全文获取类型
收费全文 | 1268篇 |
免费 | 86篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 661篇 |
金属工艺 | 23篇 |
机械仪表 | 15篇 |
建筑科学 | 17篇 |
能源动力 | 24篇 |
轻工业 | 169篇 |
水利工程 | 3篇 |
石油天然气 | 9篇 |
无线电 | 46篇 |
一般工业技术 | 220篇 |
冶金工业 | 26篇 |
原子能技术 | 6篇 |
自动化技术 | 124篇 |
出版年
2024年 | 5篇 |
2023年 | 39篇 |
2022年 | 197篇 |
2021年 | 185篇 |
2020年 | 52篇 |
2019年 | 36篇 |
2018年 | 46篇 |
2017年 | 55篇 |
2016年 | 62篇 |
2015年 | 49篇 |
2014年 | 82篇 |
2013年 | 61篇 |
2012年 | 73篇 |
2011年 | 74篇 |
2010年 | 40篇 |
2009年 | 43篇 |
2008年 | 59篇 |
2007年 | 38篇 |
2006年 | 34篇 |
2005年 | 31篇 |
2004年 | 20篇 |
2003年 | 13篇 |
2002年 | 14篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 7篇 |
1997年 | 13篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1964年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有1355条查询结果,搜索用时 11 毫秒
931.
Denise Mafra Julie A. Kemp Viviane de O. Leal Ludmila Cardozo Natalia A. Borges Livia Alvarenga Karla T. R. Teixeira Peter Stenvinkel 《Molecular nutrition & food research》2023,67(9):2200859
Fish is an excellent source of ω-3 polyunsaturated fatty acids (PUFAs), amino acids, collagen, vitamins, and iodine and its intake is associated with health benefits, mainly reduces risk of cardiovascular mortality. However, recent studies have shown that fish is also an important source of trimethylamine N-oxide (TMAO), a uremic toxin produced by the gut microbiota that promotes an increased risk of cardiovascular diseases. In patients with chronic kidney disease (CKD), TMAO levels are markedly increased due to gut dysbiosis and reduced kidney function. No study has yet evaluated the effects of a fish-rich diet on TMAO plasma levels and cardiovascular outcomes. This review discusses the pros and cons of a fish-rich diet in patients with CKD – a matter of depth. 相似文献
932.
Natalia Palacios‐Rojas Laura McCulley Mikayla Kaeppler Tyler J. Titcomb Nilupa S. Gunaratna Santiago Lopez‐Ridaura Sherry A. Tanumihardjo 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):1809-1834
Agro‐food systems are undergoing rapid innovation in the world and the system's continuum is promoted at different scales with one of the main outcomes to improve nutrition of consumers. Consumer knowledge through educational outreach is important to food and nutrition security and consumer demands guide breeding efforts. Maize is an important part of food systems. It is a staple food and together with rice and wheat, they provide 60% of the world's caloric intake. In addition to being a major contributor to global food and nutrition security, maize forms an important part of the culinary culture in many areas of Africa, the Americas, and Asia. Maize genetics are being exploited to improve human nutrition with the ultimate outcome of improving overall health. By impacting the health of maize consumers, market opportunities will be opened for maize producers with unique genotypes. Although maize is a great source of macronutrients, it is also a source of many micronutrients and phytochemicals purported to confer health benefits. The process of biofortification through traditional plant breeding has increased the protein, provitamin A carotenoid, and zinc contents of maize. The objective of this paper is to review the innovations developed and promoted to improve the nutritional profiles of maize and outcomes of the maize agro‐food system. 相似文献
933.
