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   572篇
  免费   35篇
  国内免费   4篇
电工技术   12篇
化学工业   115篇
金属工艺   4篇
机械仪表   12篇
建筑科学   18篇
矿业工程   6篇
能源动力   70篇
轻工业   113篇
水利工程   6篇
石油天然气   2篇
无线电   56篇
一般工业技术   78篇
冶金工业   26篇
原子能技术   12篇
自动化技术   81篇
  2024年   8篇
  2023年   9篇
  2022年   15篇
  2021年   30篇
  2020年   27篇
  2019年   23篇
  2018年   24篇
  2017年   27篇
  2016年   26篇
  2015年   20篇
  2014年   21篇
  2013年   43篇
  2012年   42篇
  2011年   42篇
  2010年   50篇
  2009年   45篇
  2008年   42篇
  2007年   30篇
  2006年   26篇
  2005年   11篇
  2004年   4篇
  2003年   7篇
  2002年   5篇
  2001年   2篇
  2000年   4篇
  1999年   4篇
  1998年   3篇
  1997年   8篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1990年   2篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1982年   1篇
  1980年   1篇
排序方式: 共有611条查询结果,搜索用时 31 毫秒
51.
The aim of this study was to investigate the effects of tumbling on the physicochemical and textural characteristics of squid (Loligo vulgaris), octopus (Octopus vulgaris) and cuttlefish (Sepia officinalis) muscles. Before tumbling the cephalopod samples were placed in plastic bags and 0.5 M NaCl was added. Tumbling process was performed continuously in three different tumbling times (2, 4, and 6 h). The results of the analyses showed that tumbling affected the physicochemical properties of cephalopod muscles. The increase in the time of tumbling resulted in the tenderness of the cephalopod muscles. The total soluble protein, the total free amino acid, and pH values increased with the increase of the tumbling time. The water holding capacity decreased and the cooking loss increased. The squid and octopus hardness and shear force values decreased after tumbling, according to instrumental and sensorial texture measurements. As a result, tumbling was found to be an effective method for tenderizing of squid and octopus muscle, but not for cuttlefish.  相似文献   
52.
This study was performed to investigate the antioxidant values of twelve selected Malaysian wood species. Bark and heartwood were extracted with toluene: industrial methylated spirit (Tol: IMS) and evaluated for antioxidant activity. Folin–Ciocalteu reagent was used to determine the total antioxidant activity and total phenols of plant extracts. Free radical scavenging activity was evaluated using 2,2-dipheny-2-picrylhydrazyl (DPPH). Extractive yields, antioxidant activity and total phenolic content varied among wood species. N. heimii had the highest extractive yields (23.50 and 9.16 %), antioxidant (93.60 and 83.78 %) and total phenolic content (29.11 and 24.11 mgGAE/g) for bark and heartwood, respectively. The results provided promising evidence that those tropical timbers may be useful as potential sources of natural antioxidants and could be used as drug formulations.  相似文献   
53.
For much of the twentieth century, coliform bacteria and especially Escherichia coli have been used as indicators of possible post-processing contamination and the presence of E. coli as an indicator of fecal contamination in foods. In this study, 500 foods in 10 different groups, mainly dairy products, delicatessen products, salads, spices, cream cakes and fresh fruit and vegetable samples, were analyzed for the natural contamination of fecal coliforms and E. coli by the standard most probable number (MPN) method. The difference between weighted means of fecal coliforms and E. coli counts were only 0.246 log10 MPN/g-ml (MPN/gram for solid samples, and MPN/milliliter for liquids). Enumeration results were also evaluated by Pearson's correlation coefficient ( r), Cronbach's alpha (f) and determination coefficient ( r 2) analysis. According to results, although 33 samples contained only non- E. coli fecal coliforms, the results of reliability analyses indicated that fecal coliform counts and E. coli counts may be used interchangeably ( P <0.0001). It can be said that fecal coliform or, preferably E. coli analysis is sufficient for rapid routine determination of fecal contamination, at least for those food groups analyzed in this research.  相似文献   
54.
55.
Material selection, one of the mostly encountered decision problems in material science literature, is still an onerous task for manufacturing organisations. Achieving accurate solution to this issue, the paper developed a model selection interface to enable analytical solutions to different problem concepts in material selection under multiple attribute decision-making (MADM) environments. Specifically, the generic framework of the fuzzy axiomatic design-model selection interface (FAD-MSI) is modified and successfully applied to the different material selection problem concepts. Consequently, the derived problem-model sets can be referred to accomplish further proposals on this era.  相似文献   
56.
In this study an antifungal pharmaceutical agent, terbinafine, was microencapsulated by using in situ polymerization. The polymerization was carried out at four mole ratio level and preparations were applied to the 100% cotton fabric. X‐ray diffractometry, DSC, FTIR, BET, contact angle measurements, particle size distribution and imaging techniques were performed. Best results were obtained in the case of 8 : 1 mole ratio. Strength of microcapsule applied fabrics to washing and fungus were also determined. After 25 washing cycle, microcapsules were still in the fabric and had antifungal properties against A. niger. Antifungal strength against T. rubrum was observed up to 15 washing cycles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   
57.
In this paper, preliminary support design of a tunnel was analyzed by numerical and empirical approaches. The case study for this analysis is a tunnel to be constructed on the Bilecik-Istanbul roadway in Turkey. The rock mass properties of the tunnel route and design support recommendations were obtained by using an empirical approach. The rock mass properties obtained from the empirical method were used as input parameters for the numerical analysis. The empirical and numerical results, in terms of support design, were evaluated. It was seen that the numerical analysis results supported by empirical values were logical and reliable.  相似文献   
58.
In the early 2000s, the Republic of Turkey has initiated an ambitious reform program in her electricity market, which requires privatization, liberalization as well as a radical restructuring. The most controversial reason behind, or justification for, recent reforms has been the rapid electricity demand growth; that is to say, the whole reform process has been a part of the endeavors to avoid the so-called “energy crisis”. Using cointegration analysis and autoregressive integrated moving average (ARIMA) modelling, the present article focuses on this issue by both providing an electricity demand estimation and forecast, and comparing the results with official projections. The study concludes, first, that consumers’ respond to price and income changes is quite limited and therefore there is a need for economic regulation in Turkish electricity market; and second, that the current official electricity demand projections highly overestimate the electricity demand, which may endanger the development of both a coherent energy policy in general and a healthy electricity market in particular.  相似文献   
59.
In this paper, both of current-mode and voltage-mode proportional plus integral plus derivative (PID) controllers employing the second-generation current conveyors (CCIIs) as active elements are developed. The presented novel PID controllers have grounded passive elements that do not need passive element matching, and realize independently adjustable PID parameters. Thus, it is easy to implement these PID controllers in integrated circuits. Several computer simulations are presented to demonstrate the behavior of these proposed PID controllers.  相似文献   
60.
Erkan Erdogdu   《Energy Policy》2008,36(6):2182-2190
Turkey is heavily dependent on expensive imported energy resources (oil, gas and coal) that place a big burden on the economy. Air pollution is also becoming a great environmental concern in the country. In this regard, renewable energy resources appear to be one of the most efficient and effective solutions for clean and sustainable energy development in Turkey. Turkey's renewable sources are the second largest source for energy production after coal. About two-thirds of the renewable energy produced is obtained from bioenergy, which is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles and providing process heat for industrial facilities. The amount of usable bioenergy potential of Turkey is approximately 17 Mtoe. This article not only presents a review of the potential and utilization of the bioenergy in Turkey but also provides some guidelines for policy makers.  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