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   182篇
  免费   7篇
综合类   1篇
化学工业   48篇
机械仪表   7篇
建筑科学   8篇
能源动力   8篇
轻工业   31篇
水利工程   4篇
无线电   31篇
一般工业技术   19篇
冶金工业   15篇
自动化技术   17篇
  2024年   2篇
  2023年   1篇
  2022年   4篇
  2021年   7篇
  2020年   5篇
  2019年   4篇
  2018年   3篇
  2017年   9篇
  2016年   5篇
  2015年   8篇
  2014年   6篇
  2013年   27篇
  2012年   8篇
  2011年   20篇
  2010年   4篇
  2009年   11篇
  2008年   7篇
  2007年   6篇
  2006年   11篇
  2005年   4篇
  2004年   10篇
  2003年   4篇
  2002年   1篇
  2001年   1篇
  1998年   4篇
  1997年   4篇
  1996年   4篇
  1994年   4篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1983年   1篇
排序方式: 共有189条查询结果,搜索用时 15 毫秒
1.
2.
In mergers and acquisitions (M&A), a primary objective of acquirer is to integrate IT resources of the target with its own. IT M&A integration is assumed to create synergies, which in turn increase shareholder wealth by making the value of the merged firm greater than the sum of the standalone values of the two firms. In this study, we challenge this assumption and argue that IT M&A integration does not always lead to greater value creation. Prior research on IT M&A integrations indicates that IT resources are often not scale-free in M&A: that is, they do not transfer easily and costlessly from an acquirer to its target or vice versa. In fact, IT M&A integration can destroy value rather than create it when IT resources are not scale-free. We theorize about the contingencies under which IT M&A integration can create value for shareholders of acquirers. We test our hypotheses in a sample of 549 M&A transactions between 1998 and 2007. We find that, on average, capital markets react negatively with M&A announcements of acquirers whose IT capabilities are superior relative to those of the targets. The superiority of the acquirer’s IT capabilities signals that the acquirer is likely to rip and replace IT resources of the target. This IT M&A integration approach increases risks of disruption to target’s operations and revenue growth. Capital markets take such risks into account and reduce the stock price of the acquirer. One contingency that reduces the negative reactions of capital markets is industry relatedness of target. In a same-industry acquisition, an acquirer and its target have similar operating models, competitive dynamics, and regulatory context. Thus, ripping and replacing weaker IT resources of the target with superior IT resources of the acquirer creates expectations of more efficient operation, engenders positive stock price reactions, and increases shareholder wealth. Another contingency that reduces the negative reactions of capital markets is the acquirer’s track record in profitable growth. A profitably growing acquirer that has superior IT capabilities increases the confidence of capital markets that it can minimize potential disruption risks of IT integration, continue its profitable growth pattern with newly acquired target, engender positive stock price reactions, and create shareholder wealth. These findings indicate that IT M&A integration does not always lead to greater value creation in M&A. The study makes a contribution by identifying the contingencies under which IT M&A integration creates wealth for acquirer’s shareholders.  相似文献   
3.
Societal and industrial demands for lower environmental impact, cost effectiveness, and high‐performance goods and services are increasingly impacting the choice of technologies which are developed and deployed in consumer products. Like many other sectors, food packaging is moving to new technologies; the use of biopolymers is one of the most promising strategies toward an optimized use of traditional packaging materials (e.g., oil‐based plastics) without impairing the goal of extending shelf life. Among other food packaging materials, pullulan is attracting much attention due to its unique features. The goal of this review is to provide an overview of current and emerging applications of pullulan within the food packaging sector. In particular, the functional properties of interest for the food packaging industry will be discussed in light of the physicochemical attributes of this exopolysaccharide. Future challenges that may dictate the successful penetration of pullulan in the food packaging market are also outlined. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40539.  相似文献   
4.
