全文获取类型
收费全文 | 3081篇 |
免费 | 187篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 94篇 |
综合类 | 4篇 |
化学工业 | 725篇 |
金属工艺 | 72篇 |
机械仪表 | 119篇 |
建筑科学 | 102篇 |
矿业工程 | 8篇 |
能源动力 | 125篇 |
轻工业 | 503篇 |
水利工程 | 14篇 |
石油天然气 | 13篇 |
无线电 | 191篇 |
一般工业技术 | 786篇 |
冶金工业 | 25篇 |
原子能技术 | 13篇 |
自动化技术 | 475篇 |
出版年
2023年 | 21篇 |
2022年 | 13篇 |
2021年 | 65篇 |
2020年 | 57篇 |
2019年 | 69篇 |
2018年 | 119篇 |
2017年 | 116篇 |
2016年 | 148篇 |
2015年 | 101篇 |
2014年 | 156篇 |
2013年 | 388篇 |
2012年 | 209篇 |
2011年 | 223篇 |
2010年 | 183篇 |
2009年 | 131篇 |
2008年 | 156篇 |
2007年 | 119篇 |
2006年 | 94篇 |
2005年 | 52篇 |
2004年 | 31篇 |
2003年 | 48篇 |
2002年 | 40篇 |
2001年 | 31篇 |
2000年 | 36篇 |
1999年 | 30篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 29篇 |
1993年 | 23篇 |
1992年 | 23篇 |
1991年 | 20篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1985年 | 34篇 |
1984年 | 34篇 |
1983年 | 29篇 |
1982年 | 24篇 |
1981年 | 39篇 |
1980年 | 32篇 |
1979年 | 25篇 |
1978年 | 24篇 |
1977年 | 19篇 |
1976年 | 20篇 |
1975年 | 13篇 |
1974年 | 11篇 |
1973年 | 14篇 |
1972年 | 14篇 |
排序方式: 共有3269条查询结果,搜索用时 0 毫秒
81.
82.
This research shows the effect of simultaneous contrast on a design solution that generates it, and it also shows how its manifestation affects the shift of perception attributes of the observer's color. In the conducted research, 55 subjects had to harmonize the primary stimuli from the reproduction obtained with the help of digital printing technology, with the primary stimuli presented on two computer screens. As a visual harmonization technique, simultaneous binocular harmonization was used. The primary stimuli were made achromatic, with a 50% Raster Tone value (RTV), and are surrounded by achromatic secondary stimuli whose values increase in steps from 10% RTV up to 100% RTV. A shift in the perceptual attributes of color has been shown with the help of the CIEDE2000 system. Using ANOVA with repeated-measures and Fisher's post hoc analysis, statistically significant differences were found between the perceived means of shift in the ΔC00 chroma and ΔL00 lightness on defined samples on both computer screens, while in the case of the ΔH00 hue, no statistically significant differences were observed. The research also determined colorimetric differences in the ΔE00 color difference. Moreover, the student's t test was used to determine that the effect is stronger when manifested on the Lenovo computer than on the Asus computer screen (P < .05). 相似文献
83.
84.
85.
86.
87.
88.
Milica Simović Ana Milivojević Marija Ćorović Katarina Banjanac Dejan Bezbradica 《International Journal of Food Science & Technology》2019,54(11):3074-3082
Whey represents a significant dairy industry by-product that has recently received due attention based on the rich nutrient composition and significant transformation potential. Hereby, we investigated a possibility of whey lactose bioconversion into prebiotic compounds, galacto-oligosaccharides (GOS) using β-galactosidase transgalactosylation activity. The results showed that whey could be successfully used for GOS synthesis, since the highest GOS concentration (around 62 g L−1) was obtained batchwise using 40% (w/w) sweet whey powder solution under optimum conditions (50°C, pH 4.5). Nevertheless, an efficient immobilized preparation using methacrylic Lifetech ECR8409 immobilization carrier was developed, enabling additional process improvement and ensuring at least 4 reaction cycles with unchanged yields and 2.5- fold enhanced productivity in comparison to the soluble enzyme. Therefore, this study provides a valuable contribution to the efficient and economical valorization of whey, which can be further on utilized as functional food and feed constituent. 相似文献
89.
Spray drying is a very useful method for manufacturing of amorphous solid materials. This is mainly due to the possibility of fast solvent evaporation that leads to a rapid transformation of solution to a solid state. Besides evaporation kinetics, there are various process parameters that influence physical and chemical characteristics of such obtained material. The possibility of obtaining a stable amorphous structure of the active pharmaceutical ingredient in a spray dryer was examined. A solution of the hydrochloride crystalline structure of the active pharmaceutical ingredient in a mixture of water and acetonitrile was dried at different temperatures and flowrates of nitrogen used for atomization, as well as the flowrates of the solution. The influence of the process conditions on the properties of the product was analyzed. The final dried products were characterized and identified with a variety of analytical and physical methods. The results showed that a stable amorphous structure of the high purity active pharmaceutical ingredient is obtained, and that the optimal conditions of the process are defined. The amorphous structure is stable at temperatures below 200°C when it is transformed into a new crystal structure. Conditions of high relative air humidity lead to partial transformation. 相似文献
90.
Miloje S. Radenković 《International journal of control》2019,92(2):404-415
Existing adaptive control algorithms at best guarantee that the tracking error is a l 2 sequence. This paper presents globally stable adaptive control algorithms for linear discrete-time systems providing l 1 tracking performance. Two algorithms with different degree of complexity are proposed, one for the case of known control directions, and a separate algorithm for the case of unknown control directions. It is demonstrated that in both cases the tracking error is l 1 sequence, while the input and output signals are uniformly bounded. 相似文献