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   100篇
  免费   2篇
  国内免费   1篇
电工技术   1篇
综合类   1篇
化学工业   17篇
金属工艺   1篇
机械仪表   2篇
建筑科学   8篇
能源动力   1篇
轻工业   18篇
无线电   4篇
一般工业技术   18篇
冶金工业   16篇
自动化技术   16篇
  2024年   1篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   2篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2014年   2篇
  2013年   3篇
  2012年   6篇
  2011年   5篇
  2010年   10篇
  2009年   2篇
  2008年   4篇
  2007年   2篇
  2006年   9篇
  2005年   6篇
  2004年   6篇
  2003年   7篇
  2002年   1篇
  2001年   11篇
  2000年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1989年   1篇
  1988年   1篇
  1985年   1篇
  1982年   1篇
排序方式: 共有103条查询结果,搜索用时 15 毫秒
1.
In 1996, the author attended a seminar on ethics given by C. West Churchman at the University of California, Berkeley. During that year, the author also interviewed Churchman several times regarding the future direction of information sciences in general and the information systems research field in particular. This article is a compilation of the seminar and the interviews. It is set in the context of both Churchman's earlier and his current views of a global god, good, kindness, and caring. C. West Churchman holds that global ethics should lead to the study and design of information systems to solve large and difficult problems of the humankind such as poverty, crime and disease. His Global Ethical Management (GEM) of information sciences translates into abandoning the current goals and boundaries of the information sciences fields and changing what constitutes valid research to globally ethical endeavors.  相似文献   
2.
Finite element simulations of thin-film composite BAW resonators   总被引:1,自引:0,他引:1  
A finite element method (FEM) formulation is presented for the numerical solution of the electroelastic equations that govern the linear forced vibrations of piezoelectric media. A harmonic time dependence is assumed. Both of the approaches, that of solving the field problem (harmonic analysis) and that of solving the corresponding eigenvalue problem (modal analysis), are described. A FEM software package has been created from scratch. Important aspects central to the efficient implementation of FEM are explained, such as memory management and solving the generalized piezoelectric eigenvalue problem. Algorithms for reducing the required computer memory through optimization of the matrix profile, as well as Lanczos algorithm for the solution of the eigenvalue problem are linked into the software from external numerical libraries. Our FEM software is applied to detailed numerical modeling of thin-film bulk acoustic wave (BAW) composite resonators. Comparison of results from 2D and full 3D simulations of a resonator are presented. In particular, 3D simulations are used to investigate the effect of the top electrode shape on the resonator electrical response. The validity of the modeling technique is demonstrated by comparing the simulated and measured displacement profiles at several frequencies. The results show that useful information on the performance of the thin-film resonators can be obtained even with relatively coarse meshes and, consequently, moderate computational resources  相似文献   
3.
This paper describes the system dimensioning and the radio network planning methodology for a third generation wcdma system. The applicability of each method is demonstrated using examples of likely system scenarios. The challenges of modeling the multiservice environment are described and the implications to the system performance simulations are introduced.  相似文献   
4.
Heat transfer from a rough ice surface to air is a fundamental factor determining the icing rate and ice shape on an object under conditions where the impinging water flux exceeds the icing rate. In order to examine the effect of the roughness characteristics on icing, a boundary-layer model of heat transfer from a front half of a rough circular cylinder is proposed. The model is based on the integral equations of the boundary layer, and predicts the local heat transfer coefficient along the cylinder surface and, subsequently, the overall heat transfer rate. Comparison between the results of the model and the available experimental data for three different roughnesses in the cylinder Reynolds number range 5 × 104 < Re < 4 × 106 show that the model simulates the heat transfer more precisely than the previous formulations used in icing models.  相似文献   
5.
6.
We investigated the stability of differently produced (variables being fermentation time, pH during drying, and cryoprotectant) freeze-dried Bifidobacterium animalis subsp. lactis E-2010 (Bb-12) cells in fruit juice and low-fat milk. In addition, the effect of the food matrix on the acid and bile tolerance of the cells was studied. Cells produced in different ways had comparable stability in milk, whereas in juice, sucrose-protected cells survived better than reconstituted skim milk-protected cells. The acid and bile tolerance was better in cells added to milk compared with those in phosphate buffered saline or juice. Despite good culturable stability in milk the acid and bile tolerance of cells decreased during the storage. Apparently, culturable stability data alone do not give an accurate enough prediction of the probiotic functionality in adverse conditions (e.g. survival in acid and bile stress). When choosing a cryoprotectant for a probiotic also the stability in target food applications should be considered.  相似文献   
7.
Today, any doubts about possibilities of significant profits over the Internet are a distant memory. Such has been the proliferation of Internet-based business on the public network. But electronic commerce has turned out to be more difficult to master than previously assumed. For many, ventures have been less lucrative than expected. The problem is that integrating business models with technology is a multifaceted and largely open question (Shaw, et al. 1997). How do businesses of various sizes and industries actually start their Internet activity and how do their business models change over time? More specifically, how do their different Internet strategies play out? This article is the result of a survey of the Internet strategies and business models of 280 companies that sell products and services on the public network. The results show that electronic commerce has penetrated companies of all sizes. Based on this survey it is apparent that while many companies have participated in electronic commerce for years, their business models are still in their infancy stages.  相似文献   
8.
Friction has been widely used as a measure of slipperiness. However, controversies around friction measurements remain. The purposes of this paper are to summarize understanding about friction measurement related to slipperiness assessment of shoe and floor interface and to define test conditions based on biomechanical observations. In addition, friction mechanisms at shoe and floor interface on dry, liquid and solid contaminated, and on icy surfaces are discussed. It is concluded that static friction measurement, by the traditional use of a drag-type device, is only suitable for dry and clean surfaces, and dynamic and transition friction methods are needed to properly estimate the potential risk on contaminated surfaces. Furthermore, at least some of the conditions at the shoe/floor interface during actual slip accidents should be replicated as test conditions for friction measurements, such as sliding speed, contact pressure and normal force build-up rate.  相似文献   
9.
Conducted 2 studies to examine negative social reactions from the perspective of rejecting peers. The purpose of Study 1 was to test an attributional model of negative peer reactions in which perceptions of responsibility and specific emotions mediate between deviant peer characteristics and negative social responses. The more children perceived atypical classmates to be responsible for their idiosyncrasies, the more anger and less sympathy they reported. Anger increased rejection and decreased social support, whereas sympathy facilitated social support. In Study 2, the effects of responsibility perceptions and affective reactions (annoyance) on social responses were tested with an experimental design. Perceived responsibility influenced liking and support, whereas annoyance affected sympathy, support, and rejection. The results are discussed with respect to intervention programs that would improve children's social acceptance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
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