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   201篇
  免费   19篇
电工技术   3篇
化学工业   59篇
金属工艺   1篇
机械仪表   7篇
建筑科学   3篇
能源动力   7篇
轻工业   29篇
水利工程   3篇
石油天然气   1篇
无线电   26篇
一般工业技术   40篇
冶金工业   15篇
自动化技术   26篇
  2023年   5篇
  2022年   6篇
  2021年   9篇
  2020年   5篇
  2019年   8篇
  2018年   7篇
  2017年   15篇
  2016年   16篇
  2015年   7篇
  2014年   16篇
  2013年   28篇
  2012年   13篇
  2011年   9篇
  2010年   9篇
  2009年   9篇
  2008年   6篇
  2007年   4篇
  2006年   7篇
  2005年   2篇
  2004年   2篇
  2003年   3篇
  2002年   5篇
  2001年   3篇
  2000年   2篇
  1999年   4篇
  1998年   3篇
  1997年   3篇
  1996年   4篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1987年   1篇
  1983年   1篇
  1947年   2篇
排序方式: 共有220条查询结果,搜索用时 15 毫秒
31.
Edge caching is an effective feature of the next 5G network to guarantee the availability of the service content and a reduced time response for the user. However, the placement of the cache content remains an issue to fully take advantage of edge caching. In this paper, we address the proactive caching problem in Heterogeneous Cloud Radio Access Network (H‐CRAN) from a game theoretic point of view. The problem is formulated as a bargaining game where the remote radio heads (RRHs) dynamically negotiate and decide which content to cache in which RRH under energy saving and cache capacity constraints. The Pareto optimal equilibrium is proved for the cooperative game by the iterative Nash bargaining algorithm. We compare between cooperative and noncooperative proactive caching games and demonstrate how the selfishness of different players can affect the overall system performance. We also showed that our cooperative proactive caching game improves the energy consumption of 40% as compared with noncooperative game and of 68% to no‐game strategy. Moreover, the number of satisfied requests at the RRHs with the proposed cooperative proactive caching scheme is significantly increased.  相似文献   
32.
In orthogonal frequency division multiplexing (OFDM) system, high value of peak-to-average power ratio (PAPR) is an operational problem that may cause non-linear distortion resulting in high bit error rate. Selected mapping (SLM) is a well known technique that shows good PAPR reduction capability but inflicts added computational overhead. In this paper, using Riemann sequence based SLM method, we applied reverse searching technique to find out low PAPR yielding phase sequences with significant reduction in computational complexity. Additionally, we explored side-information free transmission that achieves higher throughput but sacrifices PAPR reduction. Finally, to overcome this loss in PAPR reduction, we proposed application of Square-rooting companding technique over the output OFDM transmitted signal. Simulation results show that the proposed method is able to compensate the sacrifice in PAPR and achieved PAPR reduction of 8.9 dB with very low computational overhead.  相似文献   
33.
To enable the application of optical fiber sensors to aerospace vehicles, the sensor interrogation or data acquisition system has to meet small size and low weight requirements. This paper presents the developmental work of an echelle diffractive gratings (EDGs) demultiplexer-based optical fiber sensor interrogation system. The operation principle of this system and its application to fiber Bragg grating (FBG) sensor interrogation are presented. The experimental results have shown that the developed interrogator (not including the electronic controller) weighs less than 60 g and provides better than 1 pm measurement resolution and better than plusmn10 pm measurement accuracy.  相似文献   
34.
35.
Washing PET or PEN bottles intended for reuse with sodium hydroxide solutions appeared to affect the surface of the materials. The possible hydrolysis of the ester chemical function during the process was investigated. A new method for extracting and separating neutral and acidic products from the polymers was developed, and relative quantification of the isolated molecules was carried out by gas and liquid chromatography. Some adjuvants were no longer present after washing, but others were more easily extracted. A very weak hydrolysis reaction for PEN could not be excluded but it did not seem to occur for PET. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
36.
