全文获取类型
收费全文 | 160篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 36篇 |
金属工艺 | 1篇 |
机械仪表 | 9篇 |
建筑科学 | 1篇 |
能源动力 | 5篇 |
轻工业 | 29篇 |
无线电 | 36篇 |
一般工业技术 | 45篇 |
冶金工业 | 2篇 |
原子能技术 | 3篇 |
自动化技术 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 15篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 15篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 18篇 |
2010年 | 4篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
11.
12.
This paper investigates how market participants react to mergers and acquisitions (M&As) involving telecommunications companies. The empirical evidence suggests that such activities convey bad news to the market. This is consistent with the synergy trap hypothesis and extant empirical findings of value‐reducing diversification strategies in recent literature. The evidence also indicates that a cross‐border, rather than a domestic M&A deal, is the main driver of the negative market reaction. Further, our evidence of negative impacts on the bidder's business after an M&A reinforces our main finding that market participants, on average, perceive M&A activities to be detrimental to shareholder value. This suggests that value creation or synergy through an M&A deal is not warranted even though it can generate an increase in size of the firm. 相似文献
13.
Most of the conventional strengthening methods for metals and alloys such as work hardening, precipitation hardening, cause a decrease in ductility and are not very effective for cyclic loading. In this study, a new strengthening method, which is effective for high cycle fatigue, has been developed. The intersections of dislocations in a stainless steel are freezed by very fine martensite particles, which are supposed to suppress dislocation motion at low stress amplitudes. Fatigue life in a high cycle regime increased >60 times, and no decrease in ductility was observed in tensile tests, as compared to a work-hardened stainless steel. 相似文献
14.
15.
Do‐Hyun Kim Young K. Ju Myeong‐Han Kim Sang‐Dae Kim 《The Structural Design of Tall and Special Buildings》2014,23(7):549-562
A buckling‐restrained brace (BRB) is a system with excellent earthquake‐proof performance, but it does not dissipate energies caused by the load from weak earthquakes or winds. A hybrid BRB (H‐BRB), which improved the performance of the BRB, is a type of composite damper system consisting of a BRB and a viscoelastic damper. To explain the wind‐induced vibration control performance of H‐BRB, a 40‐story steel building was designed and used as an analysis model in this study, on the basis of the damping ratio from a structural performance test, using normal steel braces, BRB and H‐BRB. In addition, to evaluate the optimal location of H‐BRB, a time‐history analysis of four models was conducted in the study. For such time‐history analysis, wind‐load data in a 10‐year recurrence interval, which were calculated from the wind tunnel test, were used. The result of the time‐history analysis showed that H‐BRB is effective in improving both the lateral stiffness and serviceability of a building using the existing BRB. It also confirmed that it is most effective to position H‐BRBs mainly on the lower stories. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
16.
17.
Chi‐Hoon Shin Myeong‐Hoon Oh Jae‐Woo Sim Jae‐Chan Jeong Seong Woon Kim 《ETRI Journal》2011,33(3):466-469
As a fine‐grained power gating method for achieving greater power savings, our approach takes advantage of the finite state machine with a datapath (FSMD) characteristic which shows sequential idleness among subcircuits. In an FSMD‐based power gating, while only an active subcircuit is expected to be turned on, more subcircuits should be activated due to the power overhead. To reduce the number of missed opportunities for power savings, we deactivated some of the turned‐on subcircuits by slowing the FSMD down and predicting its behavior. Our microprocessor experiments showed that the power savings are close to the upper bound. 相似文献
18.
Upon conviction for particular traffic offenses, drivers can have their licenses revoked. Drivers who receive license revocation have an opportunity to apply for a sentence reduction, and some of those who apply receive a reduced sanction — license suspension. There may be differences between drivers whose license was revoked as originally sentenced and drivers who received the reduced sanction of license suspension with regard to traffic violations and crashes after driving privileges are restored. This study verified the differences during the follow-up periods of 6, 12, and 18 months using analysis of covariance and the t-test with stratified samples based on the police profiles of approximately 154,000 drivers in South Korea. The study found that drivers in the group whose license had been suspended committed traffic violations and caused traffic crashes less often for all time periods than those whose license had been revoked. However, omitted factors such as the attitude of suspended drivers and exposure to traffic violations and crashes (e.g., driving frequency after license reinstatement), are likely to affect the findings; thus, caution should be exercised when the findings are referenced for policy implications. 相似文献
19.
The field of marketing research in the satellite communication services is still in the early stage of its development. Particularly, in Korean domestic satellite service market, many theoretical and methodological opportunities now exist. In this paper we develop a model, which identifies target markets and promising application services in Korean satellite communication service market. One key contribution of this paper is a modeling approach to the assessment of market potential and priorities of the application services in each Korean industry. We define and estimate the degree of attractiveness for each segmented market which represents the market potential estimated by current usage of terrestrial services and each market segment's willingness to adopt satellite technology. Since all possible satellite application services are not equally important in the market, they should be differentiated in terms of the likelihood of success. We introduce another index prioritizing application services by tying together three important factors affecting Korean satellite service demand. Some marketing implications of model results are also discussed. Finally the findings of our model are compared with those of other similar studies. 相似文献
20.
Seung Won Choi Dong Myeong Shin Joo Sung Lee Ju Min Kim Hyun Wook Jung Jae Chun Hyun 《Korean Journal of Chemical Engineering》2009,26(1):26-31
The sensitivity of two-dimensional isothermal film casting processes to ongoing sinusoidal disturbances has been investigated
by using the frequency response method with transient simulation techniques. Amplitude ratios of state variables such as cross-sectional
area, film width and film thickness at the take-up position with respect to a sinusoidal disturbance show resonant peaks along
the frequency domain. Effects of operating conditions, such as drawdown ratio and aspect ratio, on the process sensitivity
have been examined. Increasing drawdown ratio and decreasing aspect ratio make the system more sensitive to disturbances.
Also, the dichotomous behavior in the sensitivity analysis using viscoelastic Phan-Thien and Tanner fluids has been elucidated.
This frequency response method can be a useful tool to optimally design process systems for better processability and product
quality.
This article is dedicated to Professor Chul Soo Lee in commemoration of his retirement from Department of Chemical and Biological
Engineering of Korea University. 相似文献