全文获取类型
收费全文 | 4015篇 |
免费 | 177篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 46篇 |
综合类 | 12篇 |
化学工业 | 879篇 |
金属工艺 | 159篇 |
机械仪表 | 89篇 |
建筑科学 | 64篇 |
矿业工程 | 12篇 |
能源动力 | 295篇 |
轻工业 | 297篇 |
水利工程 | 76篇 |
石油天然气 | 24篇 |
无线电 | 471篇 |
一般工业技术 | 828篇 |
冶金工业 | 373篇 |
原子能技术 | 40篇 |
自动化技术 | 538篇 |
出版年
2024年 | 11篇 |
2023年 | 80篇 |
2022年 | 115篇 |
2021年 | 169篇 |
2020年 | 117篇 |
2019年 | 153篇 |
2018年 | 195篇 |
2017年 | 157篇 |
2016年 | 160篇 |
2015年 | 104篇 |
2014年 | 173篇 |
2013年 | 359篇 |
2012年 | 185篇 |
2011年 | 268篇 |
2010年 | 169篇 |
2009年 | 203篇 |
2008年 | 182篇 |
2007年 | 140篇 |
2006年 | 111篇 |
2005年 | 94篇 |
2004年 | 73篇 |
2003年 | 80篇 |
2002年 | 65篇 |
2001年 | 46篇 |
2000年 | 54篇 |
1999年 | 45篇 |
1998年 | 68篇 |
1997年 | 64篇 |
1996年 | 53篇 |
1995年 | 54篇 |
1994年 | 45篇 |
1993年 | 36篇 |
1992年 | 42篇 |
1991年 | 32篇 |
1990年 | 31篇 |
1989年 | 27篇 |
1988年 | 37篇 |
1987年 | 26篇 |
1986年 | 20篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 12篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 12篇 |
1975年 | 5篇 |
排序方式: 共有4203条查询结果,搜索用时 31 毫秒
1.
Vijay Singh Sharanagat Prabhat K. Nema Lochan Singh Ankur Kumar 《International Journal of Food Science & Technology》2022,57(3):1654-1665
The effect of microwave roasting parameters (300, 450 and 600 W; 5, 10 and 15 min) on acrylamide content in sorghum grain was determined using High Pressure Liquid Chromatography (HPLC)-photo diode array (PDA) detector coupled with C-18 column. Samples roasted at 300 and 450 W did not possess acrylamide, whereas 600 W (15 min) favoured formation of 2740.19 µg/kg of acrylamide, levels far exceeding the defined European Union (EU) limits. The chronic daily intake (CDI) for acrylamide through consumption of such grain flour was 3.25–9.5-fold higher to Joint FAO/WHO Expert Committee on Food Additives (JECFA) defined high exposure limits. The margin of exposure (MOE) values ranged from 4.3 to 12.76 and from 11.07 to 32.27 for neoplastic and neurological effects, respectively, demonstrating high exposure and serious health concerns associated with dietary intake of this toxicant. This study assesses the risk for the Indian population and highlights the importance of optimising process parameters for food product to minimise such exposure risks. 相似文献
2.
Wireless Personal Communications - Internet of Things (IoT) is one of the emerging technologies, which is widely used across the globe. As the idea of a smart city was founded, IoT has been... 相似文献
3.
Wireless Personal Communications - Internet of Things (IoT) offers complex networks of connected devices, which are used to serve in the real-time environment. Interestingly, Wireless Sensor... 相似文献
4.
Dhirendra Kumar Mishra Gopal Pugazhenthi Tamal Banerjee 《International Journal of Hydrogen Energy》2021,46(29):15773-15779
The current work explores the usage of novel synthesized Deep Eutectic Solvent (DES) as a catalyst cum solvent media for the thermal dehydrogenation of chemical hydrides, namely Ammonia Borane (AB) and Ethylene diamine bisborane (EDAB). In the first instance, the quantum chemistry based COSMO-SAC (COnductor like Screening MOdel Segment Activity Coefficient) model was used for the selection of the pertinent solvent. 1-Butyl-3-methylimidazolium methanesulfonate: Imidazole ([BMIM][MeSO3]:[Im]) turned out to be an ideal eutectic mixture with the highest predicted solubility with amine boranes. The DES was synthesized by combining the Hydrogen Bond Acceptor (HBA), namely 1-Butyl-3-methylimidazolium methanesulfonate and Imidazole as Hydrogen Bond Donor (HBD) at a molar ratio of 1:2 and T = 70 °C. The formation of DES was confirmed by recording the NMR spectra. Further, the thermal dehydrogenation study was performed at a vacuum of 4 × 10?2 mbar (gauge pressure) of AB/DES and EDAB/DES systems at 105 °C, where a hydrogen equivalent of 1.40 and 2.55 was produced, respectively. The residual samples were further analyzed through 1H NMR analysis for the reaction mechanism and to confirm the role of Ionic Liquid-based DES as catalyst cum solvent media. 相似文献
5.
