全文获取类型
收费全文 | 114篇 |
免费 | 7篇 |
专业分类
化学工业 | 32篇 |
金属工艺 | 3篇 |
建筑科学 | 11篇 |
能源动力 | 4篇 |
轻工业 | 30篇 |
一般工业技术 | 17篇 |
冶金工业 | 7篇 |
自动化技术 | 17篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 7篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 781 毫秒
1.
Marthe Jordbrekk Blikra Sigrun Henjum Inger Aakre 《Comprehensive Reviews in Food Science and Food Safety》2022,21(2):1517-1536
Brown algae are becoming increasingly popular as a food source and dietary supplement in Europe and other Western countries. As they are highly rich in iodine, they represent a potential new dietary iodine source. Iodine deficiency has been re-emerging in Europe, and it is important to ensure adequate intake through one's diet. However, macroalgae, and especially brown algae, may contain very high amounts of iodine, and both iodine deficiency and excessive iodine may increase the risk of negative health effects. The iodine content of algae or foods containing algae is currently not regulated in the European Union. The aim of this paper is to review the literature to determine the chemical species of iodine in brown algae, the loss of iodine during processing, and the bioavailability and bioaccessibility of iodine. A systematic search of the literature was performed in April 2021, via the databases Web of Science and PubMed. The review includes studies of iodine in brown macroalgae in relation to bioavailability, bioaccessibility, processing and speciation. A meta-analysis was conducted in relation to the following topics: (i) the correlation between total iodine and iodide (I–) content in brown algae; (ii) the correlation between the loss of iodine during processing and the I– content; and (iii) the correlation between bioavailability and the I– content. The bioavailability of iodine from brown algae was generally high, with in vivo bioavailability ranging from 31% to 90%. The in vitro bioavailability of iodine (2%–28%) was systematically lower than in vivo bioavailability (31%–90%), indicating an inadequate in vitro methodology. Processing may reduce the iodine content of brown algae, and a higher I– content was positively correlated with increased iodine loss during processing. Although processing strategies may reduce the iodine content of brown algae significantly, the iodine content may still be high after processing. These findings may be used in food safety evaluations of brown algae as well as in the development of macroalgae-containing foods with iodine contents suitable for human consumption. Further research on processing techniques to reduce the iodine content in brown macroalgae are warranted. 相似文献
2.
Xueyuan ZhangWenle He Inger Odnevall Wallinder Jinshan PanChristofer Leygraf 《Corrosion Science》2002,44(9):2131-2151
Instantaneous corrosion rates of naturally patinated copper of varying age (16 months, 138 and 145 years) have been determined during continuous rain events in the laboratory with electrochemical impedance spectroscopy using a two-electrode cell. The two-electrode cell was found to yield the same information in bulk rainwater as a conventional three-electrode cell.Relatively constant corrosion rates, between 0.2 and 0.6 μm/y, were determined for samples having a two-layer structure with an inner brownish layer of cuprous oxide and an outer greenish layer of basic copper salts (138, 145 years). Samples with cuprous oxide as the dominating phase of the patina (16 months) showed higher and somewhat increasing corrosion rates during a rain event (from 0.6 to 1.2 μm/y). During a continuous rain event, corrosion rates were found to be approximately 10 (brownish patina) and 25 times (greenish patina) lower than corresponding instantaneous runoff rates. The first flush phenomena of the runoff process, with an increased concentration during first flush and a relatively constant concentration during steady state, was indirectly seen as an increase in solution conductivity during the first rain volume followed by relative constant value. The contribution of the concentration in the first flush to the total annual runoff rate was significant for panels having a greenish layer (138, 145 years) whereas it was negligible for panels having a brownish layer (16 months). 相似文献
3.
Students (N = 167) from the 4th, 8th, and 11th grades sorted meals, listed on individual cards, according to whether they would or would not eat them. Students were told to either consider eating the meals at home or at school. Forty-two different meals were selected from a pool of unique meals created by students in a previous study. The meals differed in head component, the presence or absence of vegetables, and the number of different foodstuffs. On average, approximately half of the meals were deemed acceptable, but older students accepted more meals than younger ones, boys accepted more meals than girls, and meals to be consumed at home were accepted more than those to be consumed at school. In addition, students tended to accept meals comprised of a small number of foodstuffs that did not contain vegetables. The also chose more meat-based meals over those containing fish or soup. These results suggest that students have rather unique food preferences that do not correspond well with nutritional standards. In order to address this problem we recommended that students be given more good choices in the school cafeteria through the introduction of a two-meal system and salad bars. 相似文献
4.
Inger Lytje 《AI & Society》1996,10(2):142-163
Participatory design strategies have placed the user at the center of the design process, leaving computer software designers
without guidelines for how to design and implement the software system. This paper aims to bring the designer back to the
center of the design process. and the way of doing it is to consider computer software as text. Three different text theories
are presented in order to explain what is meant by text, namely pragmatics, structuralism and deconstructivism. Finally it
is discussed how the design processes should be understood, and how they should be organized when taking the text point of
view of computer software. 相似文献
5.
