全文获取类型
收费全文 | 137篇 |
免费 | 6篇 |
专业分类
化学工业 | 58篇 |
金属工艺 | 2篇 |
建筑科学 | 3篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
石油天然气 | 6篇 |
无线电 | 8篇 |
一般工业技术 | 22篇 |
冶金工业 | 3篇 |
原子能技术 | 1篇 |
自动化技术 | 17篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 16篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1990年 | 1篇 |
1976年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有143条查询结果,搜索用时 15 毫秒
101.
Virpi Noponen Shreedhar Bhat Elina Sievänen Erkki Kolehmainen 《Materials science & engineering. C, Materials for biological applications》2008,28(7):1144-1148
Bile acids and their conjugates are physiologically important molecules. Syntheses and structure elucidation combined with investigation of properties and applications of bile acids and their derivatives are of academic interest. The concept of using bile acids and their conjugates in nanoscience is a novel idea, which opens up fascinating prospects. In this article, an easy and simple route for obtaining N-lithocholyl-l-(cysteine ethyl ester) (3), capable of effectively capping and stabilizing metal nanoparticles, is described. The whole synthetic route needs only two steps giving a moderate to good yield. The gold NPs are characterized by elemental analysis, UV spectroscopy, and TEM. Additionally, 13C CP/MAS NMR studies for different ligand/Au ratios have been performed. 相似文献
102.
103.
Pekka Manninen Elina Häivälä Seppo Sarimo H. Kallio 《European Food Research and Technology》1997,204(3):202-205
The distribution of vegetative microbial cells and their spores in a supercritical CO2 extraction process was studied. The seed and flesh/skin fractions of the press residue of sea buckthorn berries (Hippophaë rhamnoides) from a juice factory were used as raw materials. A pilot-scale extraction plant was operated at 30?MPa at temperatures of 40 and 60°C. The number of yeasts, moulds and bacteria in the pulp/skin fraction, in the extraction residues, in the extracted oils as well as in the water phases separated from the extracted oils was estimated by the spread plate technique. The microbial content of the flesh/skin material was increased in some extractions by the addition of bacterial spores. In general, the extraction process led to a decrease in the bacterial count of the extracted material, whereas no microbial growth was detected in the oils extracted or in the water phases separated from them. Neither yeasts nor moulds were found in any samples after the extraction process. The microbial status of seed oil and flesh/skin oil obtained by industrial-scale CO2 extraction at 40°C and at 30?MPa before and after gelatine encapsulation remained unchanged. This proves that supercritical CO2 can be used to manufacture edible oil products free of living micro-organisms and their spores. 相似文献
104.
Matinmikko-Blue Marja Yrjölä Seppo Ahokangas Petri Ojutkangas Kirsi Rossi Elina 《Wireless Personal Communications》2021,116(2):1361-1378
Wireless Personal Communications - With the evolution of smart grid system (SGS), many issues associated with traditional grid network, i.e., power system security, monitoring and control, energy... 相似文献
105.
Márcia Cardoso Manique Candice Schmitt Faccini Bruna Onorevoli Edilson Valmir Benvenutti Elina Bastos Caramão 《Fuel》2012,92(1):56-61
The goal of this work is to study the purification of biodiesel from waste frying oil (WFO) using rice husk ash (RHA) at concentrations of 1%, 2%, 3%, 4% and 5% (w/w) and compare it with two other different purification methods, the traditional acid solution (1% aqueous H3PO4) and with the commercial adsorbent Magnesol® 1% (w/w). The structure and composition of the RHA were studied to better understand its properties as an adsorbent. In a concentration of 4%, the RHA showed excellent results for removal impurities from biodiesel. The high concentration of silica in its composition and the presence of meso and macropores can explain its high capacity of adsorption. Thus, the RHA, that is a byproduct of the rice processing, can appear as an alternative material for biodiesel purification. 相似文献
106.
107.
108.
The development of chemical tin coatings by a replacement reaction Cu+Sn2+Cu2++Sn from hydrochloric acid based and methanesulphonic acid based baths on the inner surface of a copper tube was studied by transmission electron microscopy and scanning electron microscopy in order to explore the factors influencing the uniformity of tin coatings. Despite the fact that tin coatings develop in different ways in studied baths, uniform coatings are equally plated from both these baths when the substrate surface is clean and smooth. However, differences in the surface-sensitivity, i.e. the dependence of coating uniformity on the substrate surface condition, of plating baths materialise when plated on irregular or improperly cleaned substrate. A hydrochloric acid based bath may yield non-uniform coatings on irregular or improperly cleaned substrate, since large-sized grains develop immediately after coating initiation. These large grains are suggested to orientate to follow the contours of impurity particles or surface irregularities introducing misalignment in grain columns and, thus, non-uniformity into coatings. In contrast, a methanesulphonic acid based bath is still able to produce uniform tin coatings on contaminated or rough surfaces, as the coating is proposed to accommodate to substrate surface irregularities by the build-up of a nanocrystalline zone at the early stages of tin coating deposition. Sulfur-containing elements in this methanesulphonic acid based plating bath play the central role in the nanocrystalline layer formation. 相似文献
109.
Yixin Zhao Torbjörn Larsson Di Yuan Elina Rönnberg Lei Lei 《Optimization and Engineering》2016,17(4):695-725
We study resource allocation in cellular systems and consider the problem of finding a power efficient scheduling in an uplink single carrier frequency division multiple access system. Due to the discrete nature of this problem and its computational difficulty, particularly in a real-time setting, the use of suboptimal algorithms is common practice. We aim at an effective way of gauging the performance of suboptimal algorithms by finding tight bounds on the global optimum. Toward this end, we first provide a basic integer linear programming formulation. Then we propose a significantly stronger column-oriented formulation and a corresponding column generation method, as well as an enhanced column generation scheme. The latter extends the first scheme through the inclusion of a stabilization technique, an approximate column generation principle, and a tailored heuristic that is embedded in the column generation scheme to find high-quality though not necessarily global optimal solutions. The computational evaluation demonstrates that compared with a poor performance by the integer linear programming formulation, the column generation method can produce near-optimal schedules that enable a sharp bounding interval. The enhanced column generation method significantly sharpens the bounding interval. Hence the column generation approach serves well for the purpose of benchmarking results for large-scale instances. 相似文献
110.
Harjunen P Lehto VP Koivisto M Levonen E Paronen P Järvinen K 《Drug development and industrial pharmacy》2004,30(8):809-815
Earlies studies suggest that solution calorimetry can be used to determine the extent of amorphous content of drug and excipient, when the solubility and dissolution rate of the compound in the chosen solvent are reasonably high. In the present study, the use of solution calorimetry for assessment of amorphous content of a sample that is not completely dissolved in a solvent was evaluated. Physical mixtures of lactose and spray-dried lactose samples were analysed. The amorphous content of the physical mixtures and the spray-dried samples varied from 0% to 100% determined by isothermal microcalorimetry. The enthalpy of solution (ΔsolH) was determined in water. The lactose samples were dissolved quickly in water. In addition, the enthalpy accompanied with an addition of a lactose sample in an over saturated aqueous solution (ΔsatH) (prepared from the corresponding lactose sample) was determined. The lactose sample did not completely dissolve in the over saturated aqueous solution. An excellent correlation was observed between ΔsolH and the amorphous content of the samples. Interestingly, there was a linear correlation also between ΔsatH and the amorphous content of the samples. Further, a linear relationship was observed between the ΔsatH and the ΔsolH of the samples. Therefore, solution calorimetry may represent a rapid and simple method for determining the amorphous content also in samples that are not completely dissolved in the solvent. 相似文献