全文获取类型
收费全文 | 4586篇 |
免费 | 362篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 59篇 |
综合类 | 1篇 |
化学工业 | 1182篇 |
金属工艺 | 102篇 |
机械仪表 | 213篇 |
建筑科学 | 212篇 |
矿业工程 | 13篇 |
能源动力 | 129篇 |
轻工业 | 916篇 |
水利工程 | 36篇 |
石油天然气 | 37篇 |
无线电 | 274篇 |
一般工业技术 | 782篇 |
冶金工业 | 228篇 |
原子能技术 | 17篇 |
自动化技术 | 751篇 |
出版年
2024年 | 13篇 |
2023年 | 59篇 |
2022年 | 127篇 |
2021年 | 201篇 |
2020年 | 159篇 |
2019年 | 158篇 |
2018年 | 244篇 |
2017年 | 277篇 |
2016年 | 283篇 |
2015年 | 182篇 |
2014年 | 210篇 |
2013年 | 403篇 |
2012年 | 336篇 |
2011年 | 317篇 |
2010年 | 244篇 |
2009年 | 230篇 |
2008年 | 212篇 |
2007年 | 156篇 |
2006年 | 121篇 |
2005年 | 188篇 |
2004年 | 184篇 |
2003年 | 133篇 |
2002年 | 64篇 |
2001年 | 39篇 |
2000年 | 44篇 |
1999年 | 32篇 |
1998年 | 75篇 |
1997年 | 47篇 |
1996年 | 53篇 |
1995年 | 23篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1977年 | 2篇 |
1976年 | 8篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有4952条查询结果,搜索用时 15 毫秒
61.
Emilia Ferrer Elisa Santoni Sauro Vittori Guillermina Font Jordi Mañes Gianni Sagratini 《Food chemistry》2011
A new analytical method, using pressurised liquid extraction (PLE) and liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed for the simultaneous determination of bisphenol A (BPA), octylphenol (OP) and nonylphenol (NP) in powdered infant formulas (IF) and powdered skimmed milk (PM). The analytes were extracted by PLE, using this optimised conditions: ethyl acetate as solvent, 70 °C of temperature, reversed-phase silica C18 as dispersing agent and three cycles of extraction. The extracts were then injected in LC–MS/MS using a Gemini C18 column and a mixture of 5% water and 95% methanol/acetonitrile, both with 0.1% ammonia, as a mobile phase. Recoveries at different fortification levels (0.5 and 0.05 mg kg−1), were between 89% and 92% for BPA, 84 and 98% for OP, and 93% and 101% for NP. The method was applied to the analysis of samples of PM and IF, bought in Italian and Spanish markets. In positive samples, phenols concentration ranged from 0.07 to 1.29 mg kg−1 for BPA, from 0.028 to 1.55 mg kg−1 for OP and from 0.026 to 1.47 mg kg−1 for NP. 相似文献
62.
Adriano do Nascimento Simões Samara Lopes de Almeida Cristine Vanz Borges Kelem Silva Fonseca Aurélio Paes Barros Júnior José Ricardo Tavares de Albuquerque Camila Renata Corrêa Igor Otavio Minatel Maria Aparecida dos Santos Morais Marla Silvia Diamante Giuseppina Pace Pereira Lima 《Journal of Food Biochemistry》2020,44(8):e13322
63.
Jukka Ekberg Brian Gibson Jussi J. Joensuu Kristoffer Krogerus Frederico Magalhães Atte Mikkelson Tuulikki Seppänen‐Laakso Arvi Wilpola 《Journal of the Institute of Brewing》2015,121(4):464-473
Sahti, a strong, unhopped farmhouse beer flavoured with juniper, is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and, while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean = 9.5°P). Foam stability was negligible, as is typical for the style, and glycerol concentrations at 3.1 – 4.7 g L?1 were higher than in reference beers (commercial lager, wheat beer and porter). These features may be attributed to the very high gravity conditions employed in brewing sahti beers. Bitterness levels were relatively low (3–13 IBU) owing to the absence or moderate use of hops. All samples contained detectable levels of the clove‐like compound 4‐vinylguaiacol owing to the use of baker's rather than brewer's yeast for brewing. Concentrations of higher alcohols and esters were high, with many individual aroma compounds being above the normal flavour thresholds. Results have highlighted the uniqueness of this style of beer in comparison to commercially available beers and have contributed to our understanding of the reasons for the particular sensorial properties of this traditional beer style. Copyright © 2015 The Institute of Brewing & Distilling 相似文献
64.
Maria João Cardoso Anca Ioana Nicolau Daniela Borda Line Nielsen Rui Leandro Maia Trond Møretrø Vânia Ferreira Susanne Knøchel Solveig Langsrud Paula Teixeira 《Comprehensive Reviews in Food Science and Food Safety》2021,20(3):2716-2741
Nontyphoidal salmonellae are among the most prevalent foodborne pathogens causing gastrointestinal infections worldwide. A high number of cases and outbreaks of salmonellosis are associated with the consumption of eggs and egg products, and several of these occur at the household level. The aim of the current study is to critically evaluate the current status of knowledge on Salmonella in eggs from a consumer's perspective, analyzing the hazard occurrence and the good practices that should be applied to reduce salmonellosis risk. Following a HACCP (Hazard Analysis and Critical Control Point) based approach, some steps along the food journey were identified as Critical Consumer Handling (CCH)—steps in which consumers, through their behavior or choice, can significantly reduce the level of Salmonella in eggs and egg products. From shopping/collecting to consumption, each of these steps is discussed in this review to provide an evidence-based overview of risk factors of human salmonellosis related to egg consumption. The main message to consumers is to choose Salmonella-free eggs (those that some official entity or producer guarantees that does not contain Salmonella), when available, especially for dishes that are not fully heat treated. Second, as guaranteed Salmonella-free eggs are only available in a few countries, refrigerated storage from the point of collection and proper cooking will significantly reduce the risk of salmonellosis. This will require a revision of the actual recommendations/regulations, as not all ensure that eggs are maintained at temperatures that prevent growth of Salmonella from collection until the time of purchasing. 相似文献
65.
66.
67.
Erivan de Souza Oliveira Mighay Lovera Valessa Rios Pires Francisco Rogênio da Silva Mendes Nadya Virginia Lima Peixoto Maia João Pedro Viana Rodrigues Maria do Socorro Rocha Bastos Huai N. Cheng Atanu Biswas Renato de Azevedo Moreira Ana Cristina de Oliveira Monteiro Moreira 《Journal of Food Processing and Preservation》2022,46(3):e16408
68.
69.
70.