全文获取类型
收费全文 | 2543篇 |
免费 | 38篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 50篇 |
综合类 | 4篇 |
化学工业 | 205篇 |
金属工艺 | 11篇 |
机械仪表 | 40篇 |
建筑科学 | 108篇 |
矿业工程 | 1篇 |
能源动力 | 77篇 |
轻工业 | 56篇 |
水利工程 | 9篇 |
无线电 | 374篇 |
一般工业技术 | 254篇 |
冶金工业 | 1151篇 |
原子能技术 | 5篇 |
自动化技术 | 241篇 |
出版年
2022年 | 18篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 17篇 |
2016年 | 25篇 |
2015年 | 20篇 |
2014年 | 31篇 |
2013年 | 94篇 |
2012年 | 43篇 |
2011年 | 67篇 |
2010年 | 58篇 |
2009年 | 73篇 |
2008年 | 49篇 |
2007年 | 70篇 |
2006年 | 67篇 |
2005年 | 62篇 |
2004年 | 48篇 |
2003年 | 41篇 |
2002年 | 47篇 |
2001年 | 55篇 |
2000年 | 40篇 |
1999年 | 78篇 |
1998年 | 405篇 |
1997年 | 234篇 |
1996年 | 162篇 |
1995年 | 89篇 |
1994年 | 85篇 |
1993年 | 86篇 |
1992年 | 39篇 |
1991年 | 36篇 |
1990年 | 34篇 |
1989年 | 20篇 |
1988年 | 22篇 |
1987年 | 17篇 |
1986年 | 22篇 |
1985年 | 22篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 27篇 |
1979年 | 13篇 |
1978年 | 14篇 |
1977年 | 29篇 |
1976年 | 74篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1972年 | 6篇 |
排序方式: 共有2586条查询结果,搜索用时 15 毫秒
51.
John T. Y. Wu Sally Dreger Eva Y. W. Chow Evelyn E. Bowlby Lester S. Y. Wong 《Journal of The Association for Laboratory Automation》2003,8(1):46
An enzyme-linked immunosorbent assay (ELISA) for Neospora caninum antibodies was automated with a robotic workstation, the Beckman Coulter Biomek 2000, to screen 200 bovine sera. Comparing these results with manually run ELISA data, a 95.92% agreement (K = 0.9592) between the two assays was obtained. The automated assay was specific and sensitive with excellent positive and negative predictive values. The results were repeatable and reproducible. The automation flexibility was high and the operation complexity was minimal. High-throughput screening (HTS) for bovine antibodies to Neospora caninum was achieved. The assay was developed according to the internationally recognized ISO17025 standard requirements. 相似文献
52.
This paper identifies managers who require ethics training in using IT at work. The identification of these managers is mainly based on studying the impact of their individual characteristics on a set of seven ethical issues and attitudes, which translated into IT ethical scenarios. This paper proposes a canonical model by treating individual characteristics of managers as predictor variables and considering information describing their beliefs on those seven ethical issues and attitudes as explained variables. A questionnaire survey was used for data collection and 249 managers participated in this study. The results show that the significant explained variables are based on a combination of six ethical events of accountability, conflict of interest, disclosure, personal conduct, protection of privacy, and social responsibility. The significant predictor variables are based on a combination of four individual characteristics of age, educational level, organizational level, and working experience. Discussion on the implication of the results and recommendations for remedial action are also provided in this paper. 相似文献
53.
J L Chow D R Olson S E Anderson Q M VanderWerf G J Kost 《Computer methods and programs in biomedicine》1987,25(1):39-46
We designed an interactive microcomputer-based digital data processing system for analysis of 31-phosphorus nuclear magnetic resonance (31P-NMR) spectra from studies of cardiac metabolism in immature and neonatal hearts. This system included a digitizing tablet (Kurta Series Two), a microcomputer (IBM PC XT) and a graphics plotter (Hewlett-Packard 7470A) used in conjunction with a Nicolet 1280 NMR signal processing computer. We obtained 31P spectra from isolated perfused rabbit hearts with a Nicolet NT-200 4.7 Tesla superconducting NMR spectrometer operated in the pulsed Fourier transform mode. The small size of the hearts resulted in increased noise in spectra and demanded comparison of methods used to quantitate changes in inorganic phosphorus, phosphocreatine and ATP during ischemic stress. We performed microcomputer operations and interfacing functions with a software package written in BASIC. This system simplified documentation, data filing and statistical data processing. Our microcomputer system displayed and made hard copies of digitized spectra and results of analyses. Errors in data entry were rectified directly with this program. Consistent data reduction improved the precision of the physiological results and reduced the influence of noise on 31P spectra from neonatal hearts weighing about 0.5 g. The system flexibility extends its application to NMR spectra analysis for other in vivo organ systems, and signal processing in other biological research. 相似文献
54.
