全文获取类型
收费全文 | 3407篇 |
免费 | 426篇 |
国内免费 | 2444篇 |
专业分类
安全科学 | 127篇 |
废物处理 | 177篇 |
环保管理 | 250篇 |
综合类 | 3823篇 |
基础理论 | 782篇 |
污染及防治 | 736篇 |
评价与监测 | 308篇 |
社会与环境 | 72篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 26篇 |
2023年 | 125篇 |
2022年 | 226篇 |
2021年 | 250篇 |
2020年 | 252篇 |
2019年 | 238篇 |
2018年 | 239篇 |
2017年 | 202篇 |
2016年 | 291篇 |
2015年 | 251篇 |
2014年 | 277篇 |
2013年 | 458篇 |
2012年 | 351篇 |
2011年 | 405篇 |
2010年 | 288篇 |
2009年 | 268篇 |
2008年 | 239篇 |
2007年 | 275篇 |
2006年 | 254篇 |
2005年 | 195篇 |
2004年 | 164篇 |
2003年 | 209篇 |
2002年 | 149篇 |
2001年 | 130篇 |
2000年 | 94篇 |
1999年 | 90篇 |
1998年 | 62篇 |
1997年 | 59篇 |
1996年 | 52篇 |
1995年 | 40篇 |
1994年 | 37篇 |
1993年 | 26篇 |
1992年 | 17篇 |
1991年 | 12篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有6277条查询结果,搜索用时 343 毫秒
91.
Atsumi Miyake Nobuyoshi Yamada Terushige Ogawa 《Journal of Loss Prevention in the Process Industries》2005,18(4-6):380-383
Organic peroxides (POs) have been widely used in chemical industries as initiators of polymerization, hardening or bridge formation agents, and they are known for its self-reactive and also mixing hazard characteristics when mixed with other chemicals such as acids and alkalis. It is the purpose of this investigation to propose a simple but useful evaluation flow of mixing hazards of POs with other chemicals using conventional experimental techniques such as a glass test tube test, Dewar vessel test and DSC is proposed. 7 kinds of POs (DEPD, THP, TBEH, TBTC, MEKPO, DTBP, THHP) were mixed with sulfuric acids with various concentration, sodium hydroxide solutions, -iron(III) oxide and acrylonitrile (AN).
Based on the proposed evaluation flow the testing results were classified into 4 ranks due to the hazard criteria. Futhermore DEPD/acrylonitrile mixtures were investigated in more detail and the influences of the mixing ratio and the stirring speed were discussed. 相似文献
92.
气浮+生物接触氧化工艺处理食品加工废水 总被引:2,自引:0,他引:2
通过气浮 生物接触氧化工艺处理速冻食品加工废水的实验、设计和工程运行,结果表明:废水COD去除率能达到97%以上,使得最终出水的COD<100mg/l.该工艺对冲击负荷有较强的适应性. 相似文献
93.
论述了生物有机肥在发展农业生产中的重要地位,以及生产中存在着的大量使用集约化畜禽养殖场的畜禽粪对土壤、水体等环境质量和农产品质量安全产生严重影响的问题,提出以茶粕作为原料生产有机肥具有生产过程相对安全、克服有机肥二次污染的优点.此外,茶叶次生代谢物茶多酚、茶色素、茶皂素和茶皂甙等具有抗氧化、清除自由基、络合金属离子、调节植物生长和生物防虫、灭虫等独特生理功效,将极大地提高茶粕有机肥的生物有效性,显示出其广阔的应用前景. 相似文献
94.
从地域优势、农产品特征、生态条件等方面,论述了新疆发展有机食品生产的适宜性和重要意义.认为新疆发展有机食品生产可以利用得天独厚的气候、水土等自然资源,以及工业污染环境影响较小的有利条件,保护和改善农村生态环境,充分发挥独特的农产品资源优势,提高农产品附加值,变资源优势为经济优势,并结合新疆区情,从多方面提出了新疆发展有机食品的思路和措施. 相似文献
95.
随着城市生活水平的提高,室内装修装饰日益普及.各种新材料的引入,使得室内的各种有害气体总量日益增加.长期生活在这样的环境下,会对人体健康产生极为不利的影响.居民生活用煤气,在给人们生活带来便利的同时,作为一种可燃性、有毒气体,也具有极强的危害性.因此,研制一种能检测多种有害气体的实用仪器,具有很大的应用价值.本仪器为便携式多功能仪器,采用可充电电池供电,可以检测ppb的挥发性气体,显示气体浓度值,也可检测煤气,并具有声光报警功能. 相似文献
96.