Most cell penetrating peptides (CPPs) are unstructured and susceptible to proteolytic degradation. One alternative is to incorporate D-chirality amino acids into unstructured CPPs to allow for enhanced uptake and intracellular stability. This work investigates CPP internalization using a series of time, concentration, temperature, and energy dependent studies, resulting in a three-fold increase in uptake and 50-fold increase in stability of D-chirality peptides over L-chirality counterparts. CPP internalization occurred via a combination of direct penetration and endocytosis, with a percentage of internalized CPP expelling from cells in a time-dependent manner. Mechanistic studies identified that cells exported the intact internalized D-chirality CPPs via an exocytosis independent pathway, analogous to a direct penetration method out of the cells. These findings highlight the potential of a D-chirality CPP as bio-vector in therapeutic and biosensing applications, but also identify a new expulsion method suggesting a relationship between uptake kinetics, intracellular stability, and export kinetics.  相似文献   
37.
Various bis(silyl)ethenyl groups were attached to the aromatic ring of poly(α-methylstyrene) via Peterson olefination reaction of (RMe2Si)3CLi (R = H, Me and Ph) with formylated poly(α-methylstyrene) (Pα-MS-CHO) to give poly(α-methylstyrene)-co-[2,2-bis(silyl)ethenyl(α-methylstyrene)] as functionalized poly(α-methylstyrene) (Pα-MS-SiMe2H, Pα-MS-SiMe3 and Pα-MS-SiMe2Ph). The trimethylsilyl groups of Pα-MS-SiMe3 have been converted to 2,2-dibromoethenyl and epoxybis(silanes) groups via NBS-based bromodesilylation and MCPBA-based epoxidation respectively. The thermal degradation behaviors of the polymers were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).  相似文献   
38.
As a developing country, Turkey’s sustainable development objectives converge on robust and sustainable economic development. The increase in its energy and electricity demand is attributed to the growth of population, urbanization, and industrialization parallel to economic and social growth. Instead of fulfilling the obligation to protect the environment arising from international agreements and achieving desired sustainable development, the dependency on imported fossil fuel in electrical energy production and energy-intensive economic growth results in intensified CO2 emission as well as ironically negative economic output. Therefore, Turkey is forced to exploit its indigenous sources such as coal (which unfortunately increases atmospheric Green House Gas “GHG” emissions) and renewable resources. However, high GHG emission – mainly CO2 – of Turkey’s coal power plants impairs deployment of indigenous sources for power generation. Indeed, there is a necessity of technical approaches for higher heat extraction efficiencies and mitigation of high concentration of energy-related CO2 emission. Admittedly, “Carbon Capture, Utilization, and Storage (CCUS)” employing conventional hydrothermal resources offers highly efficient heat extraction, geological CO2 sequestration, and utilization of CO2 for power generation rather than considering CO2 as an effluent. Although there are research gaps and lack of field scale experiment, the economic and environmental viability of implementing CCUS in Turkey can be improved by pilot or field scale projects whereby the presence of these projects commences technological and experimental advances in capturing CO2 either from geothermal power plants or indigenous coal power plants, transporting it to the proven geothermal geologic site, and generating power. Apart from this, the “CO2 – Plume Geothermal Systems (CPG)” compared to unconventional and conventional geothermal systems would commit vigorous potential for continual improvement in economic feasibility of CCUS without a guaranteed return on power generation investments in Turkey. Hence, legislations concerning incentives in CCUS would foster further improvements in the deployment of geothermal resources to pursue sustainable development in Turkey.  相似文献   
39.
Legionella pneumophila is the causative agent of Legionnaires’ disease, a serious form of pneumonia. Its macrophage infectivity potentiator (Mip), a member of a highly conserved family of FK506-binding proteins (FKBPs), plays a major role in the proliferation of the gram-negative bacterium in host organisms. In this work, we test our library of >1000 FKBP-focused ligands for inhibition of LpMip. The [4.3.1]-bicyclic sulfonamide turned out as a highly preferred scaffold and provided the most potent LpMip inhibitors known so far. Selected compounds were non-toxic to human cells, displayed antibacterial activity and block bacterial proliferation in cellular infection-assays as well as infectivity in human lung tissue explants. The results confirm [4.3.1]-bicyclic sulfonamides as anti-legionellal agents, although their anti-infective properties cannot be explained by inhibition of LpMip alone.  相似文献   
40.
The Journal of Supercomputing - Depression is the most prevalent mental disorder that can lead to suicide. Due to the tendency of people to share their thoughts on social platforms, social data...  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