全文获取类型
收费全文 | 631篇 |
免费 | 49篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 220篇 |
金属工艺 | 8篇 |
机械仪表 | 18篇 |
建筑科学 | 21篇 |
能源动力 | 17篇 |
轻工业 | 126篇 |
水利工程 | 13篇 |
石油天然气 | 6篇 |
无线电 | 43篇 |
一般工业技术 | 71篇 |
冶金工业 | 25篇 |
原子能技术 | 5篇 |
自动化技术 | 108篇 |
出版年
2024年 | 3篇 |
2023年 | 17篇 |
2022年 | 20篇 |
2021年 | 38篇 |
2020年 | 40篇 |
2019年 | 45篇 |
2018年 | 35篇 |
2017年 | 42篇 |
2016年 | 37篇 |
2015年 | 34篇 |
2014年 | 33篇 |
2013年 | 61篇 |
2012年 | 37篇 |
2011年 | 42篇 |
2010年 | 28篇 |
2009年 | 28篇 |
2008年 | 26篇 |
2007年 | 14篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有685条查询结果,搜索用时 0 毫秒
681.
Starch samples separated from oat were modified with two different levels of POCl3 (0.5 and 1.0 g kg−1) as a cross-linking agent and two different levels of acetic anhydride (6% and 8% (w/w)) for acetylation. Swelling factor, thermal properties and retrogradation measurements were evaluated to characterise the influence of phosphorylation and acetylation on oat starch. Cross-linking decreased the swelling factor and did not improve gelatinization temperature while it increased synaeresis in comparison with native starch. Acetylation increased swelling factor but reduced gelatinization temperature and synaeresis of oat starch. 相似文献
682.
Escherichia coli of poultry food origin as reservoir of sulphonamide resistance genes and integrons 总被引:1,自引:0,他引:1
Soufi L Sáenz Y Vinué L Abbassi MS Ruiz E Zarazaga M Ben Hassen A Hammami S Torres C 《International journal of food microbiology》2011,144(3):497-502
The antimicrobial resistance phenotype and genotype, the flanking regions of sulphonamide resistance genes and the integrons were analyzed in 166 Escherichia coli isolates recovered from poultry meat in Tunisia. High percentages of resistance were detected to ampicillin, streptomycin, nalidixic acid, sulphonamide and tetracycline (66-95%), and lower percentages to gentamicin, amoxicillin-clavulanic acid and cefoxitin (1-4%). The blaTEM, tet(A)/tet(B), aph(3′)-Ia, aac(6′)-Ib-cr, aac(3)-II and cmlA genes were identified in 92, 82, 29, 2, 2 and 7 isolates, respectively. Class 1 and/or class 2 integrons were detected in 52% of E. coli isolates and five different gene cassette arrangements were identified in the variable regions of class 1 integrons, which included antimicrobial resistance determinants. Sixty-eight isolates contained the sul1 gene and 37 of them presented this gene into a class 1 integron structure. The sul3 gene was detected associated with non-classic class 1 integrons in 4 out of 46 sul3-positive isolates. The sul2 gene was detected in 66 isolates, 51 of them were linked to strA/B genes in seven different genetic structures. Seventy-three-per-cent of integron-positive isolates presented resistance to at least five different antimicrobial families versus 38.7% of integron-negative isolates. Our study highlights the role of commensal E. coli isolates from poultry meat as an important reservoir for sulphonamide resistance genes and integrons carrying antimicrobial resistance genes. 相似文献
683.
Essential Oil Composition and Antioxidant Capacity of Carum copticum and its Antibacterial Effect on Staphylococcus aureus,Enterococcus faecalis and Escherichia coli O157:H7 下载免费PDF全文
684.
This paper is concerned with modeling possible future paths for Lebanon’s electricity future and evaluating them. The baseline scenario (BS) reflects the business-as-usual state of affairs and thus describes the most likely evolution of the power sector in the absence of any climate change-related or other policies. Two alternative scenarios are examined in contrast to the BS; the renewable energy scenario (RES) and the natural gas scenario (NGS). Using the Long range Energy Alternatives Planning System (LEAP) software we conduct a full-fledged scenario analysis and examine the technical, economic, and environmental implications of all scenarios.From an economic standpoint as well as from an environmental perspective both alternative scenarios are superior to the baseline. Hence, the results of the simulation show that the alternative scenarios are more environmentally and economically attractive than the BS. They would help Lebanon meet its social, environmental, and economic development goals, while at the same time providing other unquantifiable benefits that are discussed further in the paper. Anticipated barriers to the shift in energy mix from conventional sources to renewable energy sources are also presented and discussed 相似文献
685.
Linear alkyl benzenes (LABs) are the main materials for detergent production. The presence of aromatic compounds in this material can decrease the quality of the final product and enhance the deactivation rate of catalysts. In this research we used zeolite NaX for de-aromatization of the recycled paraffin from the alkylation unit of an LAB production complex. The effect of different parameters on the removal efficiency of adsorbent was studied and optimized. To study the re-usability of the adsorbent, the breakthrough curves were obtained by using a fixed bed column filled with the adsorbent. The results indicated that the adsorbent capacity remained unchanged after three regeneration cycles. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. It was concluded that the Langmuir model agreed well with the experimental data. The calculated thermodynamic parameters of the adsorption showed that the adsorption process was spontaneous and exothermic. The reaction rate was estimated by the pseudo-second order kinetic model. 相似文献