全文获取类型
收费全文 | 1854篇 |
免费 | 131篇 |
国内免费 | 24篇 |
专业分类
电工技术 | 55篇 |
综合类 | 123篇 |
化学工业 | 381篇 |
金属工艺 | 20篇 |
机械仪表 | 39篇 |
建筑科学 | 95篇 |
矿业工程 | 11篇 |
能源动力 | 1篇 |
轻工业 | 930篇 |
水利工程 | 6篇 |
石油天然气 | 12篇 |
武器工业 | 3篇 |
无线电 | 51篇 |
一般工业技术 | 99篇 |
冶金工业 | 29篇 |
原子能技术 | 3篇 |
自动化技术 | 151篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 23篇 |
2020年 | 42篇 |
2019年 | 40篇 |
2018年 | 40篇 |
2017年 | 43篇 |
2016年 | 41篇 |
2015年 | 52篇 |
2014年 | 63篇 |
2013年 | 117篇 |
2012年 | 100篇 |
2011年 | 78篇 |
2010年 | 92篇 |
2009年 | 68篇 |
2008年 | 82篇 |
2007年 | 92篇 |
2006年 | 89篇 |
2005年 | 93篇 |
2004年 | 89篇 |
2003年 | 59篇 |
2002年 | 61篇 |
2001年 | 72篇 |
2000年 | 69篇 |
1999年 | 63篇 |
1998年 | 55篇 |
1997年 | 49篇 |
1996年 | 49篇 |
1995年 | 51篇 |
1994年 | 46篇 |
1993年 | 27篇 |
1992年 | 35篇 |
1991年 | 22篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 18篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 1篇 |
排序方式: 共有2009条查询结果,搜索用时 15 毫秒
61.
天然食用植物色素山兰红的研究 总被引:4,自引:0,他引:4
由爵床科植物五指山兰(Peristophe lanceolia Nees)的嫩枝和叶提制而得的一种食用天然色素,被命名为山兰红色素。该色素属水溶性,提取得率为4~8%,pH6.8~8时最大吸收峰波长为580nm,pH3~6.4时最大吸收峰波长为480nm,颜色随pH而变化,中性色素液强日晒5小时,颜色由暗紫变为红紫。100℃加热两小时,pH4色素液变化不大,更加清澈透明,pH7色素液颜色变浅而透明,较玫瑰茄色素稳定,色价E_1cm~10%=2278(580nm),主要色素成分为天竹葵宁-3-β-葡萄糖苷。食用安全,可用于饮料,低度酒,米制品等着色。 相似文献
62.
纺织品水萃取液甲醛含量的测定 总被引:1,自引:0,他引:1
按照GB/T2912.1-1998《纺织品甲醛的测定第一部分游离水解的甲醛(水萃取法)》测定纺织品、服装上游离甲醛的含量时,为减少数据的离散性,提高测试结果的正确程度,详细讨论了测试过程中所用水质、试剂、溶液的配制与标定、试样的准备、仪器的校正及有效数字的保留等对测定结果的影响。 相似文献
63.
色纺纱配色是色纺纱生产过程中的关键步骤。从色纺纱与染色纱颜色形成的对比分析中,探索出了另外一种色纺纱配色方法:固定标准色棉的颜色和数量,根据色纺纱颜色标准,选择合适的标准色棉配出所需色纺纱的颜色。 相似文献
64.
Li‐Chen Ou M. Ronnier Luo Pei‐Li Sun Neng‐Chung Hu Hung‐Shing Chen Shing‐Sheng Guan Andrée Woodcock José Luis Caivano Rafael Huertas Alain Treméau Monica Billger Hossein Izadan Klaus Richter 《Color research and application》2012,37(1):23-43
Psychophysical experiments were conducted in the UK, Taiwan, France, Germany, Spain, Sweden, Argentina, and Iran to assess colour emotion for two‐colour combinations using semantic scales warm/cool, heavy/light, active/passive, and like/dislike. A total of 223 observers participated, each presented with 190 colour pairs as the stimuli, shown individually on a cathode ray tube display. The results show consistent responses across cultures only for warm/cool, heavy/light, and active/passive. The like/dislike scale, however, showed some differences between the observer groups, in particular between the Argentinian responses and those obtained from the other observers. Factor analysis reveals that the Argentinian observers preferred passive colour pairs to active ones more than the other observers. In addition to the cultural difference in like/dislike, the experimental results show some effects of gender, professional background (design vs. nondesign), and age. Female observers were found to prefer colour pairs with high‐lightness or low‐chroma values more than their male counterparts. Observers with a design background liked low‐chroma colour pairs or those containing colours of similar hue more than nondesign observers. Older observers liked colour pairs with high‐lightness or high‐chroma values more than young observers did. Based on the findings, a two‐level theory of colour emotion is proposed, in which warm/cool, heavy/light, and active/passive are identified as the reactive‐level responses and like/dislike the reflective‐level response. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2012 相似文献
65.
Li‐Chen Ou 《Color research and application》2012,37(3):205-205
The Technical Committee 1‐86 of the International Commission on Illumination on “Models of colour emotion and harmony” is requesting the submission of datasets for use in developing new models of colour emotion and colour harmony. The data should be submitted to the TC Chair, Dr. Li‐Chen Ou at the National Taiwan University of Science and Technology. © 2012 Wiley Periodicals, Inc. Col Res Appl, 2012 相似文献
66.
