全文获取类型
收费全文 | 948篇 |
免费 | 137篇 |
国内免费 | 42篇 |
专业分类
电工技术 | 9篇 |
综合类 | 53篇 |
化学工业 | 662篇 |
金属工艺 | 14篇 |
机械仪表 | 10篇 |
建筑科学 | 23篇 |
矿业工程 | 26篇 |
能源动力 | 66篇 |
轻工业 | 37篇 |
水利工程 | 2篇 |
石油天然气 | 70篇 |
武器工业 | 6篇 |
无线电 | 13篇 |
一般工业技术 | 60篇 |
冶金工业 | 40篇 |
原子能技术 | 13篇 |
自动化技术 | 23篇 |
出版年
2024年 | 1篇 |
2023年 | 18篇 |
2022年 | 23篇 |
2021年 | 18篇 |
2020年 | 21篇 |
2019年 | 28篇 |
2018年 | 23篇 |
2017年 | 23篇 |
2016年 | 36篇 |
2015年 | 42篇 |
2014年 | 40篇 |
2013年 | 53篇 |
2012年 | 56篇 |
2011年 | 62篇 |
2010年 | 60篇 |
2009年 | 50篇 |
2008年 | 40篇 |
2007年 | 53篇 |
2006年 | 55篇 |
2005年 | 46篇 |
2004年 | 45篇 |
2003年 | 37篇 |
2002年 | 35篇 |
2001年 | 42篇 |
2000年 | 28篇 |
1999年 | 38篇 |
1998年 | 30篇 |
1997年 | 22篇 |
1996年 | 22篇 |
1995年 | 10篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1959年 | 1篇 |
1951年 | 2篇 |
排序方式: 共有1127条查询结果,搜索用时 15 毫秒
1.
Yi‐Hung Chen Ching‐Yuan Chang Wei‐Ling Su Chun‐Yu Chiu Yue‐Hwa Yu Pen‐Chi Chiang Chiung‐Fen Chang Je‐Lueng Shie Chyow‐San Chiou Sally IM Chiang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(1):68-75
This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry 相似文献
2.
3.
Pankaj Mathure Ashwin Patwardhan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(4):413-419
In this study, the mass transfer efficiencies of a novel horizontal rotating packed (h‐RPB) bed and the conventional disc‐type rotating biological contactor (RBC) were studied at four speeds and seven submergences. Pall rings of two different sizes (25, 38 mm), superintalox saddles and a wiremesh spiral bundle were used as packings in the h‐RPB. Volumetric gas–liquid mass transfer coefficients were determined by unsteady state absorption of atmospheric oxygen in de‐aerated water. Power consumption per unit liquid volume has been found for all geometries tested. The oxygen transfer efficiency values for the h‐RPB were found to be 2–5 kg kWh?1 and for the disc RBC were found to be 1–2 kg kWh?1. The performance of the h‐RPB was also compared with other gas–liquid contactors such as surface aerators. The study proves that the h‐RPB is a energy efficient alternative to conventional contactors. Copyright © 2005 Society of Chemical Industry 相似文献
4.
J. M. P. Q. Delgado 《加拿大化工杂志》2006,84(6):651-655
In this article, a simple and inexpensive experimental technique easy to build in laboratory, for the measurement of tortuosity of a packed bed of inert particles, is described. Experimental values of the tortuosity were obtained with four different packed beds of sand. The experimental results obtained are in good agreement with the theoretical values of tortuosity in a porous media; and the data reported showed the tortuosity to increase with decrease in the void fraction of the packed bed as expected. 相似文献
5.
本工作用2米401有机担体填充柱,在带四臂热导检测器的国产103型气相色谱仪上,仅8分钟将原料异丁醛、产物丙酮及水进行良好分离,并采用内标法定量,其最大平均偏差在±2%以内。方法简单、快速、准确 相似文献
6.
7.
Huu D Doan Jiangning Wu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(9):1076-1083
Wastewater containing propylene glycol methyl ether from a powder and E‐coating plant was treated biologically. The wastewater was circulated through a packed column at rates of 0.014, 0.028, and 0.042 m3 m?2 s?1 (14, 28, and 42 kg m?2 s?1) with an airflow in a countercurrent direction. Various air flowrates from 0.034 to 0.10 m3 m?2 s?1 (0.041–0.12 kg m?2 s?1) were used. The removal of the biological oxygen demand (BOD) of the wastewater did not change significantly with the air flowrate. After 4 days of treatment in the packed column the BOD was reduced by about 70% while a BOD reduction of 10% was observed with the wastewater in a stagnant tank. BOD removal with aeration in the packed column was about 40% higher than that without aeration. At the air flowrate of 0.068 m3 m?2 s?1 and the liquid flowrate of 0.028 m3 m?2 s?1, BOD removal for the wastewater seeded with Polyseed® increased by about 25% compared with that of the unseeded wastewater. In order to minimize the power consumption, cyclic pumping of the liquid to the packed column with aeration was also tested. For the liquid‐pumping cycle of 2‐h on and 4‐h off, BOD removal was about the same as that with a continuously pumping operation. © 2002 Society of Chemical Industry 相似文献
8.
本文对模拟的含酚废水,采用新型技术对乳状液膜法脱酚进行了进一步的探讨。对所采用的制乳设备———撞击流-旋转填料床对制乳率、提取设备———旋转填料床对脱酚率、破乳设备———无机微孔膜法破乳的重要参数(如透过压方式、膜孔径等对膜通量和破乳率的影响)进行了研究。并且讨论了破乳后的油相回用情况。实验结果表明:撞击流-旋转填料床的制乳效率可达99.90 %以上,脱酚率可达99%左右,且瞬间完成;膜孔径越小,破乳率越高,膜通量越小;外压内抽方式的破乳效果优于单外压方式的破乳效果。对于粒径为5~2 5 μm乳液,用膜孔径为2 .0 μm的SiC微孔膜,在外压为6 0kPa、内负压为30kPa的外压内抽破乳方式下破乳,破乳率可达96 .4 % ,膜通量可达90 0L·(m2 ·h) -1。 相似文献
9.
在对旋转填料床精馏特性研究的基础上,以塑料多孔板为填料,乙醇-水为体系,在全回流操作条件下,进一步研究了气相动能因子F、超重力因子β和回流量L对旋转填料床流体力学特性的影响,证明了旋转填料床的低耗能特性。 相似文献
10.