全文获取类型
收费全文 | 7293篇 |
免费 | 618篇 |
国内免费 | 15篇 |
学科分类
工业技术 | 7926篇 |
出版年
2024年 | 8篇 |
2023年 | 116篇 |
2022年 | 141篇 |
2021年 | 232篇 |
2020年 | 176篇 |
2019年 | 215篇 |
2018年 | 292篇 |
2017年 | 250篇 |
2016年 | 293篇 |
2015年 | 231篇 |
2014年 | 400篇 |
2013年 | 503篇 |
2012年 | 551篇 |
2011年 | 608篇 |
2010年 | 424篇 |
2009年 | 450篇 |
2008年 | 436篇 |
2007年 | 333篇 |
2006年 | 292篇 |
2005年 | 247篇 |
2004年 | 237篇 |
2003年 | 221篇 |
2002年 | 188篇 |
2001年 | 158篇 |
2000年 | 116篇 |
1999年 | 114篇 |
1998年 | 180篇 |
1997年 | 95篇 |
1996年 | 83篇 |
1995年 | 64篇 |
1994年 | 54篇 |
1993年 | 39篇 |
1992年 | 30篇 |
1991年 | 11篇 |
1990年 | 26篇 |
1989年 | 21篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有7926条查询结果,搜索用时 15 毫秒
91.
A hidden‐picture puzzle contains objects hidden in a background image, in such a way that each object fits closely into a local region of the background. Our system converts image of the background and objects into line drawing, and then finds places in which to hide transformed versions of the objects using rotation‐invariant shape context matching. During the hiding process, each object is subjected to a slight deformation to enhance its similarity to the background. The results were assessed by a panel of puzzle‐solvers. 相似文献
92.
Action-reward learning is a reinforcement learning method. In this machine learning approach, an agent interacts with non-deterministic
control domain. The agent selects actions at decision epochs and the control domain gives rise to rewards with which the performance
measures of the actions are updated. The objective of the agent is to select the future best actions based on the updated
performance measures. In this paper, we develop an asynchronous action-reward learning model which updates the performance
measures of actions faster than conventional action-reward learning. This learning model is suitable to apply to nonstationary
control domain where the rewards for actions vary over time. Based on the asynchronous action-reward learning, two situation
reactive inventory control models (centralized and decentralized models) are proposed for a two-stage serial supply chain
with nonstationary customer demand. A simulation based experiment was performed to evaluate the performance of the proposed
two models.
Chang Ouk Kim received his Ph.D. in industrial engineering from Purdue University in 1996 and his B.S. and M.S. degrees from Korea University,
Republic of Korea in 1988 and 1990, respectively. From 1998--2001, he was an assistant professor in the Department of Industrial
Systems Engineering at Myongji University, Republic of Korea. In 2002, he joined the Department of Information and Industrial
Engineering at Yonsei University, Republic of Korea and is now an associate professor. He has published more than 30 articles
at international journals. He is currently working on applications of artificial intelligence and adaptive control theory
in supply chain management, RFID based logistics information system design, and advanced process control in semiconductor
manufacturing.
Ick-Hyun Kwon is a postdoctoral researcher in the Department of Civil and Environmental Engineering at University of Illinois at Urbana-Champaign.
Previous to this position, Dr. Kwon was a research assistant professor in the Research Institute for Information and Communication
Technology at Korea University, Seoul, Republic of Korea. He received his B.S., M.S., and Ph.D. degrees in Industrial Engineering
from Korea University, in 1998, 2000, and 2006, respectively. His current research interests are supply chain management,
inventory control, production planning and scheduling.
Jun-Geol Baek is an assistant professor in the Department of Business Administration at Kwangwoon University, Seoul, Korea. He received
his B.S., M.S., and Ph.D. degrees in Industrial Engineering from Korea University, Seoul, Korea, in 1993, 1995, and 2001 respectively.
