全文获取类型
收费全文 | 20957篇 |
免费 | 2004篇 |
国内免费 | 347篇 |
专业分类
电工技术 | 144篇 |
综合类 | 926篇 |
化学工业 | 4129篇 |
金属工艺 | 292篇 |
机械仪表 | 454篇 |
建筑科学 | 436篇 |
矿业工程 | 187篇 |
能源动力 | 843篇 |
轻工业 | 12896篇 |
水利工程 | 45篇 |
石油天然气 | 379篇 |
武器工业 | 39篇 |
无线电 | 232篇 |
一般工业技术 | 1084篇 |
冶金工业 | 378篇 |
原子能技术 | 252篇 |
自动化技术 | 592篇 |
出版年
2024年 | 156篇 |
2023年 | 411篇 |
2022年 | 780篇 |
2021年 | 1007篇 |
2020年 | 966篇 |
2019年 | 903篇 |
2018年 | 813篇 |
2017年 | 776篇 |
2016年 | 791篇 |
2015年 | 834篇 |
2014年 | 1070篇 |
2013年 | 1434篇 |
2012年 | 1613篇 |
2011年 | 1489篇 |
2010年 | 988篇 |
2009年 | 947篇 |
2008年 | 846篇 |
2007年 | 1154篇 |
2006年 | 1090篇 |
2005年 | 876篇 |
2004年 | 721篇 |
2003年 | 649篇 |
2002年 | 553篇 |
2001年 | 378篇 |
2000年 | 317篇 |
1999年 | 285篇 |
1998年 | 219篇 |
1997年 | 222篇 |
1996年 | 131篇 |
1995年 | 114篇 |
1994年 | 107篇 |
1993年 | 101篇 |
1992年 | 117篇 |
1991年 | 43篇 |
1990年 | 49篇 |
1989年 | 41篇 |
1988年 | 36篇 |
1987年 | 42篇 |
1986年 | 37篇 |
1985年 | 40篇 |
1984年 | 32篇 |
1983年 | 12篇 |
1982年 | 21篇 |
1981年 | 12篇 |
1980年 | 24篇 |
1979年 | 9篇 |
1977年 | 8篇 |
1976年 | 11篇 |
1975年 | 14篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
21.
Hassan Hajjaj Gerard Goma Jean M. François 《International Journal of Food Science & Technology》2015,50(8):1731-1736
In submerged cultures performed in chemically defined fermentation medium containing glucose and glutamate, the growth and production of water‐soluble red pigments and citrinin by the filamentous fungus Monascus ruber were studied under various carbon/nitrogen (C/N) ratios. The specific production of the red pigments was optimal at a glucose/glutamate ratio of about 10 and then steadily decreased at higher C/N ratio. In contrast, the production of the mycotoxin increased with increased C/N with an optimum in the range of 30–45. In a fed‐batch mode, it was also found that the production of pigments was not favoured in fed‐batch mode by feeding the medium with glucose while keeping the C/N ratio lower than 10. This low production likely resulted from concurrent high accumulation of L‐malic acid that was reported to inhibit this production. In contrast, this mode of cultivation was rather favourable for the production of the mycotoxin. 相似文献
22.
Bioactive compounds and antioxidant activities of the Korean lotus leaf (Nelumbo nucifera) condiment: volatile and nonvolatile metabolite profiling during fermentation
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)
Recent studies have shown that lotus (Nelumbo nucifera) leaf has various pharmacological effects. However, there have been no scientific investigations into these leaves as a fermented crude liquid. This study compared the in vitro antioxidant capacity of lotus leaf‐fermented broth (LLFB) with that of 57° Brix sugar broth (SB) as a control over a period of 6 months based on 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging activity, ferric ion reducing power, superoxide dismutase‐like activity, tyrosinase inhibition and nitrite scavenging activity. The dominant species during fermentation process were Leuconostoc lactis and Saccharomyces cerevisiae for LLFB. A total of thirty‐six metabolites such as alkaloids, fatty acids, organic acids, phenolics, sugar and sugar derivatives, ethyl esters and monoterpenoids differed between SB and LLFB using gas chromatography–mass spectrometry. Meanwhile, nine volatile compounds in LLFB contributed pleasant, slightly sweetish and fruity odour of condiment and sensory evaluation score of 4.06 ± 1.52 in the proportion of 1:9 LLFB/water. 相似文献
23.
