全文获取类型
收费全文 | 1135篇 |
免费 | 86篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 479篇 |
金属工艺 | 9篇 |
机械仪表 | 23篇 |
建筑科学 | 30篇 |
能源动力 | 29篇 |
轻工业 | 278篇 |
水利工程 | 9篇 |
石油天然气 | 6篇 |
无线电 | 31篇 |
一般工业技术 | 146篇 |
冶金工业 | 24篇 |
原子能技术 | 3篇 |
自动化技术 | 146篇 |
出版年
2024年 | 4篇 |
2023年 | 11篇 |
2022年 | 93篇 |
2021年 | 135篇 |
2020年 | 54篇 |
2019年 | 42篇 |
2018年 | 40篇 |
2017年 | 50篇 |
2016年 | 38篇 |
2015年 | 29篇 |
2014年 | 53篇 |
2013年 | 65篇 |
2012年 | 78篇 |
2011年 | 96篇 |
2010年 | 62篇 |
2009年 | 78篇 |
2008年 | 61篇 |
2007年 | 51篇 |
2006年 | 39篇 |
2005年 | 25篇 |
2004年 | 25篇 |
2003年 | 19篇 |
2002年 | 22篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
排序方式: 共有1221条查询结果,搜索用时 421 毫秒
191.
Blustein David L.; Murphy Kerri A.; Kenny Maureen E.; Jernigan Maryam; Pérez-Gualdrón Leyla; Casta?eda Tani; Koepke Margaret; Land Marie; Urbano Alessandra; Davis Ophera 《Canadian Metallurgical Quarterly》2010,57(2):248
This qualitative study is an exploration of 32 urban high school students’ narratives about the connection between school, work, and societal expectations of their future success related to their racial and ethnic background. The sample varied along 2 contextual dimensions: participation in a psychoeducational intervention (Tools for Tomorrow) and developmental status (i.e., half the sample were 9th-grade students and the other half were 12th-grade students). Using consensual qualitative research, the narratives revealed 3 major domains: future orientation; students’ perceptions of society’s expectations based on race and ethnicity; and students’ perception of the role of their race and ethnicity in future success. Results reveal that the majority of students endorse a connection between school and work, believe that society holds low expectations for them based on their racial and ethnic background, and cannot predict their future success based on their background. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
192.
A tool to assure the geographical origin of local food products (glasshouse tomatoes) using labeling with rare earth elements
下载免费PDF全文
![点击此处可从《Journal of the science of food and agriculture》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Donata Bandoniene Thomas Meisel Alessandra Rachetti Christoph Walkner 《Journal of the science of food and agriculture》2018,98(12):4769-4777
BACKGROUND
Trace element fingerprinting has been widely used for identification of provenance of regional food. In the case of products from conventional agriculture, it is expected that the elemental composition will comply with that of the commercially available substrate of the plants. Therefore, for products without a direct relationship with the regional soil the region‐specific differences in elemental composition are no longer recognizable. The idea of this work is the labeling of tomatoes with rare earth elements (REE) in the ultra‐trace range for food authentication.RESULTS
Labeling of tomatoes was carried out either by watering the soil with Nd‐ and Er‐spiked water or by adding these elements as solid oxides to the soil. In both cases enrichment of Nd and Er relative to the control group was detected in tomato fruits and leaves using inductively coupled plasma–mass spectrometry. Tomato plants rapidly absorb the dissolved REE from the irrigation water, and watering for a short period just before ripeness is sufficient to induce REE labels.CONCLUSION
Labeling with trace amounts of REE could potentially be used to assure the provenance of tomatoes of local origin and separate these from products of foreign origin. © 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献193.
Evaluation of nonthermal effects of electricity on inactivation kinetics of Staphylococcus aureus and Escherichia coli during ohmic heating of infant formula
下载免费PDF全文
![点击此处可从《Journal of Food Safety》网站下载免费的PDF全文](/ch/ext_images/free.gif)
194.
195.
