全文获取类型
收费全文 | 455篇 |
免费 | 21篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 7篇 |
综合类 | 23篇 |
化学工业 | 305篇 |
金属工艺 | 6篇 |
机械仪表 | 6篇 |
建筑科学 | 4篇 |
矿业工程 | 8篇 |
能源动力 | 9篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
石油天然气 | 13篇 |
武器工业 | 3篇 |
无线电 | 17篇 |
一般工业技术 | 44篇 |
冶金工业 | 4篇 |
原子能技术 | 3篇 |
自动化技术 | 15篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 12篇 |
2018年 | 6篇 |
2017年 | 9篇 |
2016年 | 15篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 28篇 |
2012年 | 19篇 |
2011年 | 32篇 |
2010年 | 15篇 |
2009年 | 23篇 |
2008年 | 18篇 |
2007年 | 38篇 |
2006年 | 34篇 |
2005年 | 26篇 |
2004年 | 17篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 23篇 |
2000年 | 18篇 |
1999年 | 11篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1980年 | 2篇 |
排序方式: 共有487条查询结果,搜索用时 15 毫秒
481.
Dravin Pratap Singh Gopinath Packirisamy 《Journal of the science of food and agriculture》2023,103(2):479-487
Currently, modern lifestyle diseases (LSD) such as cancer, diabetes, hypertension, cardiovascular and thyroid disease are commonly seen among people of different age groups. One of the root causes of this LSD is the type of food that we are eating. Staple crops like rice, sugarcane, vegetables and wheat are grown with the application of agrochemicals (e.g., glyphosate), traces of which are found in our food; after that, it gets ultra-processed in factories; e.g., chips and snacks are fried using saturated fats (trans fat); sugar and wheat (derivatives bread, buns, cookies) are processed using toxic chemicals (bleaching agents). As a result, the nutritional value of food is compromised due to low dietary fiber content and synthetic additives – e.g., sucralose (artificial sweetener) – which promotes inflammation and weakens our immune system, causing our body to become sensitive to microbial infection and many other LSDs. To strengthen the immune system, people start taking synthetically prepared supplements and drugs for a prolonged time, which further deteriorates the body organs and their normal function; e.g., prolonged medication for hypothyroidism poses a risk of heart attack and joint pain. Nanotechnology solves the above problems in the food, nutraceuticals and agriculture sectors. Nanotechnology-based naturally processed products such as nano-nutraceuticals, nanofood, nanofertilizers and nanopesticides will benefit our health. They possess desirable properties such as high bioavailability, targeted delivery, least processing and sustained release. With the help of nanotechnology, we can get nutritional and agrochemical-free food. © 2022 Society of Chemical Industry. 相似文献
482.
483.
S. Bouzakraoui S.M. Bouzzine M. Bouachrine M. Hamidi 《Solar Energy Materials & Solar Cells》2006,90(10):1393-1402
A quantum-chemical investigation on the structural and opto-electronic properties of several alkoxy substituted 4,4′-bis(2-phenylethenyl)biphenyls (PEBP) as building blocks for π-conjugate polymer is performed in order to display the effect of changing the position of alkoxy substituents on the peripheral phenyl rings on their opto-electronic and physico-chemical properties. Added to the good agreement between theoretical and experimental observations, it has been observed that the substitution effect depends on the position of the methoxy group: in ortho- or para-positions it acts as a mesomeric electrons donor, while as an inductive electrons acceptor in meta-positions. Substitution in ortho-positions causes significant structural deformations of PEBP backbone due to the steric interaction between the substituents and the hydrogens of the vinylene functions. Bridging of ortho, para-PEBP (24PEBP) by CC(CN)2 decreases significantly its band gap. This model can have very interesting opto-electronic ownerships. 相似文献
484.
