全文获取类型
收费全文 | 154篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 45篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 1篇 |
矿业工程 | 1篇 |
能源动力 | 11篇 |
轻工业 | 26篇 |
水利工程 | 1篇 |
石油天然气 | 12篇 |
无线电 | 18篇 |
一般工业技术 | 27篇 |
冶金工业 | 3篇 |
原子能技术 | 3篇 |
自动化技术 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 16篇 |
2018年 | 17篇 |
2017年 | 12篇 |
2016年 | 19篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2004年 | 1篇 |
2003年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有175条查询结果,搜索用时 31 毫秒
51.
Drug Delivery: On‐Chip Self‐Assembly of a Smart Hybrid Nanocomposite for Antitumoral Applications (Adv. Funct. Mater. 10/2015)
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
52.
53.
Afsaneh Nabifar Neil T. McManus Eduardo Vivaldo‐Lima Liliane M.F. Lona Alexander Penlidis 《加拿大化工杂志》2008,86(5):879-892
A comprehensive experimental investigation of nitroxide‐mediated radical polymerization (NMRP) of styrene using 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) as controller is presented. Polymerizations with a bimolecular initiator (benzoyl peroxide; BPO) were carried out at 120 and 130°C, with TEMPO/BPO molar ratios ranging from 0.9 to 1.5. Results indicate that increasing temperature increases the rate of polymerization while the decrease in molecular weights is only slight. It was also observed that increasing the ratio of TEMPO/BPO decreased both the rate of polymerization and molecular weights. Probably for the first time in the history of such investigations, the paper contains a comprehensive database, appropriate for parameter estimation in aid of future modelling studies, since it comes from a systematic data collection containing independent replication. 相似文献
54.
Afsaneh Dorri Moghadam Benjamin F. Schultz J. B. Ferguson Emad Omrani Pradeep K. Rohatgi Nikhil Gupta 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(6):872-881
Many different types of advanced metal matrix composites are now available, some of which possess functional properties. Recent work on particle-reinforced, self-lubricating and self-healing metals and metal matrix nanocomposites (MMNCs) synthesized by solidification synthesis is reviewed. Particle-based MMNCs have been developed by several modern processing tools based on either solid- or liquid-phase synthesis techniques that are claimed to exhibit exciting mechanical properties including improvements of modulus, yield strength, and ultimate tensile strength. This article presents a brief and objective review of the work done over the last decade to identify the challenges and future opportunities in the area of functional nanocomposites. Increasing interest in lightweight materials has resulted in studies on hollow particle-filled metal matrix syntactic foams. Syntactic foams seem especially suitable for development with functional properties such as self-healing and self-lubrication. The metal matrix micro and nanocomposites, and syntactic foams having combinations of ultrahigh strength and wear resistance, self-lubricating, and/or self-healing properties can lead to increased energy efficiency, reliability, comfort of operation, reparability, and safety of vehicles. The focus of the present review is aluminum and magnesium matrix functional materials. 相似文献
55.
Aalami-Aleagha M. E. Hadi Behzad Shahbazi Mohammad Ali 《Journal of Mechanical Science and Technology》2016,30(8):3767-3776
Journal of Mechanical Science and Technology - A time dependent Eulerian thermal/material flow model of friction stir welding was developed and applied to the dissimilar joining of pure copper and... 相似文献
56.
Selecting the most appropriate bit for any hole section is the key feature in achieving superior drilling performance. This feature has an enormous influence on the optimized performance of drilling and also economically affects the process greatly. The most important factor to correctly select a bit is formation physical characteristics, mainly rock compressive strength. Different sources can be used to obtain rock strength along the wellbore, such as logs, cutting and rock mechanical test, or even drilling data. The use of empirical correlations based on logs is often the only way to estimate strength in many situations due to the absence of cores for laboratory tests. In this study, one of the Iranian oil fields was selected to be analyzed. The goal was calculating the compressive strength from sonic log parameters. In order to develop an exponential correlation, log, drilling data, and backward simulation were used. Log data included sonic, neutron, density, and gamma ray logs. The correlation developed is applicable to determine the quantity of compressive strength of underground formations in absence of cores. 相似文献
57.
