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   8885篇
  免费   391篇
  国内免费   338篇
电工技术   244篇
综合类   421篇
化学工业   271篇
金属工艺   516篇
机械仪表   1501篇
建筑科学   471篇
矿业工程   156篇
能源动力   111篇
轻工业   73篇
水利工程   82篇
石油天然气   40篇
武器工业   130篇
无线电   639篇
一般工业技术   562篇
冶金工业   112篇
原子能技术   47篇
自动化技术   4238篇
  2024年   11篇
  2023年   73篇
  2022年   96篇
  2021年   127篇
  2020年   153篇
  2019年   112篇
  2018年   126篇
  2017年   162篇
  2016年   196篇
  2015年   232篇
  2014年   408篇
  2013年   400篇
  2012年   469篇
  2011年   596篇
  2010年   402篇
  2009年   462篇
  2008年   543篇
  2007年   709篇
  2006年   710篇
  2005年   695篇
  2004年   621篇
  2003年   553篇
  2002年   462篇
  2001年   330篇
  2000年   229篇
  1999年   220篇
  1998年   135篇
  1997年   85篇
  1996年   60篇
  1995年   38篇
  1994年   32篇
  1993年   26篇
  1992年   14篇
  1991年   13篇
  1990年   23篇
  1989年   20篇
  1988年   10篇
  1987年   9篇
  1986年   4篇
  1985年   10篇
  1984年   6篇
  1983年   6篇
  1982年   5篇
  1981年   2篇
  1980年   4篇
  1979年   2篇
  1977年   3篇
  1975年   2篇
  1973年   2篇
  1951年   1篇
排序方式: 共有9614条查询结果,搜索用时 0 毫秒
1.
Evidence suggests that transient visual information, such as animations, may be more challenging to learn than static visualizations. However, when a procedural-manipulative task is involved, our evolved embodied cognition seems to reverse this transitory challenge. Hence, for object manipulative tasks, instructional animations may be more suitable than statics. We investigated this argument further by comparing animations with statics using a Lego task shown to university students, by examining three potential moderators of effectiveness: (a) the environment of manipulation (virtual or physical), (b) the quality of visual information (focused or unfocused), and (c) the presence of hands (no hands or with hands). In Experiment 1 we found an advantage of animation over statics, and no differences among the environments. In Experiment 2, we again observed an animation advantage, a small advantage of focused static information compared to unfocused static information, and a positive effect of not showing the hands.  相似文献   
2.
The effects of physical embodiment and physical presence were explored through a survey of 33 experimental works comparing how people interacted with physical robots and virtual agents. A qualitative assessment of the direction of quantitative effects demonstrated that robots were more persuasive and perceived more positively when physically present in a user׳s environment than when digitally-displayed on a screen either as a video feed of the same robot or as a virtual character analog; robots also led to better user performance when they were collocated as opposed to shown via video on a screen. However, participants did not respond differently to physical robots and virtual agents when both were displayed digitally on a screen – suggesting that physical presence, rather than physical embodiment, characterizes people׳s responses to social robots. Implications for understanding psychological response to physical and virtual agents and for methodological design are discussed.  相似文献   
3.
利用三转角方程,对连续梁的内力进行精确的计算,该方法简捷明了,便于应用。  相似文献   
4.
虚拟仪器(VI)将计算机采集测试分析引入到电子测量领域,用数字化和软件技术极大地提高了测量的灵活性。而VI远程测控系统是网络技术、通信技术一计算机虚拟技术结合的产物。远程控制技术能够使操作突破地域的限制,已在网络环境下PⅢ工控机上实现。  相似文献   
5.
以设防烈度为8度的框架厂房为例,详细分析了活荷载不利布置对框架梁、柱内力的影响,得出何时需要考虑活荷载不利布置、何时不需要考虑活荷载不利布置的结论,可供工程设计参考。  相似文献   
6.
A model-based method for fault detection in tapping based on torque and radial forces is proposed. The method allows the identification of faults typical of a tapping operation including axial misalignment, tap runout, tooth breakage both singly and together. The validation experiments have been run on aluminum 356 workpieces for different combinations of process faults. Results have shown that the model predictions are in good agreement with the experimental radial force and torque signals under various fault conditions.  相似文献   
7.
High vertical wave-number modes clearly dominate the internal wave field during the stratification period in Boadella reservoir in northeast Spain. In this period, the extraction of hypolimnetic water, due to summer irrigation, brought the surface level down by 6 m in one month and the epilimnetic water progressively occupied the whole water column. The temperature profile, with the exception of a few meters at the surface layer, presented an almost constant temperature gradient of about 0.7°C/m. The period of the main vertical mode is 24 h with an amplitude of around 1 m. Thermistor chain records and meteorological data allow us to deduce that this mode is, at least, a third vertical mode forced by the wind, which normally has a typical periodicity of 24 h. However, when the wind changes direction from south to north, the circulation cells developed due to this forced nonstationary oscillation are destroyed. When this occurs, the Bulk Richardson number is Rib ~ 1. Similar vertical structures as a response to wind forcing should be expected in similar systems, although this has not been reported in the literature.  相似文献   
8.
HYDRODYNAMIC FORCE ON SMOOTH HORIZONTAL CYLINDER IN UNIFORM OSCILLATORY FLOWHYDRODYNAMICFORCEONSMOOTHHORIZONTALCYLINDERINUNIF...  相似文献   
9.
以8031单片机为核心的泄漏电流测试仪的硬件结构和软件设计。  相似文献   
10.
梁辉 《铜业工程》2002,(4):69-71,76
提出VPN接入设备的体系结构 ,包括系统的应用模型、层次划分和内部详细结构 ,阐述实现VPN的关键技术。  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