Shuang Song Jing Wang Xingqi Yang Xuan Zhang Xiuli Xin Chunyan Liu Jianan Zou Xiaofei Cheng Ning Zhang Yuxi Hu Jinhui Wang Qingshan Chen Dawei Xin 《International journal of molecular sciences》2022,23(14)
Soybeans are a major crop that produce the best vegetable oil and protein for use in food and beverage products worldwide. However, one of the most well-known viral infections affecting soybeans is the Soybean Mosaic Virus (SMV), a member of the Potyviridae family. A crucial method for preventing SMV damage is the breeding of resistant soybean cultivars. Adult resistance and resistance of seedcoat mottling are two types of resistance to SMV. Most studies have focused on adult-plant resistance but not on the resistance to seedcoat mottling. In this study, chromosome segment-substituted lines derived from a cross between Suinong14 (cultivated soybean) and ZYD00006 (wild soybean) were used to identify the chromosome region and candidate genes underlying soybean resistance to seed coat mottling. Herein, two quantitative trait loci (QTLs) were found on chromosome 17, and eighteen genes were found in the QTL region. RNA-seq was used to evaluate the differentially expressed genes (DEGs) among the eighteen genes located in the QTLs. According to the obtained data, variations were observed in the expression of five genes following SMV infection. Furthermore, Nicotiana benthamiana was subjected to an Agrobacterium-mediated transient expression assay to investigate the role of the five candidate genes in SMV resistance. It has also been revealed that Glyma.17g238900 encoding a RICE SALT SENSITIVE 3-like protein (RSS3L) can inhibit the multiplication of SMV in N. benthamiana. Moreover, two nonsynonymous single-nucleotide polymorphisms (SNPs) were found in the coding sequence of Glyma.17g238900 derived from the wild soybean ZYD00006 (GsRSS3L), and the two amino acid mutants may be associated with SMV resistance. Hence, it has been suggested that GsRSS3L confers seedcoat mottling resistance, shedding light on the mechanism of soybean resistance to SMV. 相似文献
485.
对代料和段木两种栽培方式的银耳子实体采用碱式提取其多糖,通过测定多糖的营养成分、单糖组成及体外抗氧化活性,比较两种栽培方式银耳品质的差别。结果表明,脱蛋白后段木和代料银耳多糖中蛋白质残留量分别2.65±0.05、0.45±0.06 mg/mL,两种银耳多糖的单糖都由甘露糖、葡萄糖、木糖和葡萄糖醛酸组成,代料银耳与段木银耳多糖中葡萄糖的质量比为13.62:2.43。不同银耳多糖的体外抗氧化能力均小于维生素C,在两种银耳DPPH清除率趋于稳定时,段木银耳多糖的DPPH自由基清除率比代料银耳高3%,而代料银耳羟自由基清除率比段木银耳高0.25%。 相似文献
486.
《Journal of Nuclear Science and Technology》2013,50(9):798-804
The dissolution behaviour of 3.5–12.5 at% Cr substituted haematites in a citric acid-EDTA-ascorbic acid (CEA) reductive-complexing formulation with and without alkaline permanganate (AP) oxidative pre-treatment is presented. In the direct treatment, with increasing Cr content of the oxide, employing CEA formulations containing increased concentrations of ascorbic acid could either completely or significantly solubilise the oxide. In the 3.5–10 at% Cr in the oxide, the concentrations of reducing agent employed in the CEA formulation to achieve a solubility of >40% in iron have been demarcated. The AP pre-treatment resulted in a release of only <4% of Cr from the oxide irrespective of the Cr content of the oxide and the concentrations of the permanganate. Nevertheless, such a pre-treatment was found to improve the percentage dissolution of the oxide significantly in the subsequent treatment with the reductive-complexing formulation. With AP pre-treatment, CEA formulations containing a lower concentration of the reducing agent dissolved as much oxide as the one by CEA formulations containing a higher concentration of the reducing agent in the direct treatment. Both with and without pre-treatment methods of dissolution yielded a preferential solubilization of Fe over Cr. 相似文献
487.