全文获取类型
收费全文 | 5321篇 |
免费 | 294篇 |
国内免费 | 190篇 |
专业分类
电工技术 | 27篇 |
综合类 | 309篇 |
化学工业 | 1812篇 |
金属工艺 | 364篇 |
机械仪表 | 60篇 |
建筑科学 | 55篇 |
矿业工程 | 81篇 |
能源动力 | 142篇 |
轻工业 | 521篇 |
水利工程 | 6篇 |
石油天然气 | 909篇 |
武器工业 | 10篇 |
无线电 | 35篇 |
一般工业技术 | 214篇 |
冶金工业 | 1159篇 |
原子能技术 | 12篇 |
自动化技术 | 89篇 |
出版年
2024年 | 15篇 |
2023年 | 32篇 |
2022年 | 96篇 |
2021年 | 105篇 |
2020年 | 98篇 |
2019年 | 89篇 |
2018年 | 73篇 |
2017年 | 101篇 |
2016年 | 126篇 |
2015年 | 139篇 |
2014年 | 267篇 |
2013年 | 277篇 |
2012年 | 392篇 |
2011年 | 405篇 |
2010年 | 279篇 |
2009年 | 271篇 |
2008年 | 229篇 |
2007年 | 317篇 |
2006年 | 332篇 |
2005年 | 289篇 |
2004年 | 276篇 |
2003年 | 259篇 |
2002年 | 244篇 |
2001年 | 224篇 |
2000年 | 184篇 |
1999年 | 144篇 |
1998年 | 115篇 |
1997年 | 89篇 |
1996年 | 63篇 |
1995年 | 61篇 |
1994年 | 54篇 |
1993年 | 48篇 |
1992年 | 38篇 |
1991年 | 17篇 |
1990年 | 14篇 |
1989年 | 11篇 |
1988年 | 11篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有5805条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Yu Zhao Zhigang Xu Zongshi Li Weihong Qiao Lubai Cheng 《Petroleum Science and Technology》2006,24(7):821-827
Heavy alkyl benzene sulfonates (HABS) were synthesized, and their interfacial tensions were measured and compared with those of petroleum sulfonates ORS-41. Effects of their coupling with lignosulfonate were also studied. The results showed that HABS exhibited good interfacial activities and the system of HABS blending with LS displayed better interfacial activities than ORS-41 and therefore reduced the prime cost. Their best proportions of synergism were from 3:1 to 4:1. HABS might be a more promising alkali-surfactant-polymer (ASP) flooding agent. 相似文献
5.
6.
Li Junling Zheng Tinglu Han Zhaping 《中国炼油与石油化工》2006,(3):57-60
The method for refining the straight-run diesel fuel was studied in laboratory scale in order to make the acid number of diesel fraction comply with the standard while removing the naphthenic acids contained in diesel without causing environmental pollution. After comparing the effect of refining using three solvents, the isopropyl alcohol-HOA was specified as the best solvent. Meanwhile, the relationship between the acid number of diesel fraction and the amount of solvent used and the relationship between the concentration of solvent and temperature and the stability of diesel in terms of its acid number were also investigated. Experimental results had shown that when the mass fraction of the HOA-IPA solvent was 20% at a dosage of 17 mL of the solvent and a temperature of 30℃, the acid number of the refined diesel fraction was 0.015 mg KOH/g with a good stability of acidity in the diesel fraction, 相似文献
7.
我国炼油石化产业应对石油短缺时代的科技对策思考 总被引:2,自引:0,他引:2
分析了我国石油消费的增长趋势和石油的增产潜力,指出持续增长的需求和相对稳定的产量使我国对国际石油的依存度越来越高。综合了国际能源机构、能源经济学家和石油地质学家对世界石油供应前景的预测结果,认为世界石油短缺的时代并不遥远。提出了我国炼油石化产业应对世界石油供应短缺时代的科技对策:(I)抓紧开发和完善充分利用石油资源生产运输燃料和石化原料技术;(2)开发用煤炭、石油焦、沥青制氢和炼油过程耦合的廉价氢源技术和用氢优化技术;(3)开发炼油石化过程节能降耗技术;(4)开发天然气及煤制油、甲醇制乙烯、丙烯技术;(5)开发利用生物质生产车用替代燃料、生物材料和生物化学品技术。 相似文献
8.
详细介绍了中国石油抚顺石化分公司石油一厂新区以沈阳、大庆混合原油的减二、减三线馏分油为原料,采用甲苯、甲乙酮脱蜡、糠醛精制、白土补充精制工艺生产HVI润滑油基础油的生产经验。并结合理论分析,提出了完善此类工艺的一系列建议。生产HVI200基础油,要求蒸馏减二线润滑油馏分粘度不大于4.75 mm2/s,脱蜡油粘度不大于56 mm2/s。为保证HVI200基础油粘度指数合格,要降低减二线馏分中多环环烷烃含量。 相似文献
9.
Biodegradation of monoaromatic hydrocarbons in aquifer columns amended with hydrogen peroxide and nitrate 总被引:1,自引:0,他引:1
The ability of indigenous microorganisms to degrade benzene, toluene, ethylbenzene and xylenes (BTEX) in laboratory scale flow-through aquifer columns was tested separately with hydrogen peroxide (110 mg/l) and nitrate (330 mg/l as NO3−) amendments to air-saturated influent nutrient solution. The continuous removal of individual components from all columns relative to the sterile controls provided evidence for biodegradation. In the presence of hydrogen peroxide, the indigeneous microorganisms degraded benzene and toluene (> 95%), meta- plus para-xylene (80%) and ortho-xylene (70%). Nitrate addition resulted in 90% removal of toluene and 25% removal of ortho-xylene. However, benzene, ethylbenzene, meta- and para-xylene concentrations were not significantly reduced after 42 days of operation. Following this experiment, low dissolved oxygen (< 1 mg/l) conditions were initiated with the nitrate-amended column influent in order to mimic contaminated groundwater conditions distal from a nutrient injection well. Toluene continued to be effectively degraded (> 90%), and more than 25% of the benzene, 40% of the ethylbenzene, 50% of the meta- plus para-xylenes and 60% of the ortho-xylene were removed after several months of operation. 相似文献
10.