全文获取类型
收费全文 | 309篇 |
免费 | 36篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 58篇 |
金属工艺 | 6篇 |
机械仪表 | 6篇 |
建筑科学 | 17篇 |
能源动力 | 11篇 |
轻工业 | 26篇 |
水利工程 | 3篇 |
无线电 | 76篇 |
一般工业技术 | 78篇 |
冶金工业 | 26篇 |
自动化技术 | 36篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 11篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 21篇 |
2012年 | 28篇 |
2011年 | 18篇 |
2010年 | 15篇 |
2009年 | 19篇 |
2008年 | 22篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 14篇 |
2004年 | 7篇 |
2003年 | 12篇 |
2002年 | 7篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有349条查询结果,搜索用时 187 毫秒
51.
Shou Qing Wang Robert L. K. Tiong Seng Kiong Ting David Ashley 《Canadian Metallurgical Quarterly》1999,125(3):190-197
The reforms introduced by the International Monetary Fund in Asia will bring about greater transparency in the economies and innovative approaches in procurement of contracts. China has taken new initiatives in build, operate, and transfer (BOT) infrastructure projects. It is, however, important to analyze and manage the unique or critical risks associated with China's BOT projects. This is especially so after new policies were introduced in late 1996 when the first state-approved BOT project, the U.S. $650,000,000 2 × 350 MW coal-fired Laibin B Power Plant (Laibin B), was awarded. These include the competitive tendering process and 100% foreign ownership of the operating company. An international survey on risk management of BOT projects in China was conducted to seek the views of practitioners. The overall objectives of the survey are (1) to identify the unique or critical risks associated with China's BOT projects; (2) to evaluate the effectiveness of measures for mitigating these risks; (3) to examine the key contract clauses used in Laibin B's concession agreement; and (4) to provide a risk management framework for investing in future BOT projects in China. This paper discusses the adequacy of key contract clauses in Laibin B's concession agreement related to the political and force majeure risks in China, from the perspective of foreign developers, lawyers, and lenders. The contract clauses discussed include changes in law, corruption, delay in approval, expropriation, and force majeure. Areas for further improvement in the clauses are suggested. 相似文献
52.
Armen H. Zemanian Yaw‐Ruey Chan Victor A. Chang 《International Journal of Circuit Theory and Applications》1999,27(3):293-310
Proposed herein is a new method for solving arbitrary networks of nonuniform transmission ladders and lines. Two cases are considered, the first occurring when all circuit elements are purely resistive and in general non‐linear and the second occurring when they are linear but in general have both resistive and reactive components. The first case arises for example when the DC operating point of a non‐linear interconnection network is to be determined, and the second arises for example when the transient behaviour of a network of linear, possibly nonuniform, RLCG transmission lines and ladders is desired. Moreover, our method eliminates the voltages at internal nodes of a ladder and only treats nodes at which three or more ladders or lines meet or just one ladder or line terminates. The internal node voltages are obtained at the end of our procedure with very little additional computation. This provides a computational advantage, which may save orders of magnitude in computation time. A similar facility accrues to cascades of distributed lines and ladders. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
53.
Huei‐Yaw Ke 《Quality and Reliability Engineering International》1999,15(5):363-368
Today's vehicle customers' demand for better quality and reliability is increasing. A typical reliability requirement is that of a lower bound on product reliability at a pre‐specified design life target (called the ‘bogey’) with specified confidence. For the purpose of reliability verification, one way to verify conformance to the requirements is to perform a test and terminate it after running for a certain period of time, cycles or mileage and to make a decision according to the test criterion. The approach presented in this paper specifically addresses the means to design tests that satisfy these important requirements and objectives. All the mathematical derivations are primarily based on a component life distribution that is assumed to follow a Weibull distribution with an assumed value of the shape parameter. By the proposed approach, only the GEM table (derived from the exponential case) is required. The test engineer has the option of trading off between the quantity of samples and the test bogey ratio (the test length relative to the bogey) so as to meet the specific objectives under the constraints. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
54.
Zhizhao Che Teck Neng Wong Nam-Trung Nguyen 《International Journal of Heat and Mass Transfer》2012,55(7-8):1947-1956
Plug flow can significantly enhance heat transfer in microchannels as compared to single phase flow. Using an analytical model of flow field, heat transfer in plug flow is investigated. The constant-surface-temperature boundary condition is considered. Three stages of the heat transfer in plugs are identified: (i) development of thermal boundary layer; (ii) advection of heated/fresh fluid in the plug; and (iii) thermally fully developed flow. Due to the transport of heated fluid and fresh fluid within the plug by the recirculating flow, oscillations of the Nusselt number at high Peclet numbers are observed and explained. The effects of the Peclet number and the plug length on the heat transfer process are evaluated. The results show that short plugs are preferable to long plugs since short plugs result in high Nusselt numbers and high heat transfer indices. 相似文献
55.
Taiwan has been promoting public-private-partnership (PPP) projects in the wastewater treatment sector with the aim of improving its sustainable environment and increasing its wastewater treatment rate. The Nanzih Wastewater Treatment Project is the first PPP application in Taiwan’s wastewater treatment sector. It provides important experiences and lessons for both the public and private sectors. This paper presents a detailed study of its tender process, concession agreement, financial structure, payment mechanism, and risk management. It explains the key features of the project and provides conclusive findings on the lessons learned. These observations should be useful for practitioners and academia who are interested in the development of future PPP wastewater treatment projects in Taiwan. 相似文献
56.
Samuel Yaw Danso 《Urban Water Journal》2017,14(5):539-545
Annually, rivers close to communities within Sekondi-Takoradi Metropolis overflow their banks, especially during the rainy seasons; displacing thousands of residents. Despite this, little is known about the coping strategies used by the residents when flooding occurs. Using mixed method, this article examines the coping strategies employed by households within three communities at risk. Two hundred and seven heads of households residing in Eshiem, Kansawurodo and Whindo were systematically selected to fill in questionnaires, while six key informants comprising chiefs and representatives of flood management institutions were chosen for in-depth interviews. The findings suggest that the commonest coping strategies adopted by residents in all the communities were: temporary vacation of homes, transfer of relevant properties to neighbors and building of flood steps. However, the coping strategies employed by the residents varied by communities, although the majority of them resorted to self-sustaining mechanisms in restoring their losses. 相似文献
57.
58.
Phase change materials have great potential for data storage applications owing to the large optical and electrical contrasts during rapid switching between their amorphous and crystalline phases. Hence, significant efforts have been made to identify and understand their unique characteristics. Here, we report a distinct optical characteristic of phase change materials and explain its presence via electronic structure considerations. The optical response of phase change materials and non-phase change materials are investigated via experiments. Annealing them from room temperature to 400 °C, we observed that Sb2Te3 exhibits phase change properties but not Bi2Te3, despite their similar crystal structures. A red shift in the absorption spectra is observed for crystalline Sb2Te3 with respect to its amorphous phase. From first-principles calculations, we explain that the delocalized electrons in crystalline Sb2Te3 films are responsible for this red shift. In contrast, the electrons in Bi2Te3 films are localized and no absorption red shift is observed. The absorption red shift is also observed in other phase change materials from the GeTe–Sb2Te3 pseudo-binary system; hence the detection of such a red shift may be used for identifying potential phase change materials. 相似文献
59.
60.