全文获取类型
收费全文 | 1021篇 |
免费 | 51篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 200篇 |
金属工艺 | 13篇 |
机械仪表 | 41篇 |
建筑科学 | 40篇 |
矿业工程 | 1篇 |
能源动力 | 15篇 |
轻工业 | 58篇 |
水利工程 | 6篇 |
武器工业 | 2篇 |
无线电 | 317篇 |
一般工业技术 | 143篇 |
冶金工业 | 93篇 |
自动化技术 | 135篇 |
出版年
2023年 | 9篇 |
2022年 | 22篇 |
2021年 | 30篇 |
2020年 | 22篇 |
2019年 | 15篇 |
2018年 | 25篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 26篇 |
2014年 | 31篇 |
2013年 | 63篇 |
2012年 | 61篇 |
2011年 | 53篇 |
2010年 | 53篇 |
2009年 | 53篇 |
2008年 | 52篇 |
2007年 | 53篇 |
2006年 | 45篇 |
2005年 | 34篇 |
2004年 | 35篇 |
2003年 | 30篇 |
2002年 | 28篇 |
2001年 | 37篇 |
2000年 | 30篇 |
1999年 | 27篇 |
1998年 | 51篇 |
1997年 | 37篇 |
1996年 | 19篇 |
1995年 | 21篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有1075条查询结果,搜索用时 15 毫秒
21.
Jason Heikenfeld Paul Drzaic Jong‐Souk Yeo Tim Koch 《Journal of the Society for Information Display》2011,19(2):129-156
Abstract— The commercial success of monochrome electronic paper (e‐Paper) is now propelling the development of next‐generation flexible, video, and color e‐Paper products. Unlike the early battles in the 1980s and 1990s between transmissive and emissive display technologies, there is a extraordinary diversity of technologies vying to become the next generation of e‐Paper. A critical review of all major e‐Paper technologies, including a technical breakdown of the performance limitations based on device physics and commentary on possible future breakthroughs, is presented. In addition, the visual requirements for color e‐Paper are provided and compared to standards used in conventional print. It is concluded that researchers have much work remaining in order to bridge the significant gap between reflective electronic displays and print‐on‐paper. 相似文献
22.
Dissipative particle dynamics simulations for fibre suspensions in newtonian and viscoelastic fluids
Duc Duong-Hong Nhan Phan-Thien Khoon Seng Yeo Gilles Ausias 《Computer Methods in Applied Mechanics and Engineering》2010,199(23-24):1593-1602
A versatile model of fibre suspensions in Newtonian and viscoelastic fluids has been developed using dissipative particle dynamics method. The viscoelastic fluid is modelled by linear chains with linear connector spring force (the Oldroyd-B model), which is known to be a reasonable model for the so-called Boger fluid (a dilute suspension of polymer in a highly viscous solvent). The numerical results are in excellent agreement with the analytical results of the Oldroyd-B model in simple shear flow. An effective meso-scale model of fibre in DPD is proposed and then incorporated with simple Newtonian fluid and our Boger fluid to enable entirely study rheological properties of fibre suspensions in both Newtonian and viscoelastic solvents. The numerical results are well compared with available experimental data and other numerical models. 相似文献
23.
Jihoon Yeo Jejun Ryu Bong-Kee Lee Euihyeon Byeon Tai Hun Kwon Dong Sung Kim 《Microsystem Technologies》2010,16(8-9):1425-1430
Various types of polymer surfaces with a nanolens array, which has an entrant shape with a low aspect ratio, were fabricated and the wettability of the fabricated surfaces was evaluated in both theoretical and experimental ways. The nanolens array was replicated on three different polymer surfaces of polydimethylsiloxane (PDMS), cyclic olefin copolymer (COC), and polymethylmethacrylate (PMMA) by means of replica molding and hot embossing with a nanodimpled aluminum mold that was manufactured by a chemical oxidation process. From the theoretical and experimental evaluations of the wettability it was found that the measured contact angles were very similar with the theoretically estimated ones and also the hydrophilicity and hydrophobicity of the hydrophilic PMMA and hydrophobic PDMS, respectively, surfaces were reinforced by the nanolens array within the Wenzel wetting state. 相似文献
24.
In this study, we have designed and fabricated robust hydrophobic surfaces that are composed of various micropillar arrays and investigated the effect of the aspect ratio (feature height/feature size) of the micropillar on the wettability of the fabricated surfaces. The robust, micropillar-arrayed surfaces were designed to yield the same Wenzel and Cassie water contact angles (CAs). According to our design rule, one can achieve an enhanced hydrophobic surface by increasing the height of the micropillars. The designed hydrophobic surfaces were fabricated by polydimethylsiloxane (PDMS) replica molding with photolithographically micropatterned SU-8 masters. The hydrophobicity properties of the fabricated PDMS surfaces were fully characterized theoretically and experimentally. From the theoretical and experimental results, it was found that the micropillars of an intrinsically hydrophobic material with a high aspect ratio enhance the hydrophobicity of the surface by increasing the surface roughness (in view of the Wenzel state) and the opportunities for the entrapment of air beneath a water droplet (the Cassie state). 相似文献
25.
