全文获取类型
收费全文 | 5444篇 |
免费 | 313篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 61篇 |
综合类 | 1篇 |
化学工业 | 1842篇 |
金属工艺 | 157篇 |
机械仪表 | 84篇 |
建筑科学 | 159篇 |
矿业工程 | 16篇 |
能源动力 | 144篇 |
轻工业 | 693篇 |
水利工程 | 15篇 |
石油天然气 | 10篇 |
无线电 | 128篇 |
一般工业技术 | 808篇 |
冶金工业 | 1163篇 |
原子能技术 | 23篇 |
自动化技术 | 457篇 |
出版年
2023年 | 54篇 |
2022年 | 288篇 |
2021年 | 455篇 |
2020年 | 145篇 |
2019年 | 114篇 |
2018年 | 188篇 |
2017年 | 193篇 |
2016年 | 203篇 |
2015年 | 152篇 |
2014年 | 214篇 |
2013年 | 324篇 |
2012年 | 236篇 |
2011年 | 294篇 |
2010年 | 178篇 |
2009年 | 180篇 |
2008年 | 171篇 |
2007年 | 169篇 |
2006年 | 115篇 |
2005年 | 95篇 |
2004年 | 85篇 |
2003年 | 73篇 |
2002年 | 60篇 |
2001年 | 39篇 |
2000年 | 38篇 |
1999年 | 34篇 |
1998年 | 188篇 |
1997年 | 213篇 |
1996年 | 146篇 |
1995年 | 101篇 |
1994年 | 52篇 |
1993年 | 77篇 |
1992年 | 26篇 |
1991年 | 18篇 |
1990年 | 22篇 |
1989年 | 21篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 16篇 |
1985年 | 22篇 |
1984年 | 35篇 |
1983年 | 27篇 |
1982年 | 44篇 |
1981年 | 53篇 |
1980年 | 59篇 |
1979年 | 32篇 |
1978年 | 42篇 |
1977年 | 111篇 |
1976年 | 240篇 |
1975年 | 16篇 |
1973年 | 13篇 |
排序方式: 共有5761条查询结果,搜索用时 15 毫秒
141.
Organic whey as a source of Lactobacillus strains with selected technological and antimicrobial properties
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anna Rzepkowska Dorota Zielińska Aleksandra Ołdak Danuta Kołożyn‐Krajewska 《International Journal of Food Science & Technology》2017,52(9):1983-1994
Twenty‐five strains, isolated from raw, non‐pasteurised, organic whey samples, were identified phenotypically and genotypically. Biochemical tests were performed, and enzyme profiles, antibiotic resistance and antimicrobial properties were investigated. Sixteen strains were identified as genus Lactobacillus. Based on 16S rDNA gene sequence, the strains were identified as Lb. plantarum and Lb. fermentum. All of the strains had β‐galactosidase activity, and some of them reduced nitrate content. All strains utilised carbohydrates. The tested strains were characterised by low or average lipolytic and esterolytic activity. Moreover, the strains showed low proteolytic activity which is advantageous for their use as starter cultures for foods with low protein content. Strains Lb. fermentum S20, SM1, SM3, S2R and Lb. plantarum SM5 produced harmful N‐acetyl‐β‐glucosaminidase; moreover, the strain S20 produced also β‐glucuronidase. None of the strains produced α‐chymotrypsin. In phenotypic studies, most of the test strains were susceptible to gentamicin, ampicillin, tetracycline, chloramphenicol, penicillin and erythromycin. Strains Lb. plantarum S1 and Lb. fermentum S4, S7, S8, S10, SM1 and SM3 did not possess any transfer resistance genes. Antagonistic activity of the culture LAB strains was assessed as high or moderate in relation to the indicator strains, with the greatest zones of inhibition for E.coli and the smallest for L. monocytogenes ATCC 15313. This study reveals that the LAB strains isolated from organic whey have high potential for food application. Some strains of species Lb. fermentum (S4, S7, S8, S10) have been identified as the best candidates. 相似文献
142.
Rheological characteristics of oligomeric semiproducts gained via chemical degradation of polyurethane foam using crude glycerin in the presence of different catalysts
下载免费PDF全文
![点击此处可从《Polymer Engineering and Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Polyurethane (PU) recycling is a topic of growing interest due to the increasing amount of polyurethane waste. The main purpose of polyurethane chemical recycling is to recover the starting polyol. In this study, a method of polyurethane thermochemical recycling, glycerolysis by means of crude glycerin, is proposed. This work presents a comparative study of commercial catalysts used in order to accelerate the decomposition process, namely triethylamine (TEA), potassium acetate (KAc), 1,4‐diazabicyclo[2.2.2]octane (DABCO), sodium hydroxide (NaOH), dibutyltin dilaurate (DbDl), and stannous octoate (StOc).The effect of used catalyst on the chemical structure and rheological properties was studied. The type of catalyst does not have significant influence on the chemical structure, but causes different course of reaction: split‐ and single‐phase in applied conditions. Glycerolysates were measured by Brookfield Rheometer. It was found that repolyols can be described by the Herschel–Bulkely mathematical model in the best accuracy. The investigation showed that the rheological behavior of glycerolysates depended on the catalyst used in glycerolysis process. POLYM. ENG. SCI., 57:891–900, 2017. © 2016 Society of Plastics Engineers 相似文献
143.
