首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   25794篇
  免费   2321篇
  国内免费   1555篇
电工技术   460篇
技术理论   1篇
综合类   1065篇
化学工业   949篇
金属工艺   429篇
机械仪表   506篇
建筑科学   219篇
矿业工程   81篇
能源动力   946篇
轻工业   175篇
水利工程   39篇
石油天然气   56篇
武器工业   32篇
无线电   4805篇
一般工业技术   1841篇
冶金工业   71篇
原子能技术   138篇
自动化技术   17857篇
  2024年   67篇
  2023年   586篇
  2022年   918篇
  2021年   1224篇
  2020年   1178篇
  2019年   960篇
  2018年   985篇
  2017年   1965篇
  2016年   2268篇
  2015年   1664篇
  2014年   2523篇
  2013年   1719篇
  2012年   1747篇
  2011年   1717篇
  2010年   1433篇
  2009年   1637篇
  2008年   892篇
  2007年   1382篇
  2006年   1239篇
  2005年   714篇
  2004年   327篇
  2003年   366篇
  2002年   428篇
  2001年   414篇
  2000年   264篇
  1999年   299篇
  1998年   158篇
  1997年   123篇
  1996年   120篇
  1995年   40篇
  1994年   43篇
  1993年   31篇
  1992年   33篇
  1991年   27篇
  1990年   22篇
  1989年   17篇
  1988年   15篇
  1987年   6篇
  1986年   16篇
  1985年   18篇
  1984年   14篇
  1983年   8篇
  1982年   10篇
  1981年   8篇
  1980年   5篇
  1979年   5篇
  1978年   7篇
  1977年   11篇
  1976年   7篇
  1975年   3篇
排序方式: 共有10000条查询结果,搜索用时 781 毫秒
1.
2.

In this paper, we propose to use Artificial Bee Colony (ABC) optimization to solve the joint mode selection, channel assignment, and power allocation (JMSCPA) problem to maximize system throughput and spectral efficiency. JMSCPA is a problem where the allocation of channel and power depends on the mode selection. Such problems require two step solution and are called bi-level optimization problems. As bi-level optimization increases the complexity and computational time, we propose a modified version of single-level ABC algorithm aided with the adaptive transmission mode selection algorithm to allocate the cellular, reuse, and dedicated modes to the DUs along with channel and power allocation based on the network traffic load scenarios. A single variable, represented by the users (CUs and DUs) is used to allocate mode selection, and channel allocation to solve the JMSCPA problem, leading to a simpler solution with faster convergence, and significant reduction in the computational complexity which scales linearly with the number of users. Further, the proposed solution avoids premature stagnation of conventional ABC into local minima by incorporating a modification in its update procedure. The efficacy of the ABC-aided approach, as compared to the results reported in the literature, is validated by extensive numerical investigations under different simulation scenarios.

  相似文献   
3.
Multimedia Tools and Applications - The video surveillance activity generates a vast amount of data, which can be processed to detect miscreants. The task of identifying and recognizing an object...  相似文献   
4.
5.
The central claim of the paper is that the development and control of Cyber-Physical Production Systems (CPPS) requires a systematic approach to handle and include explicit ethical considerations. Since the contribution of artificial intelligence (AI) technologies, and of agent-based models in particular, was instrumental in the evolution of CPPSs, approaches of ethical AI should be endorsed in CPPS development by design. The paper discusses recent advances for ethical AI and suggests a pathway from ethical norms towards standards. As it is argued, taking the responsible AI approach is promising when tackling the main ethic-related challenges of Cyber-Physical Production Systems. We expose a number of dilemmas to be resolved so that AI systems incorporated in CPPS cause no damages either in humans, equipment or in the environment and increase the trust in the users of current and future AI technologies.  相似文献   
6.
Multimedia Tools and Applications - In this paper, a hashing based watermarking technique for the protection and authentication of document image is proposed. Message Digest 5 (MD5) hashing is...  相似文献   
7.
This editorial paper provides an overview of new advances on hardware security challenges and promising solutions for real world applications. It first presents the increasing hardware vulnerabilities with the emergence of diverse computing platforms. Then, it details the technical challenges, research opportunities, and potential solutions to cyber-attacks on -physical- devices.  相似文献   
8.
《Ceramics International》2021,47(24):34455-34462
Herein, the tungsten trioxide (WO3) nanostructure thin films with different morphologies are firstly fabricated by magnetron sputtering with glancing angle deposition technique (MS-GLAD), followed by the post annealed treatment process in air ambient for 2 h. It is demonstrated that the geometry of MS-GLAD setup, mainly substrate position, played a crucial role in determining the morphology, crystallinity, optical transmittance, and photo-electrochemical (PEC) performance of the WO3 nanostructured thin film. With the different substrate positions in the MS-GLAD system, the WO3 nanorod film layer could be precisely changed to combine an underlying dense layer with a nanorod layer and then nanocolumnar film. Moreover, the prepared samples' chemical composition and work function are studied by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS), respectively. The combining WO3 nanostructure produced high PEC efficiency compared to the single layer of the WO3 nanorods sample and the dense WO3 thin film sample. Thus, morphology-controlled nanostructure film based on the MS-GLAD technique in our study provides a simple approach to enhance the photo-anode for PEC water splitting application.  相似文献   
9.
Multimedia Tools and Applications - Discovering the relevant web services for specific applications in the dynamically changing business world becomes very critical. Researchers have used many...  相似文献   
10.
Multimedia Tools and Applications - Gastrointestinal stromal tumor is one of the critical tumors that doctors do not suggest to get frequent endoscopy, so there is a need for a diagnosis system...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号