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   330篇
  免费   13篇
电工技术   5篇
综合类   1篇
化学工业   46篇
金属工艺   14篇
机械仪表   5篇
建筑科学   25篇
能源动力   3篇
轻工业   25篇
水利工程   1篇
无线电   25篇
一般工业技术   74篇
冶金工业   80篇
原子能技术   7篇
自动化技术   32篇
  2022年   4篇
  2020年   3篇
  2019年   4篇
  2018年   8篇
  2017年   4篇
  2016年   5篇
  2015年   4篇
  2014年   8篇
  2013年   14篇
  2012年   5篇
  2011年   19篇
  2010年   11篇
  2009年   14篇
  2008年   14篇
  2007年   18篇
  2006年   14篇
  2005年   13篇
  2004年   7篇
  2003年   12篇
  2002年   9篇
  2001年   11篇
  2000年   8篇
  1999年   4篇
  1998年   22篇
  1997年   15篇
  1996年   10篇
  1995年   4篇
  1994年   7篇
  1993年   7篇
  1990年   2篇
  1989年   8篇
  1987年   2篇
  1984年   2篇
  1983年   4篇
  1982年   2篇
  1981年   3篇
  1978年   2篇
  1977年   3篇
  1976年   5篇
  1975年   3篇
  1974年   4篇
  1973年   3篇
  1971年   4篇
  1969年   4篇
  1968年   1篇
  1966年   1篇
  1964年   1篇
  1958年   1篇
  1957年   1篇
  1955年   1篇
排序方式: 共有343条查询结果,搜索用时 15 毫秒
1.
Virtual Reality - It is generally accepted that natural environments reduce stress and improve mood. Since access to natural environments is sometimes limited, virtual natural environments,...  相似文献   
2.
Capacity-achieving sequences for the erasure channel   总被引:6,自引:0,他引:6  
This paper starts a systematic study of capacity-achieving (c.a.) sequences of low-density parity-check codes for the erasure channel. We introduce a class A of analytic functions and develop a procedure to obtain degree distributions for the codes. We show various properties of this class which help us to construct new distributions from old ones. We then study certain types of capacity-achieving sequences and introduce new measures for their optimality. For instance, it turns out that the right-regular sequence is c.a. in a much stronger sense than, e.g., the Tornado sequence. This also explains why numerical optimization techniques tend to favor graphs with only one degree of check nodes.  相似文献   
3.
A new and simple method of finite-element grid improvement is presented. The objective is to improve the accuracy of the analysis. The procedure is based on a minimization of the trace of the stiffness matrix. For a broad class of problems this minimization is seen to be equivalent to minimizing the potential energy. The method is illustrated with the classical tapered bar problem examined earlier by Prager and Masur. Identical results are obtained.  相似文献   
4.
5.
The current study investigated the impact of requiring respondents to elaborate on their answers to a biodata measure on mean scores, the validity of the biodata item composites, subgroup mean differences, and correlations with social desirability. Results of this study indicate that elaborated responses result in scores that are much lower than nonelaborated responses to the same items by an independent sample. Despite the lower mean score on elaborated items, it does not appear that elaboration affects the size of the correlation between social desirability and responses to biodata items or that it affects criterion-related validity or subgroup mean differences in a practically significant way. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
The Mössbauer effect measurements of as-ball-milled mechanically alloyed Fe?Zn intermediate phases of Γ (Fe3Zn10) and Γ1 (Fe5Zn21) compositions exhibit characteristic spectra consisting of triplets. Each is characterized with an Fe site with unusually large quadrupole splittings measuring 0.940 mm/s in the cubic Fe?Zn phases and, in addition, three other doublets. In the aged state, both compositions show spectra free of the Fe site with quadrupole splitting of 0.940 mm/s, designated as MSΓFe1 and MSΓ 1Fe1, respectively. This suggests that the metastable states are similar, while their separate transformation paths to stable equilibrium lead to distinct crystal structures. The parameters for the aged states are compared with those reported in the literature for both phases.  相似文献   
7.
All vacuumpummps which use a liquid as a sealing-agent have to take care of their specific demands. In this paper liquid-ring-vacuum-pumps will be short mentioned, because the user is familiar with this pumps and alternative fluids. Using other fluids in other mecanical vacuumpumps are not in operation in the field of the various applications frequently. You will find some ideas for using other fluids which are possibly used in rotary-vane vacuum-pumps to find more consideration in the future.  相似文献   
8.
This article focuses on power analysis attacks because they have received by far the most attention in recent years. They are powerful and can be executed relatively easily. This article provides an introduction to these attacks and discusses countermeasures against them. In particular, we focus on countermeasures that can be implemented at the cell level. This article presents an overview of power analysis attacks, which are based on the measurement of the power consumed by cryptographic ICs, and countermeasures against them.  相似文献   
9.
10.
We briefly discuss variants of (extended) spiking neural P systems that combine features from the areas of membrane computing and spiking neurons. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008  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