全文获取类型
收费全文 | 306篇 |
免费 | 7篇 |
国内免费 | 34篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 14篇 |
环保管理 | 26篇 |
综合类 | 108篇 |
基础理论 | 32篇 |
污染及防治 | 51篇 |
评价与监测 | 18篇 |
社会与环境 | 1篇 |
出版年
2023年 | 11篇 |
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 16篇 |
2019年 | 11篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 27篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2012年 | 16篇 |
2011年 | 17篇 |
2010年 | 5篇 |
2009年 | 16篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
排序方式: 共有347条查询结果,搜索用时 15 毫秒
101.
This paper presents an experimental study on employing a pellet form of catalyst in photo-reduction of carbon dioxide with water. Water was first absorbed into titania pellets. Highly purified carbon dioxide gas was then discharged into a reactor containing the wet pellets, which were then illuminated continuously for 65 hours using UVC lamps. Analysing the products accumulated in the reactor confirmed that methane and hydrogen were produced through photo-reduction of carbon dioxide with water. No other hydrocarbons were detected. Increasing the temperature in the reactor has showed little change on the amount of methane produced. 相似文献
102.
103.
Carmen Difiglio Dolf Gielen 《Mitigation and Adaptation Strategies for Global Change》2007,12(3):387-405
If hydrogen (H2) is to significantly reduce greenhouse gas emissions and oil use, it needs to displace conventional transport fuels and be
produced in ways that do not generate significant greenhouse gas emissions. This paper analyses alternative ways H2 can be produced, transported and used to achieve these goals. Several H2 scenarios are developed and compared to each other. In addition, other technology options to achieve these goals are analyzed.
A full fuel cycle analysis is used to compare the energy use and carbon (C) emissions of different fuel and vehicle strategies.
Fuel and vehicle costs are presented as well as cost-effectiveness estimates. Lowest hydrogen fuel costs are achieved using
fossil fuels with carbon capture and storage. The fuel supply cost for a H2 fuel cell car would be close to those for an advanced gasoline car, once a large-scale supply system has been established.
Biomass, wind, nuclear and solar sources are estimated to be considerably more expensive. However fuel cells cost much more
than combustion engines. When vehicle costs are considered, climate policy incentives are probably insufficient to achieve
a switch to H2. The carbon dioxide (CO2) mitigation cost would amount to several hundred US$ per ton of CO2. Energy security goals and the eventual need to stabilize greenhouse gas concentrations could be sufficient. Nonetheless,
substantial development of related technologies, such as C capture and storage will be needed. Significant H2 use will also require substantial market intervention during a transition period when there are too few vehicles to motivate
widely available H2 refueling.
相似文献
Dolf GielenEmail: |
104.
Hydrogen safety is a critical component of modern industrial safety production. In this study, a set of hydrogen explosion suppression equipment is designed independently. The suppression effects of the equipment on hydrogen explosions are studied at normal room temperature and pressure. The experimental results show that the actuation time of the equipment and the spraying mode of the suppressant are the main factors leading to the failure of the hydrogen explosion suppression equipment. The flame, with a hydrogen equivalence ratio of 0.7 and 1.0, spreads out of control when the suppressant touches the flame front. At this time, the addition of the suppressant enhances flame propagation and increases pressure. In addition, because the suppressant does not fully cover the developing flame, the hydrogen flame with the equivalence ratio of 0.5 eventually breaks through the suppressant cloud, and the explosion happens. However, when the initial flame is completely covered by the suppressant, the hydrogen explosion is suppressed by hydrogen explosion suppression equipment. This research provides a solid and reliable foundation for hydrogen explosion suppression equipment in industrial safety and production protection. 相似文献
105.
106.
Xiaomin Zhang Wenjie Xiong Zengyu Yin Yongle Chen Youting Wu Xingbang Hu 《绿色能源与环境(英文)》2022,7(1):137-144
In this work, a series of novel proton-gradient-transfer acid complexes (PGTACs) were developed. Their physicochemical properties, including thermal stability, melting point, and Hammett acidity, were measured. The effects of catalyst loading, reaction temperature, and substrate expansion on the catalytic performance were systematically studied. It is found that the combination of bidentate N-heterocycle and H2SO4 (1:2 M ratio) could form simultaneously N–H covalent bond and N…H hydrogen bond, which makes the PGTACs excellent catalysts integrate the advantages of strong acids (high catalytic activity) and ionic liquids (phase separation) in the esterification reaction. Moreover, these PGTACs can be reused by convenient phase separation without obvious diminution of catalytic activity. It is concluded that these PGTACs are potential alternative candidates for esterification reaction in the process of industrial catalysis. 相似文献
107.