Andreja Rajkovic Jelena Jovanovic Silvia Monteiro Marlies Decleer Mirjana Andjelkovic Astrid Foubert Natalia Beloglazova Varvara Tsilla Benedikt Sas Annemieke Madder Sarah De Saeger Mieke Uyttendaele 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):1605-1657
Bacterial toxins are food safety hazards causing about 10% of all reported foodborne outbreaks in Europe. Pertinent to Gram‐positive pathogens, the most relevant toxins are emetic toxin and diarrheal enterotoxins of Bacillus cereus, neurotoxins of Clostridium botulinum, enterotoxin of Clostridium perfringens, and a family of enterotoxins produced by Staphylococcus aureus and some other staphylococci. These toxins are the most important virulence factors of respective foodborne pathogens and a primary cause of the related foodborne diseases. They are proteins or peptides that differ from each other in their size, structure, toxicity, toxicological end points, solubility, and stability, types of food matrix to which they are mostly related to. These differences influence the characteristics of required detection methods. Therefore, detection of these toxins in food samples, or detection of toxin production capacity in the bacterial isolate, remains one of the cornerstones of microbial food analysis and an essential tool in understanding the relevant properties of these toxins. Advanced research has led into new insights of the incidence of toxins, mechanisms of their production, their physicochemical properties, and their toxicological mode of action and dose‐response profile. This review focuses on biological, immunological, mass spectrometry, and molecular assays as the most commonly used detection and quantification methods for toxins of B. cereus, C. botulinum, C. perfringens, and S. aureus. Gathered and analyzed information provides a comprehensive blueprint of the existing knowledge on the principles of these assays, their application in food safety, limits of detection and quantification, matrices in which they are applicable, and type of information they provide to the user. 相似文献
934.
The present study reveals the utility of high-performance thin-layer chromatographic (HPTLC) fingerprinting of phenolic constituents for the authentication of monofloral honeys. The obtained data enables a more complete assessment of honey quality and the identification of emerging threats to honey quality. The developed procedure facilitates differentiation of varietal honeys and detection of honey adulterations. We used an HPTLC fingerprint analysis to determine the characteristic patterns of different honey types (willow, buckwheat, heather, pine honeydew, and manuka honey). The HPTLC chromatograms were used to determine the differences in the botanical origin of the honey samples on the basis of the band profiles, which are characteristic for each honey type. Identification of 11 polyphenols was performed by comparison of the color and Rf of the bands with available standards. Additionally, the results were confirmed by an HPLC analysis. 相似文献
935.
936.
Grażyna Bortnowska Natalia Krzemińska Katarzyna Mojka 《International Journal of Food Science & Technology》2013,48(12):2668-2675
Stability and physicochemical properties of model sauces containing 2.5 wt% fresh beef meat (related to raw material), 30 wt% rapeseed oil and native waxy maize starch (WMS) or potato starch (PS) at concentrations ranged from 0.5 to 4.0 wt% were assessed. Sauces thickened with WMS showed a significantly (P < 0.05) higher stability than respective ones made with PS. All studied systems exhibited non‐Newtonian, pseudoplastic behaviour. The Ostwald–de Waele and Herschel–Bulkley models were used to describe the flow properties of model sauces. In comparison with control sample (prepared without starch), addition of this polysaccharide (WMS or PS) increased consistency index, yield stress and apparent viscosity and decreased flow behaviour index of model sauces. The Arrhenius equation was used to determine the effects of temperature (20–50 °C) on the apparent viscosity. The activation energy values were in ranges 7.66–10.59 kJ mol?1 and 8.87–11.82 kJ mol?1 in sauces prepared with WMS and PS, respectively. The instrumentally detected changes in consistency and whiteness of model sauces were found, which may be used as the good predictors of the perceived sensory consistency and whiteness. 相似文献
937.
Rilla N Martínez B Delgado T Rodríguez A 《International journal of food microbiology》2003,85(1-2):23-33
Lactococcus lactis ssp. lactis IPLA 729 is a nisin Z producer isolated from raw milk cheese able to grow and produce nisin Z in milk. The ability of this strain to inhibit the growth of Clostridium tyrobutyricum CECT 4011, a late blowing agent, in Vidiago cheese, a semi-hard farmhouse variety, manufactured in Asturias, Northern Spain, was investigated. For control purposes, cheeses were manufactured with the mesophilic mixed starter IPLA-001. In experimental cheeses, the nisin-producing strain L. lactis IPLA 729 was combined with this starter. Nisin Z activity reached a concentration of 1600 AU/ml in 1-day cheeses and this level was maintained until 15 days of ripening. Furthermore, to compare the inhibitory activity of the nisin-producing strain to nitrate, cheeses were also manufactured with a commercial starter culture and potassium nitrate as anti-blowing agent was added in accordance with Vidiago's cheesemakers. The control, experimental and commercial cheeses were contaminated with C. tyrobutyricum CECT 4011. The composition of the three different cheeses showed only slight differences with respect to total solids, protein and fat, although control and experimental cheeses showed a richer flavour-compound profile than commercial cheeses. The level of the spoilage strain C. tyrobutyricum CECT 4011 decreased from 1.2x10(6) to 1.3x10(3) cfu/g during ripening in presence of the nisin Z producer, while it increased to 1.99x10(9) cfu/g in control cheeses and to 3.5x10(7) cfu/g in commercial cheeses. 相似文献
938.
