全文获取类型
收费全文 | 2058篇 |
免费 | 145篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 28篇 |
综合类 | 5篇 |
化学工业 | 558篇 |
金属工艺 | 27篇 |
机械仪表 | 87篇 |
建筑科学 | 55篇 |
矿业工程 | 2篇 |
能源动力 | 174篇 |
轻工业 | 206篇 |
水利工程 | 14篇 |
石油天然气 | 32篇 |
无线电 | 220篇 |
一般工业技术 | 403篇 |
冶金工业 | 54篇 |
原子能技术 | 17篇 |
自动化技术 | 332篇 |
出版年
2024年 | 6篇 |
2023年 | 67篇 |
2022年 | 132篇 |
2021年 | 157篇 |
2020年 | 114篇 |
2019年 | 122篇 |
2018年 | 130篇 |
2017年 | 105篇 |
2016年 | 135篇 |
2015年 | 78篇 |
2014年 | 135篇 |
2013年 | 194篇 |
2012年 | 111篇 |
2011年 | 115篇 |
2010年 | 86篇 |
2009年 | 88篇 |
2008年 | 55篇 |
2007年 | 50篇 |
2006年 | 51篇 |
2005年 | 30篇 |
2004年 | 32篇 |
2003年 | 21篇 |
2002年 | 19篇 |
2001年 | 19篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 21篇 |
1997年 | 11篇 |
1996年 | 16篇 |
1995年 | 7篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有2214条查询结果,搜索用时 15 毫秒
81.
Energy consumption for developing countries is sharply increasing due to the higher economic growth due to industrialisation along with population growth and urbanisation. The increasing demand of energy leads to global energy crisis. Selecting the best energy technology and conservation requires both quantitative and qualitative evaluation criteria. The fuzzy set-based approach is one of the well-known theories to handle fuzziness, uncertainty in decision-making and vagueness of information. This paper proposes a new method of intuitionistic fuzzy analytic hierarchy process (IF-AHP) to deal with the uncertainty in decision-making. The new IF-AHP is applied to establish a preference in the sustainable energy planning decision-making problem. Three decision-makers attached with Malaysian government agencies were interviewed to provide linguistic judgement prior to analysing with the new IF-AHP. Nuclear energy has been decided as the best alternative in energy planning which provides the highest weight among all the seven alternatives. 相似文献
82.
Hameed Al‐Attar Aula A Alwattar Athir Haddad Bassil A Abdullah Peter Quayle Stephen G Yeates 《Polymer International》2021,70(1):51-58
In this work we demonstrate, for the first time, the use of polylactic acid (PLA) as a biodegradable host matrix for the construction of the active emissive layer of organic light‐emitting diode (OLED) devices for potential use in bioelectronics. In this preliminary study, we report a robust synthesis of two fluorescent PLA derivatives, pyrene‐PLA ( AH10 ) and perylene‐PLA ( AH11 ). These materials were prepared by the ring opening polymerisation of l ‐lactide with hydroxyalkyl‐pyrene and hydroxyalkyl‐perylene derivatives using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as catalyst. OLEDs were fabricated from these materials using a simple device architecture involving a solution‐processed single‐emitting layer in the configuration ITO/PEDOT:PSS/PVK:OXD‐7 (35%): AH10 or AH11 (20%)/TPBi/LiF/Al (ITO, indium tin oxide; PEDOT:PSS, poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid); PVK, poly(vinylcarbazole); OXD‐7, (1,3‐phenylene)‐bis‐[5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole]; TPBi, 2,2′,2″‐(1,3,5‐benzenetriyl)tris(1‐phenyl‐1H‐benzimidazole)). The turn‐on voltage for the perylene OLED at 10 cd m–2 was around 6 V with a maximum brightness of 1200 cd m–2 at 13 V. The corresponding external quantum efficiency and device current efficiency were 1.5% and 2.8 cd A–1 respectively. In summary, this study provides proof of principle that OLEDs can be constructed from PLA, a readily available and renewable bio‐source. © 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry. 相似文献
83.
84.
M. J. Ghoushji Reza Alebrahim R. Zulkifli A. B. Sulong S. Abdullah C. H. Azhari 《Iranian Polymer Journal》2018,27(8):563-575
Using metallic materials in automotive structures increases weight, fuel consumption and cost, therefore, certain trends have begun to use lightweight and cheaper materials. Fibre composites are used in automotive applications because they are stiff, lightweight and stronger than bulk material, as well as they have a comparable energy-absorbing capacity to that of metallic materials. The aim of this study is to investigate the potentials in natural ramie/bio-epoxy composite in crash energy absorption applications. Cubic specimens consisted of 12, 24 and 30 plies of ramie/bio-epoxy laminates with 50, 80 and 120 mm long which were prepared by hand layup method. Static axial compression load was then applied and the energy-absorbing capability of the ramie/epoxy composite was evaluated. The crashworthiness characteristics of the composite tubes were evaluated by measuring the average and peak crushing load, specific energy absorption, total absorbed energy and crush force efficiency in quasi-static axial compression. The failure mode and behaviour of the tubes were investigated by taking photographs and recording the load–displacement curves during the test accomplishment. The test results indicated that natural ramie/bio-epoxy composite tube has the great potential to be used as an effective energy-absorbing device. 相似文献
85.
86.
87.
Hamdy Mohamed S. Al-Zaqri Nabil Sahlabji Taher Eissa Murad Haija Mohammad Abu Alhanash Abdullah M. Alsalme Ali Alharthi Fahad A. Abboud Mohamed 《Catalysis Letters》2021,151(6):1612-1622
Catalysis Letters - To avoid the aggregation problem and activity loss of nickel oxide (NiO) nanoparticles (NPs) in organic reactions, NiO NPs were incorporated into TUD-1 mesoporous material.... 相似文献
88.
89.
Nursolehah Abd Aziz Coswald Stephen Sipaut Amirul Al‐Ashraf Abdullah 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(11):1607-1614
BACKGROUND: The aim of this work is to enhance the production of terpolyester poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate‐co‐4‐hydroxybutyrate) (P(3HB‐co‐3HV‐co‐4HB)) produced by a locally isolated bacterium, Cupriavidus sp. USMAA2‐4. The monomer composition was varied by supplementing different carbon precursors and by manipulating the culture condition through one‐stage cultivation. The effect of C/N ratio and different concentrations of carbon source and precursors were investigated in order to produce higher content of this terpolyester. Although research on this biodegradable polyester is abundant, studies on terpolyester P(3HB‐co‐3HV‐co‐4HB) are still limited. RESULTS: Supplementation of oleic acid in accumulation medium increased the bacterial growth and polyhydroxyalkanoate (PHA) accumulation. It was also shown that medium consisting of assorted carbon precursors at C/N 20 gave relatively high dry cell weight and P(3HB‐co‐3HV‐co‐4HB) content. Various compositions of terpolyester were obtained when the concentration of oleic acid and 4HB precursors were manipulated. The combination of oleic acid with γ‐butyrolactone and 1‐pentanol was found to be the best combination to produce high PHA content (81 wt%). The composition of monomer in P(3HB‐co‐3HV‐co‐4HB) was produced in the range 8–13 mol% for 3HV and 9–24 mol% for 4HB, respectively. CONCLUSIONS: The production of P(3HB‐co‐3HV‐co‐4HB) in shake‐flasks successfully produced 81 wt% of PHA content. This manipulated culture condition can be used at larger scale to provide modeling for the production of terpolyester in a bioreactor. Copyright © 2012 Society of Chemical Industry 相似文献
90.