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   6010篇
  免费   287篇
  国内免费   50篇
电工技术   86篇
综合类   76篇
化学工业   1296篇
金属工艺   233篇
机械仪表   225篇
建筑科学   267篇
矿业工程   50篇
能源动力   448篇
轻工业   865篇
水利工程   42篇
石油天然气   61篇
武器工业   2篇
无线电   341篇
一般工业技术   1031篇
冶金工业   431篇
原子能技术   78篇
自动化技术   815篇
  2024年   28篇
  2023年   82篇
  2022年   158篇
  2021年   207篇
  2020年   220篇
  2019年   212篇
  2018年   284篇
  2017年   256篇
  2016年   277篇
  2015年   164篇
  2014年   243篇
  2013年   592篇
  2012年   341篇
  2011年   350篇
  2010年   278篇
  2009年   354篇
  2008年   318篇
  2007年   261篇
  2006年   199篇
  2005年   135篇
  2004年   135篇
  2003年   154篇
  2002年   185篇
  2001年   138篇
  2000年   81篇
  1999年   69篇
  1998年   158篇
  1997年   84篇
  1996年   60篇
  1995年   33篇
  1994年   35篇
  1993年   27篇
  1992年   24篇
  1991年   26篇
  1990年   18篇
  1989年   15篇
  1988年   10篇
  1987年   14篇
  1986年   18篇
  1985年   18篇
  1984年   13篇
  1983年   13篇
  1982年   8篇
  1981年   8篇
  1979年   6篇
  1978年   5篇
  1976年   8篇
  1970年   3篇
  1967年   3篇
  1965年   3篇
排序方式: 共有6347条查询结果,搜索用时 15 毫秒
71.
In this paper we present storage structures for efficiently processing XML path queries on healthcare data stored in smart cards using XML format. In the design of the storage structures that we present, properties of healthcare data and fundamental types of queries on the healthcare data are taken into account as well as the constraints of the smart cards. We compare the space and time efficiency of the proposed storage structures for various types of queries.  相似文献   
72.
分析了传统单一C/S结构的不足以及新型N层B/S结构的优越性,阐述了基于Web技术的网络管理是未来网络管理的发展趋势,结合现代软件开发中的软件复用理论,提出并设计实现了一种基于COM技术与N层B/S结构的SNMP网管系统模型,着重叙述了该系统中所使用的关键技术与设计要点。  相似文献   
73.
快速移植的微型呼叫中心设计   总被引:1,自引:0,他引:1  
介绍了如何构建微型呼叫中心的系统设计及组成,给出了相应的系统结构,并对微型呼叫中心核心部分的设计进行了描述。该设计方案的优点是投资少,软件开发和扩展均较容易,实施快速,特别适合接入线路不多的微型呼叫中心。  相似文献   
74.
The main purpose of this study was to investigate the views of primary students about interactive whiteboard [IWB] use in their classes from attitudinal and pedagogical perspectives. Research was designed as an empirical approach to phenomenology. Data was collected from fifty primary students (fourth to eighth) through focus group interviews. Nvivo 9 qualitative data analysis software was used to analyze data. Results showed that students like instruction with IWB especially for such reasons/capabilities as practical and economical use, better visual presentation, and test-based use. Students were predominantly uncomfortable with the technical problems. They believed that instruction with IWB positively impacted their learning especially because of visualization and contextualization, effective presentation, test-based use, and motivational factors. Finally it was inferred that IWBs were not used to their full potential, and both technical problems and common practices indicated that teachers were still at an initial stage of transmission to instruction with IWB and they needed both technical and pedagogical training.  相似文献   
75.
