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   1240篇
  免费   37篇
  国内免费   1篇
电工技术   22篇
综合类   1篇
化学工业   222篇
金属工艺   18篇
机械仪表   20篇
建筑科学   44篇
矿业工程   1篇
能源动力   21篇
轻工业   177篇
水利工程   20篇
石油天然气   5篇
无线电   67篇
一般工业技术   190篇
冶金工业   322篇
原子能技术   6篇
自动化技术   142篇
  2023年   20篇
  2022年   33篇
  2021年   47篇
  2020年   20篇
  2019年   24篇
  2018年   30篇
  2017年   20篇
  2016年   29篇
  2015年   21篇
  2014年   24篇
  2013年   57篇
  2012年   54篇
  2011年   73篇
  2010年   59篇
  2009年   45篇
  2008年   67篇
  2007年   51篇
  2006年   48篇
  2005年   37篇
  2004年   31篇
  2003年   34篇
  2002年   26篇
  2001年   23篇
  2000年   18篇
  1999年   15篇
  1998年   64篇
  1997年   59篇
  1996年   25篇
  1995年   19篇
  1994年   22篇
  1993年   27篇
  1992年   8篇
  1991年   9篇
  1990年   6篇
  1989年   10篇
  1988年   9篇
  1986年   12篇
  1985年   6篇
  1983年   5篇
  1982年   8篇
  1981年   6篇
  1979年   5篇
  1978年   5篇
  1977年   7篇
  1976年   11篇
  1975年   7篇
  1974年   4篇
  1973年   5篇
  1971年   4篇
  1956年   4篇
排序方式: 共有1278条查询结果,搜索用时 1 毫秒
991.
Successful learning is mainly based on metacognitive activities which have to be performed and constantly monitored during learning. Research reveals that many learners have difficulties in performing such metacognitive activities spontaneously, which most probably results in lower learning outcomes. The aim of this study is to experimentally analyse the effects of a metacognitive support device combined with a paper-based prompting scheme. With this support device, students are instructed to activate their repertoire of metacognitive knowledge and skills which should further enhance learning and transfer.  相似文献   
992.
We are delighted to bring you this special issue on speech and language processing for assistive technology. It addresses an important research area that is gaining increased recognition from researchers in speech and language processing as a rich and fulfilling area on which to focus their work, and by researchers in assistive technology as the means to dramatically improve communication technologies for individuals with disabilities. This special issue brings a wide swath of approaches and applications highlighting the variety this area offers.  相似文献   
993.
This study analyses the influence of vegetation structure (i.e. leaf area index and canopy cover) and seasonal background changes on moderate-resolution imaging spectrometer (MODIS)-simulated reflectance data in open woodland. Approximately monthly spectral reflectance and transmittance field measurements (May 2011 to October 2013) of cork oak tree leaves (Quercus suber) and of the herbaceous understorey were recorded in the region of Ribatejo, Portugal. The geometric-optical and radiative transfer (GORT) model was used to simulate MODIS response (red, near-infrared) and to calculate vegetation indices, investigating their response to changes in the structure of the overstorey vegetation and to seasonal changes in the understorey using scenarios corresponding to contrasting phenological status (dry season vs. wet season). The performance of normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), and enhanced vegetation index (EVI) is discussed. Results showed that SAVI and EVI were very sensitive to the emergence of background vegetation in the wet season compared to NDVI and that shading effects lead to an opposing trend in the vegetation indices. The information provided by this research can be useful to improve our understanding of the temporal dynamic of vegetation, monitored by vegetation indices.  相似文献   
994.
Researchers have begun to explore tools that allow multiple users to collaborate across multiple devices in collocated environments. These tools often allow users to simultaneously place and interact with information on shared displays. Unfortunately, there is a lack of experimental tasks to evaluate the effectiveness of these tools for information coordination in such scenarios. In this article, we introduce job-shop scheduling as a task that could be used to evaluate systems and interactions within computer-supported collaboration environments. We describe properties that make the task useful, as well as evaluation measures that may be used. We also present two experiments as case studies to illustrate the breadth of scenarios in which this task may be applied. The first experiment shows the differences when users interact with different communicative gesturing schemes, while the second demonstrates the benefits of shared visual information on large displays. We close by discussing the general applicability of the tasks.  相似文献   
995.