This article proposes an asymmetric topology for transmit/receive (T/R) switches and more importantly presents a comparative study of both LC‐tuned and resistive body‐floating techniques for improving the power‐handling capability of the T/R switches in the same 0.18‐μm triple‐well CMOS. It is shown from simulations and measurements that the switches adopting either technique achieve comparable performances. For instance, the switch employing the LC‐tuned body‐floating technique exhibits insertion loss of 1.5 dB, isolation of 23.5 dB, and power‐handling capability of 22.5 dBm at 5.2 GHz, whereas the switch using the resistive body‐floating technique exhibits insertion loss of 1.3 dB, isolation of 24 dB, and power‐handling capability of 22.2 dBm, respectively. Therefore, one can conclude that the asymmetric topology with the resistive body‐floating technique is more suitable for designing T/R switches for wireless local area network applications as it consumes smaller silicon area. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. 相似文献
26.
This paper presents an evolutionary algorithm, called the multi-objective symbiotic evolutionary algorithm (MOSEA), to solve a multi-objective FMS process planning (MFPP) problem with various flexibilities. The MFPP problem simultaneously considers four types of flexibilities related to machine, tool, sequence, and process and takes into account three objectives: balancing the machine workload, minimizing part movements, and minimizing tool changes. The MOSEA is modeled as a two-leveled structure to find a set of well-distributed solutions close to the true Pareto optimal solutions. To promote the search capability of such solutions, two main processes imitating symbiotic evolution and endosymbiotic evolution are introduced, together with an elitist strategy and a fitness sharing scheme. Evolutionary components suitable for the MFPP problem are provided. With a variety of test-bed problems, the performance of the proposed MOSEA is compared with those of existing multi-objective evolutionary algorithms. The experimental results show that the MOSEA is promising in solution convergence and diversity. 相似文献
27.
Junwei Zhang Bu-Sung Lee Xueyan Tang Chai-Kiat Yeo 《The Journal of supercomputing》2011,56(3):245-269
Data Grid has evolved to be the solution for data-intensive applications, such as High Energy Physics (HEP), astrophysics,
and computational genomics. These applications usually have large input of data to be analyzed and these input data are widely
replicated across Data Grid to improve the performance. The job scheduling performance on traditional computing jobs can be
studied using queuing theory. However, with the addition of data transfer, the job scheduling performance is too complex to
be modeled. In this research, we study the impact of data transfer on the performance of job scheduling in the Data Grid environment.
We have proposed a parallel downloading system that supports replicating data fragments and parallel downloading of replicated
data fragments, to improve the job scheduling performance. The performance of the parallel downloading system is compared
with non-parallel downloading system, using three scheduling heuristics: Shortest Turnaround Time (STT), Least Relative Load
(LRL) and Data Present (DP). Our simulation results show that the proposed parallel download approach greatly improves the
Data Grid performance for all three scheduling algorithms, in terms of the geometric mean of job turnaround time. The advantage
of parallel downloading system is most evident when the Data Grid has relatively low network bandwidth and relatively high
computing power. 相似文献
28.
In this paper, we have first reviewed the state-of-the-art technologies related to DOCSIS 3.0 high-speed data transmission
system and also looked at current trends in the next generation Gbps transmission technology, which is one of key technology
for ubiquitous high performance multimedia service environments. Also, we implemented the RS encoder which was designed using
VHDL and verified its operation in order to confirm our design through the ModelSim simulation analysis tool. 相似文献
29.
Muhammad Sajjad Khan Muhammad Sung Wook Baik Seungmin Rho Zahoor Jan Sang-Soo Yeo Irfan Mehmood 《Multimedia Tools and Applications》2017,76(3):3519-3536
In this paper, the problem of outsourcing the selective encryption of a medical image to cloud by resource-constrained devices such as smart phone is addressed, without revealing the cover image to cloud using steganography. In the proposed framework, the region of interest of the medical image is first detected using a visual saliency model. The detected important data is then embedded in a host image, producing a stego image which is outsourced to cloud for encryption. The cloud which has powerful resources, encrypts the image and sent back the encrypted marked image to the client. The client can then extract the selectively encrypted region of interest and can combine it with the region of non-interest to form a selectively encrypted image, which can be sent to medical specialists and healthcare centers. Experimental results and analysis validate the effectiveness of the proposed framework in terms of security, image quality, and computational complexity and verify its applicability in remote patient monitoring centers. 相似文献
30.
Undoped (IO) and Sn-doped In2O3 (ITO) films have been deposited on glass and polymer substrates by an advanced ion beam technologies including ion-assisted deposition (IAD), hybrid ion beam, ion beam sputter deposition (IBSD), and ion-assisted reaction (IAR). Physical and chemical properties of the oxide films and adhesion between films and substrates were improved significantly by these technologies. By using the IAD method, non-stoichiometry and microstructure of the films were controlled by changing assisted oxygen ion energy and arrival ratio of assisted oxygen ion to evaporated atoms. Relationships between structural and electrical properties in ITO films on glass substrates were intensively investigated by using the IBSD method with changing ion energy, reactive gas environment, and substrate temperature. Smooth-surface ITO films (Rrms ≤ 1 nm and Rp-v ≤ 10 nm) for organic light-emitting diodes were developed with a combination of deposition conditions with controlling microstructure of a seed layer on glass. IAR surface treatment enormously enhanced the adhesion of oxide films to polymer substrate. The different dependence of IO and ITO films' properties on the experimental parameters, such as ion energy and oxygen gas environment, will be intensively discussed. 相似文献