全文获取类型
收费全文 | 46020篇 |
免费 | 15012篇 |
国内免费 | 45篇 |
专业分类
电工技术 | 872篇 |
综合类 | 41篇 |
化学工业 | 18844篇 |
金属工艺 | 714篇 |
机械仪表 | 1370篇 |
建筑科学 | 1823篇 |
矿业工程 | 8篇 |
能源动力 | 1208篇 |
轻工业 | 7809篇 |
水利工程 | 328篇 |
石油天然气 | 55篇 |
武器工业 | 1篇 |
无线电 | 8329篇 |
一般工业技术 | 13121篇 |
冶金工业 | 1098篇 |
原子能技术 | 104篇 |
自动化技术 | 5352篇 |
出版年
2024年 | 16篇 |
2023年 | 157篇 |
2022年 | 231篇 |
2021年 | 574篇 |
2020年 | 1619篇 |
2019年 | 3338篇 |
2018年 | 3325篇 |
2017年 | 3640篇 |
2016年 | 4128篇 |
2015年 | 4159篇 |
2014年 | 4232篇 |
2013年 | 5500篇 |
2012年 | 3289篇 |
2011年 | 3098篇 |
2010年 | 3119篇 |
2009年 | 3010篇 |
2008年 | 2513篇 |
2007年 | 2268篇 |
2006年 | 2021篇 |
2005年 | 1664篇 |
2004年 | 1584篇 |
2003年 | 1548篇 |
2002年 | 1466篇 |
2001年 | 1290篇 |
2000年 | 1228篇 |
1999年 | 614篇 |
1998年 | 328篇 |
1997年 | 234篇 |
1996年 | 142篇 |
1995年 | 125篇 |
1994年 | 103篇 |
1993年 | 88篇 |
1992年 | 74篇 |
1991年 | 63篇 |
1990年 | 56篇 |
1989年 | 46篇 |
1988年 | 16篇 |
1987年 | 30篇 |
1986年 | 27篇 |
1985年 | 21篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1975年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Jyh‐Wen Shiu Kuo‐Chang Lee Chao‐Chiun Liang Yuan‐Chang Liao Chen‐Chu Tsai Janglin Chen 《Journal of the Society for Information Display》2009,17(10):811-820
Abstract— A 3‐m‐long rugged flexible display having a novel single‐plastic‐substrate structure has been demonstrated with a coated cholesteric liquid‐crystal mixture. The display is designed to be fabricated by a roll‐to‐roll process to increase productivity at a competitive cost. It has the advantage of having almost no limitation in display length. The high‐resolution (300‐dpi) monochrome cholesteric liquid‐crystal display (ChLCD) can be achieved by using a photo‐addressing method. A single‐layered 10.4‐in. color ChLCD also has been developed with good color and contrast. 相似文献
992.
Hyun‐Sang Park Seon‐Beom Ji Min‐Koo Han Jae‐Sic Lee Chi‐Woo Kim Kwang‐Soo Choi 《Journal of the Society for Information Display》2009,17(8):681-686
Abstract— A new digital ambient‐light sensor system is presented which employs two linear light sensors with different sensitivities and automatically adjusts the sensitivity based on the illumination condition. The adaptation mechanism allows a very wide range of light intensity to be detected, and the input dynamic range of the system is substantially improved from 22.5 to 45.1 dB. The proposed method does not require any additional precision bits for output data. Due to the small number of the output bits and the simple conversion process, the system can be easily integrated on the display panel. 相似文献
993.
Jae Kyeong Jeong Jong Han Jeong Hui Won Yang Tae Kyung Ahn Minkyu Kim Kwang Suk Kim Bon Seog Gu Hyun‐Joong Chung Jin‐Seong Park Yeon‐Gon Mo Hye Dong Kim Ho Kyoon Chung 《Journal of the Society for Information Display》2009,17(2):95-100
Abstract— A full‐color 12.1‐in.WXGA active‐matrix organic‐light‐emitting‐diode (AMOLED) display was, for the first time, demonstrated using indium‐gallium‐zinc oxide (IGZO) thin‐film transistors (TFTs) as an active‐matrix backplane. It was found that the fabricated AMOLED display did not suffer from the well‐known pixel non‐uniformity in luminance, even though the simple structure consisting of two transistors and one capacitor was adopted as the unit pixel circuit, which was attributed to the amorphous nature of IGZO semiconductors. The n‐channel a‐IGZO TFTs exhibited a field‐effect mobility of 17 cm2/V‐sec, threshold voltage of 1.1 V, on/off ratio >109, and subthreshold gate swing of 0.28 V/dec. The AMOLED display with a‐IGZO TFT array is promising for large‐sized applications such as notebook PCs and HDTVs because the a‐IGZO semiconductor can be deposited on large glass substrates (larger than Gen 7) using the conventional sputtering system. 相似文献
994.
Tzu‐Ming Wang Yu‐Hsuan Li Ming‐Dou Ker 《Journal of the Society for Information Display》2009,17(10):785-794
Abstract— Low‐temperature polysilicon (LTPS) technology has a tendency towards integrating all circuits on glass substrate. However, the poly‐Si TFTs suffered poor uniformity with large variations in the device characteristics due to a narrow laser process window for producing large‐grained poly‐Si TFTs. The device variation is a serious problem for circuit realization on the LCD panel, so how to design reliable on‐panel circuits is a challenge for system‐on‐panel (SOP) applications. In this work, a 6‐bit R‐string digital‐to‐analog converter (DAC) with gamma correction on glass substrate for TFT‐panel applications is proposed. The proposed circuit, which is composed of a folded R‐string circuit, a segmented digital decoder, and reordering of the decoding circuit, has been designed and fabricated in a 3‐μm LTPS technology. The area of the new proposed DAC circuit is effectively reduced to about one‐sixth compared to that of the conventional circuit for the same LTPS process. 相似文献
995.
