首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   601篇
  免费   52篇
  国内免费   7篇
电工技术   2篇
综合类   5篇
化学工业   23篇
金属工艺   12篇
机械仪表   9篇
建筑科学   7篇
矿业工程   3篇
能源动力   8篇
轻工业   432篇
水利工程   2篇
石油天然气   10篇
无线电   59篇
一般工业技术   70篇
冶金工业   7篇
原子能技术   1篇
自动化技术   10篇
  2024年   14篇
  2023年   16篇
  2022年   10篇
  2021年   21篇
  2020年   36篇
  2019年   34篇
  2018年   26篇
  2017年   28篇
  2016年   24篇
  2015年   29篇
  2014年   38篇
  2013年   83篇
  2012年   32篇
  2011年   33篇
  2010年   19篇
  2009年   19篇
  2008年   27篇
  2007年   37篇
  2006年   20篇
  2005年   20篇
  2004年   16篇
  2003年   11篇
  2002年   6篇
  2001年   7篇
  2000年   5篇
  1999年   5篇
  1998年   8篇
  1997年   7篇
  1996年   4篇
  1995年   8篇
  1994年   7篇
  1993年   3篇
  1992年   4篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
排序方式: 共有660条查询结果,搜索用时 15 毫秒
131.
The objective of this study was to describe the dependence of textural properties (hardness, cohesiveness, and relative adhesiveness) of processed cheese spreads on the proportion of disodium phosphate (DSP), tetrasodium diphosphate (TSPP), and sodium salts of polyphosphate in ternary mixtures of emulsifying salts. Sodium salts of polyphosphate with different mean lengths (n ≈ 5, 9, 13, 20, and 28) were used. Pentasodium triphosphate (PSTP) was used instead of TSPP in the second part of the study. Products with and without pH adjustment were tested (the target pH value was 5.60–5.80). Textural properties of the processed cheese were observed after 2, 9, and 30 d of storage at 6°C. Hardness of the processed cheese with a low content of polyphosphate increased at a specific DSP:TSPP ratio (~1:1 to 3:4). This trend was the same for all the polyphosphates used; only the absolute values of texture parameters were different. The same trends were observed in the ternary mixtures with PSTP, showing lower final values of hardness compared with samples containing TSPP. Hardness and cohesiveness decreased and relative adhesiveness increased in the samples with increased pH values and vice versa; the main trend remained unchanged.  相似文献   
132.
Pickled peppers are preferred by certain consumer groups at reduced pungency. To investigate the reduction in pepper pungency and capsaicin content, fresh ‘Makedoniko’ hot peppers were treated with 0, 0.5 or 1% NaOH before preserved in acid brine for 60 days. Pepper physicochemical traits were monitored following NaOH treatment and during preservation. Capsaicin content was measured in the beginning and at the end of preservation, and the peppers were also tested organoleptically. Preservation in acid brine induced the typical green–yellow product colour, increased firmness and decreased the dry mass in all treatments. NaOH‐treated pepper increased phenolics, chlorophyll and antioxidant content in dry mass during preservation faster than the control. Capsaicin content was reduced by 25 or 50% following 0.5 or 1% NaOH treatment, respectively. Pepper organoleptic pungency was also decreased following 1% NaOH treatment. NaOH reduces capsaicin content and pungency of ‘Makedoniko’ pepper, with minor effects on its processed product quality.  相似文献   
133.
乳化盐是再制乳酪的关键原料。通过测定烘焙功能性和流变性,研究乳化盐对再制马苏里拉乳酪品质的影响,结果表明,乳化盐对再制马苏里拉乳酪烘焙功能性有显著影响,随着型号为"JOHA PZ14"的复合磷酸盐添加比例的提高,再制马苏里拉乳酪融化性和油脂析出性增加,拉伸性先增加后降低,褐变性降低。选择型号为"JOHA PZ7":"JOHA PZ14"乳化盐=4:1时,再制马苏里拉乳酪烘焙功能性最接近天然马苏里拉乳酪。  相似文献   
134.