Helio Langoni Carolina Polo Camargo da Silva Marcella Zampoli Troncarelli Alessandra Tata Katia Roberta Anacleto Belaz Marcos Nogueira Eberlin Samea Fernandes Joaquim Felipe Freitas Guimarães Renata Bonini Pardo Eduardo Nardini Gomes 《Journal of dairy science》2017,100(6):4287-4289
Corynebacterium bovis is a mastitis-causing microorganism responsible for economic losses related to decrease in milk production. The aim of the study was identify Corynebacterium spp. strains recovered from milk samples of subclinical mastitis by using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Samples were collected during a 10-mo mastitis-monitoring program in a high-production dairy farm. In this study, 80 strains were analyzed; from these 54 (67.5%) were identified at species level as Corynebacterium bovis, 24 (31.2%) isolates were identified at the genus level as Corynebacterium spp., and only 1 (1.35%) isolated had unreliable identification. Results demonstrated that MALDI-MS could be an important technique for the identification of Corynebacterium spp. in milk. 相似文献
196.
In Vitro Starch Digestibility of Commercial Gluten‐Free Pasta: The Role of Ingredients and Origin
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alessandra Marti Parisa Abbasi Parizad Mauro Marengo Daniela Erba Maria Ambrogina Pagani Maria Cristina Casiraghi 《Journal of food science》2017,82(4):1012-1019
Gluten replacement in gluten‐free (GF) products presents major challenges for the food industry in terms of sensorial, technological and nutritional characteristics. The absence of gluten reportedly affects starch digestibility, thus increasing the postprandial glycaemic response. However, the role of ingredients and processing conditions has been addressed only seldom. We investigated the in vitro starch digestibility of 9 commercial GF products (5 Italian pasta and 4 Oriental noodles) differing in formulation and processing conditions. Content of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) were assessed and combined with information on starch pasting properties and on the overall protein organization. Oriental noodles presented higher relative levels of RS and RDS than Western‐style pasta, that often had SDS levels compatible with low rates of starch digestion. As regard formulation, presence of multiple ingredients seems to likely increase the RDS level, as did the different protein organization in the various samples. 相似文献
197.
Quality Characteristics of Wholemeal Flour and Bread from Durum Wheat (Triticum turgidum L subsp. durum Desf.) after Field Treatment with Plant Water Extracts
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alessandra Carrubba Andrea Comparato Andrea Labruzzo Serena Muccilli Virgilio Giannone Alfio Spina 《Journal of food science》2016,81(9):C2158-C2166
The use of selected plant water extracts to control pests and weeds is gaining growing attention in organic and sustainable agriculture, but the effects that such extracts may exert on the quality aspects of durum wheat are still unexplored. In 2014, 5 plant water extracts (Artemisia arborescens, Euphorbia characias, Rhus coriaria, Thymus vulgaris, Lantana camara) were prepared and distributed on durum wheat cv Valbelice to evaluate their potential herbicidal effects. After crop harvesting, the major physicochemical and technological parameters of wholemeal flours obtained from each treatment were measured and compared with those from chemical weeding and untreated controls. A baking test was also performed to evaluate the breadmaking quality. In wholemeal flours obtained after the treatment with plant extracts protein and dry gluten content were higher than in control and chemical weeding. Wholemeal flours obtained after chemical weeding reached the highest Mixograph parameters, and that from durum wheat treated with R. coriaria extract demonstrated a very high α‐amylase activity. We concluded that the treatments with plant water extracts may influence many quality traits of durum wheat. This occurrence must be taken into account in overall decisions concerning the use of plant extracts in pest and weed management practice. 相似文献
198.