Hydrogen is an indispensable energy carrier for the sustainable development of human society. Nevertheless, its storage, transportation, and in situ generation still face significant challenges. Methanol can be used as an intermediate carrier for hydrogen supplies, providing hydrogen energy through instant methanol conversion. In this study, a sorption-enhanced, chemical-looping, oxidative steam methanol-reforming (SECL-OSRM) process is proposed using CuO–MgO for the on-board hydrogen supply, which could be a promising method for safe and efficient hydrogen production. Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process. The effects of CuO/CH3OH, MgO/CH3OH, and H2O/CH3OH mole ratios and of temperature on H2 production rate, H utilization efficiency, CH3OH conversion, CO concentration, and system heat balance are discussed thoroughly. The results indicate that the system can be operated in auto-thermal conditions with high-purity hydrogen (99.50 vol%) and ultra-low-concentration CO (<50 ppm) generation, which confirms the pos-sibility of integrating low-temperature proton-exchange membrane fuel cells (LT-PEFMCs) with the SECL-OSRM process. The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H2O/CH3OH and MgO/CH3OH mole ratios. 相似文献
108.
Surface sediments were collected from the Yangtze River Estuary (YRE) in May 2012, August 2012, November 2012 and February 2013 to analyse the seasonal and spatial distributions of acid-volatile sulphide (AVS), simultaneously extracted metals (SEM) and the sediment toxicity. An optimised method was used for the AVS and SEM analysis and the results showed that the seasonal variations of AVS were positively correlated with changes in water temperature and the position of higher AVS was relatively fixed. The average of SEM was gradually increased from May 2012 to February 2013 and there were abnormally high values of SEMCu and SEMNi in the YRE. Concentrations of the five SEM components were in the following order: Cd?相似文献
109.
焦化装置腐蚀原因分析及预防措施 总被引:1,自引:0,他引:1
张书忠 《安全.健康和环境》2004,4(7):8-11
介绍了焦化装置的腐蚀情况,特别是对加热炉空气预热器的腐蚀做了详细的分析,并提出了预防措施. 相似文献
110.
Rüdiger Riesch Virginia Duwe Nina Herrmann Lisa Padur Annemarie Ramm Kristin Scharnweber Matthias Schulte Tanja Schulz-Mirbach Madlen Ziege Martin Plath 《Behavioral ecology and sociobiology》2009,63(10):1515-1526
One potential trade-off that bold individuals face is between increased predation risks and gains in resources. Individuals
experiencing high predation and hungry individuals (or individuals with low body condition) are predicted to show increased
boldness. We examined one behavioral trait previously reported to be associated with boldness (the time individual fish needed
to emerge from shelter) in various populations of mollies (Poecilia spp.). Our study system included several southern Mexican surface streams with high piscine predation and high food availability,
sulfidic surface streams with high avian predation, in which the inhabiting fish show reduced body condition, and a sulfidic
cave, where predation and body condition are low. Our comparison revealed very short times to emerge from the start box in
populations from non-sulfidic streams. In sulfidic habitats (whether surface or cave), it took individual Poecilia mexicana considerably longer to emerge from the start box, and the same difference was also found in an independent comparison between
P. mexicana and the closely related, highly sulfide-adapted Poecilia sulphuraria. Fish reared under common garden conditions (in the absence of predators and hydrogen sulfide) showed intermediate boldness
scores to the extremes observed in the field. Our data thus indicate that (a) boldness is shaped by environmental conditions/experiential
effects, but is not heritable, (b) predation affects boldness in the predicted direction, but (c) low body condition leads
to reduced boldness. Extremophile Poecilia spp. spend most of their time surfacing to survive under sulfidic and hypoxic conditions, which exposes them to increased
levels of predations, but the fish forage on the bottom. Hence, in this system, increased boldness does not increase foraging
success. We argue that energy limitation favors reducing energetically costly behaviors, and exploring novel environments
may be just one of them. 相似文献