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   279349篇
  免费   3041篇
  国内免费   1308篇
电工技术   4814篇
综合类   521篇
化学工业   40445篇
金属工艺   11139篇
机械仪表   8451篇
建筑科学   6449篇
矿业工程   1585篇
能源动力   6990篇
轻工业   22566篇
水利工程   3043篇
石油天然气   5785篇
武器工业   43篇
无线电   33587篇
一般工业技术   56597篇
冶金工业   51227篇
原子能技术   7497篇
自动化技术   22959篇
  2021年   2164篇
  2019年   2072篇
  2018年   3586篇
  2017年   3675篇
  2016年   3910篇
  2015年   2492篇
  2014年   4363篇
  2013年   11996篇
  2012年   7084篇
  2011年   9736篇
  2010年   7553篇
  2009年   8768篇
  2008年   9120篇
  2007年   9167篇
  2006年   7824篇
  2005年   7278篇
  2004年   7215篇
  2003年   6999篇
  2002年   6731篇
  2001年   6857篇
  2000年   6499篇
  1999年   6786篇
  1998年   16418篇
  1997年   11663篇
  1996年   8954篇
  1995年   6877篇
  1994年   6044篇
  1993年   6081篇
  1992年   4412篇
  1991年   4196篇
  1990年   4083篇
  1989年   4063篇
  1988年   3765篇
  1987年   3403篇
  1986年   3400篇
  1985年   3767篇
  1984年   3475篇
  1983年   3229篇
  1982年   3040篇
  1981年   3051篇
  1980年   3046篇
  1979年   2844篇
  1978年   2889篇
  1977年   3166篇
  1976年   4131篇
  1975年   2430篇
  1974年   2397篇
  1973年   2408篇
  1972年   2032篇
  1971年   1788篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Through a series of model tests of five scales for 2-D free hydraulic jump, the da-ta of fluctuating pressure acting on the floor level within the hydraulic jump were obtained. Dur-ing the experiments, Froude number varied from 2.94 to 8.61, and Reynolds number rangedfrom 2×10~4 to 6×10~5. Experiment results indicate that the amplitude scale of fluctuating pres-sure is the length scale of model, i. e. P'=L, which agrees with gravity similarity law: Thefrequency scale of the fluctuating pressure is a unity i. e., f=1, which does not satisfy thegravity similarity law.  相似文献   
992.
The interstitial assemblages of the River Rhine were studied in the Rhinau sector (France). The studied area is located in aVegulated channel of the river, controlled by a hydroelectric dam. Twenty stations were sampled in September 1988. Ten litres of interstitial water were pumped at 50 cm depth in each station using the Bou-Rouch technique. Interstitial waters were poorly oxygenated and the hyporheic fauna had three major characteristics: (1) microcrustaceans were dominant, (2) the insects were rare and (3) the stygofauna was absent. The richest stations were well oxygenated and did not correspond to any particular geomorphological features. These findings contrast with the situation observed on other large European rivers (Rhǒne, Danube) where the interstitial assemblages appear to be locally more diversified and rich in stygofauna.  相似文献   
993.
994.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 1, p. 32, January, 1992.  相似文献   
995.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 10, pp. 8–10, October, 1992.  相似文献   
996.
997.
998.
999.
1000.
Face to virtual face   总被引:1,自引:0,他引:1  
The first virtual humans appeared in the early 1980s in such films as Dreamflight (1982) and The Juggler (1982). Pioneering work in the ensuing period focused on realistic appearance in the simulation of virtual humans. In the 1990s, the emphasis has shifted to real-time animation and interaction in virtual worlds. Virtual humans have begun to inhabit virtual worlds and so have we. To prepare our place in the virtual world we first develop techniques for the automatic representation of a human face capable of being animated in real time using both video and audio input. The objective is for one's representative to look, talk, and behave like oneself in the virtual world. Furthermore, the virtual inhabitants of this world should be able to see our avatars and to react to what we say and to the emotions we convey. We sketch an overview of the problems related to the analysis and synthesis of face-to-virtual-face communication in a virtual world. We describe different components of our system for real-time interaction and communication between a cloned face representing a real person and an autonomous virtual face. It provides an insight into the various problems and gives particular solutions adopted in reconstructing a virtual clone capable of reproducing the shape and movements of the real person's face. It includes the analysis of the facial expression and speech of the cloned face, which can be used to elicit a response from the autonomous virtual human with both verbal and nonverbal facial movements synchronized with the audio voice  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