全文获取类型
收费全文 | 1051篇 |
免费 | 78篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 306篇 |
金属工艺 | 33篇 |
机械仪表 | 50篇 |
建筑科学 | 30篇 |
矿业工程 | 2篇 |
能源动力 | 52篇 |
轻工业 | 177篇 |
水利工程 | 3篇 |
石油天然气 | 7篇 |
无线电 | 77篇 |
一般工业技术 | 162篇 |
冶金工业 | 43篇 |
原子能技术 | 7篇 |
自动化技术 | 173篇 |
出版年
2024年 | 11篇 |
2023年 | 22篇 |
2022年 | 23篇 |
2021年 | 51篇 |
2020年 | 42篇 |
2019年 | 29篇 |
2018年 | 58篇 |
2017年 | 53篇 |
2016年 | 63篇 |
2015年 | 54篇 |
2014年 | 70篇 |
2013年 | 207篇 |
2012年 | 50篇 |
2011年 | 47篇 |
2010年 | 68篇 |
2009年 | 63篇 |
2008年 | 34篇 |
2007年 | 23篇 |
2006年 | 24篇 |
2005年 | 15篇 |
2004年 | 14篇 |
2003年 | 3篇 |
2002年 | 13篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 13篇 |
1998年 | 12篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1131条查询结果,搜索用时 46 毫秒
991.
纺织服装业一直以来在欧洲许多国家和地区的制造业中扮演着重要的角色。纺织服装业正处在传统加工与创新制造的交叉点,并正在建立一个复杂而又强大的互通价值链,包括设计、材料的加工、时尚、家用产品和产业用产品,以及在销售给最终消费者时的分配和零售方式。这使得欧洲在这种产业链中维持主导地位。 相似文献
992.
Mutlu Pilavtepe‐Çelik 《International Journal of Food Science & Technology》2013,48(4):673-677
Consumption of unpasteurised fruit/vegetable juices has increased in recent years due to their freshness, low calorie contribution and good nutritional quality. However, unpasteurised fresh juices with low acidity (pH > 4.6) and high water activity (aw > 0.85) can support the growth of pathogens. Hence, pasteurisation is a necessary process in the production of low‐acid juices. Consumer demand has required minimally processed high‐quality foods that are free from additives, that are fresh tasting and microbiologically safe, and with an extended shelf life. High hydrostatic pressure (HHP) treatment is considered to be an alternative to thermal pasteurisation for fruit and vegetable juices. HHP treatment could preserve nutritional value and the sensory properties of fruits and vegetables due to its limited effect on the covalent bonds of low‐molecular‐mass compounds such as colour, flavour compounds and vitamins. However, inactivation of important foodborne pathogens in low‐acid foods by HHP is most urgent and critical. More research should be performed in order to satisfy consumer demands for fresh‐tasting products while retaining safety. 相似文献
993.
994.
在2009法兰克福展上,菲斯曼采用"效能城市"的形象展现各种领域的供暖系统。在所有参观者头上,一个宽50米,竖向的城市模型吸引所有人的眼光。全方位的投影仪将它打造成3D屏幕。建筑总是从雕刻般的屏幕后面不断涌现。通过这个,参观者可以 相似文献
995.
996.
Serdar Doǧruel Merve Köktuna Emine Ubay Çokgör Seval Sözen Derin Orhon 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(11):1364-1373
BACKGROUND: The study evaluated the relationship between particle size distribution (PSD) of chemical oxygen demand (COD) and treatability of leachate generated by organic waste. PSD determinations were performed together with physico‐chemical and biological treatability studies. Leachate biodegradation was also evaluated by means of oxygen uptake rate (OUR) profiles and experimental results were used for calibration of the adopted mathematical model. RESULTS: The leachate was characterized by a COD content of 80 000 mg L?1 in summer. PSD analysis showed a bimodal distribution with around 60% of the COD below 2 nm and 25% above 1600 nm. Chemical treatment by lime and alum provided limited COD removal (30‐35%). The extent of COD removal was higher than the particulate COD fraction above 1600 nm, it also occurred in the soluble range below 2 nm through adsorption. A modeling study indicated three major COD fractions that could be correlated with PSD analysis: readily biodegradable COD and slowly biodegradable COD in the soluble range and hydrolyzable COD fraction in the particulate range. CONCLUSION: PSD‐based COD fractionation adequately explained limitations of chemical treatment efficiency; it was also a reliable complement to the currently used respirometric tests for biodegradation, providing insight to the fate of different COD fractions included in the soluble range (<2 nm) and yielding concrete supporting information on the generation of soluble residual microbial products. Copyright © 2011 Society of Chemical Industry 相似文献
997.