Midori Umekawa Kaito Hamada Naoto Isono Shuichi Karita 《Journal of Applied Glycoscience》2020,67(4):103
Hexokinases catalyze glucose phosphorylation at the first step in glycolysis in eukaryotes. In the budding yeast Saccharomyces cerevisiae , three enzymes for glucose phosphorylation have long been known: Hxk1, Hxk2, and Glk1. In this study, we focus on Emi2, a previously uncharacterized hexokinase-like protein of S. cerevisiae . Our data show that the recombinant Emi2 protein (rEmi2), expressed in Escherichia coli , possesses glucose-phosphorylating activity in the presence of ATP and Mg 2+ . It was also found that rEmi2 phosphorylates not only glucose but also fructose, mannose and glucosamine in vitro . In addition, we examined changes in the level of endogenous Emi2 protein in S. cerevisiae in the presence or absence of glucose and a non-fermentable carbon source. We found that the expression of Emi2 protein is tightly suppressed during proliferation in high glucose, while it is strongly upregulated in response to glucose limitation and the presence of a non-fermentable carbon source. Our data suggest that the expression of the endogenous Emi2 protein in S. cerevisiae is regulated under the control of Hxk2 in response to glucose availability in the environment. 相似文献
24.
Qiang Xia Tao Feng Xiaowei Lou Ying Wang Yangying Sun Daodong Pan Jinxuan Cao 《International Journal of Food Science & Technology》2020,55(2):669-680
As a decisive attribute, flavour could be influenced by HP treatments through multiple physical and chemical pathways within the high pressure (HP)-assisted meat curing process. This investigation aimed to identify the major pathway influencing volatile flavour patterns of two representative vinasse-cured duck (VCD) products with HP treatments (150–300 MPa/15 min), including wet and dry types, by employing headspace fingerprinting as an untargeted approach. Results suggested that HP treatments greatly lowered moisture contents and increased Warner-Bratzler shear force and thiobarbituric acid reactive substances of the cured samples. According to multivariate models, the volatile flavour patterns of the HP-processed VCD could be clearly separated from the unprocessed samples, but the VCD pressurised at different intensities represented similar volatile fingerprinting, which was validated by e-nose analysis. The discriminant analysis (OPLS-DA) model outlined vinasse-derived ethanol, acetic acid, 3-methyl-1-butanol, 2-methyl-1-butanol, phenethyl alcohol and 2-methyl-3-octanone as the major discriminant aromas across the unpressurised and pressurised samples. 相似文献
25.
Francielo Vendruscolo 《国际能源研究杂志》2015,39(3):293-302
Hydrogen is a clean energy carrier with great potential to be an alternative fuel. Anaerobic hydrogen fermentation seems to be more favorable, since hydrogen is yielded at high rates and various organic waste and wastewater enriched with carbohydrates as substrate result in low cost for hydrogen production. Abundant biomass from various industries could be a source for biohydrogen production where combination of waste treatment and energy production would be an advantage. Carbohydrate‐rich nitrogen‐deficient solid wastes such as starch residues can be used for hydrogen production by using suitable bioprocess technologies. Alternatively, converting biomass into gaseous fuels, such as biohydrogen, is possibly the most efficient way to use these agroindustrial residues. This review summarizes the potential of starch agroindustrial residues as a substrate for biohydrogen production. Types of potential starch agroindustrial residues, recent developments and bio‐processing conditions for biohydrogen production will be discussed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
26.
27.