Chang‐Wook Han Yoon‐Heung Tak In Byeong Kang Byung‐Chul Ahn In Jae Chung 《Journal of the Society for Information Display》2009,17(2):101-106
Abstract— An improved AMOLED with an a‐Si TFT backplane based on a unique structure is reported. The new structure is refered to as a dual‐plate OLED display (DOD). While a top‐emission OLED array is directly fabricated on a TFT backplane, the DOD consists of an upper OLED substrate and a lower TFT substrate, which are independently fabricated. Because the OLED substrate, which is fabricated through the process flow of bottom emission, is attached to the TFT substrate, the light is emitted in the opposite direction to the TFT backplane. The DOD enables the design of large‐sized TFTs and a complicated pixel circuit. It can also not only achieve higher uniformity in luminance in large‐sized displays due to the low electrical resistance of the common electrode, but also wider viewing angles. 相似文献
996.
Soo-Yong Shin In-Hee Lee Young-Min Cho Kyung-Ae Yang Byoung-Tak Zhang 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2009,39(6):1606-1616
Probe design is one of the most important tasks in successful deoxyribonucleic acid microarray experiments. We propose a multiobjective evolutionary optimization method for oligonucleotide probe design based on the multiobjective nature of the probe design problem. The proposed multiobjective evolutionary approach has several distinguished features, compared with previous methods. First, the evolutionary approach can find better probe sets than existing simple filtering methods with fixed threshold values. Second, the multiobjective approach can easily incorporate the user's custom criteria or change the existing criteria. Third, our approach tries to optimize the combination of probes for the given set of genes, in contrast to other tools that independently search each gene for qualifying probes. Lastly, the multiobjective optimization method provides various sets of probe combinations, among which the user can choose, depending on the target application. The proposed method is implemented as a platform called EvoOligo and is available for service on the Web. We test the performance of EvoOligo by designing probe sets for 19 types of Human Papillomavirus and 52 genes in the Arabidopsis Calmodulin multigene family. The design results from EvoOligo are proven to be superior to those from well-known existing probe design tools, such as OligoArray and OligoWiz. 相似文献
997.
An extension of the Cauer ladder development for synthesizing singly terminated filters with symmetric and asymmetric responses is presented. Basically, a driving‐point immittance including reactive constant elements is carried out in such a way that provides the transmission zeros. The reactive constant elements are introduced into the synthesis for two reasons. The first is to consider the possibility of the asymmetric position of transmission zeros in the real frequency axis. The second one is to obtain canonical forms, i.e. networks with the minimum number of elements in the case of symmetrical responses. To validate the proposed method, a filter with asymmetrical response has been synthesized, comparing different topologies for its use in multiplexers. This fact is illustrated with a Ku‐band elliptic response diplexer designed in H‐plane rectangular waveguide. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. 相似文献
998.
This study explodes the relationships between the height adjustment of bed sectors and subjective comfort depending on three types of sleeping positions. An adjustable bed system that regulates the heights of 8 adjustment sectors of the bed was developed. To evaluate the comfort of 9 body areas, subjective ratings were requested from 64 subjects ranging in age from 25 to 50. The subjects included 29 males and 35 females. For an objective evaluation, the patterns of pressure distribution were investigated according to the three sleeping positions. During two separate states (before bed adjustment and after bed adjustment), measurements of the adjusted bed height and pressure distribution, and subjective ratings according to three sleeping positions were performed. Based on the results of the adjusted heights of the 8 sectors in the bed, the subjects preferred the W‐shaped sleeping posture in both the supine and side positions. However, the U‐shaped sleeping posture was preferred in the prone position. With respect to these sleeping positions, the heights of sectors significantly correlated with the subjective ratings presented by the subjects, as well as the ratios of pressure. © 2009 Wiley Periodicals, Inc. 相似文献
999.
Hak-Man Kim Jong-Joo Lee Myong-Chul Shin Seok-Soo Kim 《Information Systems Frontiers》2009,11(5):523-528
For more efficient and economical management of substations under SCADA (Supervisory Control and Data Acquisition) systems, the concept of a smart substation has been introduced using intelligent and ubiquitous IT (Information Technology) techniques. A multi-functional platform needs to perform more intelligent and ubiquitous functions of smart substation effectively. In this paper, we propose a multi-functional platform to implement smart substations effectively. A prototype hardware, functions and communication interfaces on an embedded platform are introduced. Also, we suggest operating system architecture for smart substations. 相似文献
1000.
PID control systems are widely used in many fields, and many methods to tune the parameters of PID controllers are known.
When the characteristics of the object are changed, the traditional PID control should be adjusted by empirical knowledge.
This may result in a worse performance by the system. In this article, a new method to tune PID parameters, called the back-propagation
network modified by particle swarm optimization, is proposed. This algorithm combines conventional PID control with a back
propagation neural network (BPNN) and particle swarm optimization (PSO). This method is demonstrated in the engine idling-speed
control problem. The proposed method provides considerable performance benefits compared with a traditional controller in
this simulation. 相似文献