全文获取类型
收费全文 | 13035篇 |
免费 | 1445篇 |
国内免费 | 1216篇 |
专业分类
电工技术 | 1552篇 |
综合类 | 1307篇 |
化学工业 | 1427篇 |
金属工艺 | 868篇 |
机械仪表 | 632篇 |
建筑科学 | 854篇 |
矿业工程 | 543篇 |
能源动力 | 670篇 |
轻工业 | 624篇 |
水利工程 | 353篇 |
石油天然气 | 1513篇 |
武器工业 | 73篇 |
无线电 | 959篇 |
一般工业技术 | 1235篇 |
冶金工业 | 522篇 |
原子能技术 | 191篇 |
自动化技术 | 2373篇 |
出版年
2024年 | 42篇 |
2023年 | 199篇 |
2022年 | 367篇 |
2021年 | 460篇 |
2020年 | 437篇 |
2019年 | 426篇 |
2018年 | 386篇 |
2017年 | 514篇 |
2016年 | 543篇 |
2015年 | 523篇 |
2014年 | 751篇 |
2013年 | 931篇 |
2012年 | 923篇 |
2011年 | 1014篇 |
2010年 | 717篇 |
2009年 | 820篇 |
2008年 | 741篇 |
2007年 | 814篇 |
2006年 | 771篇 |
2005年 | 669篇 |
2004年 | 623篇 |
2003年 | 466篇 |
2002年 | 415篇 |
2001年 | 324篇 |
2000年 | 269篇 |
1999年 | 240篇 |
1998年 | 196篇 |
1997年 | 189篇 |
1996年 | 156篇 |
1995年 | 141篇 |
1994年 | 118篇 |
1993年 | 108篇 |
1992年 | 80篇 |
1991年 | 59篇 |
1990年 | 54篇 |
1989年 | 44篇 |
1988年 | 38篇 |
1987年 | 25篇 |
1986年 | 28篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1960年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
This paper reports the results of current fundamental research at the Department of Process Engineering, University of Miskolc on the processing of clean coal from Mecsek bituminous coal, Southern Hungary. The theoretical possibility of the separation of different petrographic components was proven experimentally and their liberation degree was determined based on the petrographic composition, flotation kinetic study of isolated components (groups of components), scanning electron microscopy and microprobe analyses. The mill with stirred ball media was chosen for the ultra-fine liberation of the coal components. It was revealed that along with the liberation of coal components, their surface oxidation and spontaneous agglomeration, entrapping the mineral impurities take place in ultra-fine grinding. This paper discusses the interfacial phenomena occurring in the ultra-fine grinding process and their influence on the flotation. The concept for the advanced preparation of clean coal was developed, tested and proved. The main steps of this concept are the ultra-fine liberation in the stirred-media mill, the de-agglomeration of flocs spontaneously formed during the ultra-fine grinding and the induced (hydrophobic) flocculation with the following two-step flotation in a flotation column. 相似文献
32.
朱绍军 《油气地质与采收率》2003,10(5):52-53
建立了油藏能量势的定义,阐述了其物理意义。油藏能量势好地揭示油藏开发过程中流体运动的本质,运用该定义能较好地解释油藏开发过程中的水窜、气窜、间歇注水和脉冲注水、注水井调剖和注氮气采油技术机理,对指导油藏勘探、开发具有一定的意义。 相似文献
33.
34.
Ashok K. Vijh 《Drying Technology》1995,13(1):215-224
An attempt is made to elucidate the electrochemical aspects of the electroosmotic dewatering (EOD) of clays as reported in some recent work, especially that on interrupted DC power electroosmotic dewatering published by Rabie, Mujumdar and Weber (2). These authors showed that the dewatering by EOD stops after the DC power has been on for several minutes or hours; on interruption of their power and on short-circuiting of the electrodes, conditions can be created again for some further dewatering by DC power EOD. This discovery, of Rabie et al. is interpreted as a fuel cell effect and it is shown that it affords clues to several other electrochemical strategies for the possible enhancement of the efficiency of the EOD by DC power.
Further, the open circuit potentials observed by Rabie et al. (2) on the interruption of DC power are given an electrochemical interpretation which leads to quantitative estimates in agreement with the experimental values. 相似文献
Further, the open circuit potentials observed by Rabie et al. (2) on the interruption of DC power are given an electrochemical interpretation which leads to quantitative estimates in agreement with the experimental values. 相似文献
35.
Preparation and Properties of Sintering Additives Coated Si3N4 from Heterogeneous Nucleation Processing 总被引:1,自引:0,他引:1
The sintering additives such as Al2O3 and /or Y2O3 were coated on the surfaces of Si3N4 particles via heterogeneous nucleation processing using a buffered pH solution as the precipitation reagent .They nucleated and grew only on the surfaces of Si3N4 and did not form sol particles in solution by TEM observation .The isoelectric point(IEP) of coated Si3N4 was different from that of as-received Si3N4.The IEP of Al(OH)3-coated Si3N4 occurred at pH8.4, which is close to that of alumina .When Al(OH)3-coated Si3N4 particles were coated with Y(OH)3,the IEP of coated Si3N4 powder shifted from pH8.4 to pH9.2 ,similar to that of yttria.In addition ,the rheological data showed that Al2O3 and /or Y2O3 coated Si3N4 suspension is nearly Newtonian and that added Si3N4 suspension shows a shear rate thinning behavior. 相似文献
36.
本文提出励磁电流可自动控制的他励式双高调速系统设计方案。系统在提升特别是在下放重物时,具有较硬的机械性;在负载10-100%的变化范围内,可实现最大偏差Δnmax/nmin100%≤10%,调速范围D≥10;在满载运行条件下,可节约电能80%以上。 相似文献
37.
Li2O在保护渣中的作用 总被引:7,自引:0,他引:7
采用在不同玻璃性的两种基渣中加入Li2O为研究Li2O对保护渣粘度,熔化温度及玻璃性能的影响,并对Li2O改善保护渣玻璃性的机理进行了探讨,提出了寻找高速连铸保护渣中Li2O的代用物的一种方法。 相似文献
38.
本文推荐陈林根编著的《工程化学》对化学热力学基本公式△G=△H-T△S的引出方法,试探基础教学的改革。 相似文献
39.
The second virial coefficients of refrigerants HFC-32 (CH2F2), HFC-23 (CHF3), and HCFC-22 (CHC1F2) have been correlated on the bisis of site site model potential and have been compared with experimental results. The molecular interactions consisted of repulsion dispersion and electrostatic parts. From the site site potentials adjusted to the experimental second virial coefficients, spherically averaged potentials have been determined and a subsequent calculation of gaseous viscosity has been carried out. Agreement between measured and calculated values of second virial coellicients and gaseous viscosity is satisfactory. Calculated values of second virial coefficients and gaseous viscosity beyond available experimental data, therefore. can be assumed as a reliable extrapolation to lower and higher temperatures. 相似文献
40.
我国天然彩棉的研发现状及发展趋势 总被引:1,自引:0,他引:1
对天然彩棉的历史、纤维特点、纤维的形态结构及性能作了简要介绍,重点介绍了我国彩棉的研发现状及研发中亟待解决的瓶颈问题,最后对彩棉在我国的发展前景进行了展望。 相似文献