Maria Grazia Basanisi Gianfranco La Bella Gaia Nobili Rosa Coppola Annita Maria Damato Maria Assunta Cafiero Giovanna La Salandra 《International Journal of Food Science & Technology》2020,55(3):1145-1150
The authenticity and traceability of meat products are issues of primary importance to ensure food safety. Unfortunately, food adulteration (e.g. the addition of inexpensive cuts to minced meat products) and mislabelling (e.g. the inclusion of meat from species other than those declared) happens frequently worldwide. The aim of this study was to apply a droplet digital PCR assay for the detection and quantification (copies μL−1) of the beef, pork, horse, sheep, chicken and turkey in meat products. The analysis conducted on commercial meat showed the presence of traces of DNA from other animal species than those declared. We show that the method is highly sensitive, specific and accurate (accuracy = 100%). This method could be adopted by competent food safety authorities to verify compliance with the labelling of meat products and to ensure quality and safety throughout the meat supply chain, from primary production to consumption. 相似文献
28.
《Food Control》2015
The aim of this study was to evaluate the dietary exposure to fumonisin B1 (FB1) through determination of residual FB1 in hair and corn products consumed by 56 volunteers from Pirassununga and Erval Velho, Brazil. Data from FB1 analyses in corn products and a Food Frequency Questionnaire (FFQ) were used for estimating the mean probable daily intake (PDIM) for FB1. FB1 was detected in 4 human hair samples (7.2%), at a mean level of 21.3 ± 12.1 ng g−1. The mean FB1 level found in corn products was 360.4 ± 555.1 μg kg−1. The PDIM value of FB1 in volunteers was 159 ± 47 ng kg−1 body weight day−1 which represents 7.9% of the provisional maximum tolerable daily intake (PMTDI) recommended for fumonisins. The FB1 levels found in human hair samples from each volunteer were associated with their individual PDI of FB1, indicating that exposure to FB1 in the sample studied do not represent a health concern. This is the first report on the incidence of FB1 in individual human hair in Brazil. 相似文献
29.
Karolina M. Wójciak Dariusz M. Stasiak Joanna Stadnik Karolina Ferysiuk Anna Kononiuk 《International Journal of Food Science & Technology》2019,54(1):75-83
In this study, the influence of sonication time on the biogenic amines formation as a critical point in uncured dry-fermented beef manufacturing was studied. Samples of musculus semimembranosus were sonicated at different times (5 and 10 min) using ultrasound cold bath (4 °C) in acid whey (US 40 kHz and acoustic power 480 W). The effect of sonication on biogenic amine (BA) formation was investigated during 93 days of ripening period. Other parameters (pH value, water activity, microbial counts) that might provide further information on the product under study were also determined. The use of ultrasound during beef marinating in acid whey has a positive effect on retarding histamine (HIS), cadaverine (CAD), tyramine (TYR) and putrescine (PUT) formation. Moreover, the sonication treatment did not inhibit the growth of lactic acid bacteria (LAB) in dry-fermented beef during the whole ripening period. The pathogen bacteria (Staphylococcus aureus, Clostridium sp., Listeria monocytogenes) were not detected in all samples neither after 31 nor after 93 days of ripening period. 相似文献
30.
《International Journal of Hydrogen Energy》2020,45(19):11000-11010
The objective of this work was to comparatively evaluate the production of biohydrogen (bio-H2) from tequila vinasses at optimized mesophilic and thermophilic conditions and to elucidate the main metabolic routes involved. Optimal temperatures of 35 °C and 55 °C, and pH of 5.5 maximized the bio-H2 production rates, 25.5 ± 0.01 NmL h−1 and 169.9 ± 8.9 NmL h−1 in the mesophilic and thermophilic regimens, respectively. During the operation of anaerobic sequencing batch reactors, the thermophilic process allowed a volumetric bio-H2 production rate of 519 ± 13 NmL-H2 L−1 d−1 equivalent to 750 ± 19 NmL-H2 Lvinasse−1, while the mesophilic one 448 ± 23 NmL-H2 L−1 d−1 and 647 ± 33 NmL-H2 Lvinasse−1, respectively. Furthermore, the gas produced under thermophilic conditions showed high hydrogen content (86.5%). Finally, formate degradation and glucose fermentation to acetic and butyric acids were the main metabolic routes involved in bio-H2 production under thermophilic conditions, while at mesophilic conditions, the lactate and formate degradation pathways governed. 相似文献