首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   168篇
  免费   10篇
化学工业   47篇
金属工艺   3篇
建筑科学   8篇
能源动力   30篇
轻工业   32篇
石油天然气   1篇
无线电   7篇
一般工业技术   21篇
冶金工业   10篇
原子能技术   1篇
自动化技术   18篇
  2023年   2篇
  2022年   8篇
  2021年   13篇
  2020年   6篇
  2019年   7篇
  2018年   6篇
  2017年   9篇
  2016年   2篇
  2015年   5篇
  2014年   6篇
  2013年   20篇
  2012年   3篇
  2011年   18篇
  2010年   10篇
  2009年   12篇
  2008年   10篇
  2007年   5篇
  2006年   7篇
  2005年   4篇
  2004年   7篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1996年   3篇
  1991年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1972年   1篇
排序方式: 共有178条查询结果,搜索用时 15 毫秒
11.
In this study, safflower oil oleogels were made using propolis wax and carnauba wax in three different concentrations each, and their effectiveness as a fat substitute in cake was evaluated afterward. Oleogels' oxidative stability and characterization were looked into. In oleogels, the oil binding capacity, solid fat content, and crystallization time were all assessed. The cakes underwent an examination for moisture content, texture, and sensory evaluation. Additionally, analyses of fatty acid composition, free fatty acidity, oxidative stability (peroxide value, conjugated diene-triene), 3-monochloropropane-1,2-diol (3-MCPD), and glycidyl were carried out both before and after baking in oleogels and shortening. Several of the physical, textural, and sensory qualities of the oleogel-based cakes were acceptable when compared to those of the shortening-based cakes. The general acceptability of cakes made with carnauba wax was very high and almost under control. The acceptability of cakes made with propolis wax oleogels was lower than this. The study of these criteria has shown that safflower oil-based carnauba and propolis wax oleogels can be utilized to produce high-quality, healthful cakes with a high amount of unsaturated fatty acids. Practical Applications : To replace fat phases in cake products high in saturated fatty acids and to enhance the fatty acid profile of the cakes, safflower oil-based oleogels with propolis wax and carnauba wax are a very good option. The results obtained provide useful information for the production of high-quality cakes with higher unsaturated fatty acid content, recommended for a healthier diet, with these oleogels containing different concentrations of oleogelator.  相似文献   
12.
This study aimed to evaluate the in vitro antioxidant and enzyme inhibitory activities of ethyl acetate, methanol, and water extracts of Bituminaria bituminosa. In phosphomolybdenum assay, the methanol extract showed the highest activity (166.78 μmol TEs/g dry plant). The water extract exhibited the highest scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH?) and 2,2-azino-bis (3-ethylbenzothiazloine-6-sulphonic acid) (ABTS?+). In addition, it exhibited the highest activity in cupric ion reducing (CUPRAC) and ferric reducing antioxidant power (FRAP) assays (41.26 and 46.82 μmol TEs/g dry plant). The extracts did not show cholinesterase and tyrosinase inhibitory activity. However, α-glucosidase inhibition assay resulted in the superiority of water extract (1233.86 μmol ACEs/g dry plant). In the case of α-amylase inhibitory assay, the ethyl acetate extract showed the highest activity (53.65 μmol ACEs/g dry plant). The water extract exhibited the highest phenolic content (31.70 μmol GAEs/g dry plant). In contrast, the methanol extract was found rich in flavonoid compounds (5.29 μmol REs/g dry plant). The water extract contained considerable amounts of rosmarinic acid, luteolin, quercetin, and rutin. Therefore, it can be used as a source of new and alternative antioxidant and enzyme inhibitory agents.  相似文献   
13.
A nominal compositions of BiSrCaCuO (3:2:2:3), (2:2:2:3), (4:3:3:4), and BiPbGaSrCaCuO (3:0.5:2:2:3), (3:0.3:0.3:2:2:3) have been prepared by conventional melt-quenching method. The oxidation behaviors of samples prepared were analyzed using a thermogravimetric analyser, TGA. Total mass gains of samples, average oxidation rates and maximum oxidation rates were calculated separately. TGA measurements of all samples were carried out under the normal atmosphere pressure.  相似文献   
14.
