全文获取类型
收费全文 | 127618篇 |
免费 | 9567篇 |
国内免费 | 4856篇 |
专业分类
电工技术 | 4898篇 |
技术理论 | 11篇 |
综合类 | 10129篇 |
化学工业 | 24701篇 |
金属工艺 | 7999篇 |
机械仪表 | 3122篇 |
建筑科学 | 18841篇 |
矿业工程 | 6448篇 |
能源动力 | 6067篇 |
轻工业 | 9149篇 |
水利工程 | 20221篇 |
石油天然气 | 8998篇 |
武器工业 | 337篇 |
无线电 | 2048篇 |
一般工业技术 | 7247篇 |
冶金工业 | 7801篇 |
原子能技术 | 1348篇 |
自动化技术 | 2676篇 |
出版年
2024年 | 423篇 |
2023年 | 1361篇 |
2022年 | 2902篇 |
2021年 | 3499篇 |
2020年 | 3667篇 |
2019年 | 2911篇 |
2018年 | 2875篇 |
2017年 | 3552篇 |
2016年 | 3881篇 |
2015年 | 3986篇 |
2014年 | 7562篇 |
2013年 | 7437篇 |
2012年 | 9280篇 |
2011年 | 9498篇 |
2010年 | 7344篇 |
2009年 | 7700篇 |
2008年 | 6414篇 |
2007年 | 8596篇 |
2006年 | 8213篇 |
2005年 | 7276篇 |
2004年 | 5902篇 |
2003年 | 5366篇 |
2002年 | 4572篇 |
2001年 | 3662篇 |
2000年 | 2988篇 |
1999年 | 2289篇 |
1998年 | 1719篇 |
1997年 | 1410篇 |
1996年 | 1069篇 |
1995年 | 1003篇 |
1994年 | 725篇 |
1993年 | 546篇 |
1992年 | 464篇 |
1991年 | 357篇 |
1990年 | 254篇 |
1989年 | 297篇 |
1988年 | 177篇 |
1987年 | 184篇 |
1986年 | 135篇 |
1985年 | 129篇 |
1984年 | 126篇 |
1983年 | 78篇 |
1982年 | 43篇 |
1981年 | 13篇 |
1980年 | 20篇 |
1979年 | 22篇 |
1977年 | 11篇 |
1966年 | 10篇 |
1964年 | 9篇 |
1951年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
902.
The feasibility of the removal of Ag+ ions in a model solution and a sample of rinse water provided from an industrial plating plantwas investigated in a batch electrodialysis system. The experiments were carried out using two different types of ion-exchange membranes. The effects of applied potential, pH value and initial silver concentration on the duration of electrodialysis and energy consumption were examined. Full removal of Ag+ ions was achieved from model solutions and the sample of rinse water. The most convenient applied voltage and energy consumption values to remove silver ions are reported. These results will be useful for designing and operating different capacities of electrodialysis plants for recovering Ag+ ions. 相似文献
903.
904.
Toshikazu Takenouchi Shin-ichi Wakabayashi 《Journal of Applied Electrochemistry》2006,36(10):1127-1132
The improvement in the surface cleanliness of electroplated nickel by rinsing in alkaline electrolyzed water (AEW) was determined. When the nickel plated sample was rinsed with the AEW, it was found that the amount of residual sulfate ion on the surface of a sample decreased approximately by half compared to one rinsed only with de-ionized pure water. Because nanosize hydrogen bubbles are present in the AEW, and the zeta-potential has a negative value, we then surmised that the mechanism of rinsing was as follows: The sulfate ions are selectively absorbed on the nanosize colloidal hydrogen bubbles, or substituted for anions absorbed on the hydrogen bubbles. The sulfate ions absorbed on the nickel surface then become detached. The detached sulfate ions are absorbed on the surface of the hydrogen bubbles, and negatively charge the hydrogen bubbles. It can be considered that any detached sulfate ions do not re-adhere due to the electrical repulsion force of the negatively charged nickel surface. Thus the sample is efficiently rinsed. 相似文献
905.
