全文获取类型
收费全文 | 238篇 |
免费 | 19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 | 50篇 |
金属工艺 | 4篇 |
机械仪表 | 8篇 |
建筑科学 | 17篇 |
能源动力 | 1篇 |
轻工业 | 18篇 |
水利工程 | 10篇 |
无线电 | 42篇 |
一般工业技术 | 39篇 |
冶金工业 | 17篇 |
原子能技术 | 1篇 |
自动化技术 | 48篇 |
出版年
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 21篇 |
2020年 | 11篇 |
2019年 | 17篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 19篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 14篇 |
2011年 | 19篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 13篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有258条查询结果,搜索用时 15 毫秒
211.
Nguyen Thai Ha Waizenegger Lena Techatassanasoontorn Angsana A. 《Information Systems Frontiers》2022,24(3):797-838
Information Systems Frontiers - Interactions with conversational agents (CAs) become increasingly common in our daily life. While research on human-CA interactions provides insights into the role... 相似文献
212.
213.
Kinetics of miniemulsion polymerizations of ethylene glycol dimethacrylate and/or methyl methacrylate
下载免费PDF全文
![点击此处可从《Polymer International》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Quoc‐Thai Pham Chun‐Ta Lin Chia‐Hung Chen Chorng‐Shyan Chern 《Polymer International》2016,65(3):290-298
Two types of reactive acrylic microgel particles of methyl methacrylate (MMA)/ethylene glycol dimethacrylate (EGDMA) (66.4/33.6 and 0/100 (mol/mol)) were prepared by miniemulsion polymerization with 2,2′‐azobisisobutyronitrile as the initiator in the temperature range 60–80 °C. Ostwald ripening occurred during the very early stage of polymerization. In addition to the predominant droplet nucleation, homogeneous nucleation was also observed. The polymerization rate for MMA/EGDMA miniemulsion was higher than that for EGDMA miniemulsion. By contrast, comparable apparent limiting conversions were observed for the polymerizations of MMA/EGDMA and EGDMA. The mole fractions of MMA and EGDMA units incorporated into the copolymer product were estimated to be 0.62 and 0.38, respectively, for the polymerization of MMA/EGDMA at 70 °C. The mole fraction of the EGDMA unit containing one ? C?C? within the MMA/EGDMA microgel particle product was estimated to be 0.23, which was comparable to that (0.22) of the EGDMA unit containing one ? C?C? within the EGDMA microgel particle product. © 2015 Society of Chemical Industry 相似文献
214.
Local Structure and Chemistry of C‐Doped ZnO@C Core–Shell Nanostructures with Room‐Temperature Ferromagnetism
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)
Duc‐The Ngo Le Thanh Cuong Nguyen Huu Cuong Cao Thai Son Pham Thanh Huy Nguyen Duc Dung 《Advanced functional materials》2018,28(8)
A superior approach is presented to study quantitatively fine structure of C‐doped ZnO nanostructure using transmission electron microscopy (TEM) from which the role of carbon in ZnO crystal to form ferromagnetism is revealed at the first time. Electron diffraction in TEM shows Wurtzite structure in the nanoparticles with lattice parameters (a = 0.327 ± 0.03 nm and c = 0.529 ± 0.04 nm) slightly different from the original structure. Interestingly, the Zn–C bonding with a bonding length of 2.58 Å is experimentally determined using atomic pair distribution function (PDF) calculated from electron diffraction data. Together with other bondings, such as C–C, Zn–O obtained from the PDF, this demonstrates migration of C atoms into ZnO crystal to substitute O vacancies. This is furthermore visualized by high‐resolution TEM imaging and elemental mapping, and strongly supports the proposal of origin of ferromagnetism in the C‐doped ZnO nanoparticles where the s–p and p–p hybridizations formed by C2p–Zn4s, and O2p–C2p orbitals are believed to cause ferromagnetism. 相似文献
215.
General non-linear functional differential equations are considered. New explicit criteria for the exponential stability are presented. The stability criteria given in this paper include many existing results as particular cases. In particular, they unify, generalise and improve some ones published recently in [Ngoc, P. H. A. (2012). On exponential stability of non-linear differential systems with time-varying delay. Applied Mathematics Letters, 25(9), 1208–1213 and Ngoc, P. H. A. (2013b). Novel criteria for exponential stability of functional differential equations. Proceedings of the American Mathematical Society, 141(9), 3083–3091]. Two examples are given to show the effectiveness and advantage of the obtained results. 相似文献
216.
Kyoung Kwan Ahn Nguyen Huynh Thai Chau 《Journal of Mechanical Science and Technology》2007,21(8):1196-1206
Pneumatic cylinders are one kind of low cost actuation sources which have been applied in industrial and robotics field, since
they have a high power/weight ratio, a high-tension force and a long durability. To overcome the shortcomings of conventional
pneumatic cylinders, a number of newer pneumatic actuators have been developed such as McKibben Muscle, Rubber Actuator and
Pneumatic Artificial Muscle (PAM) Manipulators. However, some limitations still exist, such as the air compressibility and
the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion.
In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize
motion with high accuracy and high speed and with respect to various external inertia loads.