Detection of Virulence Genes and Growth Potential in Listeria monocytogenes Strains Isolated from Ricotta Salata Cheese
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Valentina Coroneo Valentina Carraro Nadhem Aissani Adriana Sanna Alessandra Ruggeri Sara Succa Barbara Meloni Antonella Pinna Clara Sanna 《Journal of food science》2016,81(1):M114-M120
Ricotta Salata is a traditional ripened and salted whey cheese made in Sardinia (Italy) from sheep's milk. This product is catalogued as ready‐to‐eat food (RTE) since it is not submitted to any further treatment before consumption. Thus, foodborne pathogens, such as Listeria monocytogenes, can represent a health risk for consumers. In September 2012, the FDA ordered the recall of several batches of Ricotta Salata imported from Italy linked to 22 cases of Listeriosis in the United States. This study was aimed at evaluating the presence and virulence properties of L. monocytogenes in 87 samples of Ricotta Salata produced in Sardinia. The ability of this product to support its growth under foreseen packing and storing conditions was also evaluated in 252 samples. Of the 87 samples 17.2% were positive for the presence of L. monocytogenes with an average concentration of 2.2 log10 cfu/g. All virulence‐associated genes (prfA, rrn, hlyA, actA, inlA, inlB, iap, plcA, and plcB) were detected in only one isolated strain. The Ricotta Salata samples were artificially inoculated and growth potential (δ) was assessed over a period of 3 mo. The value of the growth potential was always >0.5 log10 cfu/g under foreseen packing and storing conditions. This study indicates that Ricotta Salata supports the L. monocytogenes growth to levels that may present a serious risk to public health, even while stored at refrigeration temperatures. 相似文献
199.
Tania Aparecida Becker‐Algeri Denise Castagnaro Kennidy de Bortoli Camila de Souza Deisy Alessandra Drunkler Eliana Badiale‐Furlong 《Journal of food science》2016,81(3):R544-R552
This paper presents a literature review of the occurrence of several mycotoxins in bovine milk and dairy products, because it is the main type of milk produced and marketed worldwide. Mycotoxins are produced by different genera of filamentous fungi and present serious health hazards such as carcinogenicity and mutagenicity. Under favorable growth conditions, toxigenic fungi produce mycotoxins which contaminate the lactating cow's feedstuff. During metabolism, these mycotoxins undergo biotransformation and are secreted in milk. Data show that there is a seasonal trend in the levels of mycotoxins in milk, with these being higher in the cold months probably due to the prolonged storage required for the cattle feeds providing favorable conditions for fungal growth. Good agricultural and storage practices are therefore of fundamental importance in the control of toxigenic species and mycotoxins. Although aflatoxins (especially aflatoxin M1) are the mycotoxins of greater incidence in milk and dairy products, this review shows that other mycotoxins, such as fumonisin, ochratoxin A, trichothecenes, zearalenone, T‐2 toxin, and deoxynivalenol, can also be found in these products. Given that milk is widely consumed and is a source of nutrients, especially in childhood, a thorough investigation of the occurrence of mycotoxins as well the adoption of measures to minimize their contamination of milk is essential. 相似文献
200.
Alessandra Gentili Valeria De Pratti Fulvia Caretti Virginia Pérez-Fernández Pierpaolo Tomai Roberta Curini 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(12):1793-1802
This paper describes a rapid method for confirming residues of thyreostats in meat-based baby foods by using liquid chromatography – dual polarity electrospray – tandem mass spectrometry (LC-ES(±)-MS/MS). Six thioureylenes, belonging to the group of thiouracil and imidazole, were selected for this work: thiouracil (TU), methylthiouracil (MTU), propylthiouracil (PTU), phenylthiouracil (PhTU), mercaptobenzimidazole (MBI) and tapazole (TAP).The amphoteric nature of these compounds allows their electrospray detection in both positive and negative ionisation. Nevertheless, MS detection is not favoured by their low molecular weights, while their chromatographic retention is also thwarted by their high polarity. A pentafluorophenyl (PFP) core-shell phase column was selected to avoid peak asymmetry or peak splitting, and a dual-polarity ionisation method was optimised to obtain a sensitivity as high as possible. The method was validated according to the Commission Decision 657/2002/EC. A simple and fast procedure based on matrix solid phase dispersion (MSPD) was optimised to extract analytes from baby foods with recoveries exceeding 82%. Limit of decision (CCα) and detection capability (CCβ) were lower than the permissible maximum concentration (10 ng g?1). The validated method was then applied to assess the potential occurrence of the six selected thyreostats in nine commercial products. All the samples were found free of contamination. 相似文献