全文获取类型
收费全文 | 2948篇 |
免费 | 51篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 165篇 |
综合类 | 3篇 |
化学工业 | 696篇 |
金属工艺 | 94篇 |
机械仪表 | 56篇 |
建筑科学 | 45篇 |
能源动力 | 98篇 |
轻工业 | 255篇 |
无线电 | 327篇 |
一般工业技术 | 468篇 |
冶金工业 | 570篇 |
原子能技术 | 86篇 |
自动化技术 | 146篇 |
出版年
2023年 | 13篇 |
2022年 | 18篇 |
2021年 | 45篇 |
2020年 | 21篇 |
2019年 | 28篇 |
2018年 | 41篇 |
2017年 | 41篇 |
2016年 | 31篇 |
2015年 | 29篇 |
2014年 | 37篇 |
2013年 | 146篇 |
2012年 | 76篇 |
2011年 | 91篇 |
2010年 | 84篇 |
2009年 | 118篇 |
2008年 | 114篇 |
2007年 | 123篇 |
2006年 | 91篇 |
2005年 | 90篇 |
2004年 | 93篇 |
2003年 | 85篇 |
2002年 | 74篇 |
2001年 | 67篇 |
2000年 | 73篇 |
1999年 | 87篇 |
1998年 | 237篇 |
1997年 | 152篇 |
1996年 | 130篇 |
1995年 | 84篇 |
1994年 | 66篇 |
1993年 | 66篇 |
1992年 | 52篇 |
1991年 | 31篇 |
1990年 | 32篇 |
1989年 | 41篇 |
1988年 | 31篇 |
1987年 | 27篇 |
1986年 | 46篇 |
1985年 | 37篇 |
1984年 | 27篇 |
1983年 | 27篇 |
1982年 | 23篇 |
1981年 | 22篇 |
1980年 | 23篇 |
1979年 | 32篇 |
1978年 | 12篇 |
1977年 | 24篇 |
1976年 | 33篇 |
1974年 | 6篇 |
1973年 | 8篇 |
排序方式: 共有3009条查询结果,搜索用时 297 毫秒
991.
Development of a database of low energy homes around the world and analyses of their trends 总被引:1,自引:0,他引:1
Yasuhiro Hamada Makoto Nakamura Kiyoshi Ochifuji Shintaro Yokoyama Katsunori Nagano 《Renewable Energy》2003,28(2):321-328
This study aims to develop a database of low energy techniques for homes around the world, for use in systematically evaluating the low energy home in each region, where climate, culture and policy differ. First, a database was made for the purpose of the systemizing passive and active techniques. Data were input according to seven chapters and 155 items, and 66 homes in 17 nations have been recorded. Homes adopting super insulation, high airtightness and solar energy utilization are common in the each country. The thermal insulation performance of wall and window of the housing in Japan is somewhat inferior to that overseas. It was shown that exhaust heat recovery is rarely adopted in Japan and that the underground thermal energy utilization was seen in less than 10% of recorded homes. Second, recorded homes were categorized according to characteristics of adopted strategies, and the reduction rate of purchased energy versus the purchased energy for a typical home was calculated. This revealed the purchased energy reduction rate of homes with both solar heat utilization and photovoltaic power generation to be very high. 相似文献
992.
Kiyoshi Nosu Makiko Ikeda 《IEEJ Transactions on Electrical and Electronic Engineering》2014,9(5):569-571
E‐commerce is spreading into various fields in our daily lives as a result of the growth of interactive Internet communication technologies. Two‐dimensional computer graphics (2D CG) image presentations, which are simple and inexpensive, can be displayed directly on apparel e‐commerce sites. This study uses sequential pattern mining to analyze the item‐selection behavior of Japanese female university students examining a 2D virtual fashion Web site. It is found that most users did not initially examine their favorite category items; instead, they examined the commonly viewed items first, and then examined various other fashion items before making their final selection. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
993.
994.
Debittering of enzymatic hydrolysates using an aminopeptidase from the edible basidiomycete Grifola frondosa 总被引:3,自引:0,他引:3
Nishiwaki T Yoshimizu S Furuta M Hayashi K 《Journal of Bioscience and Bioengineering》2002,93(1):60-63
Bitter peptide solutions, prepared by the enzymatic hydrolysis of soy protein and milk casein, were treated with an aminopeptidase from the edible basidiomycete Grifola frondosa. As the incubation time elapsed, the amount of free amino acids released increased and the bitterness of the enzyme reaction mixtures decreased. However, the debittering of the milk casein hydrolysate by the aminopeptidase was less effective than that observed for the soy protein hydrolysate. Hydrophobic amino acids such as valine, leucine, phenylalanine, tyrosine, and isoleucine were preferentially released from the bitter solutions by the action of the aminopeptidase. 相似文献
995.
Furuse H Yabe I Asakura T Miyawaki O Toda K 《Journal of Bioscience and Bioengineering》2003,95(5):544-547
The culture fluid of the fungus Aureobasidium pullulans and the exopolysaccharide solution obtained by removal of the microbial cells exhibit a marked shear dependence of viscosity. The viscosity in a high shear rate region was a little higher than that predicted by a non-Newtonian viscosity equation derived previously on the basis of the concept of traveling force. In a sample exhibiting such high shear rate dependence, a hydrodynamic effect based on the fluid structure of the binding of contacting polymers and suspended microbial cells on viscosity becomes comparatively significant. A model for the shear rate dependence of the viscosity is needed to elucidate the mechanism of the viscosity behavior. A term concerning the increase in viscosity caused by the binding of polymers and the microbial cells suspended in a medium was added to the previous viscosity equation. The experimental shear dependence of the viscosity was well simulated by the modified viscosity equation. 相似文献
996.