Haiyue Zu Kelvin Chau Temitope Olumide Olugbade Lulu Pan Chris Halling Dreyer Dick Ho-Kiu Chow Le Huang Lizhen Zheng Wenxue Tong Xu Li Ziyi Chen Xuan He Ri Zhang Jie Mi Ye Li Bingyang Dai Jiali Wang Jiankun Xu Kevin Liu Jian Lu Ling Qin 《材料科学技术学报》2021,63(4):145-160
In this study,perforated cannulated magnesium(Mg)hip stents were fabricated via modified Mg injection molding and conventional machining,respectively.Additionally,the stent canal was filled with paraffin to simulate injection of biomaterials.The microstructure,mechanical performance,corrosion behavior,and biocompatibility were comparably studied.Scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)showed higher affinity of interstitial element such as oxygen and carbon as consequences of routine molding process.After immersion in SBF,machining stents showed reduced degradation rate and increased deposition of calcium phosphate compared to molding stents.Corrosion resistance was improved via paraffin-filling.Consistently,the hemolysis and in vitro osteoblast cell culture models showed favourable biocompatibility in machining stents compared to molding ones,which was improved by paraffin-filling treatment as well.These results implied that the feasibility of the prepared machining stents as the potential in vivo orthopaedic application where slower degradation is required,which could be enhanced by designing canal-filling injection of biomaterials as well. 相似文献
55.
Bharadwaj Veeravalli Long Chen Hun Yen Kwoon Goh Kar Whee See Ying Lai Lim Peng Hian Ho Chin Chow 《Multimedia Tools and Applications》2006,28(1):89-118
The problem of employing multiple servers to serve a pool of clients on a network based multimedia service is addressed. We
have designed and practically implemented a prototype system employing multiple servers to render a long duration movie to
the customers. We have employed a multiple server retrieval strategy proposed in the literature [39] to realize this system.
In the system, server coordination, client behavior and service facilities are completely controlled by an Agent based approach
in which we have used the recent Jini technology. Several issues, ranging from data retrieval from individual server, behavior
of the underlying network infrastructure, to client management and resource (client buffers) management, are considered in
this implementation. We describe in detail our experiences in this complete design process of every module in the software
architecture, its purpose, and working style. Further, the system is shown to be robust amidst unpredictable failures, i.e.,
in the event of server crashes. The load balancing capability is built-in as a safe guard measure to assure a continuous presentation.
We present a comprehensive discussion on the software architecture to realize this working system and present our experiences.
A system comprising a series of Pentium III PCs on a fast Ethernet network is built as a test-bed. Through this prototype,
a wider scope of research challenges ahead are highlighted as possible extensions.
Bharadwaj Veeravalli Member, IEEE & IEEE-CS, received his BSc in Physics, from Madurai-Kamaraj Uiversity, India in 1987, Master's in Electrical
Communication Engineering from Indian Institute of Science, Bangalore, India in 1991 and PhD from Department of Aerospace
Engineering, Indian Institute of Science, Bangalore, India in 1994. He did his post-doctoral research in the Department of
Computer Science, Concordia University, Montreal, Canada, in 1996. He is currently with the Department of Electrical and Computer
Engineering, Computer and Information Engineering (CIE) division, at The National University of Singapore, Singapore, as a
tenured Associate Professor. His main stream research interests include, Multiprocessor systems, Cluster/Grid computing, Scheduling
in parallel and distributed systems, Bioinformatics & Computational Biology, and Multimedia computing. He is one of the earliest
researchers in the field of divisible load theory. He has published over 75 papers in high-quality International Journals
and Conferences. He had secured several externally funded projects. He has co-authored three research monographs in the areas
of Parallel and Distributed Systems, Distributed Databases, and Multimedia systems, in the years 1996, 2003, and 2005, respectively.
He had guest edited a special issue on Cluster/Grid Computing for IJCA, USA journal in 2004. He has been recently invited
to contribute to Multimedia Encyclopedia, Kluwer Academic Publishers, 2005. He is currently serving the Editorial Board of
IEEE Transactions on Computers, IEEE Transactions on SMC-A and International Journal of Computers & Applications, USA, as an Associate Editor. He had served as a program committee member and as a session chair in several International Conferences.
Long Chen received the B.E. degree in Electrical Engineering and M.E. degree in Electrical Engineering from the Northwestern Polytechnic
University, P. R. China, in 1998 and 2001, respectively, and the M.E. degree in Computer Engineering from the National University
of Singapore, Singapore, in 2004. He is currently a Ph.D. candidate at the Department of Electrical and Computer Engineering,
the University of Delaware, United States. His research interests include multimedia systems, distributed system, network
security, and computer architecture. 相似文献
56.
A high-performance planar piezoresistive accelerometer 总被引:12,自引:0,他引:12
Partridge A. Reynolds J.K. Chui B.W. Chow E.M. Fitzgerald A.M. Zhang L. Maluf N.I. Kenny T.W. 《Journal of microelectromechanical systems》2000,9(1):58-66
The micromachined piezoresistive accelerometer is now 20 years old. Design variations have been investigated, but commercial devices have generally maintained a consistent topology with incremental improvements. In this paper, a new approach is introduced to the design and construction of this device that offers functional and manufacturing advantages. Piezoresistive accelerometers are described that combine deep reactive ion etching and oblique ion implantation to form self-caging proof masses and flexures with vertical sidewalls and sidewall piezoresistive strain sensors. These devices deflect in-plane rather than out-of-plane, which allows one to form multiaxis accelerometers on one substrate. Performance is comparable to inexpensive commercial capacitive accelerometers and is limited by 1/f noise. The design, fabrication, and experimental characterization is presented. This new topology provides the foundation for a new category of piezoresistive accelerometers 相似文献
57.
