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   18221篇
  免费   466篇
  国内免费   21篇
电工技术   243篇
综合类   9篇
化学工业   3594篇
金属工艺   283篇
机械仪表   310篇
建筑科学   1102篇
矿业工程   109篇
能源动力   510篇
轻工业   1383篇
水利工程   158篇
石油天然气   194篇
武器工业   1篇
无线电   1114篇
一般工业技术   2896篇
冶金工业   4174篇
原子能技术   163篇
自动化技术   2465篇
  2022年   138篇
  2021年   214篇
  2020年   170篇
  2019年   223篇
  2018年   266篇
  2017年   260篇
  2016年   319篇
  2015年   238篇
  2014年   380篇
  2013年   1105篇
  2012年   664篇
  2011年   872篇
  2010年   677篇
  2009年   667篇
  2008年   864篇
  2007年   875篇
  2006年   695篇
  2005年   730篇
  2004年   565篇
  2003年   577篇
  2002年   513篇
  2001年   332篇
  2000年   302篇
  1999年   308篇
  1998年   326篇
  1997年   305篇
  1996年   304篇
  1995年   337篇
  1994年   273篇
  1993年   306篇
  1992年   276篇
  1991年   166篇
  1990年   238篇
  1989年   285篇
  1988年   206篇
  1987年   216篇
  1986年   214篇
  1985年   266篇
  1984年   261篇
  1983年   230篇
  1982年   218篇
  1981年   213篇
  1980年   172篇
  1979年   187篇
  1978年   176篇
  1977年   177篇
  1976年   147篇
  1975年   178篇
  1974年   165篇
  1973年   133篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
In this paper, we present a thorough mathematical analysis of the use of neural networks to solve a specific classification problem consisting of a bilinear boundary. The network under consideration is a three-layered perceptron with two hidden neurons having the sigmoid serving as the activation function. The analysis of the hidden space created by the outputs of the hidden neurons will provide results on the network’s capacity to isolate two classes of data in a bilinear fashion, and the importance of the value of the sigmoid parameter is highlighted. We will obtain an explicit analytical function describing the boundary generated by the network, thus providing information on the effect each parameter has on the network’s behavior. Generalizations of the results are obtained with additional neurons, and a theorem concerned with analytical reproducibility of the boundary function is established.  相似文献   
63.
64.
65.
66.
Some students (base group) played the Circuit Game, a 10-level computer-based learning activity intended to help students learn how electrical circuits work. Other students (competition group) played the same game but with competition features added - including a score bar showing performance on each level, the opportunity to earn one ticket per level if a performance criterion is met, and the opportunity to win a prize based on the number of tickets earned. On a retention test given after the game, the competition group remembered significantly more than the base group (d = 0.47). On an embedded transfer test constituting the final level of the game, the groups did not differ significantly. However, on the transfer test there was a significant gender by group interaction in which men performed worse in the competition group than the base group (d = −0.54) and women performed better in the competition group than the base group (d = 0.24). Overall, adding game-like features to a computer-based learning activity caused students to pay attention to game details but did not motivate students - particularly men - to learn more deeply.  相似文献   
67.
Semiconductor wafer fabrication system (SWFS) is the most complex and capital-intensive phase in the entire semiconductor manufacturing cycle. With characteristics of re-entrant processing routes, equipment uncertainty, product diversity and improving technologies, great challenges are presented in SWFS’s modeling, scheduling and simulation. To implement efficient production control, this paper provides a timed extended object-oriented Petri nets (TEOPNs) approach to performance modeling, real-timed dispatching and simulation of SWFSs. The TEOPNs models are constructed in a hierarchy to accord with the real-world SWFS’s organization, and a new type of signal place is added into the TEOPNs to respond the dynamic states of all processing facilities. A novel autonomy and coordination-based real-time dispatching mechanism (A&C-RDM) is developed in this paper, which executes under the support of the TEOPNs-based hybrid real-time dispatching control system (HRDCS). Owning to the ability of gathering dynamic real-time information of all production facilities and WIP products, the HRDCS can make adaptive dispatching decisions according to the local and global real-time processing status. Two sets of key elements of real-time dispatching, i.e. the state thresholds and dispatching rules, are defined in the HRDCS so that the A&C-RDM can integrate different types of dispatching rules. A set of simulation experiments prove the efficiency of the proposed modeling and dispatching algorithm. In summary, the proposed TEOPNs, HRDCS and A&C-RDM form the cornerstones of a real-time dispatching simulation prototype of SWFS, and the work described in this paper carries out an advanced integrated “modeling–dispatching–simulation” methodology.  相似文献   
68.
This paper introduces the concept of the temporal think tank™ (T3™), a temporary in-house research center, based on case studies with a highly automated global manufacturer and in various small-sized manufacture (SME's). The T3™ brings individuals from across the organization together in a team setting in which they are charged to look at the future, develop their decision-making skills, and use entrepreneurial thinking to incubate new processes and/or products. After an appropriate time in the temporal think tank™, the individuals are asked to return to their regular positions to implement the best practices and best ideas and doing so spur the organization forward. At intervals, the temporal think tanks™ can be reconvened, or reconstituted with new participants. This approach prepares technology champions for the SME, who can return to the organization with a fresh outlook and renewed energy to keep the enterprise at the peak of efficiency and effectiveness.  相似文献   
69.
70.
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