Abstract One of the most important characteristics of rocks in drilling operations is unconfined rock strength (UCS), which is critical in different aspects of drilling operations. Several laboratory-based correlations have been generated for specific rocks to estimate UCS from physical properties (such as transient time, porosity, and Young's modulus) of the rocks. In drilling analysis, when UCS information is required and direct methods for estimation of UCS are not available, it is common to use correlations that have been developed for other formations with the same or similar lithology. Obviously, the results of estimations based on UCS correlations for other formations will not be accurate and can affect subsequent analyses. Therefore, it is highly recommended to generate a correlation for the formation of interest, though it is not always possible to reach this goal from experimental works on core samples retrieved from the formation. In this study, a sonic correlation that shows that it can provide relatively better global estimation of UCS for limestone rocks is modified for one of the Iranian carbonate formations by determining new coefficients for the correlation based on drilling data. For this purpose, the drilling information recorded in mud logging data is analyzed to backward simulate the drilling process based on a modified penetration rate model and calculate the rock strengths of the formation. The apparent rock strength log generated from this calculation proceeds quality-controlled steps according to statistical and pattern recognition methods to eliminate the noises and fluctuations that normally exist while working with field data. Then, a new correlation is developed from the formation response to sonic logs and apparent rock strength log. Because this new correlation is originally generated for the formation of interest, UCS is estimated more accurately and analyses dependent on UCS show fewer errors. 相似文献
58.
Kh. Shahbazi M. K. Razavi Aghjeh F. Abbasi M. Partovi Meran M. Mehrabi Mazidi 《Polymer Bulletin》2012,69(2):241-259
Attempts were made to study the effect of reactive compatibilization via Friedel?CCrafts alkylation reaction, using AlCl3 as a catalyst, on rheology, morphology, and mechanical properties of polyethylene/polystyrene (PE/PS) blends. The results of linear viscoelastic measurements in conjunction with the results of the mixing torque variation indicated that PS showed much more degradation than that of PE in the presence of AlCl3. It was also found that while for PE-rich blends, the viscosity, and storage modulus increased by reactive compatibilization, they decreased for PS-rich blends. The variation of viscosity and storage modulus for 50/50 blend was found to be dependent on frequency ranges showing the competitive effects of PE?Cg?CPS copolymer formation and PS degradation. The results of morphological studies showed that reactive compatibilization decreased the particle size and particle-size distribution broadness because of in situ graft copolymer formation. Reactive compatibilization enhanced the tensile strength and elongation at break for PE-rich blends. It was demonstrated that there is a close interrelationship between rheology, morphology, and mechanical properties of reactive compatiblized PE/PS blends. It was also demonstrated that rheological behaviors have a reliable sensitivity to follow the structural and morphological changes during compatibilization process, so that, those information can be used to predict the morphology as well as mechanical properties of the blends. 相似文献
59.
Marjan Nassiri-Asl Mohammad-Reza SarookhaniEsmail Abbasi Amir-Abdollah ZangivandElmira Shakiba Afsaneh SedighiMasomeh Rahbari 《Food chemistry》2012,132(2):1046-1048
The effects of pre-treatment with vitamin B6 on memory retrieval in adult male Wistar rats were evaluated using a step-through passive avoidance task. The rats were divided into three groups of 10 each. All animals were fed standard rodent chow. Vitamin B6 (50 or 100 mg/kg) was administered intraperitoneally (i.p.) every other day for 1 month before training was initiated. Three retention tests were performed to assess the memory of the rats. Vitamin B6 (100 mg/kg) significantly increased the step-through latency of the passive avoidance response compared with the control in the first retention test of the passive avoidance paradigm (p < 0.05). In addition, vitamin B6 at 100 mg/kg significantly increased memory retrieval in the second and third retention tests conducted 2 days and 1 week after training, respectively, compared with the control (p < 0.05). These results indicate that pre-treatment with vitamin B6 potentially enhances memory retrieval. 相似文献
60.
In this paper, we study the case of a limited number of mobile nodes trying to communicate in a large geographic area, forming
a delay/disruption tolerant network (DTN). In such networks the mobile nodes are disconnected for significantly long periods
of time. Traditional routing protocols proposed for mobile ad hoc networks or mesh networks, which assume at least one path
between each source and destination, are ineffective in DTNs. One approach to improve communication is through gossip based
protocols because these protocols do not rely on a fixed path. Another approach is to control the movement of the mobile nodes
and/or use special mobile nodes called ferry nodes. Others try to employ a fixed infrastructure including stationary relay
points. One scheme in stationary relay point approach is to use base stations as relay points which need their own power supply.
In this paper, we study a passive approach where mobile nodes deposit/retrieve messages to/ from known stationary locations
in the geographic region. Messages are delivered from a source by being deposited at one or more locations that are later
visited by the destination. A proposed implementation of our approach using read/writable passive Radio Frequency Identification
(RFID) tags, one per point location, is considered in this work. Passive RFID technology is desirable because it operates
wirelessly and without the need for attached power. Our simulation results indicate that our approach can achieve competitive
message delay and delivery rates. We also demonstrate several techniques for optimizing the stationary relay node placement,
namely relay pruning, probability based relay distribution and a genetic algorithm; the genetic algorithm is shown to provide
the best solutions to this problem. 相似文献