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   217篇
  免费   13篇
  国内免费   1篇
电工技术   1篇
化学工业   146篇
金属工艺   5篇
机械仪表   1篇
建筑科学   2篇
能源动力   10篇
轻工业   28篇
无线电   2篇
一般工业技术   31篇
冶金工业   2篇
自动化技术   3篇
  2024年   1篇
  2023年   5篇
  2022年   34篇
  2021年   59篇
  2020年   13篇
  2019年   11篇
  2018年   5篇
  2017年   2篇
  2016年   16篇
  2015年   5篇
  2014年   17篇
  2013年   7篇
  2012年   6篇
  2011年   13篇
  2010年   5篇
  2009年   4篇
  2008年   11篇
  2007年   6篇
  2006年   3篇
  2005年   3篇
  2004年   1篇
  2002年   2篇
  1999年   1篇
  1982年   1篇
排序方式: 共有231条查询结果,搜索用时 15 毫秒
1.
In this work, we report on effects of post-deposition annealing on electrical characteristics of metal–insulator–semiconductor (MIS) structures with HfO2/SiO2 double gate dielectric stacks. Obtained results have shown the deterioration of electro-physical properties of MIS structures, e.g. higher interface traps density in the middle of silicon forbidden band (Ditmb), as well as non-uniform distribution and decrease of breakdown voltage (Ubr) values, after annealing above 400 °C. Two potential hypothesis of such behavior were proposed: the formation of interfacial layer between hafnia and silicon dioxide and the increase of crystallinity of HfO2 due to the high temperature treatment. Furthermore, the analysis of conduction mechanisms in investigated stacks revealed Poole–Frenkel (P–F) tunneling at broad range of electric field intensity.  相似文献   
2.
3.
We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization models: the block replacement models, group maintenance models, and opportunistic maintenance models. Moreover, an example of a two-unit system maintenance process is provided in order to compare various maintenance policies.  相似文献   
4.
Cardiovascular diseases (CVDs) are the leading cause of human mortality worldwide. Oxidative stress and inflammation are pathophysiological processes involved in the development of CVD. That is why bioactive food ingredients, including lycopene, are so important in their prevention, which seems to be a compound increasingly promoted in the diet of people with cardiovascular problems. Lycopene present in tomatoes and tomato products is responsible not only for their red color but also for health-promoting properties. It is characterized by a high antioxidant potential, the highest among carotenoid pigments. Mainly for this reason, epidemiological studies show a number of favorable properties between the consumption of lycopene in the diet and a reduced risk of cardiovascular disease. While there is also some controversy in research into its protective effects on the cardiovascular system, growing evidence supports its beneficial role for the heart, endothelium, blood vessels, and health. The mechanisms of action of lycopene are now being discovered and may explain some of the contradictions observed in the literature. This review aims to present the current knowledge in recent years on the preventive role of lycopene cardiovascular disorders.  相似文献   
5.
An increasing number of people experience disorders related to the central nervous system (CNS). Thus, new forms of therapy, which may be helpful in repairing processes’ enhancement and restoring declined brain functions, are constantly being sought. One of the most relevant physiological processes occurring in the brain for its entire life is neuroplasticity. It has tremendous significance concerning CNS disorders since neurological recovery mainly depends on restoring its structural and functional organization. The main factors contributing to nerve tissue damage are oxidative stress and inflammation. Hence, marine carotenoids, abundantly occurring in the aquatic environment, being potent antioxidant compounds, may play a pivotal role in nerve cell protection. Furthermore, recent results revealed another valuable characteristic of these compounds in CNS therapy. By inhibiting oxidative stress and neuroinflammation, carotenoids promote synaptogenesis and neurogenesis, consequently presenting neuroprotective activity. Therefore, this paper focuses on the carotenoids obtained from marine sources and their impact on neuroplasticity enhancement.  相似文献   
6.
Sour cherry (Prunus cerasus) is rich in biologically active phenolic compounds. These compounds are concentrated in fruit skin and most of them remain in the leftovers during the production of juice. Supercritical carbon dioxide extraction was used to separate phenolic compounds from sour cherry pomace. The effects of temperature, pressure and the addition of ethanol on anthocyanin and the total phenolic content and radical scavenging activity of the extracts were investigated. The best results were acquired for 35°C, 10 MPa and 80% ethanol addition. A strong correlation was found between the phenolic content and other features of the extracts.  相似文献   
7.
Journal of Inorganic and Organometallic Polymers and Materials - The fabrication of graphene/graphene oxide bounded metal nanostructures, to form hybrid composites, and their utilization for the...  相似文献   
8.
Carbon cloth was studied as solid-contact material in potentiometric ion sensors by using electrochemical impedance spectroscopy and potentiometry. The ion-to-electron transduction process was studied by electrochemical impedance spectroscopy by using a two-electrode symmetrical cell where a liquid electrolyte was sandwiched between two solid electrodes, including bare glassy carbon (GC), GC/carbon cloth and GC/poly(3,4-ethylenedioxythiophene). Impedance data for different electrode/electrolyte combinations were evaluated and compared. Solid-contact K+-selective electrodes were fabricated by coating the carbon cloth with a conventional plasticized PVC-based K+-selective membrane via drop casting. These K+-sensors showed proper analytical performance and acceptable long-term potential stability (potential drift ≈ 1 mV/day). Solid contact reference electrodes were fabricated in an analogous manner by coating the carbon cloth with a plasticized PVC membrane containing a moderately lipophilic salt. The results indicate that carbon cloth can be used as a solid-contact material in potentiometric ion sensors and pseudo-reference electrodes.  相似文献   
9.
The importance of coenzyme A (CoA) as a carrier of acyl residues in cell metabolism is well understood. Coenzyme A participates in more than 100 different catabolic and anabolic reactions, including those involved in the metabolism of lipids, carbohydrates, proteins, ethanol, bile acids, and xenobiotics. However, much less is known about the importance of the concentration of this cofactor in various cell compartments and the role of altered CoA concentration in various pathologies. Despite continuous research on these issues, the molecular mechanisms in the regulation of the intracellular level of CoA under pathological conditions are still not well understood. This review summarizes the current knowledge of (a) CoA subcellular concentrations; (b) the roles of CoA synthesis and degradation processes; and (c) protein modification by reversible CoA binding to proteins (CoAlation). Particular attention is paid to (a) the roles of changes in the level of CoA under pathological conditions, such as in neurodegenerative diseases, cancer, myopathies, and infectious diseases; and (b) the beneficial effect of CoA and pantethine (which like CoA is finally converted to Pan and cysteamine), used at pharmacological doses for the treatment of hyperlipidemia.  相似文献   
10.
The growing role of fatty acid amides in medicinal chemistry has recently been observed. Therefore, using simple and fast methods, a series of chiral amide derivatives (24 compounds) of ricinoleic and 3-hydroxynonanoic acid was obtained with 31–95% yields. Then, the evaluation of their antimicrobial activity against 13 microorganisms representing Gram-positive and Gram-negative bacteria, yeast, and molds was performed. The obtained compounds showed antimold potential; however, the tested species of molds were more susceptible to derivatives of 3-hydroxynonanoic acid than to amides obtained from ricinoleic acid (RA). Interestingly, hydroxamic acids derived from RA exhibited the best activity against Candida albicans and Candida tropicalis. On the other hand, hydroxamic acids derived from 3-hydroxynonanoic acid showed the best antimicrobial potential against the remaining tested microorganisms, especially against Pseudomonas cedrina. The obtained derivatives can be considered compounds of potential pharmacological significance, which is important due to the increasing problem of microbial resistance.  相似文献   
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