全文获取类型
收费全文 | 7202篇 |
免费 | 338篇 |
国内免费 | 56篇 |
专业分类
电工技术 | 133篇 |
综合类 | 26篇 |
化学工业 | 1858篇 |
金属工艺 | 118篇 |
机械仪表 | 215篇 |
建筑科学 | 278篇 |
矿业工程 | 6篇 |
能源动力 | 462篇 |
轻工业 | 731篇 |
水利工程 | 76篇 |
石油天然气 | 123篇 |
武器工业 | 1篇 |
无线电 | 660篇 |
一般工业技术 | 1155篇 |
冶金工业 | 340篇 |
原子能技术 | 83篇 |
自动化技术 | 1331篇 |
出版年
2024年 | 25篇 |
2023年 | 151篇 |
2022年 | 318篇 |
2021年 | 412篇 |
2020年 | 297篇 |
2019年 | 338篇 |
2018年 | 423篇 |
2017年 | 368篇 |
2016年 | 362篇 |
2015年 | 238篇 |
2014年 | 325篇 |
2013年 | 665篇 |
2012年 | 369篇 |
2011年 | 510篇 |
2010年 | 354篇 |
2009年 | 329篇 |
2008年 | 290篇 |
2007年 | 217篇 |
2006年 | 201篇 |
2005年 | 143篇 |
2004年 | 111篇 |
2003年 | 118篇 |
2002年 | 90篇 |
2001年 | 64篇 |
2000年 | 75篇 |
1999年 | 53篇 |
1998年 | 79篇 |
1997年 | 43篇 |
1996年 | 49篇 |
1995年 | 40篇 |
1994年 | 37篇 |
1993年 | 45篇 |
1992年 | 38篇 |
1991年 | 32篇 |
1990年 | 32篇 |
1989年 | 22篇 |
1988年 | 36篇 |
1987年 | 31篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 28篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 20篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1976年 | 18篇 |
1975年 | 19篇 |
1974年 | 12篇 |
排序方式: 共有7596条查询结果,搜索用时 15 毫秒
991.
Mokhtar Benhanifia Wessam M. Mohamed Yuva Bellik Hama Benbarek 《International Journal of Food Science & Technology》2013,48(12):2521-2527
The aim of this study was the investigation of antimicrobial and antioxidant activities of different ethanolic extracts of propolis (EEP) collected from north‐western Algeria. Total polyphenols and flavonoids contents of extracts were measured. The UV absorption spectrum showed and confirmed their polyphenols constituents. All EEPs exerted antibacterial activity against Gram‐positive bacteria, but no effect on Gram‐negative bacteria. The minimum inhibitory concentration (MIC) of EEPs ranged from 0.01% to 2.6% v/v. The antioxidant activity was measured using ferric‐reducing power (FRAP), 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical‐scavenging and ESR methods. Propolis TIA‐2 and MOH‐MAS samples showed the highest antioxidative capacity, after 35 min, while TIA‐1, NED‐TL and SFS‐SBA samples showed the highest antioxidative potential of measured EEPs, after 3 min. TIA‐2 sample showed the highest antibacterial, antioxidant activity and highest DPPH free radical‐scavenging activity as well as the highest polyphenols and flavonoids content, compared with other propolis samples. 相似文献
992.
Functional components of grape pomace: their composition,biological properties and potential applications 总被引:1,自引:0,他引:1
The roles of functional foods on human health have been realised by more and more researchers, food producers and consumers. Functional food ingredients from both plant and animal sources such as dietary fibre, soy protein isolate, whey protein isolate and omega 3 fatty acid have been widely used in functional food product development. Many fruit processing by‐products such as grape, apple and orange peels are rich in bioactive phytochemicals, dietary fibre and unsaturated fatty acids, hence have potential to serve as functional food ingredients. In this review, we summarise recent advancement of research in grape pomace (GP), the residual of grapes after wine making. The polyphenol profile of GP and their biological, antioxidant and antimicrobial activities, the stability of GP polyphenols in food system, the interaction between GP polyphenol and other food ingredients, as well as the functionalities of grape seed oil and GP fibre are covered. 相似文献
993.