The monitoring of food additives and recent dietary surveys carried out in Denmark have earlier been used to estimate the intake of sweeteners and nitrite in relation to acceptable daily intakes. The ubiquitous use of the preservatives benzoic and sorbic acids raises the question of the magnitude of the intake of these preservatives in relation to acceptable daily intakes. This area is explored in this paper. The content of benzoic and sorbic acids in all food groups, where they are allowed, was monitored in Denmark 17 times between 2001 and 2006 with a total of 1526 samples. Transgressions of maximum limits, illegal use or declaration faults were found in about 3% of samples. From repeated investigations on fat-based foods (salads and dressings), marmalade and stewed fruit, it is concluded that the amounts used in industry have been relatively stable throughout the whole period, although limited data for marmalade show some variation. Most foods in the categories soft drinks, dressings, fat-based salads, pickled herrings, and marmalade contain benzoic and sorbic acid, and sliced bread also contains in some cases sorbic acid. The median daily intake and intake distribution of benzoic and sorbic acids were calculated with data from the Danish National Survey of Dietary Habits and Physical Activity (age from 4 to 75 years) conducted in 2000–2004 with 5785 participants. The median intakes of both benzoic acid and sorbic acid are well below the acceptable daily intakes of 0–5 and 0–25 mg kg?1 body weight (bw) day?1 for benzoic and sorbic acid, respectively. However, the 90th percentile based on the average of the samples with a content of benzoic acid is higher than the acceptable daily intake for both men and women, with the highest value of 16 mg kg?1 bw day?1 for both boys and girls in the 4–6-year-old age group. Based on the average of all samples, the 95th percentile is over the acceptable daily intake for men up to 34 years and for women up to 24 years, and the 90th percentile for men up to 18 years and for women up to 10 years. Soft drinks, salads and dressings are the main contributors to benzoic acid intake. The sorbic acid intake based on the average of all samples is well below the acceptable daily intake. However, for the intake based on the average of samples with content, the 95th percentile exceeds the acceptable daily intake. This is caused by the dominating contribution to the intake of sorbic acid from sliced bread, but since only seven out of 42 samples have added sorbic acid, the calculation based on the average of samples with content will exaggerate the intake. With a built-in safety factor of 100 in the acceptable daily intakes and judging from the literature, the high intakes of benzoic acid should not cause any concern for ill-effects. However, there must be a reason to reconsider the maximum limits especially for benzoic acid in soft drinks, dressings and salads and for sorbic acid in sliced bread.  相似文献   
135.
Young, old, pregnant and immuno-compromised persons are of great concern for risk assessors as they represent the sub-populations most at risk. The present paper focuses on risk assessment linked to furan exposure in children. Only the Belgian population was considered because individual contamination and consumption data that are required for accurate risk assessment were available for Belgian children only. Two risk assessment approaches, the so-called deterministic and probabilistic, were applied and the results were compared for the estimation of daily intake. A significant difference between the average Estimated Daily Intake (EDI) was underlined between the deterministic (419?ng?kg?1 body weight (bw) day?1) and the probabilistic (583?ng?kg?1 bw day?1) approaches, which results from the mathematical treatment of the null consumption and contamination data. The risk was characterised by two ways: (1) the classical approach by comparison of the EDI to a reference dose (RfDchronic-oral) and (2) the most recent approach, namely the Margin of Exposure (MoE) approach. Both reached similar conclusions: the risk level is not of a major concern, but is neither negligible. In the first approach, only 2.7 or 6.6% (respectively in the deterministic and in the probabilistic way) of the studied population presented an EDI above the RfDchronic-oral. In the second approach, the percentage of children displaying a MoE above 10,000 and below 100 is 3–0% and 20–0.01% in the deterministic and probabilistic modes, respectively. In addition, children were compared to adults and significant differences between the contamination patterns were highlighted. While major contamination was linked to coffee consumption in adults (55%), no item predominantly contributed to the contamination in children. The most important were soups (19%), dairy products (17%), pasta and rice (11%), fruit and potatoes (9% each).  相似文献   
136.
