species in Co nanoparticle/N‐doped carbon nanotube (Co/N‐CNT) hybrids. Specifically, the configuration predominantly promoting water oxidation in an alkaline medium is identified as pyridinic N–Co–C. Furthermore, a physicochemical intact interface between metallic Co nanoparticles and conductive N‐CNTs is demonstrated to induce synergetic effects for accelerating charge transfer and enhancing electrocatalytic activity as well as stability in the hybrid catalysts. The optimized hybrid catalyst is revealed to exhibit outstanding alkaline OER activity and stability, outperforming RuO2, a benchmark novel OER electrocatalyst. 相似文献
87.
Metal Organic Framework Derived Materials: Progress and Prospects for the Energy Conversion and Storage 下载免费PDF全文
Exploring new materials with high efficiency and durability is the major requirement in the field of sustainable energy conversion and storage systems. Numerous techniques have been developed in last three decades to enhance the efficiency of the catalyst systems, control over the composition, structure, surface area, pore size, and moreover morphology of the particles. In this respect, metal organic framework (MOF) derived catalysts are emerged as the finest materials with tunable properties and activities for the energy conversion and storage. Recently, several nano‐ or microstructures of metal oxides, chalcogenides, phosphides, nitrides, carbides, alloys, carbon materials, or their hybrids are explored for the electrochemical energy conversion like oxygen evolution, hydrogen evolution, oxygen reduction, or battery materials. Interest on the efficient energy storage system is also growing looking at the practical applications. Though, several reviews are available on the synthesis and application of MOF and MOF derived materials, their applications for the electrochemical energy conversion and storage is totally a new field of research and developed recently. This review focuses on the systematic design of the materials from MOF and control over their inherent properties to enhance the electrochemical performances. 相似文献
88.
Yanjun Ma Anthony Edgeton Hanjong Paik Brendan D. Faeth Christopher T. Parzyck Betül Pamuk Shun-Li Shang Zi-Kui Liu Kyle M. Shen Darrell G. Schlom Chang-Beom Eom 《Advanced materials (Deerfield Beach, Fla.)》2020,32(34):2000809
Topological materials are derived from the interplay between symmetry and topology. Advances in topological band theories have led to the prediction that the antiperovskite oxide Sr3SnO is a topological crystalline insulator, a new electronic phase of matter where the conductivity in its (001) crystallographic planes is protected by crystallographic point group symmetries. Realization of this material, however, is challenging. Guided by thermodynamic calculations, a deposition approach is designed and implemented to achieve the adsorption-controlled growth of epitaxial Sr3SnO single-crystal films by molecular-beam epitaxy (MBE). In situ transport and angle-resolved photoemission spectroscopy measurements reveal the metallic and electronic structure of the as-grown samples. Compared with conventional MBE, the used synthesis route results in superior sample quality and is readily adapted to other topological systems with antiperovskite structures. The successful realization of thin films of Sr3SnO opens opportunities to manipulate topological states by tuning symmetries via strain engineering and heterostructuring. 相似文献
89.
Ungyu Paik Sangkyu Lee Vincent A. Hackley 《Journal of the American Ceramic Society》2003,86(10):1662-1668
Hysteresis in the electrokinetic behavior of colloidal hydrothermal BaTiO3 occurs during sequential acid and base titrations. Ba dissolution during acid titration results in an oxide-rich surface. When the acid-treated BaTiO3 is titrated back to pH 10, dissolved Ba is specifically adsorbed and/or precipitated onto the particle surface. The combined effects of dissolution and subsequent adsorption–precipitation results in titration hysteresis. Most of the labile Ba can be removed by multiple acid treatments, which result in a TiO2 -like surface layer composition. Barium dissolution increases with decreasing pH but levels off below pH 4 due to diffusion through the surface oxide layer as predicted previously. A phenomenological model is offered to explain the electrokinetic behavior as a function of pH. It is suggested that inherent BaCO3 contamination is not the primary source of dissolved Ba from hydrothermal BaTiO3 in acidic solution. 相似文献
90.
Vincent A. Hackley Ungyu Paik Bong-Ho Kim Subhas G. Malghan 《Journal of the American Ceramic Society》1997,80(7):1781-1788
An aqueous-based system (Si-Al2 O3 -Y2 O3 -Fe2 O3 ) for processing sintered reaction-bonded silicon nitride (SRBSN) was investigated with an emphasis on chemical control of suspension component interactions. Chemical stability and dispersion properties of a commercial silicon powder were characterized using electroacoustic, adsorption isotherm, and rheological measurements. The interactions of silicon with nitriding agent, sintering aids, dispersants, and binder were considered. The effects of pH, electrolyte, aging, particle size, and solids loading were examined. The suspension properties of the silicon powder were influenced by the native oxide film and powder treatment history. The silicon-oxide composite particles exhibit dispersion behavior similar to silica, characterized by a negative surface potential above pH 2. A method to improve the dispersion and homogeneity of suspension components based on the use of quaternary amine dispersants is proposed. 相似文献