In the present study biodegradable, environmentally friendly polysaccharide-based polycarboxylate, carboxymethyl inulin (CMI), was used to produce hydroxyapatite (HAP) particles by wet chemical synthesis under controlled temperature, pH, and atmospheric conditions. The morphology and microstructure of the HAP nanoparticles were investigated by XRD, SEM, DTA–TGA and FTIR. CMI affects morphology, surface area, dimension and particle size distribution of the crystals. The reduction in size is greater in the direction of the c-axis. The increase in the polymer concentration to 7.5 g/L resulted in the mixture of nanoparticles with particle sizes of less than 100 nm. The SEM micrograph shows the formation of well-crystallized, agglomerated small particles of HAP. X-ray analysis has shown that the resulting particles have high thermal stability.The obtained crystals were used to produce tablets by direct compression of HAP. The influence of sample's CMI concentration on drug release profiles was investigated by using ibuprofen (C13H18O2) as a model drug. The model was used to determine the effective diffusion coefficient of the drug from the tablets. A good agreement between experimental data and model predictions was obtained as calculated in the present work. The values of the diffusion coefficients range from 1.62 × 10? 7 to 4.72 × 10? 7 m2 h? 1.  相似文献   
5.
Network on chip (NoC) has been proposed as an appropriate solution for today’s on-chip communication challenges. Power dissipation has become a key factor in the NoCs because of their shrinking sizes. In this paper, we propose a new encoding approach aimed at power reduction by decreasing the number of switching activities on the buses. This approach assigns the symbols to data word in such a way that the more frequent words are sent by less power consumption. This algorithm dedicates the symbols with less ones to high probability data and uses transition signaling to transmit data. The proposed method, unlike the existing low power encoding, does not rely on spatial redundancy and keeps the width of the bus constant. Experimental evaluations show that our approach reduces the power dissipation up to 46 % with 2.70, 0.51, and 15.43 % power, critical path and area overhead in the NoCs, respectively.  相似文献   
6.
Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene-based species and polyurethane block copolymers are of great interest. Poly(styrene-ethylene-butadiene-styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO2) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application.  相似文献   
7.
Power dividers are inevitable components in most microwave systems. Well known topologies like Wilkinson power divider are widely studied in the literature. An “all 50 ohm power divider” is another topology presented in the some works. In this study, an all 50 ohm structure is taken as the basis and a compact-easy to implement modification the power divider is proposed. A sample structure is designed, implemented and measured to prove the topology. The decreased sensitivity to production tolerances is demonstrated by various design modifications. Comparisons with well-known topologies are given for reference.  相似文献   
8.
9.
Core–shell nanostructured Ni-coated Al2O3 composite powders were synthesised by using the electroless plating method. The influence of the chemical components and powder concentration in the Ni coating was investigated by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction techniques. The results show that the concentration of the plating components plays an important role in the formation of core–shell Al2O3/Ni composite powders. The nickel content in the composite powders could be effectively controlled by adjusting the nickel chloride content and the concentration of NaH2PO2·H2O in the plating solution. The nanostructure of the crystalline Ni coatings was observed to be very attractive for achieving good bonding between ceramic particles and matrices for composite production.  相似文献   
10.
White and red grape juices (GJs) were subjected to ultraviolet C (UV-C) light as a non-thermal preservation technology using a coiled tube UV-C reactor with nine lamps. The effects of UV-C light on microbial (total aerobic count and yeast and mould count) and some chemical quality characteristics (total phenolics, antioxidant capacity, anthocyanin and polymeric colour, etc.) of white and red GJs were investigated. The results were compared with control (untreated) and heat-treated juice samples. Single-pass UV-C treatment (12.6 J/mL) of white and red GJs resulted in 3.51 and 3.59 log reductions in total aerobic count and, 2.71 and 2.89 log reductions in yeast and mould counts, respectively. The microbial loads of both GJs were completely eliminated after two passes through the reactor (25.2 J/mL). After UV-C and heat treatments, there were no significant changes in antioxidant capacity, total phenolics, titratable acidity, soluble solids and pH of white and red GJs (P?>?0.05). The losses in monomeric anthocyanins were 6.1% and 8.7% after UV-C treatment of 12.6 and 25.2 J/mL doses, respectively. However, anthocyanin level of red GJ was significantly affected by the heat treatment with an 11.8% loss (P?<?0.05). The percent polymeric colour of the red GJ with heat treatment was significantly higher compared to the colour with the UV-C treatment.  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