Sirena Soriano Kristen Curry Qi Wang Elsbeth Chow Todd J. Treangen Sonia Villapol 《International journal of molecular sciences》2022,23(9)
Traumatic brain injury (TBI) causes neuroinflammation and neurodegeneration, both of which increase the risk and accelerate the progression of Alzheimer’s disease (AD). The gut microbiome is an essential modulator of the immune system, impacting the brain. AD has been related with reduced diversity and alterations in the community composition of the gut microbiota. This study aimed to determine whether the gut microbiota from AD mice exacerbates neurological deficits after TBI in control mice. We prepared fecal microbiota transplants from 18 to 24 month old 3×Tg-AD (FMT-AD) and from healthy control (FMT-young) mice. FMTs were administered orally to young control C57BL/6 (wild-type, WT) mice after they underwent controlled cortical impact (CCI) injury, as a model of TBI. Then, we characterized the microbiota composition of the fecal samples by full-length 16S rRNA gene sequencing analysis. We collected the blood, brain, and gut tissues for protein and immunohistochemical analysis. Our results showed that FMT-AD administration stimulates a higher relative abundance of the genus Muribaculum and a decrease in Lactobacillus johnsonii compared to FMT-young in WT mice. Furthermore, WT mice exhibited larger lesion, increased activated microglia/macrophages, and reduced motor recovery after FMT-AD compared to FMT-young one day after TBI. In summary, we observed gut microbiota from AD mice to have a detrimental effect and aggravate the neuroinflammatory response and neurological outcomes after TBI in young WT mice. 相似文献
58.
Pingfan Chen Zhen Huang Changjian Li Bangmin Zhang Nina Bao Ping Yang Xiaojiang Yu Shengwei Zeng Chunhua Tang Xiaohan Wu Jingsheng Chen Jun Ding Stephen John Pennycook A. Ariando Thirumalai Venky Venkatesan Gan Moog Chow 《Advanced functional materials》2018,28(33)
The complex interfacial correlations provide new routes toward tunable functionalities. Here, the wide range of tunabilities for magnetic properties are presented, including Curie temperature (from 245 to 320 K), coercive field (from 2 to 205 Oe), and saturated magnetic moment (from 0.9 to 2.8 µB Mn?1), in a 9‐unit‐cell La2/3Sr1/3MnO3 (LSMO) layer via modifying interfacial boundary conditions. Moreover, the LSMO/PbTiO3‐based multilayers and superlattices that consist of PbTiO3/LSMO/NdGaO3 and PbTiO3/LSMO/PbTiO3 interfaces are characterized by two distinct Curie temperatures and coercive fields. The results reveal the feasibility of the interface‐resolved strategy based on boundary modification in fabricating potential devices with multiple accessible states for information storage. The wide‐range modulations on magnetic properties at LSMO/titanate interfaces are explained in terms of binary controls arising from the oxygen octahedral coupling (OOC) and magnetoelectric coupling (MEC). The results not only shed some light on understanding interfacial correlations in oxide heterostructures, but also pave an alternative path for exploring multiple accessible states in all‐oxide‐based electronic devices. 相似文献
59.
Melanie Po-Leen Ooi Hong Kuan Sok Ye Chow Kuang Serge Demidenko Chris Chan 《Engineering Applications of Artificial Intelligence》2013,26(3):1029-1043
The International Technology Roadmap for Semiconductors (ITRS) identifies production test data as an essential element in improving design and technology in the manufacturing process feedback loop. One of the observations made from the high-volume production test data is that dies that fail due to a systematic failure have a tendency to form certain unique patterns that manifest as defect clusters at the wafer level. Identifying and categorising such clusters is a crucial step towards manufacturing yield improvement and implementation of real-time statistical process control. Addressing the semiconductor industry’s needs, this research proposes an automatic defect cluster recognition system for semiconductor wafers that achieves up to 95% accuracy (depending on the product type). 相似文献
60.
This paper introduces a numerical simulation model for investigating the influence of moving subjects on the dispersion and deposition of expiratory droplets, rather than on the dispersion of surrogate gaseous counterparts generally adopted in related research works. In our work, the Lagrangian discrete trajectory model is used for tracing the motion of droplets, the Eulerian RANS method is used for solving the airflow field, and the dynamic mesh model for describing the human movement. The model validation was performed through result comparisons with published data from literatures. A case study on the influence of human walking on the dispersion and deposition of expiratory droplets in an airborne infection isolation room (AIIR) is then presented. Our findings show that the human walking disturbs the local velocity field with wake formation. The increase of walking speed could effectively reduce the overall number of suspended droplets, which may have a positive impact on releasing the infection risk of health workers in AIIR. 相似文献