Beam-induced voltage contrast has been demonstrated in a superconducting thin film of YBa2Cu3O7-x (YBCO) grown on MgO. Copper-rich inclusions in the material contribute to spatially varying resistive behaviour but do not account for all the observed details. A new method of scanning in which the beam was moved away from the sample between each data acquisition point was found to increase the resolution by limiting thermalisation, to allow imaging of resistive features as small as 0.5 μm. Direct comparisons of beam-induced contrast and micro-structure at 9000 times magnification were possible using simultaneous image acquisition via a purpose-built image store. Mounting a preamplifier within the scanning electron microscope chamber, to give a variable overall gain of 1000–100,000, was also found to significantly improve the signal-to-noise ratio.  相似文献   
996.
We investigated the effects of automation as applied to different stages of information processing on team performance in a complex decision-making task. Forty teams of 2 individuals performed a simulated Theater Defense Task. Four automation conditions were simulated with computer assistance applied to realistic combinations of information acquisition, information analysis, and decision selection functions across two levels of task difficulty. Multiple measures of team effectiveness and team coordination were used. Results indicated different forms of automation have different effects on teamwork. Compared with a baseline condition, an increase in automation of information acquisition led to an increase in the ratio of information transferred to information requested; an increase in automation of information analysis resulted in higher team coordination ratings; and automation of decision selection led to better team effectiveness under low levels of task difficulty but at the cost of higher workload. The results support the use of early and intermediate forms of automation related to acquisition and analysis of information in the design of team tasks. Decision-making automation may provide benefits in more limited contexts. Applications of this research include the design and evaluation of automation in team environments.  相似文献   
997.
This paper describes the implementation of an intelligent navigation system, based on the integrated use of the global positioning system (GPS) and several inertial navigation system (INS) sensors, for autonomous underwater vehicle (AUV) applications. A simple Kalman filter (SKF) and an extended Kalman filter (EKF) are proposed to be used subsequently to fuse the data from the INS sensors and to integrate them with the GPS data. The paper highlights the use of fuzzy logic techniques to the adaptation of the initial statistical assumption of both the SKF and EKF caused by possible changes in sensor noise characteristics. This adaptive mechanism is considered to be necessary as the SKF and EKF can only maintain their stability and performance when the algorithms contain the true sensor noise characteristics. In addition, fault detection and signal recovery algorithms during the fusion process to enhance the reliability of the navigation systems are also discussed herein. The proposed algorithms are implemented to real experimental data obtained from a series of AUV trials conducted by running the low-cost Hammerhead AUV, developed by the University of Plymouth and Cranfield University.  相似文献   
998.
A set of four hypotheses about the relationships between word processor attributes and employee perceptions of control and satisfaction are developed and then tested in a sample of 109 clerical workers. Findings from this perliminary study support the first hypothesis, that electronic word processors, in contrast to typewriters, increase an employee's ability to control his or her work. The second hypothesis, that users of both word processors and typewriters will report the highest levels of control, was not supported. The second part of the study concerns attributes of electronic word processors. The third hypothesis was that employees who use computers that are more dependable, easier to use, and have higher quality screens will report higher levels of control. This hypothesis was only partially supported. Support was found for the fourth hypothesis, that the above trio of computer attributes Would be positively related to employee satisfaction with the word processor. Practical implications and suggestions for future research are discussed.  相似文献   
999.
The growing reliance of biomedical investigations on computer software in almost all facets of their work places considerable emphasis on the need for the integrated management of the software. In order to efficiently develop, distribute, and maintain the software, tools are required which not only automate these tasks but also, wherever possible, 'semi-intelligently', alert their user to irregular situation. We describe an assortment of such tools routinely used in the management of the SAAM/CONSAM biokinetic software and illustrate their application. Furthermore, using these techniques we have presented some comparative performances of numerical integrators and of computer processors.  相似文献   
1000.
155 managers in 14 organizations completed a questionnaire in which they described their jobs and their responses to work. A high-level manager in each firm provided information of organizational and environmental characteristics during a structured interview. Findings indicate that both organizational and environmental characteristics were related to individual responses and job perceptions. Further, job perceptions mediated the relationship of both organizational and environmental characteristics to individual responses. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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