An optimal caseinate-acetylated monoglyceride edible coating consisting of 1.5% Alanate-310 (a calcium caseinate) and 1.5% Myvacet-5-07 (an acetylated monoglyceride) produced a reduction (75%) in moisture loss from celery (Apium graveolens) sticks. Similar edible coatings on apple (Malus domestica) fruits produced higher water vapor resistance. However, since apples have a natural high resistance to water vapor, edible coatings did not decrease water loss from whole fruit. Edible coatings did not modify respiration or ethylene production by apples or celery sticks. Quality of minimally processed fruits and vegetables that are susceptible to water loss could be improved with edible coatings, but quality of commodities with high water vapor resistance would not.  相似文献   
137.
Advanced glycation end products (AGEs) are a heterogeneous group of molecules produced, non‐enzymatically, from the interaction between reducing sugars and the free amino groups of proteins, nucleic acids, and lipids. AGEs are formed as a normal consequence of metabolism but can also be absorbed from the diet. They have been widely implicated in the complications of diabetes affecting cardiovascular health, the nervous system, eyes, and kidneys. Increased levels of AGEs are also detrimental to metabolic health and may contribute to the metabolic abnormalities induced by the Western diet, which is high in processed foods and represents a significant source of AGEs. While increased AGE levels are a consequence of diabetic hyperglycaemia, AGEs themselves activate signaling pathways, which compromise insulin signaling and pancreatic β‐cell function, thus, contributing to the development of type 2 diabetes mellitus (T2DM). Furthermore, AGEs may also contribute to the obesogenic effects of the Western diet by promoting hypothalamic inflammation and disrupting the central control of energy balance. Here, the role of dietary AGEs in metabolic dysfunction is reviewed with a focus on the mechanisms underpinning their detrimental role in insulin resistance, pancreatic β‐cell dysfunction, hypothalamic control of energy balance, and the pathogenesis of T2DM and obesity.  相似文献   
138.
论述了有较高精度要求且结构复杂孔的加工工艺,介绍加工该零件钻孔模具的设计及制作过程。  相似文献   
139.
A method to detect volatile nitrosamines in meat samples was developed using headspace sampling by solid-phase microextraction (HS-SPME), with analysis by GC-MS. A 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane fused silica fibre was selected to extract a total of nine volatile nitrosamines: N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosodi-n-propylamine, N-nitrosomorpholine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosodi-n-butylamine, and N-nitrosodiphenylamine. Extraction at 65°C for 45 min with 36% (w/v) NaCl were the optimal conditions determined for the extraction of nine nitrosamines. Excellent linearity was obtained for all analytes with determination coefficients greater than 0.997. Recovery rates were between 92 and 113%. The relative standard deviation ranged from 0.81 to 8.0% for six of the nine compounds, and from 16 to 32% for the other three. For seven out of nine nitrosamines, limits of detection were below 3.6 µg kg?1 and the limits of quantification were below 12 µg kg?1. The nitrosamine levels in four varieties of processed meat products were investigated to assess the applicability of the method. Based on the results, the developed HS-SPME-GC-MS method proved to be a simple and efficient technique to detect seven out of nine nitrosamines in meat products with adequate sensitivity, accuracy and precision.  相似文献   
140.
张敏  焦宏  郭捷 《食品工程》2014,(4):19-23
试验采用基于NMR代谢组学的技术,分别对生山药饮片、麸炒山药及食用山药的化学成分进行了研究,检测出30多种化合物,包括腺苷、胆碱、多种氨基酸、有机酸及糖类等物质,其中有14种是3种山药的共有成分。另外,对引起生山药与麸炒山药、食用山药与药用山药差异的化学成分进行了指认,初步了解了炮制对山药化学成分的影响及山药药材与食材的差异。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号