全文获取类型
收费全文 | 23283篇 |
免费 | 1886篇 |
国内免费 | 918篇 |
专业分类
电工技术 | 1218篇 |
技术理论 | 2篇 |
综合类 | 1380篇 |
化学工业 | 3937篇 |
金属工艺 | 1266篇 |
机械仪表 | 1431篇 |
建筑科学 | 2058篇 |
矿业工程 | 770篇 |
能源动力 | 616篇 |
轻工业 | 1331篇 |
水利工程 | 362篇 |
石油天然气 | 1527篇 |
武器工业 | 121篇 |
无线电 | 2374篇 |
一般工业技术 | 2844篇 |
冶金工业 | 1485篇 |
原子能技术 | 311篇 |
自动化技术 | 3054篇 |
出版年
2024年 | 105篇 |
2023年 | 440篇 |
2022年 | 659篇 |
2021年 | 921篇 |
2020年 | 752篇 |
2019年 | 638篇 |
2018年 | 689篇 |
2017年 | 774篇 |
2016年 | 657篇 |
2015年 | 860篇 |
2014年 | 1149篇 |
2013年 | 1313篇 |
2012年 | 1449篇 |
2011年 | 1536篇 |
2010年 | 1355篇 |
2009年 | 1228篇 |
2008年 | 1234篇 |
2007年 | 1194篇 |
2006年 | 1259篇 |
2005年 | 1163篇 |
2004年 | 709篇 |
2003年 | 626篇 |
2002年 | 549篇 |
2001年 | 505篇 |
2000年 | 476篇 |
1999年 | 626篇 |
1998年 | 574篇 |
1997年 | 448篇 |
1996年 | 405篇 |
1995年 | 351篇 |
1994年 | 278篇 |
1993年 | 177篇 |
1992年 | 159篇 |
1991年 | 141篇 |
1990年 | 103篇 |
1989年 | 89篇 |
1988年 | 84篇 |
1987年 | 65篇 |
1986年 | 49篇 |
1985年 | 34篇 |
1984年 | 37篇 |
1983年 | 19篇 |
1982年 | 25篇 |
1981年 | 21篇 |
1980年 | 19篇 |
1979年 | 19篇 |
1978年 | 14篇 |
1977年 | 23篇 |
1976年 | 19篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
81.
本文介绍和评述了化学气相沉积法制备人造金刚石薄膜及其进展。重点评述了反应机理、发展历史、沉积方法、补底材料、检测手段。论述了有利于形成立方晶系金刚石材料的沉积条件。 相似文献
82.
Real-time frame rate is an important factor for practical deployment of computer vision systems. Field programmable gate array (FPGA) technology has been considered for many applications due to its parallel computing capability. FPGA implementations of computer vision algorithms normally involve buffering data on external memory devices, which could slow down the whole system. This paper proposes a buffering scheme suitable for implementing real-time vision-based systems on an FPGA that does not require external memory to buffer data. A stop sign detection system implemented on an FPGA employing the proposed buffering scheme is presented as an example system. This system is capable of processing over 200?fps at the frame size of 480?×?752 pixels. 相似文献
83.
Clotilde LM Bernard C Sequera DE Karmali A Fusellier A Carter JM 《Journal of laboratory automation》2012,17(4):309-314
Conventional enzyme-linked immunosorbent assay (ELISA) is a gold standard for screening antibodies and testing for protein or antigen presence. A significant limitation of this assay resides in the fact that only one analyte can be assessed per microplate well. Here, we describe and investigate a new technology consisting of an automated ELISA system in which up to 10 analytes can be measured within one single well, thus improving productivity, accuracy, and repeatability by reducing the amount of human labor required. Another strength of the platform is that a user can load any necessary sets/subsets of beads to perform required assays, with improved flexibility compared to manufactured-loaded arrays for multiplex analysis. We also demonstrate that this system can be used to determine the pathogenicity (i.e., presence of Shiga toxins) and serotype (i.e., Escherichia coli O157) of E. coli isolates. 相似文献
84.
Neural Computing and Applications - In recent years, researchers have proposed many methods to solve the problem of obstacle detection. However, computer vision-based vehicle detection and... 相似文献
85.
Neural Computing and Applications - Image classification method is currently the more popular image technology, but it still has certain problems in practice. In order to improve the image... 相似文献
86.
Xu Furong Liu Ke Yu Zhuliang Deng Xin Wang Guoyin 《Neural computing & applications》2021,33(14):8513-8524
Neural Computing and Applications - It is a long-standing challenge to reconstruct the locations and extents of cortical neural activities from electroencephalogram (EEG) recordings, especially... 相似文献
87.
针对在利用倾角传感器实现混凝土泵车之类的大型操作机的臂架姿态的间接测量方案中存在的因为臂架的柔性和操作机在不同姿态下自身水平状态的不同可能导致的臂架末端的理论计算值存在较大测量误差的问题,采用了一种在臂架的不同位置增加传感器来实现对臂架柔性变形大小和自身水平状态的实时检测的方法,并着重研究了针对具体的柔性变形及水平状态变化所导致的理论偏差进行实时补偿的切实可行的方法,实验检测的数据证明,相对补偿前臂架的定位精度提升了75%以上. 相似文献
88.
为改善石英晶体振荡器的频率特性,减小温度影响,通过对石英晶体振荡器的频率-温度特性的研究,提出了以微处理器(STC89C52RC)为核心的基于AT切晶体谐振器的温度补偿技术,并介绍了系统结构、补偿原理及硬件电路,给出了补偿结果。本设计具有结构简单、功耗低等优点。 相似文献
89.
Chen G Deng Q Szymczak A Laramee RS Zhang E 《IEEE transactions on visualization and computer graphics》2012,18(5):767-782
Morse decomposition provides a numerically stable topological representation of vector fields that is crucial for their rigorous interpretation. However, Morse decomposition is not unique, and its granularity directly impacts its computational cost. In this paper, we propose an automatic refinement scheme to construct the Morse Connection Graph (MCG) of a given vector field in a hierarchical fashion. Our framework allows a Morse set to be refined through a local update of the flow combinatorialization graph, as well as the connection regions between Morse sets. The computation is fast because the most expensive computation is concentrated on a small portion of the domain. Furthermore, the present work allows the generation of a topologically consistent hierarchy of MCGs, which cannot be obtained using a global method. The classification of the extracted Morse sets is a crucial step for the construction of the MCG, for which the Poincare′ index is inadequate. We make use of an upper bound for the Conley index, provided by the Betti numbers of an index pair for a translation along the flow, to classify the Morse sets. This upper bound is sufficiently accurate for Morse set classification and provides supportive information for the automatic refinement process. An improved visualization technique for MCG is developed to incorporate the Conley indices. Finally, we apply the proposed techniques to a number of synthetic and realworld simulation data to demonstrate their utility. 相似文献
90.
Distributed virtual environments (DVEs) are becoming very popular in recent years, due to the rapid growing of applications, such as massive multiplayer online games (MMOGs). As the number of concurrent users increases, scalability becomes one of the major challenges in designing an interactive DVE system. One solution to address this scalability problem is to adopt a multi-server architecture. While some methods focus on the quality of partitioning the load among the servers, others focus on the efficiency of the partitioning process itself. However, all these methods neglect the effect of network delay among the servers on the accuracy of the load balancing solutions. As we show in this paper, the change in the load of the servers due to network delay would affect the performance of the load balancing algorithm. In this work, we conduct a formal analysis of this problem and discuss two efficient delay adjustment schemes to address the problem. Our experimental results show that our proposed schemes can significantly improve the performance of the load balancing algorithm with neglectable computation overhead. 相似文献