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   161篇
  免费   12篇
  国内免费   2篇
电工技术   2篇
化学工业   41篇
金属工艺   4篇
机械仪表   3篇
建筑科学   5篇
能源动力   2篇
轻工业   12篇
水利工程   3篇
无线电   33篇
一般工业技术   24篇
冶金工业   12篇
原子能技术   2篇
自动化技术   32篇
  2020年   3篇
  2019年   6篇
  2018年   4篇
  2017年   2篇
  2016年   6篇
  2015年   5篇
  2014年   2篇
  2013年   12篇
  2012年   4篇
  2011年   10篇
  2010年   16篇
  2009年   12篇
  2008年   16篇
  2007年   11篇
  2006年   8篇
  2005年   7篇
  2004年   5篇
  2003年   9篇
  2002年   2篇
  2001年   3篇
  2000年   6篇
  1999年   2篇
  1998年   5篇
  1997年   4篇
  1996年   1篇
  1995年   1篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1988年   1篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1979年   1篇
  1976年   1篇
排序方式: 共有175条查询结果,搜索用时 31 毫秒
51.
Knowledge sharing and learning behaviors in the workplace are believed to be very important to the success of firms. In this study, the relationships between knowledge sharing and learning behaviors, business process improvement, product and service offerings, and organizational performance are examined based on a sample of 134 firms engaged in manufacturing, and wholesale or retailing operations. Data analyses using the partial least squares statistical technique revealed that knowledge sharing and learning behaviors are positively associated with business process improvement, and product and service offerings. Business process improvement and product and service offerings are positively associated, and they in turn are positively related to organizational performance. The findings reinforce the importance of knowledge sharing and learning to companies. Executives should encourage knowledge management and organizational learning activities within their firms, and give proper considerations to the strategies and implementation of programs supporting these activities in order to enhance firm performance.  相似文献   
52.

BACKGROUND

2‐phenylethanol (2PE) is a fragrance molecule predominantly used in perfumes and the food industry. It can be made from petrochemicals inexpensively, however, this is unsuitable for most food applications. Currently, the main method of production for the bio‐derived compound is to extract the trace amounts found in rose petals, which is extremely costly. Potentially fermentation could provide an inexpensive, naturally sourced, alternative.

RESULTS

In this investigation, 2PE was produced from the yeast Metschnikowia pulcherrima, optimised in flasks before scaling to 2 L batch and continuous operation. 2PE can be produced in high titres under de novo process conditions with up to 1500 mg L?1 achieved in a 2 L stirred bioreactor. This is the highest reported de novo titre to date, and achieved through high sugar loadings coupled with low nitrogen conditions. The process successfully ran in continuous mode also, with a concentration of 650 mg L?1 of 2PE being maintained. The 2PE production was further increased by the ex novo conversion of phenylalanine and semi‐continuous solid phase extraction from the supernatant. Under optimal conditions 14 000 mg L?1 of 2PE was produced.

