全文获取类型
收费全文 | 121篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 24篇 |
金属工艺 | 5篇 |
机械仪表 | 3篇 |
建筑科学 | 12篇 |
能源动力 | 7篇 |
轻工业 | 11篇 |
无线电 | 10篇 |
一般工业技术 | 24篇 |
冶金工业 | 11篇 |
自动化技术 | 18篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1973年 | 1篇 |
1971年 | 3篇 |
排序方式: 共有125条查询结果,搜索用时 0 毫秒
31.
A fuzzy multi-objective covering-based vehicle location model for emergency services 总被引:1,自引:0,他引:1
Timeliness is one of the most important objectives that reflect the quality of emergency services such as ambulance and firefighting systems. To provide timeliness, system administrators may increase the number of service vehicles available. Unfortunately, increasing the number of vehicles is generally impossible due to capital constraints. In such a case, the efficient deployment of emergency service vehicles becomes a crucial issue. In this paper, a multi-objective covering-based emergency vehicle location model is proposed. The objectives considered in the model are maximization of the population covered by one vehicle, maximization of the population with backup coverage and increasing the service level by minimizing the total travel distance from locations at a distance bigger than a prespecified distance standard for all zones. Model applications with different solution approaches such as lexicographic linear programming and fuzzy goal programming (FGP) are provided through numerical illustrations to demonstrate the applicability of the model. Numerical results indicate that the model generates satisfactory solutions at an acceptable achievement level of desired goals. 相似文献
32.
33.
Wireless Information Delivery Environment (WIDE) is a distributed data dissemination system, which uses IEEE 802.11b technology.
WIDE aims to deliver popular information services to registered mobile clients in WLAN hot spots. Data delivery is based on
broadcasting and multicasting to provide scalability and efficient use of the wireless channel. Reliability is assured with
a combination of Forward Error Correction (FEC), data carousel, and ARQ techniques. This paper presents the proposed system
architecture with the details of reliable and secure data dissemination mechanisms. Functional evaluation of the proposed
system and mechanisms on the implemented prototype are also included in this paper.
This work is partially supported by the State Planning Organization of Turkey under the grant number 98K120890, and by the
Bogazici University Research Projects under the grant number 02A105D. A shorter version of this paper was presented in WONS
2004 in Madonna di Campiglio, Italy.
Sinan Isik received the B.S. degree in mathematics, and the M.S. degree in computer engineering from Bogazici University, Istanbul,
Turkey in 1999 and 2003, respectively. He is currently working toward for the PhD degree in computer engineering in the same
university. His research interests include wireless communication, wireless ad-hoc networks and wireless sensor networks.
Mehmet Yunus Donmez received his B.S. degree from Mathematics Department in 1999 and his MS degree from the Computer Engineering Department of
Bogazici University, Istanbul, Turkey in 2003. He is currently studying for his PhD degree in computer engineering. His research
interests are wireless networks and content delivery systems, along with QoS, multicasting and fairness issues in MANETs.
Cem Ersoy received his BS and MS degrees in electrical engineering from Bogazici University, Istanbul, in 1984 and 1986, respectively.
He worked as an R&D engineer in NETAS A.S. between 1984 and 1986. He received his PhD in electrical engineering from Polytechnic
University, Brooklyn, New York in 1992. Currently, he is a professor and department head in the Computer Engineering Department
of Bogazici University. His research interests include performance evaluation and topological design of communication networks,
wireless communications and mobile applications. Dr. Ersoy is a Senior Member of IEEE. 相似文献
34.
