全文获取类型
收费全文 | 78593篇 |
免费 | 15587篇 |
国内免费 | 69篇 |
专业分类
电工技术 | 972篇 |
综合类 | 130篇 |
化学工业 | 26047篇 |
金属工艺 | 1061篇 |
机械仪表 | 1587篇 |
建筑科学 | 3064篇 |
矿业工程 | 99篇 |
能源动力 | 1849篇 |
轻工业 | 14488篇 |
水利工程 | 692篇 |
石油天然气 | 291篇 |
武器工业 | 2篇 |
无线电 | 8693篇 |
一般工业技术 | 17893篇 |
冶金工业 | 6931篇 |
原子能技术 | 173篇 |
自动化技术 | 10277篇 |
出版年
2024年 | 97篇 |
2023年 | 470篇 |
2022年 | 942篇 |
2021年 | 1687篇 |
2020年 | 2426篇 |
2019年 | 4191篇 |
2018年 | 4475篇 |
2017年 | 4747篇 |
2016年 | 5376篇 |
2015年 | 4970篇 |
2014年 | 5345篇 |
2013年 | 8175篇 |
2012年 | 5535篇 |
2011年 | 5059篇 |
2010年 | 4620篇 |
2009年 | 4346篇 |
2008年 | 3875篇 |
2007年 | 3489篇 |
2006年 | 2928篇 |
2005年 | 2418篇 |
2004年 | 2261篇 |
2003年 | 2207篇 |
2002年 | 1990篇 |
2001年 | 1656篇 |
2000年 | 1548篇 |
1999年 | 951篇 |
1998年 | 2238篇 |
1997年 | 1491篇 |
1996年 | 956篇 |
1995年 | 556篇 |
1994年 | 470篇 |
1993年 | 441篇 |
1992年 | 179篇 |
1991年 | 145篇 |
1990年 | 109篇 |
1989年 | 116篇 |
1988年 | 134篇 |
1987年 | 120篇 |
1986年 | 100篇 |
1985年 | 121篇 |
1984年 | 112篇 |
1983年 | 73篇 |
1982年 | 72篇 |
1981年 | 101篇 |
1980年 | 97篇 |
1979年 | 64篇 |
1978年 | 54篇 |
1977年 | 131篇 |
1976年 | 242篇 |
1973年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Mario Garcia‐Sanz 《国际强度与非线性控制杂志
》2016,26(12):2643-2651
》2016,26(12):2643-2651
The Nyquist stability criterion is a widely used technique for determining in the complex s‐plane the stability of a dynamical system with feedback. This paper presents a practical and comprehensive method to compute the Nyquist stability criterion directly in the Nichols (magnitude/phase) chart. The proposed method also gives guidelines to design controllers to stabilize unstable plants when dealing with frequency domain techniques like the quantitative feedback theory robust control. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
992.
A timing controller embedded driver IC with 3.24‐Gbps eDP interface for chip‐on‐glass TFT‐LCD applications 下载免费PDF全文
Tae‐Jin Kim Changhoon Baek Sengsub Chun Kil‐Hoon Lee Jong‐Il Hwang Kyeonghwan Kwon Yong‐Hun Kim Hyun‐Sang Park Youngmin Shin Seong‐young Ryu Jae‐Youl Lee Gyoocheol Hwang Gyeongnam Kim 《Journal of the Society for Information Display》2016,24(5):299-306
This paper presents a timing controller embedded driver (TED) IC with 3.24‐Gbps embedded display port (eDP), which is implemented using a 45‐nm high‐voltage CMOS process for the chip‐on‐glass (COG) TFT‐LCD applications. The proposed TED‐IC employs the input offset calibration scheme, the zero‐adjustable equalizer, and the phase locked loop‐based bang‐bang clock and data recovery to enhance the maximum data rate. Also, the proposed TED‐IC provides efficient power management by supporting advanced link power management feature of eDP standard v1.4. Additionally, the smart charge sharing is proposed to reduce the dynamic power consumption of output buffers. Measured result demonstrates the maximum data rate of 3.24 Gbps from a 1.1 V supply voltage with a 7.9‐inch QXGA 60‐Hz COG‐LCD prototype panel and 44% power saving from the display system. 相似文献
993.
Fei‐Bo Duan Peng‐Fei Bai Alex Henzen Ling‐Ling Shui Biao Tang Guo‐Fu Zhou 《Journal of the Society for Information Display》2016,24(11):676-685
Electrophoretic display (EPD) technology is attractive when used for reading devices such as e‐paper because of its paper‐like appearance. EPD driving is more complex than other display technologies such as liquid crystal display or organic light emission diode because the driving result of a pixel strongly depends on the initial display state. The particle size and distribution in the EPD film may vary, even if the initial state is the same. Therefore, the display devices vary between different manufacturing batches. Furthermore, different display modes such as videos, pictures or documents need different driving waveforms to achieve an optimal result. EPD manufacturers need to build a customized driving waveform for every manufacturing batch. This is very inconvenient if new applications on EPD are to be developed. And the workload is huge. In this work, an adaptive method is described for automatically creating EPD driving waveforms to fit different conditions. The central idea of this method is generally adjusting the driving time and the voltage state after getting the feedback from a measurement model. In this method, a new driving waveform is used to reduce refresh time and visual flicker. The experimental results show that the proposed approach can automatically and adaptively generate an EPD driving waveform with reasonable quality. 相似文献
994.