CONCLUSIONS

The work presented here offers a novel route to naturally sourced 2PE through a scalable fermentation with a robust yeast highly suited to industrial biotechnology. © 2018 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
  相似文献   
53.
Middle Eastern Countries are experiencing the emergence of high volume production and retail marketing over traditional unit baking and retailing. This phenomenon has revealed a shortcoming in quality issues in Arabic flat bread (AFB) manufacture. Therefore, shelf-life extension and quality improvement are in demand to limit economic loss. Five improvers and a control (without any improver) were selected for improving shelf-life and quality of AFB. The improver treatments included: (1) sodium 9 stearoyl-2-lactylate (SSL), (2) monoglycreides (MG), (3) hydroxy propyl methyl cellulose gum (HPMC), (4) high-fructose corn syrup (HFCS), and (5) a combination of all the aforementioned improvers. The texture analysis data indicated that the presence of HFCS may act as a plasticizer through contributing to the longer tearing time. The other treatments exhibited a significant decline in tearing time throughout storage. The NIRS data indicated that after 3 days, the control was less fresh than AFB formulated with HFCS or improver combinations. The sensory evaluation of AFB exhibited that the improver combination significantly improved the quality attributes.  相似文献   
54.
Plan synthesis and language comprehension, or more generally, the act of discovering how one perception relates to others, are two sides of the same coin, because they both rely on a knowledge of cause and effect—algorithmic knowledge about how to do things and how things work. I will describe a new theory of representation for commonsense algorithmic world knowledge, then show how this knowledge can be organized into larger memory structures, as it has been in a LISP implementation of the theory. The large-scale organization of the memory is based on structures called bypassable causal selection networks. A system of such networks serves to embed thousands of small commonsense algorithm patterns into a larger fabric which is directly usable by both a plan synthesizer and a language comprehender. Because these bypassable networks can adapt to context, so will the plan synthesizer and a language comprehender. I will propose that the model is an approximation to the way humans organize and use algorithmic knowledge, and as such, that it suggests approaches not only to problem solving and language comprehension, but also to learning. I'll describe the commonsense algorithm representation, show how the system synthesizes plans using this knowledge, and trace through the process of language comprehension, illustrating how it threads its way through these algorithmic structures.  相似文献   
55.
Small-format aerial photography (SFAP) is a low-cost solution for bridge-surface imaging and is proposed as a remote bridge-inspection technique to supplement current bridge visual inspection. Providing top-down views, photos taken from airplanes flying at 305?m (1,000?ft) allow for the visualization of subinch (i.e., large) cracks and joint openings on bridge decks or highway pavements. An onboard global positioning system can help geo-reference images collected and allow automated damage detection. However, the site lighting, surrounding tree shades, and highway surface reflectivity may affect the quality of the images. Several examples of bridge evaluation using SFAP are presented to demonstrate the capability of remote sensing as an effective tool for bridge-construction monitoring and condition assessment. A deck condition rating technique for large crack detection is proposed to quantify the condition of the existing bridge decks.  相似文献   
56.
When a food product is cooked at high temperature with different proportions of water, the differential degradation that occurs in the molecular structure promotes changes in their functional characteristics. In this study, water and soya bean flour (dry base) were mixed in different ratios (3:1, 2:1, 1:1, 0.25:1 and 0:1) and pressure cooked at 130 °C, 1.5 kg cm?2 for 30 min, cooled down to 40 °C and air dried for 24 h. Protein changes due to thermal process were determined with the ATR‐FTIR, as well as some functional parameters and in vitro protein digestibility. At higher water:soya bean flour ratios (3:1 and 2:1), the protein digestibility increased due to denaturation of tertiary structures, while urease activity (UA) and the functional characteristics of water absorption index (WAI) and water solubility index (WSI) decreased. Pearson's correlation analysis revealed that molecular changes on amide I, II and in α‐helix: β‐sheet ratios were directly related with the amount of added water.  相似文献   
57.
The distribution and physical form of technetium in a Hanford low‐activity waste (LAW) glass was examined with scanning electron microscopy (SEM) and X‐ray diffraction (XRD). A simulated Hanford LAW glass was spiked with varying amounts of potassium pertechnetate and melted at 1000°C. The glass was melted in a sealed quartz ampoule with the air pumped out, so that volatile material could leave the glass but would not be lost from the system. Previous studies have shown that technetium remains in the glass up to about 2000 ppm, but rises to the top of the melt as a separate salt phase above this concentration. Examination by SEM shows that crystals of technetium compounds appear to grow out of the hot glass, which implies that the hot glass was supersaturated in technetium salts. Some of the technetium compound crystals had apparently melted, but other crystals had obviously not melted and must have formed after the glass had partially cooled. The technetium compounds in the salt layer are KTcO4 and NaTcO4, according to SEM and XRD. No TcO2 was found in the salt phase, even though Tc(IV) has been previously reported in the glass.  相似文献   
58.
The need for global‐scale cyber physical system (CPS) is increasing with the evolution of CPS research. A global‐scale CPS requires additional considerations beyond the well‐known CPS requirements, such as security, reliability, and timely delivery, which cannot be easily satisfied when a CPS becomes global scale. Building an entire dedicated network for a global‐scale CPS cannot be a solution, because it requires a large capital outlay in order to be actualized. To overcome these obstacles, we implement a virtual platform named Xebra that includes effective CPS middleware for realizing a global‐scale CPS and isolation techniques based on virtualization. In this paper, we discuss the requirements for realizing global‐scale CPS network, and also, we introduce our implementation as a virtual platform with its performance evaluation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
59.
60.
Do QH  Zeng C  Zhang C  Wang B  Zheng J 《Nanotechnology》2011,22(36):365402
Composite electrodes were fabricated for supercapacitor applications by depositing vanadium oxide onto multi-walled carbon nanotube (MWCNT) buckypaper using supercritical fluid deposition (SFD). The deposited thin vanadium oxide layer showed amorphous structure with excellent uniformity. In aqueous KCl electrolyte, the vanadium oxide exhibited a constant pseudo-capacitance of ~ 1024 F g(-1), which was independent of the oxide material loading (up to 6.92 wt%) and voltage scan rate (up to 100 mV s(-1)). The highest specific electrode capacitance achieved was ~ 85 F g(-1), which was almost four times that of the pristine buckypaper electrode.  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