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   188篇
  免费   6篇
化学工业   33篇
金属工艺   1篇
机械仪表   5篇
建筑科学   17篇
能源动力   1篇
轻工业   26篇
水利工程   3篇
无线电   13篇
一般工业技术   11篇
冶金工业   66篇
原子能技术   2篇
自动化技术   16篇
  2021年   3篇
  2019年   1篇
  2018年   3篇
  2017年   4篇
  2015年   1篇
  2014年   5篇
  2013年   10篇
  2012年   12篇
  2011年   2篇
  2010年   1篇
  2009年   5篇
  2008年   4篇
  2007年   4篇
  2006年   2篇
  2005年   2篇
  2003年   5篇
  2002年   4篇
  2001年   1篇
  2000年   3篇
  1999年   2篇
  1998年   17篇
  1997年   14篇
  1996年   5篇
  1995年   2篇
  1994年   7篇
  1993年   4篇
  1992年   4篇
  1991年   3篇
  1990年   5篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   6篇
  1985年   1篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   6篇
  1980年   3篇
  1979年   3篇
  1978年   1篇
  1977年   4篇
  1976年   7篇
  1975年   1篇
  1973年   4篇
  1972年   4篇
  1971年   3篇
  1966年   1篇
  1944年   1篇
  1927年   1篇
排序方式: 共有194条查询结果,搜索用时 0 毫秒
1.
In this time of flat, team-based and technology-enabled organizations the effectiveness of communication and team leadership practices will be more important than ever before. Therefore, we believe that some of the earlier, time-tested classic works on group dynamics and leadership are worthy of re-reading. We are particularly impressed by how relevant one of the oldest classics, Benne and Sheats' (1948) article on functional roles of group members, remains to this day.  相似文献   
2.
The effect of a range of organic additives on the thermal stability of poly(vinyl chloride), both with and without a chloroparaffin extender, was studied using a number of experimental techniques. Of the additives used the best overall balance was provided by pentaerythritol, which increased stability when the extender was present and had no effect when it was absent. The congo red test emerged as the most suitable technique, being consistent and inexpensive and able to screen several additives simultaneously. Isothermal differential thermal analysis correlated with the congo red test but required more expensive equipment, was time-consuming and demanded good mixing of the poly(vinyl chloride) compound to give reproducible results. Thermogravimetry was not sufficiently sensitive and the heat stability test was the least useful of all.  相似文献   
3.
Drug discovery today requires the focused use of lab automation and other resources in Combinatorial Chemistry and High-Throughput Screening (HTS). The ultimate value of both Combinatorial Chemistry and High-Throughput Screening technologies and the lasting impact they will have on the drug discovery process is a chapter that remains to be written. Central to their success and impact is how well they are integrated with each other and with the rest of Drug Discovery - and Informatics is key to this success. This presentation will focus on Informatics and the integration of the disciplines of combinatorial chemistry and HTS in modern drug discovery. Examples from experiences at Neurogen from the last five years will be described.  相似文献   
4.
High resolution CHIRP (Compressed High Intensity Radar Pulse) seismic profiles reveal the presence of two lacustrine sediment drifts located in Lake Champlain's Juniper Deep. Both drifts are positive features composed of highly laminated sediments. Drift B sits on a basement high while Drift A is built on a trough-filling acoustically-transparent sediment unit inferred to be a mass-transport event. These drifts are oriented approximately north–south and are parallel to a steep ridge along the eastern shore of the basin. Drift A, located at the bottom of a structural trough, is classified as a confined, elongate drift that transitions northward to become a system of upslope asymmetric mudwaves. Drift B is perched atop a structural high to the west of Drift A and is classified as a detached elongate drift. Bottom current depositional control was investigated using Acoustic Doppler Current Profilers (ADCPs) located across Drift A. Sediment cores were taken at the crest and at the edges of the Drift A and were dated. Drift source, deposition, and evolution show that these drifts are formed by a water column shear with the highest deposition occurring along its crest and western flank and began developing circa 8700–8800 year BP.  相似文献   
5.
Survey results provide a preliminary assessment of the relative contribution of a range of tactical business strategies to innovation performance by firms in the Australian construction industry. Over 1,300 firms were surveyed in 2004, resulting in a response rate of 29%. Respondents were classified as high, medium or low innovators according to an innovation index based on the novelty and impact of their innovations and their adoption of listed technological and organizational advances. The relative significance of 23 business strategies concerning (1) employees; (2) marketing; (3) technology; (4) knowledge; and (5) relationships was examined by determining the extent to which they distinguished high innovators from low innovators. The individual business strategies that most strongly distinguished high innovators were (1) investing in R&D; (2) participating in partnering and alliances on projects; (3) ensuring project learnings are transferred into continuous business processes; (4) monitoring international best practice; and (5) recruiting new graduates. Of the five types of strategies assessed, marketing strategies were the least significant in supporting innovation. The results provide practical guidance to managers in project-based industries wishing to improve their innovation performance.  相似文献   
6.
The use of a fluidised bed reactor and a conductivity cell provide a technique for the study of degradation of PVC with greatly increased sensitivity. The kinetics of the reaction may be studied at 350 K and for small (1%) amounts of degradation. The effects of diffusion within the particles may be distinguished from that of diffusion in the surrounding atmosphere. The influence of temperature and particle size and sintering were examined. The catalytic effect of HCl was confirmed and an apparent activation energy of 29 kcal mol?1 was observed.  相似文献   
7.
We theoretically compare the scattering and near field of nanoparticles from different types of materials, each characterized by specific optical properties that determine the interaction with light: metals with their free charge carriers giving rise to plasmon resonances, dielectrics showing zero absorption in wide wavelength ranges, and semiconductors combining the two beforehand mentioned properties plus a band gap. Our simulations are based on Mie theory and on full 3D calculations of Maxwell’s equations with the finite element method. Scattering and absorption cross sections, their division into the different order electric and magnetic modes, electromagnetic near field distributions around the nanoparticles at various wavelengths as well as angular distributions of the scattered light were investigated. The combined information from these calculations will give guidelines for choosing adequate nanoparticles when aiming at certain scattering properties. With a special focus on the integration into thin film solar cells, we will evaluate our results.  相似文献   
8.
This paper describes work undertaken as part of a three-stranded project. The main deliverable will be a suite of software tools, classes and components, as well as teaching resources and methodologies to facilitate the production of intelligent multimedia tutoring systems.