994.
995.
Fatma Bouaziz Mohamed Koubaa Khaoula Ben Jeddou Francisco J. Barba Fatma Chaari Souhail Besbes Rhoudha Ellouz Ghorbel Semia Ellouz Chaabouni 《International Journal of Food Science & Technology》2017,52(1):205-213
The aim of this work was to investigate the effect of almond gum as dietary fibre source in enhancing the wheat bread quality. Different amounts of almond gum (2%, 5% and 10% (w/w)) were used in bread formulation. The volume, texture, crust and crumb colour, as well as the sensorial properties, were evaluated and compared to control (without almond gum). The obtained results showed that almond gum addition enhanced significantly the volume of bread. The highest volume was obtained using 2% almond gum concentration with 23.6% increase, compared to control. Using almond gum in bread formulation improved considerably its texture with a notable decrease in hardness by 61.7% and 42.5% when using 2% and 5% almond gum, respectively. The sensory analysis scores showed that the better overall acceptability was found for breads supplemented with 2% almond gum, as compared to control and breads supplemented with 5% or 10% almond gum. 相似文献
996.
Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.) 下载免费PDF全文
997.
Micro powders of recycled wool and cotton from textile waste is prepared and characterized. Wool and cotton waste fibers were frozen in liquid nitrogen and milled for various period times to produce fine powders. The powders sizes distribution depends on the milling time. Scanning electron microscopy micrographs confirm that, the fine cotton and wool powders have average size around 60 μm, and that, there are powder particle with size even less than 20 μm. Differential scanning calorimeter (DSC) and thermal gravimetrical analysis (TGA) results show that as the powder particle size decreases, its thermal stability increases slightly. Fourier transform infrared spectroscopy, Raman spectroscopy, and amino acid analysis confirm that, the freeze milling technique is a safe technique to produce ultrafine powder, with no effect on the chemical structure of cotton and wool. 相似文献
998.
Purification,structural data and biological properties of polysaccharide from Prunus amygdalus gum 下载免费PDF全文
Fatma Bouaziz Mohamed Koubaa Claire Boisset Helbert Fatma Kallel Dorra Driss Imen Kacem Raoudha Ghorbel Semia Ellouz Chaabouni 《International Journal of Food Science & Technology》2015,50(3):578-584
This work demonstrates the efficiency of almond gum polysaccharides (AGPs) as bioactive compounds. AGPs were first extracted using H2O2, in the presence of NaOH, at different times and temperatures. The optimal extraction conditions were 4% H2O2 and 2 N NaOH, for 7 h at 50 °C, leading to an extraction yield of 58.2% (w/w). After a purification step, the retained AGPs were characterised using high‐performance liquid chromatography showing a molecular weight of 99.3 kDa. The monosaccharide composition of AGPs were assessed using gas chromatography–mass spectrometry. AGPs were found to be a complex heteropolysaccharide with a repeating unit mainly composed of galactose, arabinose, xylose, mannose, rhamnose, and glucuronic acid with the respective ratios: 45:26:7:10:1:11. The acidic nature of the polysaccharide is due to the presence of glucuronic acid. Total antioxidant activity, free radical‐scavenging activity and reducing power assay of AGPs were investigated. The obtained results showed high antioxidant activities of AGPs. Furthermore, beyond 60 mg mL?1, AGPs exhibited bacterial growth inhibition for five pathogenic strains: Escherichia coli, Staphylococcus aureus, Enterococcus feacalis, Pseudomonas aeruginosa and Salmonella typhimurium. 相似文献
999.
The ellagitannin colonic metabolite urolithin D selectively inhibits EphA2 phosphorylation in prostate cancer cells 下载免费PDF全文
1000.