Loulouda A. Bosnea Yiannis Kourkoutas Natalia Albantaki Constantina Tzia Athanasios A. Koutinas Maria Kanellaki 《LWT》2009,42(10):1696-1702
Lactobacillus casei cells were immobilized on wheat grains and the effect of nine cryoprotectants during freeze-drying was investigated. Survival and fermentative activity of the freeze-dried immobilized biocatalysts was studied by monitoring pH, lactic acid and lactose content in successive fermentations batches of both synthetic lactose medium and milk. Freeze-dried L. casei cells immobilized on wheat grains without using cryoprotectants resulted in high cell survival and metabolic activity. The same biocatalysts were stored at room temperature for 9 months and at 4 °C and −18 °C for 12 months. Reactivation of the stored biocatalysts was carried out in synthetic lactose medium. Storage at room and low temperatures (4 °C and −18 °C) resulted in about 5.11, 4.9 and 4.3 final pH respectively during fermentations, indicating the suitability of the immobilized biocatalysts for the production of mild and low pH dairy products. The immobilization of a probiotic microorganism, such as L. casei, on boiled wheat which contains prebiotic compounds might provide a potential synbiotic preparation. 相似文献
939.
Kristin Kirchhof Kamelia Hristova Natalia Krasteva George Altankov Thomas Groth 《Journal of materials science. Materials in medicine》2009,20(4):897-907
Here, the layer-by-layer technique (LbL) was used to modify glass as model biomaterial with multilayers of chitosan and heparin
to control the interaction with MG-63 osteoblast-like cells. Different pH values during multilayer formation were applied
to control their physico-chemical properties. In the absence of adhesive proteins like plasma fibronectin (pFN) both plain
layers were rather cytophobic. Hence, the preadsorption of pFN was used to enhance cell adhesion which was strongly dependent
on pH. Comparing the adhesion promoting effects of pFN with an engineered repeat of the FN III fragment and collagen I which
both lack a heparin binding domain it was found that multilayers could bind pFN specifically because only this protein was
capable of promoting cell adhesion. Multilayer surfaces that inhibited MG-63 adhesion did also cause a decreased cell growth
in the presence of serum, while an enhanced adhesion of cells was connected to an improved cell growth. 相似文献
940.
Hornero R Abásolo D Jimeno N Sánchez CI Poza J Aboy M 《IEEE transactions on bio-medical engineering》2006,53(2):210-218
We analyzed time series generated by 20 schizophrenic patients and 20 sex- and age-matched control subjects using three nonlinear methods of time series analysis as test statistics: central tendency measure (CTM) from the scatter plots of first differences of data, approximate entropy (ApEn), and Lempel-Ziv (LZ) complexity. We divided our data into a training set (10 patients and 10 control subjects) and a test set (10 patients and 10 control subjects). The training set was used for algorithm development and optimum threshold selection. Each method was assessed prospectively using the test dataset. We obtained 80% sensitivity and 90% specificity with LZ complexity, 90% sensitivity, and 60% specificity with ApEn, and 70% sensitivity and 70% specificity with CTM. Our results indicate that there exist differences in the ability to generate random time series between schizophrenic subjects and controls, as estimated by the CTM, ApEn, and LZ. This finding agrees with most previous results showing that schizophrenic patients are characterized by less complex neurobehavioral and neuropsychologic measurements. 相似文献