Fengnong Chen Yan Luo Fang Cheng 《International Journal of Food Science & Technology》2012,47(6):1272-1278
Wheat is one of the most consumed grains in the world. The identification of wheat based on surface characteristics is important for the market. This study is aimed at identifying unsound kernels (Triticum durum Desf), including 710 black germ kernels, 627 broken kernels and 1169 sound kernels from several seed distributors in China. The system is mainly composed of a liner charge‐coupled device for image capture and a software package for extracting various morphological, colour and texture features. The models built by partial least squares discriminate analysis, support vector machine discrimination analysis (SVMDA) and principal component analysis‐artificial neural networks for identifying the unsound kernels have been explored. After comparisons of these three methods, it has been found that SVMDA got the best accuracy: 95.1%, 96.0% and 98.3% (black germ kernels, broken kernels and sound kernels). Obviously, the experimental results have shown that SVMDA is the most feasible and effective choice for the identification. 相似文献
67.
M.B. SÁNCHEZ‐ILÁRDUYA C. SÁNCHEZ‐FERNÁNDEZ M. VILORIA‐BERNAL D.M. LÓPEZ‐MÁRQUEZ L.A. BERRUETA B. GALLO F. VICENTE 《Australian Journal of Grape and Wine Research》2012,18(2):203-214
Background and Aims: During wine ageing, a great variety of reactions take place, resulting in an immense variety of products whose structure sometimes remains unknown. The aim of this work is the study of different fragmentation patterns of flavanol‐anthocyanin derivatives formed along the wine ageing; these patterns are useful for elucidating the different structures of these compounds and other new related ones. Methods and Results: Several wines from the Protected Denomination of Origin Rioja have been studied by an analytical method that combines column chromatography and high‐performance liquid chromatography with diode array and mass and tandem mass spectrometric detections. Thirty‐five coloured flavanol‐anthocyanin compounds formed by direct reaction or by acetaldehyde‐mediated condensation have been identified. For direct reaction derivatives, two different fragmentation patterns (one of them not previously reported) have been observed depending on the position of flavanol in the coloured derivative. Several compounds have been identified in aged wines for the first time to the authors' knowledge, like (+)‐gallocatechin‐cyanidin‐3‐glucoside and (+)‐catechin‐cyanidin‐3‐glucoside Conclusions: The developed analytical procedure has allowed the identification of some compounds for the first time, and two different fragmentation patterns have been observed depending on the position of flavanol in the pigment. Significance of the Study: The establishment of different fragmentation patterns allows the structural elucidation of unknown compounds. 相似文献
68.
Rashid Heidari‐Moghadam Alireza Mortezapour Saeedeh Mosaferchi Iman Dianat 《Color research and application》2019,44(6):1042-1044
The key role of colour in ergonomics has been emphasized by a number of researchers and design professionals. Although several research studies have been published regarding the use of colour in ergonomics, there are still some areas that need to be considered. The issue of deciding a “colour of the year” is an example, which represents a new challenge for researchers in the field of ergonomics. This is of particular interest considering the fact that the nature of research on the selection of a “colour of the year” is generally based on user experience. This paper argues that ergonomics should play a more prominent role in this field to ensure better user experience and performance. This paper highlights specific areas that need further study and development. 相似文献
69.
The paper reviews the utilization of colour analyses for the assessment and rating of atmospheric corrosion products, whereas particular attention is spent to flash rusting. The background of flash rust formation is discussed first, along with a brief review about the composition of flash rust. The fundamentals of the HSV colour model, which is selected as a simple suitable model, are introduced. Finally, the author discusses the utilization of the suggested approach for the evaluation of steel substrate cleanliness and rust assessment. 相似文献
70.
Agnieszka Owczarek‐Fendor An Vermeulen Ilse Van Bree Markus Eriksson Stefaan Lescouhier Stefaan De Smet Bruno De Meulenaer Frank Devlieghere 《International Journal of Food Science & Technology》2014,49(4):1090-1098
The objective of this study was to evaluate the influence of two different vacuum ageing times (7 and 14 days) and the impact of the modified atmosphere packaging (MAP) configuration (gas/product ratios: 0.5 and 1 and gas composition: 70% O2 + 30% CO2 and 40% O2 + 30% CO2 + 30% N2) on the quality of fresh beef during subsequent storage at 4 °C. For this purpose, three separate experiments were performed. For each experiment, two different muscles (Longissimus dorsi and Biceps femoris) were sampled from four double‐muscled Belgian Blue beef carcasses. Next to colour, also the evolution in microbial load, pH, O2 and CO2 in the headspace and lipid oxidation at the meat surface were evaluated. A vacuum ageing for 14 days compared with 7 days resulted in a higher initial microbial load on the day of MAP packaging, which resulted finally in a significantly shorter shelf life. This ageing effect was less pronounced on the colour stability and lipid oxidation of the meat samples. No significant influence of the packaging configuration on any of the analysed parameters (colour, microbial load, pH and lipid oxidation at the meat surface) was observed. 相似文献