Natural rubber vulcanizates of two formulations, with sulfur/N-cyclohexyl-2-benzothiazolesulfenamide (CBS) and tetramethylthiuram disulfide (TMTD), respectively, were analyzed by pyrolysis gas chromatography. A sulfur-selective flame-photometric detector was utilized. The main pyrolysis products were identified as CS2 and some thiophenes. The yields of the pyrolysis products from the two types of rubber were very different. The yields also varied with the curing time of the rubbers. 相似文献
6.
Borage oil sterols were isolated by TLC and characterized using GC and GC-MS. Several diunsaturated Δ5-sterols, some of them not previously recorded in vegetable oils, were found. Of these, 24-methylcholesta-5,23-dienol and
24-ethylcholesta-5,23-dienol could be useful markers for borage oil. Two other diunsaturated Δ5-sterols that are rarely found in vegetable oils, 24-methylcholesta-5,24(25)-dienol and 24-ethylcholesta-5,24(25)-dienol,
were identified. The diunsaturated C-24(28)-sterol, isofucosterol, was also found, as well as the monounsaturated Δ5-sterols campesterol and sitosterol. These are normally present in vegetable oils, which makes them unsuitable as markers
for borage oil. 相似文献
7.
Prolonged computer work with an extended neck is commonly believed to be associated with an increased risk of neck-shoulder disorders. The aim of this study was to compare neck postures during computer work between female cases with neck-shoulder disorders, and healthy referents. Based on physical examinations, 13 cases and 11 referents were selected among 70 female air traffic controllers with the same computer-based work tasks and identical workstations. Postures and movements were measured by inclinometers, placed on the forehead and upper back (C7/Th1) during authentic air traffic control. A recently developed method was applied to assess flexion/extension in the neck, calculated as the difference between head and upper back flexion/extension. Results: cases and referents did not differ significantly in neck posture (median neck flexion/extension: -10 degrees vs. -9 degrees ; p=0.9). Hence, the belief that neck extension posture is associated with neck-shoulder disorders in computer work is not supported by the present data. 相似文献
8.
Pille Mänd Lea Hallik Josep Peñuelas Pierpaolo Duce Claus Beier János Garadnai Inger Kappel Schmidt Patricia Prieto Joke W. Westerveld 《Remote sensing of environment》2010,114(3):626-297
The aim of this study was to evaluate the use of ground-based canopy reflectance measurements to detect changes in physiology and structure of vegetation in response to experimental warming and drought treatment at six European shrublands located along a North-South climatic gradient. We measured canopy reflectance, effective green leaf area index (green LAIe) and chlorophyll fluorescence of dominant species. The treatment effects on green LAIe varied among sites. We calculated three reflectance indices: photochemical reflectance index PRI [531 nm; 570 nm], normalized difference vegetation index NDVI680 [780 nm; 680 nm] using red spectral region, and NDVI570 [780 nm; 570 nm] using the same green spectral region as PRI. All three reflectance indices were significantly related to green LAIe and were able to detect changes in shrubland vegetation among treatments. In general warming treatment increased PRI and drought treatment reduced NDVI values. The significant treatment effect on photochemical efficiency of plants detected with PRI could not be detected by fluorescence measurements. However, we found canopy level measured PRI to be very sensitive to soil reflectance properties especially in vegetation areas with low green LAIe. As both soil reflectance and LAI varied between northern and southern sites it is problematic to draw universal conclusions of climate-derived changes in all vegetation types based merely on PRI measurements. We propose that canopy level PRI measurements can be more useful in areas of dense vegetation and dark soils. 相似文献
9.
Jan Gulliksen Bengt G ransson Inger Boivie Stefan Blomkvist Jenny Persson sa Cajander 《Behaviour & Information Technology》2003,22(6):397-409
The concept of user-centred systems design (UCSD) has no agreed upon definition. Consequently, there is a great variety in the ways it is applied, which may lead to poor quality and poor usability in the resulting systems, as well as misconceptions about the effectiveness of UCSD. The purpose of this paper is to propose a definition of UCSD. We have identified 12 key principles for the adoption of a user-centred development process, principles that are based on existing theory, as well as research in and experiences from a large number of software development projects. The initial set of principles were applied and evaluated in a case study and modified accordingly. These principles can be used to communicate the nature of UCSD, evaluate a development process or develop systems development processes that support a user-centred approach. We also suggest activity lists and some tools for applying UCSD. 相似文献
10.
Sensors: Detection Beyond Debye's Length with an Electrolyte‐Gated Organic Field‐Effect Transistor (Adv. Mater. 5/2015) 下载免费PDF全文