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   627篇
  免费   59篇
  国内免费   42篇
电工技术   27篇
综合类   41篇
化学工业   133篇
金属工艺   31篇
机械仪表   28篇
建筑科学   44篇
矿业工程   19篇
能源动力   30篇
轻工业   57篇
水利工程   18篇
石油天然气   16篇
武器工业   1篇
无线电   67篇
一般工业技术   92篇
冶金工业   32篇
原子能技术   2篇
自动化技术   90篇
  2024年   1篇
  2023年   7篇
  2022年   7篇
  2021年   21篇
  2020年   22篇
  2019年   33篇
  2018年   31篇
  2017年   29篇
  2016年   19篇
  2015年   21篇
  2014年   19篇
  2013年   39篇
  2012年   30篇
  2011年   34篇
  2010年   16篇
  2009年   22篇
  2008年   20篇
  2007年   16篇
  2006年   17篇
  2005年   8篇
  2004年   29篇
  2003年   47篇
  2002年   81篇
  2001年   80篇
  2000年   34篇
  1999年   15篇
  1998年   8篇
  1997年   1篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
排序方式: 共有728条查询结果,搜索用时 15 毫秒
81.
软件内建自测试是软件测试和可测性设计研究领域中的一个新概念,其思想来源于硬件内建自测试BIST(BuildinSelfTest)。软件内建自测试为程序员提供一套预先设计好的模板,由模板对所编写的程序植入测试信息,实现软件内建自测试以解决软件测试难的问题。模板是软件内建自测试系统的基石,其内容关系到整个系统的性能和效果。具体讨论了模板的实现,根据软件故障模型对代码进行改装,从而减少程序出错的概率,同时为软件内建自测试系统中测试用例的生成提供了更丰富的信息。  相似文献   
82.
Neural Computing and Applications - In this study, two-channel surface electromyography (sEMG) signals were used to classify hand finger movements. Bicoherence analysis of the sEMG signal recorded...  相似文献   
83.
The study evaluated the potential mismatch between classroom furniture dimensions and anthropometric characteristics of 978 Iranian high school students (498 girls, 480 boys), aged 15-18 years. Nine anthropometric measurements (stature, sitting height, sitting shoulder height, popliteal height, hip breadth, elbow-seat height, buttock-popliteal length, buttock-knee length and thigh clearance) and five dimensions from the existing classroom furniture were measured and then compared together (using match criterion equations) to identify any potential mismatch between them. The results indicated a considerable mismatch between body dimensions of the students and the existing classroom furniture, with seat height (60.9%), seat width (54.7%) and desktop height (51.7%) being the furniture dimensions with a higher level of mismatch. The levels of mismatch varied between the high-school grade levels and between genders, indicating their special requirements and possible problems. The proposed dimensions of the classroom furniture more appropriate for the students were given. This additional information on students' anthropometry can be used by local furniture industries as a starting point for designing more appropriate furniture for school children, or used by schools to aid in furniture selection.  相似文献   
84.
The Aerial Refueling Scheduling Problem (ARSP) can be defined as determining the refueling completion times for fighter aircrafts (jobs) on multiple tankers (machines) to minimize the total weighted tardiness. ARSP can be modeled as a parallel machine scheduling with ready times and due date-to-deadline window to minimize total weighted tardiness. ARSP assumes that the jobs have different ready times and a due date-to-deadline window between refueling due date and a deadline to return without refueling. In this paper, we first formulate the ARSP as a mixed integer programming model. The objective function is a piece-wise tardiness cost that takes into account due date-to-deadline windows and job priorities. Since ARSP is NP-hard, two heuristics are proposed to obtain solutions in reasonable computation times, namely (1) modified ATC rule (MATC), (2) a simulated annealing method (SA). The proposed heuristic algorithms are tested in terms of solution quality and CPU time through computational experiments with data randomly generated to represent aerial refueling operations of an in-theater air operation. Solutions provided by both algorithms were compared to optimal solutions for problems with up to 12 jobs and to each other for larger problems with up to 60 jobs. The results show that, MATC is more likely to outperform SA especially when the problem size increases, although it has significantly worse performance than SA in terms of deviation from optimal solution for small size problems. Moreover CPU time performance of MATC is significantly better than SA in both cases.  相似文献   
85.
ABSTRACT

This paper proposes a robust tracking controller for a class of nonlinear second-order systems with time-varying uncertainties. The controller is mainly based on the robust integral of the sign of the error (RISE) control approach to achieve an asymptotic stability result with a continuous control command in the presence of additive uncertainties. An adaptive feedforward neural network control term is blended with a new RISE controller to improve the system's transient performance. The proposed RISE controller is a modified version of the existing saturated RISE controller such that only sign of the derivative of the output is needed. The stability of the closed-loop system is well studied, where a local asymptotic stability is proven. The controller performance is validated through simulations on a two-degree-of-freedom lower limb robotic exoskeleton.  相似文献   
86.
集中监控系统中软件的设计和实现   总被引:1,自引:0,他引:1  
实时集中监控系统的实时性、可靠性取决于系统的硬件结构与软件体系结构 ,文中介绍了集中监控系统的结构和实现方案 ,描述了集中监控系统的软件模型 ,阐述了软件的具体设计方法及各软件模块的运行优先级问题。设计体现了集中管理、分散控制的思想 ,运用分布式计算方法 ,在保证集中监控可靠性的同时 ,提高了集中监控的实时性、安全性  相似文献   
87.
采用分级萃取--柱层析法分离除去松香中的树脂酸,得到铝化合物,通过红外光谱分析与对照,确定铝在松香中的存在形式为碱式树脂酸铝,从而为松香除铝技术提供理论依据.  相似文献   
88.
89.
介绍了钻孔水力采矿射流水枪试验台的设计原理,在该试验台上可以模拟水枪在大气中的自由射流、模拟无压流体淹没条件下的射流以及模拟有压流体淹没条件下的射流等.设计的测试系统能对水枪射流能力、不同喷距下的射流打击力、流体流量、压力等参数进行测试.可以准确地衡量不同喷嘴、不同喷距、不同工矿条件下的射流效果.  相似文献   
90.
为了取得更好的识别效果,受支持向量机的几何解释和最近点问题启发,提出了一种新的模式分类算法——仿射子空间最近点算法。该算法是将支持向量机最近点法的最近点搜索区域由两类训练集凸包推广到两类训练样本各自张成的仿射子空间,并以仿射子空间作为样本分布的粗略估计,通过仿射子空间中的最近点对来构造平分仿射子空间间隔的最优分类超平面。该算法在ORL人脸识别数据库上进行的比较实验中取得了较好的识别效果,从而证实了该方法的可行性和有效性。  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