提高甘薯淀粉中抗消化淀粉含量的技术研究 总被引:3,自引:0,他引:3
抗消化淀粉是一种具有保健功能作用的淀粉,老化淀粉是制备抗消化淀粉最主要的方法.本文研究了酶水解预处理和冷冻解冻循环处理对甘薯老化淀粉中抗消化淀粉形成的影响,得到了提高甘薯淀粉中抗消化淀粉含量的适宜的工艺路线和参数,即:先用300U/g淀粉的普鲁兰酶水解2h,再用10U/g淀粉的α-淀粉酶水解0.5h,浓度为12%的酶处理淀粉胶在4℃条件下老化20h后,再经冷冻(-20℃,2h)-解冻(50℃,30min)-老化(4℃,6h)循环处理3次,淀粉中RS含量可达31.21%.实验结果表明,甘薯淀粉通过普鲁兰酶和α-淀粉酶复合水解处理和冷冻解冻循环处理能明显提高老化淀粉中抗消化淀粉的含量. 相似文献
997.
Yuji Teramoto Noriaki Saigusa Seinosuke Ueda Kiyoshi Yoshizawa 《Journal of the Institute of Brewing》1994,100(3):163-166
The quality of rice wine made from uncooked, unpolished aromatic red rice grain was improved by use of a commercial preparation of acid protease from Aspergillus niger during ethanol fermentation. The fermentation rate of the mash which contained the acid protease was much higher than that of mash that did not contain the preparation of acid protease. The rice wine made from uncooked, polished aromatic red rice, which usually had a less acceptable aroma, was improved by use of the preparation of acid protease, and large amounts of isobutyl alcohol, n-propyl alcohol and ethyl acetate were detected in the resultant rice wine. By contrast, the quality of rice wine made from the bran fraction of aromatic red rice was not improved by the preparation of acid protease. The polished rice fraction of aromatic red rice was affected by the acid protease and the aromatic quality of the rice wine was improved. The aromatic characteristics of red rice wine made from cooked, unpolished aromatic red rice grains, which was rather inferior in terms of both aroma and color, were also improved by the addition of the preparation of acid protease during ethanol fermentation. Thus acid protease has beneficial effects on the production of aromatic red rice wine. 相似文献
998.
Jinhu Tian Yukiharu Ogawa John Shi Shiguo Chen Huiling Zhang Donghong Liu 《Critical reviews in food science and nutrition》2019,59(19):3117-3128
ABSTRACTStarch is the main carbohydrate in human nutrition and shows a range of desired food properties. It has been demonstrated that fast digestion of starchy food can induce many health issues (e.g., hyperglycaemia, diabetes, etc.); therefore, how to modulate its digestion is an interesting topic. Previous studies have revealed that the microstructure and digestibility of starchy food of different botanical origin or from multiple processes are quite different; modulating starch digestion by retaining or altering its microstructure may be effective. In the present review, the current knowledge of the relationship between microstructural changes to starchy food and its digestibility at molecular, cell and tissue, and food processing levels is summarized. New technologies focused on microstructure studies and ways to manipulate food microstructure to modulate starch digestibility are also reviewed. In particular, some insights focusing on the future study of microstructure and the digestibility of starchy food are also suggested. 相似文献
999.
Yuji Teramoto Noriaki Saigusa Yasuo Yoshida Seinosuke Ueda Kiyoshi Yoshizawa 《Journal of the Institute of Brewing》1994,100(1):3-6
Red rice sake was efficiently produced from unpolished red rice without cooking by use of rice koji prepared with shochu koji mold, Aspergillus kawachii, as saccharifying agent. A comparative study was made of red rice sake made with rice koji and red rice wine made with a preparation of glucoamylase known as Sumizyme. Red rice sake contained about 13% ethanol and its acidity was 8.6. Large amounts of volatile compounds, such as isobutyl alcohol and ethyl acetate, were found in the red rice sake. The red color of the red rice sake was more intense than that of the red rice wine. The quality of red rice sake was better than that of red rice wine, as assessed by gas chromatography, spectrophotometric analysis and organoleptic testing. In accordance with the traditional method for sake brewing, red rice, rice koji and tap water were added to the initial mash. The red color of the red rice sake made with these additions was more intense than that of red rice sake made without these additions. The rice wine was somewhat improved by these additions, as assessed by organoleptic testing. The body of the resultant rice wine was fortified with dextrin and its mild characteristics were derived from sugar and dextrin. 相似文献
1000.
ABSTRACT: A new combination of sample preparation, imaging and image processing techniques allowing new insights into the structure of biological objects has been developed as a method for the visualization and quality evaluation. This method is for the first time transferred to soybeans ( Glycine soja L.) of the Nattousyoryu variety as an example of food and agricultural produce using volume rendering of thin slice microscopy images. By this method, soybeans are displayed as three-dimensional data representations for visualization. Internal structures like the dormant cotyledon leafs are visualized and highlighted. 相似文献