In this paper, a new method for aggregating the opinions of experts in a preferential voting system is proposed. The method, which uses fuzzy concept in handling crisp data, is computationally efficient and is able to completely rank the alternatives. Through this method, the number of votes for certain rank position that each alternative receives are first grouped together to form fuzzy numbers. The nearest point to a fuzzy number concept is then used to introduce an artificial ideal alternative. Data envelopment analysis is next used to find the efficiency scores of the alternatives in a pair-wise comparison with the artificial ideal alternative. Alternatives are rank based on these efficiency scores. If the alternatives are not completely ranked, a weight restriction method also based on fuzzy concept is used on the un-discriminated alternatives until they are completely ranked. Two examples are given for illustration of the method.  相似文献   
76.
This paper considers the problem of multirobot coordination in pick-and-place tasks on a conveyor band. The robot team is composed of identical robots with mutually exclusive, but neighboring workspaces. The products are fed in at one end of the band, move through each workspace sequentially until being picked up and are collected at the other end—if not picked up interim. Each robot has the same task—that is picking up and packaging as many products as possible. We propose an approach based on noncooperative game theory where each robot uses local observations of the conveyor band and their neighbors' actions in order to decide on its actions. The developed algorithm has been implemented and tested in a simulated manufacturing environment using Webots. Results obtained from the simulations are analyzed using a variety of statistical performance measures.  相似文献   
77.
Unmanned Aircraft (UA) have become an integral part of the present-day joint air operations. UA have potential to be employed across the full spectrum of Air Force functions. On the other hand, UA technology could be a subject of an asymmetric use by state actors in high or low density conflict, and/or by non-state actors in many ways including terrorism, drug smuggling, and limited attack with unconventional payloads i.e. biological or chemical agents. Therefore countering the threat associated with the hostile UA use could be necessary in the future. First part of the research revealed that UA can be a threat in the future. In the second part of the research, the SWOT (Strengths-Weaknesses-Opportunities-Threats) analysis supplemented with the Tree analysis (SWOT+Tree) provided a broader look for investigating the factors related to hostile UA use analytically. In literature, there is little information about the concepts for CUAOPS. The final goal of the paper is to find possible solutions and means for a better understanding of the nature of CUAOPS.  相似文献   
78.
In this work, several robust vision modules are developed and implemented for fully automated micromanipulation. These are autofocusing, object and end-effector detection, real-time tracking and optical system calibration modules. An image based visual servoing architecture and a path planning algorithm are also proposed based on the developed vision modules. Experimental results are provided to assess the performance of the proposed visual servoing approach in positioning and trajectory tracking tasks. Proposed path planning algorithm in conjunction with visual servoing imply successful micromanipulation tasks.  相似文献   
79.
This paper demonstrates a new hierarchical Dynamic Bandwidth Allocation algorithm using the Russian Doll Model (RDM) to allocate bandwidth for intra-Optical Network Unit (ONU) in an Ethernet Passive Optical Network (EPON). The allocation of bandwidth is based on the classification and prioritization of service. The algorithm addresses the requests of ONUs and provides differentiated services by balancing priority and fairness. The simulation results show that the proposed algorithm performs well in supporting the triple-play services, i.e. video, voice, and data, as well as making effective adjustment in balancing bandwidth sharing between the ONUs compared with two other existing Dynamic Bandwidth Allocation (DBA) algorithm. The proposed algorithms shows significant performance improvements in terms of bandwidth utilization, packet delay and the fairness.  相似文献   
80.
A multivariable regression (MVR) approach is proposed to identify the real power transfer between generators and loads. Based on solved load flow results, it first uses modified nodal equation method (MNE) to determine real power contribution from each generator to loads. Then, the results of MNE method and load flow information are utilized to determine suitable regression coefficients using MVR model to estimate the power transfer. The 25-bus equivalent system of south Malaysia is utilized as a test system to illustrate the effectiveness of the MVR output compared to that of the MNE method. The error of the estimate of MVR method ranges from 0.001 4 to 0.007 9. Furthermore, when compared to MNE method, MVR method computes generator contribution to loads within 26.40 ms whereas the MNE method takes 360 ms for the calculation of same real power transfer allocation. Therefore, MVR method is more suitable for real time power transfer allocation.  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