Glyphosate has become the most commonly used herbicide worldwide and is reputedly environmentally benign, nontoxic, and safe for use near wildlife and humans. However, studies indicate its toxicity is underestimated and its persistence in the environment is greater than once thought. Its actions as a neurotoxin and endocrine disruptor indicate its potential to act in similar ways to persistent organic pollutants such as the organochlorines dichlorodiphenyltrichloroethane (DDT) and dioxin. Exposure to glyphosate and glyphosate‐based herbicides for both wildlife and people is likely to be chronic and at sublethal levels, with multiple and ongoing exposure events occurring in urban and agricultural landscapes. Despite this, there has been little research on the impact of glyphosate on wildlife populations, and existing studies appear in the agricultural, toxicology, and water‐chemistry literature that may have limited visibility among wildlife biologists. These studies clearly demonstrate a link between chronic exposure and neurotoxicity, endocrine disruption, cell damage, and immune suppression. There is a strong case for the recognition of glyphosate as an emerging organic contaminant and substantial potential exists for collaborative research among ecologists, toxicologists, and chemists to quantify the impact of glyphosate on wildlife and to evaluate the role of biosentinel species in a preemptive move to mitigate downstream impacts on people. There is scope to develop a decision framework to aid the choice of species to biomonitor and analysis methods based on the target contaminant, spatial and temporal extent of contamination, and perceived risk. Birds in particular offer considerable potential in this role because they span agricultural and urban environments, coastal, inland, and wetland ecosystems where glyphosate residues are known to be present. 相似文献
97.
ABSTRACTThe present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J0V0Y0, J1V0Y0, J0V1Y0, J0V0Y1, J1V1Y0, J1V0Y1, J0V1Y1, J1V1Y1. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J0 – no straw powder, J1 – 0.2 kg straw powder, Y0 – no manure, Y1 – 0.3 kg manure, V0 – no microbial fertilizer, V1 – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments. 相似文献
98.
Kun Zhang Jialuo Xu Qing Huang Lei Zhou Qingyan Fu Yusen Duan Guangli Xiu 《Frontiers of Environmental Science & Engineering》2020,14(6):92
99.
Raiane Costa Souza Roberto Bagattini Portella Paula Valéria Nunes Brito Almeida Caroline Oliveira Pinto Priscila Gubert 《Journal of environmental science and health. Part. B》2020,55(6):530-538
AbstractOrganochlorine pesticides (OCPs) are widely used around the world as insecticides, herbicides, fungicides, nematicides, and rodenticides. Despite banned in Brazil, the usage remains occurring in many countries. The persistence and extreme mobility of OCPs contribute to the contamination of the environment and the human body. The OCPs bioaccumulation in adipose tissue triggers the excretion into human milk during breastfeeding. Hence, the present study determined eighteen OCPs residues in the breast milk of mothers from the Western Region of Bahia State, Brazil. Nine different residue species were found, including beta-Hexachlorocyclohexane (9.24?±?0.00?ng g?1 fat), delta- Hexachlorocyclohexane (22.15?±?10.48?ng g?1 fat), Heptachlor (58.08?±?74.13?ng g?1 fat), Aldrin (142.65?±?50.65?ng g?1 fat), Dieldrin (774.62?±?472.68?ng g?1 fat), Endosulfan I (408.44?±?245.51?ng g?1 fat), Dichloro-diphenyl-dichloro-ethylene (29.17?±?22.42?ng g?1 fat), Dichloro-diphenyl-trichloro-ethane (28.87?±?0.00?ng g?1 fat) and Methoxychlor (1699.67?±?797.43?ng g?1 fat). The Methoxychlor presence in all samples may reveal a recent exposure, while Dieldrin and Endosulfan I analyses can point to distant past exposure. 相似文献
100.
Natural gas is a kind of clean, efficient green energy source, which is used widely. Liquefied natural gas (LNG) is produced by cooling natural gas to −161 °C, at which it becomes the liquid. Once LNG was released, fire or explosion would happen when ignition source existed nearby. The high expansion foam (Hi-Ex foam) is believed to quickly blanket on the top of LNG spillage pool and warm the LNG vapor to lower the vapor cloud density at the ground level and raising vapor buoyancy. To identify the physical structure after it contacted with LN2 and to develop heat transfer model, the small-scale field test with liquid nitrogen (LN2) was designed. In experiment, three layers including frozen ice layer, frozen Hi-Ex layer and soft layer of Hi-Ex foam were observed at the steady state. By characterizing physical structure of the foam, formulas for calculating the surface of single foam bubble and counting foam film thickness were deduced. The micro heat transfer and evaporation model between cryogenic liquid and Hi-Ex foam was established. Indicating the physical structure of the frozen ice layer, there were a certain number of icicles below it. The heat transfer and evaporation mathematical model between the frozen ice layer and LNG was derived. Combining models above with the heat transfer between LNG, ground and cofferdam, the heat transfer and evaporation mathematical model of LNG covered by Hi-Ex foam was developed eventually. Finally, LN2 evaporation rate calculated by this model was compared with the measured evaporation rate. The calculated results are 1.2–2.1 times of experimental results, which were acceptable in engineering and proved the model was reliable. 相似文献