Poly(glycidyl methacrylate) (PGMA) microbeads were synthesized by a simple suspension polymerization of glycidyl methacrylate and ethylene glycol dimethacrylate. The epoxy groups of the microbeads were firstly modified with 3,3′‐iminodipropionitrile (IDPN) and the resulting nitrile groups were then converted to amidoxime. From scanning electron microscopy studies, the average size of the PGMA microbeads was determined as 170 µm, which was not changed by the modification processes. For the modification of epoxy groups with IDPN, the intensity of the C≡N absorption band at 2249 cm?1 increased proportionally with reaction time; for the conversion of nitrile groups to amidoxime, it decreased. Attenuated total reflectance Fourier transform infrared spectroscopy measurements clearly showed the disappearance of the original nitrile groups and the formation of amidoxime groups through treatment with hydroxylamine under the reaction conditions specified. The microbeads possessed good thermal and morphological properties and chemical stability suitable for practical use. Therefore, the amidoximated PGMA microbeads could be used in batch and continuous processes for the adsorption of uranyl ions from seawater or aqueous media. Copyright © 2010 Society of Chemical Industry 相似文献
998.
Effluent from the Pa?aköy Wastewater Treatment Plant was oxidized by using O3 and O3/H2O2. DOC, COD, UV254, total coliform, dissolved ozone and some endocrine disrupting compounds were monitored during oxidation. Results showed that O3 provided superior disinfection, however, lower reductions in DOC, COD and endocrine disrupting compounds were exhibited compared to O3/H2O2. The highest removal efficiency of DOC, COD and endocrine disrupting compounds were achieved at 0.5 molar ratio of O3/H2O2. The benefit of H2O2 addition for advanced oxidation reduced significantly when the mole ratio was increased to 2. Therefore, the mole ratio of H2O2 to O3 is a critical parameter for the design of wastewater oxidation by O3/H2O2. 相似文献
999.
The accelerating use of fossil fuels since the Industrial Revolution and the rapid destruction of forests causes a significant increase in greenhouse gases. The increasing threat of global warming and climate change has been the major, worldwide, ongoing concern especially in the last two decades. The impacts of global warming on the world economy have been assessed intensively by researchers since the 1990s. Worldwide organizations have been attempting to reduce the adverse impacts of global warming through intergovernmental and binding agreements. Carbon dioxide (CO2) is one of the most foremost greenhouse gases in the atmosphere. The energy sector is dominated by the direct combustion of fuels, a process leading to large emissions of CO2. CO2 from energy represents about 60% of the anthropogenic greenhouse gas emissions of global emissions. This percentage varies greatly by country, due to diverse national energy structures. The top-25 emitting countries accounted 82.27% of the world CO2 emissions in 2007. In the same year China was the largest emitter and generated 20.96% of the world total. Trend analysis is based on the idea that what has happened in the past gives traders an idea of what will happen in the future. In this study, trend analysis approach has been employed for modelling to forecast of energy-related CO2 emissions. To this aim first, trends in CO2 emissions for the top-25 countries and the world total CO2 emissions during 1971–2007 are identified. On developing the regression analyses, the regression analyses with R2 values less than 0.94 showing insignificant influence in statistical tests have been discarded. Statistically significant trends are indicated in eleven countries namely, India, South Korea, Islamic Republic of Iran, Mexico, Australia, Indonesia, Saudi Arabia, Brazil, South Africa, Taiwan, Turkey and the world total. The results obtained from the analyses showed that the models for those countries can be used for CO2 emission projections into the future planning. The calculated results for CO2 emissions from fitted curves have been compared with the projected CO2 emissions given in International Energy Outlook 2009 of U.S. Department of Energy calculated from “high economic growth case scenario”, “reference case scenario” and “low economic growth case scenario” respectively. Agreements between calculated results and the projected CO2 emissions from different scenarios are in the acceptable range. 相似文献
1000.
In recent years, knowledge has received significant attention in manufacturing to built a competitive advantage in the sector. Knowledge induction from data is an important issue in manufacturing to find the failure of the process then predict and improve the future system performance.This research examines the improvement of manufacturing process via data mining. Not only do we detect and isolate machine breakdowns in carpet manufacturing, but also we propose a C4.5 decision tree model. In addition, we use attribute relevance analysis to select the qualitative attribute’s variables. Consequently, manufacturing process is redeveloped. 相似文献