Finite‐time asynchronous
filtering for discrete‐time Markov jump systems over a lossy network 下载免费PDF全文
This paper is concerned with the problem of finite‐time asynchronous filtering for a class of discrete‐time Markov jump systems. The communication links between the system and filter are assumed to be unreliable, which lead to the simultaneous occurrences of packet dropouts, time delays, sensor nonlinearity and nonsynchronous modes. The objective is to design a filter that ensures not only the mean‐square stochastic finite‐time bounded but also a prescribed level of performance for the underlying error system over a lossy network. With the help of the Lyapunov–Krasovskii approach and stochastic analysis theory, sufficient conditions are established for the existence of an admissible filter. By using a novel simple matrix decoupling approach, a desired asynchronous filter can be constructed. Finally, a numerical example is presented and a pulse‐width‐modulation‐driven boost converter model is employed to demonstrate the effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
995.
Saeed Salah Gabriel Maciá-Fernández Jesús E. Díaz-Verdejo Leovigildo Sánchez-Casado 《Journal of Network and Systems Management》2016,24(1):57-91
In Information Technology Service Management (ITSM), network management teams typically use an Incident Ticket System (ITS) as a tool to track, troubleshoot, and coordinate the resolution of network incidents that occur during the daily operation of the network. A well organized ITS may positively impact on the efficiency of the incident management process. Nevertheless, in many cases the handling of tickets by the management team is not completely systematic and may be incoherent and inefficient. This way, irrelevant or redundant tickets for the same incident may be issued, thus creating a redundancy in the system that leads to inefficiencies. In this paper, we suggest a model aimed to correlate redundant tickets in order to reduce the information to a single ticket per incident. We validate the proposed correlation model by evaluating it with two datasets taken from a real ticketing system of a telecommunications network company. Using this model as a basis, we also develop and evaluate a methodology that assesses the efficiency of the management team during the process of tickets creation and management. Based on it, we also get some insights on the performance of the different management groups involved in the ticket creation process. These analyses can be leveraged for improving both the management groups functioning and the policies for the tickets’ creation. 相似文献
996.
Jong‐Ju Hong Seungjun Shin Woo‐Jin Song Kyung Joon Kwon Seong Gyun Kim 《Journal of the Society for Information Display》2016,24(1):44-56
The impression of quality of images can be enhanced on a high dynamic range (HDR) displays. Generally, a conventional 8‐bit image can be processed to an HDR image by inverse tone mapping operators. Among the operators, brightness discrimination mapping by applying brightness adaptation model attempted to mimic the human visual system. In this paper, we use a brightness adaptation model to derive a brightness discrimination mapping algorithm for HDR displays. The proposed algorithm maximizes a function, which represents the local and global brightness discrimination range by exploiting characteristics of the human visual system. Enhancement of details is verified by visualizing HDR images from dark to bright regions. Improvement of dynamic range is quantified by measuring increased discrimination ratio. 相似文献
997.
This paper studies the partial consensus problem for identical feedforward dynamic systems with input saturations. We construct two consensus protocols using the partial‐state information and full‐state information, respectively. Applying a change of coordinates, feedforward system is transformed into the block diagonal form. Then, by utilizing the bounded real lemma and small gain theorem, we solve the partial consensus problem, and the existence of each protocol is derived. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
998.
Chatter is an unstable nonlinear dynamical phenomenon often encountered in machining operations because of the self‐excitation mechanism, which may lead to overcut or rapid tool wear, and hence, greatly influence the surface quality and productivity in milling operations. Recent years have witnessed an increasing industrial demand of high quality and high efficiency machining. This paper hereby develops a constrained active adaptive control method to mitigate the chatter dynamics with input saturations. To guarantee the feasibility of the proposed approach, moderate stable conditions of the closed‐loop system are afterwards derived by using the LaSalle–Yoshizawa theorem as well. Finally, numerical simulations are conducted to show the substantially enlarged stable region in the Lobe Diagram. Thus, the method can be expected to improve the efficiency of milling processes. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
The current landscape of communication technologies is characterized by a wide variety of choices. As each medium provides different affordances, each may occupy a different niche and be used in different relationships. Drawing on the theory of the niche, we did a meta‐analysis involving 27 effect sizes from 22 independent samples to test the correlation between media selection/use and friendship closeness. Results showed that the 5 communication channels filled 2 different friendship closeness niches. Mobile phone calls and texting had stronger positive correlations with friendship closeness than instant messaging, social network sites, and online gaming. Culture, but not gender, moderated some of these correlations: Friendship closeness had a stronger positive association with SNS use and online gaming in collectivist cultures. 相似文献
1000.
M. Lucena A. L. Martínez-Carrillo J. M. Fuertes F. Carrascosa A. Ruiz 《Multimedia Tools and Applications》2016,75(7):3677-3691
We present a decision support system to help archaeologists in classifying wheel-made pottery pieces by its profile. A novel shape characterization method, using Mathematical Morphology, is introduced for this purpose. Each profile is represented as a vector, obtained by sampling the so called morphological curves (erosion, dilation, opening and closing), and Euclidean Distance is used as a similarity measure. We show results of our method applied to a profile database of Iberian Pottery from the upper valley of Guadalquivir River (Spain). 相似文献