全文获取类型
收费全文 | 6146篇 |
免费 | 130篇 |
国内免费 | 46篇 |
专业分类
电工技术 | 179篇 |
综合类 | 150篇 |
化学工业 | 652篇 |
金属工艺 | 169篇 |
机械仪表 | 417篇 |
建筑科学 | 845篇 |
矿业工程 | 159篇 |
能源动力 | 640篇 |
轻工业 | 280篇 |
水利工程 | 31篇 |
石油天然气 | 137篇 |
武器工业 | 91篇 |
无线电 | 443篇 |
一般工业技术 | 1371篇 |
冶金工业 | 268篇 |
原子能技术 | 67篇 |
自动化技术 | 423篇 |
出版年
2024年 | 4篇 |
2023年 | 43篇 |
2022年 | 72篇 |
2021年 | 88篇 |
2020年 | 89篇 |
2019年 | 70篇 |
2018年 | 73篇 |
2017年 | 111篇 |
2016年 | 121篇 |
2015年 | 117篇 |
2014年 | 304篇 |
2013年 | 353篇 |
2012年 | 350篇 |
2011年 | 520篇 |
2010年 | 405篇 |
2009年 | 410篇 |
2008年 | 321篇 |
2007年 | 437篇 |
2006年 | 406篇 |
2005年 | 328篇 |
2004年 | 260篇 |
2003年 | 279篇 |
2002年 | 247篇 |
2001年 | 163篇 |
2000年 | 127篇 |
1999年 | 133篇 |
1998年 | 93篇 |
1997年 | 62篇 |
1996年 | 63篇 |
1995年 | 48篇 |
1994年 | 44篇 |
1993年 | 24篇 |
1992年 | 26篇 |
1991年 | 24篇 |
1990年 | 13篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1958年 | 6篇 |
1956年 | 2篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有6322条查询结果,搜索用时 109 毫秒
31.
32.
The medium coking coal fines of − 0.5 mm from Jharia coal field were taken for this investigation. The release analysis of the composite coal reveals that yield is very low at 10.0% ash, about 25% at 14% ash and 50% at 17% ash level. The low yield is caused by the presence of high ash finer fraction. The size-wise ash analysis of − 0.5 mm coal indicated that − 0.5 + 0.15 mm fraction contains less ash than − 0.15 mm fraction. Thus, the composite feed was split into − 0.5 + 0.15 mm and − 0.15 mm fractions and subjected to flotation separately. The low ash bearing fraction (− 0.5 + 0.15 mm) was subjected to two stages collectorless flotation to achieve the concentrate with 10% ash. The cleaner concentrate (18.9%) with 10% ash was recovered which has an application in metallurgical industries. The concentrate of 30.2% yield with 12.5% ash could be achieved in one stage collectorless flotation which is suitable for use in coke making as sweetener. As the − 0.15 mm fraction contains relatively high ash, collector aided flotation using sodium silicate was performed to get a concentrate of 23.6% yield with about 17% ash. The blending of this product with cleaner tail obtained from − 0.5 + 0.15 mm produces about 35.0% yield with 17% ash and that can be utilized for coke making. The reject from the two fractions can be used for conventional thermal power plant or cement industries using a 23.5% ash after one stage collector aided flotation and the final tailings produced content ash of 61.6% can be used for fluidization combustion bed (FBC). This eventually leads to complete utilization of coal. 相似文献
33.
34.
关于空调水系统节能的探讨 总被引:6,自引:0,他引:6
以空调冷冻水系统的节能为例 ,探讨空调系统节能的途径、存在的问题及解决办法 相似文献
35.
In this paper, the dynamic behavior of pico slider in contact with the disk was calculated. The analysis model consists of a simplified suspension model, an air bearing model, and a slider–disk contact model. The contact model consists of two elements. One is surface roughness model measured by Atomic Force Microscope (AFM) and the other is micro-waviness model. The dynamic behaviors of the tri-pad slider are calculated at several rotation speeds to investigate slider vibration modes during slider–disk contact. The slider oscillation frequency depends on the rotation speed and it saturates about twice as much as eigen frequency of air bearing pitch mode. 相似文献
36.
T. RONALD A. MAGEE CAROLE P.D. WILKINSON 《International Journal of Food Science & Technology》1992,27(5):541-549
Investigation of the effects of varying air velocity, slice thickness, and pre-treatment with sodium chloride solutions and surface active agents on drying potato slices indicated that the drying occurred entirely in the falling rate period and was controlled by the mechanism of liquid diffusion. The rate of drying, and therefore the diffusion coefficients, increased with the addition of sodium chloride and surface active agents. Diffusion coefficients were also influenced by air velocity and slice thickness, suggesting that the rate of drying of potato slices is controlled by a combination of internal and external resistances. 相似文献
37.
引入空分设备“有效产品成本”概念,以气体成本算法和液体成本算法对空分设备正常产品单位成本和有效产品单位成本进行了比较,举例计算了液化装置的产品成本,提出利用“有效产品成本”概念来组织空分设备生产。 相似文献
38.
39.
彭光荣 《制冷与空调(北京)》2003,3(1):66-69,72
太阳能是绿色能源,户式太阳能空调应用的途径分为供热与制冷两部分,本文从技术经济性,如何计算太阳能设备间的匹配等几个方面进行了探讨。 相似文献
40.