The three strands of this project explore differing aspects of multimedia, and while they stand as separate pieces of work in their own right, they also form the building blocks of the final deliverable, which is an intelligent tutoring system. Intermediate outcomes include a multimedia shell and the Manley Group Demonstrator.

This paper focuses on the design and development of the “true multimedia” demonstrator that has now reached the stage of being a fairly mature prototype. It is used commercially by a communications company to illustrate the varying levels of sophistication which can be achieved in presentation systems and provides an exemplar demonstrating the varying degrees of functionality possible using current technology. The main requirement in the design and implementation has been usability both for end users and content developers.

Real-time control of the multimedia devices is achieved using sophisticated software which is tightly integrated with dedicated control hardware. The software can be used to produce canned presentations or highly interactive systems.

The system is installed in a dedicated presentation suite, thus allowing the true nature of multimedia to be demonstrated. It is scaleable in that it can be used to produce stand-alone portable solutions, highly interactive touch-screen controlled applications or complete multi-device high end presentations. This is achieved using the appropriate combination of software tools and hardware for a specific application.

Macromedia Director is used to produce visual and creative material for the system, while Macromedia Authorware can be used to provide interactivity. © 1997 Elsevier Science B.V.  相似文献   

9.
Although the use of technology in the K12 classroom has been shown to have a positive impact, research on the use of open education resources (OER) is relatively limited, especially research focusing on low‐achieving students. The present study examines the relationship between usage of Algebra Nation, a self‐guided system that provided instructional videos and practice problems, and the performance of students who had failed the state‐administered Algebra I end‐of‐course (EOC) assessment the previous year. Indicators of usage of Algebra Nation consisted of logins, video views, and practice questions answered. Path analyses and logistic regressions were used to evaluate relationships between usage indicators and algebra scores, controlling for number of absences, free/reduced lunch eligibility, Hispanic/Latino origin, race, and gender. The results indicate that higher levels of logins, video views, and practice questions answered were related to higher scores when the students re‐took the assessment. Logins and practice questions were also related to increases in odds of passing the Algebra I EOC assessment, but not video views. The results suggest that there may be benefits to technology use in the form of an OER adopted by students and teachers on an informal basis and link self‐regulated learning strategies to student achievement.  相似文献   
10.
Some elements of writing technical papers for publication within a technical corporate environment are discussed. Major incentives and barriers to publishing are outlined, and suggestions are offered for addressing the barriers from both the authors' viewpoint and that of management. A workshop designed to encourage technical professionals to write for publication is described  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