全文获取类型
收费全文 | 27527篇 |
免费 | 2374篇 |
国内免费 | 860篇 |
专业分类
电工技术 | 667篇 |
综合类 | 1534篇 |
化学工业 | 11215篇 |
金属工艺 | 2617篇 |
机械仪表 | 1063篇 |
建筑科学 | 1764篇 |
矿业工程 | 850篇 |
能源动力 | 250篇 |
轻工业 | 2622篇 |
水利工程 | 261篇 |
石油天然气 | 647篇 |
武器工业 | 319篇 |
无线电 | 475篇 |
一般工业技术 | 3356篇 |
冶金工业 | 2828篇 |
原子能技术 | 123篇 |
自动化技术 | 170篇 |
出版年
2024年 | 78篇 |
2023年 | 390篇 |
2022年 | 680篇 |
2021年 | 856篇 |
2020年 | 791篇 |
2019年 | 618篇 |
2018年 | 691篇 |
2017年 | 824篇 |
2016年 | 813篇 |
2015年 | 836篇 |
2014年 | 1433篇 |
2013年 | 1469篇 |
2012年 | 1762篇 |
2011年 | 1771篇 |
2010年 | 1401篇 |
2009年 | 1369篇 |
2008年 | 1136篇 |
2007年 | 1745篇 |
2006年 | 1738篇 |
2005年 | 1591篇 |
2004年 | 1331篇 |
2003年 | 1233篇 |
2002年 | 1102篇 |
2001年 | 910篇 |
2000年 | 790篇 |
1999年 | 670篇 |
1998年 | 556篇 |
1997年 | 418篇 |
1996年 | 396篇 |
1995年 | 321篇 |
1994年 | 295篇 |
1993年 | 202篇 |
1992年 | 161篇 |
1991年 | 99篇 |
1990年 | 81篇 |
1989年 | 73篇 |
1988年 | 27篇 |
1987年 | 17篇 |
1986年 | 11篇 |
1985年 | 25篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1978年 | 1篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
72.
Toru Ikegami Hideyuki Negishi Dai Kitamoto Keiji Sakaki Tomohiro Imura Masayoshi Okamoto Yasushi Idemoto Nobuyuki Koura Tsuneji Sano Kenji Haraya Hiroshi Yanagishita 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(4):381-387
In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry 相似文献
73.
Vibro-fluidized beds are widely used in drying sticky powders and agglomerated materials as milk powder. Using a vibro-fluidized laboratory scale dryer, this work is aiming at analyzing preliminarily the effect of its operational variables on the drying kinetics and characteristics of whole milk powder. The full-factorial design technique with three replications at the central point has been employed to generate data and correlations to quantify the effect of inlet air temperature, air flow rate, and vibration bed amplitude on the drying curves and the milk powder properties related to its faster reconstitution in water (as tapped density, Hausner cohesion ratio, agglomerate size distribution, and internal pore concentration). Results obtained are analyzed and discussed to identify the adequate operation condition for final drying whole milk powder in vibro-fluidized beds, assuring a high product quality. 相似文献
74.
对比了典型进口及国产粉末喷涂设备对过喷粉末的利用情况,介绍了一种获得实用新型专利权的涂装装置。该装置综合了进口及国产设备的优点,具有很高的性价比。 相似文献
75.
76.
77.
78.
Porous NiTi shape memory alloy (SMA) is a novel biomedical material used for human hard tissue implant .The influence of elemental titanium powder characteristics such as powder morphology, particle size and specific surface area( SSA) on the minimal ignition temperature ,combustion temperature and final product of porous Ni-Ti SMA fabricated by combustion synthesis method was investigated in this paper by scanning electron microscopy (SEM) and laser diffraction.The preliminary data indicated that the titanium powder characteristics had a strong effect on combustion synthesis of porous NiTi SMA. 相似文献
79.
80.