144.
Urszula Krupa-Kozak Natalia Drabińska Cristina M. Rosell Costantino Fadda Andrzej Anders Tomasz Jeliński Anita Ostaszyk 《International Journal of Food Science & Technology》2019,54(4):1121-1129
Broccoli by-products, in particular leaves, are rich sources of nutritional and bioactive components thus could constitute a valuable food additive. Although an upsurge in quantity of gluten-free products is observed further studies are required on improvement of their nutritional quality and palatability. This study aimed to investigate the influence of broccoli leaf powder (BLP) on dough behaviour, and technological characteristics and sensory quality of gluten-free mini sponge cake (GFS). Broccoli leaf powder replaced an equivalent amount (2.5%, 5%, 7.5%; w/w) of corn and potato starches in GFS formulation. Applied BLP increased the instrumental firmness of GFS but sensorial attributes (elasticity, crustiness, mastication and adhesiveness) were similar to the control. All broccoli GFS were vividly green, had small size pores properly distributed. Among them, sample with 2.5% BLP was distinguished for its desirable sensory quality, despite a slightly perceived cabbage aroma and taste. Moderate amount of BLP allows to preserve a good quality GFS improving its attractiveness and palatability. 相似文献
145.
146.
Effects of various roasting conditions on antioxidant properties of five Theobroma cacao L. varieties were investigated. The cocoa beans were roasted at four different temperatures (110–150°C) and three different air humidities (0.3–5.0%). The raw cocoa beans were characterized by high antioxidant activities. The antioxidant properties of the roasted cocoa beans varied markedly among the analyzed cultivars and geographical regions and were affected by roasting conditions. Generally, cocoa beans of the cv. Forastero from Brazil exhibited higher total phenolic content, free radical scavenging activity, and metal chelating ability than samples of the other analyzed cocoa varieties. Roasting at 110°C caused negligible changes in total phenolics content and antioxidant activity of cocoa beans, while almost all samples tended to have lower antioxidant potential when roasting temperature increased. The air humidity used in roasting did not affect the total phenolics content and antioxidant activity for lowest roasting temperature (110°C). Moreover, the obtained results revealed that thermal processing at the higher temperatures and elevated air humidity resulted in the higher antioxidant capacities. It was also found that the ferrous ion chelating activity of cocoa beans increased with the roasting temperature (in the range from 110 to 150°C), with the exception of cv. Trinitario from Papua New Guinea. The data showed that roasting at lower temperatures with humid air are more favorable in terms of preserving the bioactivity of roasted cocoa beans. 相似文献
147.
Emilia Szymańska Katarzyna Winnicka Piotr Wieczorek Pawe? Tomasz Sacha El?bieta Anna Tryniszewska 《International journal of molecular sciences》2014,15(10):17765-17777
The combination of an antifungal agent and drug carrier with adjunctive antimicrobial properties represents novel strategy of complex therapy in pharmaceutical technology. The goal of this study was to investigate the unmodified and ion cross-linked chitosan’s influence on anti-Candida activity of clotrimazole used as a model drug in hydrogels. It was particularly crucial to explore whether the chitosans’ structure modification by β-glycerophosphate altered its antifungal properties. Antifungal studies (performed by plate diffusion method according to CLSI reference protocol) revealed that hydrogels obtained with chitosan/β-glycerophosphate displayed lower anti-Candida effect, probably as a result of weakened polycationic properties of chitosan in the presence of ion cross-linker. Designed chitosan hydrogels with clotrimazole were found to be more efficient against tested Candida strains and showed more favorable drug release profile compared to commercially available product. These observations indicate that novel chitosan formulations may be considered as promising semi-solid delivery system of clotrimazole. 相似文献
148.
149.
150.
Gra?yna A. P?aza Joanna Chojniak Ibrahim M. Banat 《International journal of molecular sciences》2014,15(8):13720-13737
Developing a reliable experimental protocol for the synthesis of nanomaterials is one of the challenging topics in current nanotechnology particularly in the context of the recent drive to promote green technologies in their synthesis. The increasing need to develop clean, nontoxic and environmentally safe production processes for nanoparticles to reduce environmental impact, minimize waste and increase energy efficiency has become essential in this field. Consequently, recent studies on the use of microorganisms in the synthesis of selected nanoparticles are gaining increased interest as they represent an exciting area of research with considerable development potential. Microorganisms are known to be capable of synthesizing inorganic molecules that are deposited either intra- or extracellularly. This review presents a brief overview of current research on the use of biosurfactants in the biosynthesis of selected metallic nanoparticles and their potential importance. 相似文献