Hamed Dehghanpour Baruj Iklim Bozkaya Betul Canimkurbey Ahmet Tarik Isik Farzan Shabani Savas Delikanli Sushant Shendre Onur Erdem Furkan Isik Hilmi Volkan Demir 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(29):2206582
Semiconductor colloidal quantum wells (CQWs) provide anisotropic emission behavior originating from their anisotropic optical transition dipole moments (TDMs). Here, solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) of a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that collectively enable a supreme level of IP TDMs at 92% in the ensemble emission are shown. This significantly enhances the outcoupling efficiency from 22% (of standard randomly-oriented emitters) to 34% (of face-down oriented emitters) in the LED. As a result, the external quantum efficiency reaches a record high level of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with the hybrid organic-inorganic evaporation-based CQW-LEDs and all other best solution-processed LEDs. This SAM-CQW-LED architecture allows for a high maximum brightness of 19,800 cd m−2 with a long operational lifetime of 247 h at 100 cd m−2 as well as a stable saturated deep-red emission (651 nm) with a low turn-on voltage of 1.7 eV at a current density of 1 mA cm−2 and a high J90 of 99.58 mA cm−2. These findings indicate the effectiveness of oriented self-assembly of CQWs as an electrically-driven emissive layer in improving outcoupling and external quantum efficiencies in the CQW-LEDs. 相似文献
35.
Rolland J O'Daniel J Akcay C DeLemos T Lee KS Cheong KI Clarkson E Chakrabarti R Ferris R 《Journal of the Optical Society of America. A, Optics, image science, and vision》2005,22(6):1132-1142
Optimization of an optical coherence imaging (OCI) system on the basis of task performance is a challenging undertaking. We present a mathematical framework based on task performance that uses statistical decision theory for the optimization and assessment of such a system. Specifically, we apply the framework to a relatively simple OCI system combined with a specimen model for a detection task and a resolution task. We consider three theoretical Gaussian sources of coherence lengths of 2, 20, and 40 microm. For each of these coherence lengths we establish a benchmark performance that specifies the smallest change in index of refraction that can be detected by the system. We also quantify the dependence of the resolution performance on the specimen model being imaged. 相似文献
36.
Certain network functions of ladder networks are formulated by using continuants, and closed-form formulas are given for their sensitivities. 相似文献
37.
Conditions under which a modified form of Tellegen's theorem is possible in considering interreciprocity are stated. 相似文献
38.
Thermoluminescence (TL) measurements in Tl2InGaSe4-layered single crystals have been carried out in the temperature range of 10–200 K at various heating rates (0.2–1.0 K s?1) to get information about the characteristics of traps. Two TL overlapping glow peaks related to defect levels have been clearly observed. Thermal cleaning procedure was applied to the glow curves to separate overlapped peaks. Initial rise, peak shape, and heating rate methods were used to calculate the activation energies of the revealed traps. The energy values of 5 and 28 meV were evaluated for the peaks observed at low and high temperatures, respectively. Moreover, heating rate dependence and traps distribution analysis were also investigated on the curve obtained after thermal cleaning. The activation energies of the distributed trapping centers were found to be increasing from 29 to 151 meV with increasing the illumination temperature from 42 to 80 K. 相似文献
39.
Turgut A. Isik N. S. Kasapoglu K. Ercin 《Bulletin of Engineering Geology and the Environment》2017,76(1):383-392
Bulletin of Engineering Geology and the Environment - This study aimed to investigate the effects of magnitude, focal depth and the thickness of the overburden material on the length of the surface... 相似文献
40.
Nazan Demir Hayrunnisa Nadaroglu Yasar Demir Ceyhun Isik Esen Taskin Ahmet Adiguzel Medine Gulluce 《European Food Research and Technology》2014,239(1):127-135
An alkaline pectin lyase (PNL) (EC 4.2.2.10) secreted by Brevibacillus borstelensis P35 (GenBank Number: FJ417406) was purified using ammonium sulfate fractionation, anion exchange chromatography on DEAE-cellulose and gel filtration chromatography on Sephadex G-150. The pH and temperature optima of the enzyme were found to be 8.0 and 60 °C. The enzyme does not loose activity up to 60 °C if exposed for 1 h. The values of K m and V max of the enzyme were 0.625 mg/mL and 126.32 s?1, respectively. The molecular weight was found to be 36 ± 01 kDa. The presence of 10 mM concentration of Ca2+, Cu2+, Mn2+, Mg2+, Zn2+, Hg2+, Fe2+ and EDTA, l-cystein, ascorbic acid significantly enhanced the PNL of the purified enzyme. In the course of the laboratory trials, it was demonstrated that PNL from B. borstelensis (P35) could be successfully applied to the production and clarification of fruit juice and oil extraction. 相似文献