A multidisciplinary methodology is proposed for analyzing opportunities to use existing boreholes and an open-loop groundwater heat pump to provide summer cooling needs for large university buildings in Turin (NW Italy). The approach starts from a model of the buildings to determine the time profile of the cooling load. This curve is then coupled with a model of the off-design behaviour of the heat pump, which allows calculation of its energy performance (coefficient of performance, electricity consumption, etc.) as well as profiles of water discharge to the aquifer in terms of mass flow rate and temperature.Covering the peak energy needs of the buildings requires a variable amount of groundwater during the day. This could be provided varying the withdrawals from the aquifer but, as possible alternatives, two storage system solutions are examined: (1) chilled water storage and (2) groundwater storage. Simulations show that in both cases the use of storage systems produces environmental advantages, as the extent of the thermal plume reduces significantly. Moreover, chilled water storage presents a benefit in terms of reduced total primary energy consumption. The additional costs incurred by storage systems could necessitate public funding as well as system optimization.  相似文献   
15.
Quality function deployment (QFD) is a process that has been used for managing the development of new manufactured products. In this process, both spoken and unspoken needs of the customers are determined, prioritized, and translated to design parameters. Such design parameters are assigned specific target values and are frequently checked against customers’ needs throughout the development cycle to ensure customers’ satisfaction with the end product. This paper describes a pilot study in which QFD was implemented in a design-construction project. The project scope involved the preparation of a conceptual design for a modern large-size classroom for college students. The design was intended to become a model for the university’s future classrooms. The study proved that QFD could be successfully adopted in engineering-construction projects. However, the study identified a number of implementation challenges. In addition, more applications are necessary to take the process throughout the full project delivery cycle, as the pilot study involved only the preliminary engineering and conceptual design phase.  相似文献   
16.
OBJECTIVE: To search for the effect and safety of coral porous hydroxyapatite (CHA) implanted material in orbital rim reconstruction. METHODS: 7 cases of orbital rim reconstruction were treated with CHA which is a plate form mass with an interconnected system of canals of approximately 200 microns in size. It has three types: 1.0 cm x 1.5 cm x 5.0 cm, 0.6 cm x 1.5 cm x 5.0 cm and 0.4 cm x 1.5 cm x 5.0 cm. According to the shape of a contralateral healthy orbit, a rubber putty model was made before the operation. An incision was designed at the upper 1/3 of the face for the elimination of wrinkles or a prolonged incision of lower lid bag plastic surgery was made. After the exposure of the defective part of the orbit, a correctly molded CHA tamponade was inserted. RESULTS: The orbital rim reconstruction in 7 cases with orbital defect was successfully treated with CHA. During a follow-up of 3-12 months (average 6.6 months), there was no extrusion or migration of implant. CONCLUSION CHA is a good material for substitution of bone graft and is much better than autogenous tissue of other artificial materials.  相似文献   
17.
We have studied the influence of the spacer alkyl chain length of perylenemonoimide (PMI) dyes on the device performance in dye-sensitized solar cells (DSSCs). We observed that the dyes with longer and brunched alkyl chains exhibit higher efficiencies in DSSCs. In line with these statements we now report the highest efficiency obtained under standard conditions for a perylene imide derivative with PMI-DA1 that performs 300 mV open circuit voltage, 9.79 mA/cm2 short-circuit current and 1.61% overall conversion efficiency.  相似文献   
18.
Incorporating medicinal plant extracts in membranes have a great potential as scaffolds for tissue engineering applications or vehicles for delivering therapeutic agents. Herein, Hypericum perforatum oil (0.25, 0.50, % vol/vol) loaded membranes were developed with Polyvinyl alcohol and chitosan polymer, where Genipin works as a chemical crosslinker to obtain a wound dressing material with acceptable characterization properties. Chemical groups, surface morphology, water uptake capacity, water vapor permeability rate, hydrophilicity, and mechanical properties of membranes were thoroughly investigated. Increasing oil concentration had a significant effect on the water uptake, surface morphology. and water vapor permeability rate of the membranes. Cytocompatibility of the membrane was also investigated with mouse embryonic fibroblasts (MEF) by 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for direct and indirect cell culture studies. SEM was used to investigate the cell morphology on the membranes. The MTT assay findings prove that Genipin crosslinked H. perforatum oil loaded scaffolds are highly biocompatible and enhance the adhesion and proliferation of MEF cells. In addition to this, the genotoxicity test was performed to show DNA fragmentation. Results showed that the H. perforatum oil loaded polyvinyl alcohol-chitosan membrane presents suitable properties for potential skin tissue engineering applications.  相似文献   
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号