To overcome these problems, a novel controller which harmonizes a phase plane switching control method (PPSC) with conventional
PID controller and the adaptabilities of neural network is newly proposed. In order to realize satisfactory control performance
a variable damper, Magneto-Rheological Brake (MRB), is equipped to the joint of the robot. The mixture of conventional PID
controller and an intelligent phase plane switching control using neural network (IPPSC) brings us a novel controller. The
experiments were carried out in a robot arm, which is driven by two PAM actuators, and the effectiveness of the proposed control
algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly
in a high gain control by using MRB with 1PPSC and without regard for the changes of external inertia loads. 相似文献
217.
Ngoc Minh Ho Thuy Chinh Nguyen Thi Thanh Van Tran Tien Dung Nguyen Hoang Thai 《应用聚合物科学杂志》2021,138(29):50685
The epoxy/silica nanocomposites containing a wide range of isopropyltri[di(octyl) phosphate] titanate coupling agent (KR-12) modified nanosilica (m-nanosilica) loading (0–7 wt%) cured with tetrabutyl titanate hardener were prepared. Their morphology, thermal stability, thermal expansion, and mechanical properties including hardness, abrasion resistance were investigated. The wetting ability of epoxy-nanosilica systems on glass surface was assessed based on static contact angle. The obtained results showed that the contact angle of the nanocomposites containing m-nanosilica is slightly changed as compared to the contact angle of pure epoxy resin and lower than that of the nanocomposite containing unmodified nanosilica. The data of dynamic mechanical analysis of the nanocomposites using different nanosilica content indicated that the presence of m-nanosilica lowered the recovery energy of the nanocomposites to 41.62% as compared to neat epoxy. The limiting oxygen index (LOI) of the nanocomposites confirmed that the m-nanosilica increased the flame retardance of epoxy matrix. When using 7 wt% of m-nanosilca, the LOI value of the nanocomposite was 27.4 while this index of neat epoxy was 21.6. The scanning electron microscopic images of residual char combustion of the nanocompsites indicated a formation of nanosilica layer contributed to restrain combustion of the material. 相似文献
218.
Buonyavong Sengthong Ho Van Tuyen Nguyen Thi Thai An Phan Van Do Nguyen Thi Quy Hai Pham Thi Minh Chau Vu Xuan Quang 《Journal of Electronic Materials》2018,47(4):2316-2321
Aluminosilicate (AS) glasses doped with different Dy3+ concentrations were synthesized via sol–gel method. Absorption, photoluminescence spectra and lifetime of this material have been studied. From analytical results of absorption spectra, the Judd–Ofelt (JO) parameters of prepared samples have been determined. These JO parameters combined with photoluminescence spectra have been used to evaluate transition probabilities (AR), branching ratios (β) and the calculated oscillator strengths of AS:Dy3+ glasses. The radiative branching ratio of 4F9/2 → 6H13/2 transition has a minimum value at 62.2% for βR which predicts that this transition in AS:Dy3+ glasses can give rise to lasing action. JO parameters show that the Ω2 increases with the increasing of Dy3+ ion concentration due to the increased polarizability of the average coordination medium and decreased average symmetry. 相似文献
219.
Steve Schneider Thai Son Hoang Ken Robinson Helen Treharne 《Formal Aspects of Computing》2006,18(3):308-328
The introduction of probabilistic behaviour into the B-method is a recent development. In addition to allowing probabilistic behaviour to be modelled, the relationship between expected values of the machine state can be expressed and verified. This paper explores the application of probabilistic B to a simple case study: tracking the volume of liquid held in a tank by measuring the flow of liquid into it. The flow can change as time progresses, and sensors are used to measure the flow with some degree of accuracy and reliability, modelled as non-deterministic and probabilistic behaviour respectively. At the specification level, the analysis is concerned with the expectation clause in the probabilistic B machine and its consistency with machine operations. At the refinement level, refinement and equivalence laws on probabilistic GSL are used to establish that a particular design of sensors delivers the required level of reliability. 相似文献
220.
Thai Giang Truong Noriko Saito Norio Saito Thi Kim Ngan Nguyen 《Science and Technology of Advanced Materials》2016,17(1):443-453
The development of phosphor devices free of heavy metal or rare earth elements is an important issue for environmental reasons and energy efficiency. Different mixtures of ZnO nanocrystals with Cs2Mo6I8(OOC2F5)6 cluster compound (CMIF) dispersed into polyvinylpyrrolidone matrix have been prepared by very simple and low cost solution chemistry. The resulting solutions have been used to fabricate highly transparent and luminescent films by dip coating free of heavy metal or rare earth elements. The luminescence properties of solution and dip-coated films were investigated. The luminescence of such a system is strongly dependent on the ratios between ZnO and CMIF amounts, the excitation wavelength and the nature of the system. By varying these two parameters (ratio and wavelength), a large variety of colors, from blue to red as well as white, can be achieved. In addition, differences in the luminescence properties have been observed between solutions and thin films as well as changes of CMIF emission band maximum wavelength. This may suggest some possible interactions between the different luminophore centers, such as energy transfer or ligands exchange on the Mo6 clusters. 相似文献