From March 2002 to February 2007, he was an assistant professor in the Department of Industrial Systems Engineering at Induk
Institute of Technology, Seoul, Korea. His research interests include machine learning, data mining, intelligent machine diagnosis,
and ubiquitous logistics information systems.
An erratum to this article can be found at 相似文献
93.
Hyun Sup Lee Tai Hun Kwon Jong Hyun Kim Suk Sang Chang 《Microsystem Technologies》2008,14(8):1149-1155
The present study proposes a simple method to replicate nano/micro combined multiscale structures using an intermediate film
mold and anodic aluminum oxide (AAO) nanomold in hot embossing process. The proposed method is simply to add an intermediate
film mold with microscale thru-hole patterns to the ordinary mold system, on which nanostructures are patterned, in the hot
embossing process. The intermediate film mold is inserted between polymer substrate and AAO nanomold. During the hot embossing
process, the polymer first fills microscale thru-hole patterns in the intermediate film mold and subsequently fills nanopores
in AAO nanomold, resulting in the nano/micro combined structures. The intermediate film molds, which have microscale thru-hole
patterns were fabricated by micro-milling, laser ablation, etching methods and/or LIGA process. The nano/micro combined structures
were successfully replicated by the proposed method. 相似文献
94.
Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications 总被引:1,自引:0,他引:1
Dong Sung Kim Hyun Sup Lee Jungyoup Han Se Hwan Lee Chong H. Ahn Tai Hun Kwon 《Microsystem Technologies》2008,14(2):179-184
Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present
a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length
on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure
equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique,
two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels
were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared
two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip
were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with
the help of the HPEP. 相似文献
95.
F.A. Pasha M. Muddassar M.M. Neaz Seung Joo Cho 《Journal of molecular graphics & modelling》2009,28(1):54-61
The growth and metastasis of solid tumors is dependent on angiogenesis. The vascular endothelial growth factor (VEGF) and its cell surface receptor in human KDR (kinase domain containing receptor or VEGFR-2) have particular interest because of their importance in angiogenesis. The development of novel inhibitors of VEGFR-2 would be helpful to check the growth of tumors. Quantitative structure activity relationship (QSAR) analyses used to understand the structural factors affecting inhibitory potency of thiazole-substituted pyrazolone derivatives. Several pharmacophore-based models indicated the importance of steric, hydrophobic and hydrogen bond acceptor groups to inhibitory activity. The comparative molecular field analyses (CoMFA) and comparative molecular similarity indices analyses (CoMSIA) based 3D-QSAR models were derived using pharmacophore-based alignment. Both CoMFA (q2 = 0.70, r2 = 0.97 and ) and CoMSIA (q2 = 0.54, r2 = 0.82 and ) gave reasonable results. The molecular docking (receptor-guided technique) with a recently reported receptor structure (PDB = 1YWN) were performed. The docked alignment was subsequently used for 3D-QSAR (CoMFA; q2 = 0.56, r2 = 0.97, , CoMSIA; q2 = 0.58 r2 = 0.91, ). The overall both studies were indicated, steric, electrostatic and hydrogen bond acceptor effects contribute to the inhibitory activity. CoMFA and CoMSIA models suggested that a positive bulk with hydrophobic effect is desirable around position 4 and 5 and hydrogen bond acceptor groups around pyrazolones ring will be helpful. 相似文献
96.
Wonpil Yu Jae-Yeong Lee Young-Guk Ha Minsu Jang Joo-Chan Sohn Yong-Moo Kwon Hyo-Sung Ahn 《Automation Science and Engineering, IEEE Transactions on》2009,6(4):633-640
This paper describes a concerted effort to design and implement a robotic service framework. The proposed framework is comprised of three conceptual spaces: physical, semantic, and virtual spaces, collectively referred to as a ubiquitous robotic space. We implemented a prototype robotic security application in an office environment, which confirmed that the proposed framework is an efficient tool for developing a robotic service employing IT infrastructure, particularly for integrating heterogeneous technologies and robotic platforms. 相似文献
97.