ABSTRACTA mathematical model has been developed by coupling genetic algorithm (GA) with heat and material balance equations to estimate rate parameters and solid-phase evolution related to the reduction of iron ore-coal composite pellets in a multi-layer bed Rotary hearth Furnace (RHF). The present process involves treating iron ore-coal composite pellets in a crucible over the hearth in RHF. The various solid phases evolved at the end of the process are estimated experimentally, and are used in conjunction with the model to estimate rate parameters. The predicted apparent activation energy for the wustite reduction step is found to be lower than those of the reduction of higher oxides. The thermal efficiency is found to decrease significantly with an increase in the carbon content of the pellet. Thermal efficiency was also found to increase mildly up to three layers. Multilayer bed remains as a potential design parameter to increase thermal efficiency. 相似文献
6.
Wireless Personal Communications - In this paper the conventional circular patch has been reshaped by two circular arcs with the FR4 Epoxy material for substrate. This is supported by the... 相似文献
7.
In India, little attention has been paid on antimicrobial resistance (AMR) in the context of developing “One Health” approach. Hence, utilizing multi-disciplinary approach, we assess the AMR level and dynamics/pattern of multi-drug resistance (MDR) in Escherichia coli, Salmonella spp., and Staphylococcus aureus circulating over the different stages of poultry in India. A total of 342 isolates including E. coli (n = 143), Salmonella spp. (n = 104), and S. aureus (n = 95) were recovered from fecal (n = 80) and cecal (n = 80) samples of chicken, collected across the different poultry-retail shops and poultry-farms located at urban and rural areas of Rajasthan, India, respectively. High rates of AMR to drugs that are critically/highly important both in human and veterinary medicine were observed among all the isolates. Upward trends in AMR prevalence was observed in poultry-retail shops than in poultry-farms. Notably, >90% of all the isolates were MDR, of particular, pattern/prevalence of MDR was substantially varied across the poultry-farms vs. poultry-retail shops. Our results indicate AMR including MDR to be common in E. coli, Salmonella spp., and S. aureus distributed frequently in poultry. The study encourages the formulation of national policy, programmes and further research with a “One Health” approach that can benefits to the human/animal and the environment. 相似文献
8.
High‐performance thermosets with tailored properties derived from methacrylated eugenol and epoxy‐based vinyl ester
下载免费PDF全文
![点击此处可从《Polymer International》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yuehong Zhang Yuzhan Li Vijay Kumar Thakur Zhenhua Gao Jiyou Gu Michael R Kessler 《Polymer International》2018,67(5):544-549
A renewable chemical, eugenol, is methacrylated to produce methacrylated eugenol (ME) employing the Steglich esterification reaction without any solvent. The resulting ME is used as a low‐viscosity co‐monomer to replace styrene in a commercial epoxy‐based vinyl ester resin (VE). The volatility and viscosity of ME and styrene are compared. The effect of ME loading and temperature on the viscosity of the VE–ME resin is investigated. Moreover, the thermomechanical properties, curing extent and thermal stability of the fully cured VE–ME thermosets are systematically examined. The results indicate that ME is a monomer with low volatility and low viscosity, and therefore the incorporation of ME monomer in VE resins allows significant reduction of viscosity. Moreover, the viscosity of the VE–ME resin can be tailored by adjusting the ME loadings and processing temperature to meet commercial liquid molding technology requirements. The glass transition temperatures of VE–ME thermosets range from 139 to 199 °C. In addition, more than 95% of the monomer is incorporated and fixed in the crosslinked network structure of VE–ME thermosets. Overall, the developed ME monomer exhibits promising potential for replacing styrene as an effective low‐viscosity co‐monomer. The VE–ME resins show great advantages for use in polymer matrices for high‐performance fiber‐reinforced composites. This work is of great significance to the vinyl ester industry by providing detailed experimental support. © 2018 Society of Chemical Industry 相似文献
9.
10.