M Mahbubul Hassan Christopher J Hawkyard 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(7):834-841
Combined oxidation with ozone and Fenton's reagent (‘Fentozone’ process) for decolourisation of aqueous dyes was studied and compared with traditional Fenton's reagent. Although the ‘Fentozone’ process was found to be effective at a wide range of pH values, the maximum colour removal was achieved at pH 4. The effect of pre‐ozonation on colour removal efficiency of aqueous dyestuffs in the subsequent treatment with Fenton's reagent was investigated. The reaction kinetics using water‐soluble acid and reactive dyes were also studied. Our experimental results show that pre‐ozonation can considerably accelerate decomposition of dyestuffs in the subsequent treatment with Fenton's reagent. Different concentrations of ferrous sulfate were used to investigate their influences on the removal of colour. The rate of reaction increased with increasing doses of ferrous sulfate. © 2002 Society of Chemical Industry 相似文献
906.
Graft copolymerization of acrylic acid (AA) onto polyphenylene sulfide (PPS) nonwoven initiated by low temperature plasma was studied. The effects of various conditions on graft reaction and the grafting rate were investigated. SEM images showed that PPS nonwoven was grafted, and the graft copolymerization only occurred on the surface of PPS. It may be due to the chain transference going with the graft copolymerization. It was found that with the increasing of plasma power, treatment time, space between electrodes, monomer concentration, and temperature of graft polymerization, the grafting rate increased at first, went to the top, and then decreased. The PPS nonwoven surface graft reaction could be optimized by the following processing conditions: 120 s of plasma treatment time, 50 W of plasma power, 1.5 cm of space between electrodes, 30% (w/w) of monomer concentration, and 50°C of temperature of graft polymerization. Measurement of XPS showed that the peak of C1s of graft polyacrylic acid was existed, and the peak area increased with the increase of the grafting rate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5884–5889, 2006 相似文献
907.
More than 90% of the population of the Gaza Strip depends on desalinated water for drinking purposes. About 90% of the groundwater is unacceptable for drinking as a result of contamination by nitrate and chloride. One of the major options for resolving the water problems is the utilization of desalination technology for both sea and brackish water. The objective of this article is to address desalination water management in its embryonic stage in the Gaza Strip. The sources of drinking water supply, distribution system and the environmental impact of brine water will be fingered in detail. Desalination facilities range from large seawater plants to small brackish desalination units on a home scale. Governmental, non-governmental and private desalination plants are common. The distribution system of desalinated water is a responsibility of governmental, non-governmental, private small community bodies and even individuals. Disposal of brine water is made either directly or indirectly into the sea, sewage system, poor land, channels, wadies, etc. Brine constituents have an adverse impacton the surrounding environment, e.g., sea life, soil, wastewater treatment plants and the groundwateraquifer. The lack of real environmental impact assessments, especially for mid- and home-scale units may lead to a deterioration of the environment. The fragmentation of the responsibilities of water desalination, distribution of desalinated water and the disposal of brine water suggest that urgent action should be taken (e.g., legislation or establishment of a supervisory body). In other words, strict policies and management actions are to be taken in order to alleviate the health and environmental impact of an important and uncontrolled new system. 相似文献
908.
电石渣在酸性废水治理中的应用 总被引:10,自引:0,他引:10
叙述了用电石渣做中和剂,治理酸性废水的“以废治废”方法,阐述了电石渣与酸性废水的反应原理运行方式及沉渣产生量的计算方法,并列举了两个应用实例。 相似文献
909.
制革工业污泥中Cr~(3+)的回收试验 总被引:3,自引:0,他引:3
对制革工业污泥中Cr回收与再利用进行了试验。试验表明:Cr的总回收率的高低主要决定于Cr3+的氧化是否彻底,在n(H2O2):n(Cr3+)为7.5,pH=10,温度为60℃以及反应时间为30min的条件下,污泥中Cr3+氧化率接近90%,总回收率可以达到80%以上。 相似文献
910.
劣质铁尾矿制备聚硅酸铝混凝剂 总被引:5,自引:3,他引:5
研究了以劣质铁尾矿为原料制备高效混凝剂聚硅酸铝(PSA)的方法,确定了合理的生产工艺和操作条件。用该混凝剂处理工业废水,并与传统混凝剂进行了比较,结果表明,PSA混凝剂处理效果好,用药量少。 相似文献