3-D manipulation of millimeter- and micro-sized objects using an acoustically excited oscillating bubble 总被引:1,自引:1,他引:0
This communication describes novel 3-D manipulations of objects using an acoustically excited oscillating bubble deposited
on a hydrophobic rod tip. The oscillating bubble captures various millimeter- and micron-sized neighboring objects including
glass and polystyrene beads (~100 μm), fish egg, and live water flea (~1 mm). The captured objects are carried in a 3-D space
by traversing the bubble tip, and released at desired positions by simply turning off the oscillation. Carrying performance
is characterized along with high-speed imaging of oscillating bubbles by varying the frequency and amplitude of the acoustic
excitation and the carrying speed. The higher the oscillation amplitude, the higher the carrying efficiency. The maximum carrying
speed is measured at over 3 mm/s. This method is effective with a low-level acoustic excitation (bubble oscillation amplitude
relative to the diameter ≤5%), possibly providing a cost-effective, soft-contact manipulating tool for handling biological
objects. 相似文献
98.
Jungkyu Kim Michael Junkin Deok-Ho Kim Seunglee Kwon Young Shik Shin Pak Kin Wong Bruce K. Gale 《Microfluidics and nanofluidics》2009,7(2):149-167
Biosensors based on nanotechnology are rapidly developing and are becoming widespread in the biomedical field and analytical
chemistry. For these nanobiosensors to reach their potential, they must be integrated with appropriate packaging techniques,
which are usually based on nano/microfluidics. In this review we provide a summary of the latest developments in nanobiosensors
with a focus on label-based (fluorescence and nanoparticle) and label-free methods (surface plasmon resonance, micro/nanocantilever,
nanowires, and nanopores). An overview on how these sensors interface with nano/microfluidics is then presented and the latest
papers in the area summarized. 相似文献
99.
This paper documents a study of an Au nano-dot array that was fabricated by electron beam lithography on a glass wafer. The patterns that had features of 100nm dots in diameter with a 2-mum pitch comprised a total area of 200x200mum(2). The dot-shaped Cr underlayer was open to the air after developing Poly(methyl methacrylate) (PMMA). When dipped into the Cr etchant, the exposed Cr layer was eliminated from the glass wafer in a short period of time. In order to ultimately fabricate the Ti/Au dot arrays, Ti and Au were deposited onto the arrays with a thickness of 2 and 40nm, respectively. The lift-off procedure was carried out in the Cr etchant using sonication in order to completely remove the residual Cr/PMMA layer. The fabricated Au nano-dot array was then immersed in an Ag enhancing solution and then into an ethanol solution containing (N-(6-(Biotinamido)hexyl)-3'-(2'-pyridyldithio)-propionamide (Biotin-HPDP). The substrate was analyzed using a correlated atomic force microscopy (AFM) and confocal Raman spectroscopy. Through this procedure, position-dependent surface-enhanced Raman spectroscopy (SERS) signals could be obtained. 相似文献
100.
Hwan Seong Moon Jae Suk Lee Sung Wook Han Jong Wan Park Jae Hak Lee Seung Kee Yang Hyung Ho Park 《Journal of Materials Science》1994,29(6):1545-1548
Tantalum oxide film formation by plasma-enhanced chemical vapour deposition (PECVD) using TaCl5 as a source material was examined. The effects of deposition temperature on the formation, structure and electric properties of the Ta2O5 film were investigated for Al/Ta2O5/ p-Si (MTS) capacitors. The deposition rate and refractive index increased with increasing deposition temperature. It was found that the structure of Ta2O5 deposited by PECVD was amorphous as-deposited. However, crystalline -Ta2O5 of hexagonal structure was formed by a 700 °C, 1 h heat treatment in argon. Capacitance and relative dielectric constant of the PECVD Ta2O5 were found to be 2.54 fF m–2 and 23.5, respectively. The PECVD films obtained in this study have higher dielectric constants and remarkably better general film characteristics than those obtained by other deposition methods. 相似文献