全文获取类型
收费全文 | 1207篇 |
免费 | 139篇 |
国内免费 | 386篇 |
专业分类
安全科学 | 116篇 |
废物处理 | 62篇 |
环保管理 | 106篇 |
综合类 | 777篇 |
基础理论 | 229篇 |
污染及防治 | 195篇 |
评价与监测 | 163篇 |
社会与环境 | 60篇 |
灾害及防治 | 24篇 |
出版年
2024年 | 12篇 |
2023年 | 30篇 |
2022年 | 61篇 |
2021年 | 61篇 |
2020年 | 74篇 |
2019年 | 62篇 |
2018年 | 53篇 |
2017年 | 56篇 |
2016年 | 66篇 |
2015年 | 79篇 |
2014年 | 71篇 |
2013年 | 139篇 |
2012年 | 105篇 |
2011年 | 97篇 |
2010年 | 73篇 |
2009年 | 69篇 |
2008年 | 49篇 |
2007年 | 85篇 |
2006年 | 73篇 |
2005年 | 47篇 |
2004年 | 57篇 |
2003年 | 50篇 |
2002年 | 44篇 |
2001年 | 45篇 |
2000年 | 36篇 |
1999年 | 22篇 |
1998年 | 20篇 |
1997年 | 35篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有1732条查询结果,搜索用时 218 毫秒
441.
以模拟烟气为气源,去离子水为水源,通过微纳米气泡发生器形成微纳米气液分散体系,吸收模拟烟气中的NO,考察了多种因素对脱硝率(η)和气相体积总传质系数(KGa)的影响,分析了微纳米气液分散体系吸收NO的反应机理。结果表明:η和KGa随着进气NO体积分数和十二烷基苯磺酸钠(SDBS)质量浓度的提高而下降;随着吸收液初始pH的提高先降低后升高;随着进气O_2体积分数的增大而提高;随着吸收液温度的升高先提高后降低;控制进气NO体积分数为0.06%时,在吸收液初始pH为2.0、吸收剂为去离子水、吸收液温度为25℃、进气O_2体积分数为10%的最佳条件下,脱硝率可达81.0%。微纳米气液分散体系是通过产生羟基自由基从而对NO进行氧化吸收的。 相似文献
442.
Global food production and security rely heavily on finite reserves of newly mined phosphate for fertilizers. However, systemic inefficiencies result in the deposition in aquatic ecosystems of much of the phosphorus mined for food production causing costly eutrophication problems that damage aquatic ecosystems and human health. The Sustainable Phosphorus Alliance (SPA, formerly named North American Partnership for Phosphorus Sustainability) was created to implement sustainable phosphorus solutions through active engagement of stakeholders in both the private and public sectors. This paper describes a conceptual model of transformative change to a sustainable phosphorus system for the North American region. The model emerged from discussions at a series of formal and informal meetings held in conjunction with a ‘Future of Phosphorus’ event (National Science Foundation’s Phosphorus Sustainability Research Coordination Network) and an inaugural SPA Board meeting. Model development drew on the multi-level perspective of socio-technical transitions to develop a series of pathways to a transformed phosphorus system. The uses of the model and transition pathways are discussed in terms of their potential to form an important first step towards the development of a regional vision for improved phosphorus sustainability. The process provides an example of how research in sustainability science can contribute to action on environmental improvement. 相似文献
443.
运用Agilent(安捷伦)1200系列高效液相色谱和多环芳烃专用柱ZORBAX Eclipse PAH(4.6×250mm、5μm,P.N.959990-918,S.N.USPAB01066),对16种多环芳烃化合物混合溶液进行分析,根据具体实验条件优化EPA8310中色谱分离条件并得到了更节省时间、分离效率更好的流动相梯度变化程序。 相似文献
444.
Anthony M. Rizzuti Arthur D. Cohen Patrick G. Hunt Matias B. Vanotti 《Journal of environmental science and health. Part. B》2013,48(4):709-748
Abstract This paper reports on research designed to investigate the capacities of different highly characterized peats to remove odorous compounds from liquid swine manure (LSM). Peat types representing a wide range of properties were tested in order to establish which chemical and physical properties might be most indicative of their capacities to remediate odors produced by LSM. Eight percent slurries (of peat/LSM) were measured for odor changes after 24 hours using odor panel and GC/MS‐Solid‐phase microextraction (GC/MS‐SPME) analysis. The GC/MS‐SPME and odor panel results indicated that, although all peats tested in this study were found to be effective at removing odor‐causing compounds found in LSM, some peats tended to work better than others. Overall, the peats that were the most effective at removing odor‐causing compounds tended to have lower bulk densities, ash contents, fulvic acids contents, and guaiacyl lignins contents,and higher water holding capacities, hydraulic conductivities, “total other lignins”; contents, hydrogen contents, carbon contents, and total cellulose contents. GC/MS‐SPME analysis was found to be a reasonably inexpensive and efficient way of conducting this type of research. It allows one to identify a large number of the odor‐causing compounds found in LSM, and more importantly, to detect with some precision specific differences in the amounts of these compounds between peat types. 相似文献
445.
W. Spieszalski H. D. Niemczyk 《Journal of environmental science and health. Part. B》2013,48(5-6):575-588
Abstract An improved Gas Chromatographic method utilizing simple extraction and one‐step purification on solid phase extraction tubes was developed for analysis of trichlorfon as an intact insecticide compound in turfgrass thatch and soil. A Gas Chromatograph/Mass Spectrum (GC/MS) was used for confirmation of trichlorfon structure. The method readily determines trichlorfon in the presence of dichlorvos. Using an electron capture (EC) detector, the detection limits were 0.02 ppm in soil, 0.04 ppm in turfgrass thatch, and 0.09 ppm in soil, and 0.2 ppm in turfgrass thatch using an nitrogen phosphorus (NP) detector. 相似文献
446.
硅酸盐工业灰渣的基本化学成人是CaO、SiO2,Al2O3等,目前主要用于生产水泥等建筑材料, 西方对工业灰渣CaO-SiO2-Al2O3三元系高钙相平衡过程进行了分析讨论和数学处理。 相似文献
447.
This paper tests the Hotelling Valuation Principle (HVP) for natural resources using data from oil and gas ‘pure plays’ such as royalty trusts and master limited partnerships. The results support the HVP which specifies that the value of any mineral reserve may be predicted by the market price of the resource, net of extraction costs. Regression results also indicate that a Box-Cox transformation of variables provide a better means of estimating the functional relationship between the value of an exhaustible natural resource and its market price. 相似文献
448.
Solid phase microextraction (SPME) as an effective means to isolate degradation products in polymers 总被引:2,自引:0,他引:2
Minna Hakkarainen Ann- Christine Albertsson Sigbritt Karlsson 《Journal of Polymers and the Environment》1997,5(2):67-73
A new sample preparation technique, solid phase microextraction (SPME), was compared with direct headspace-GC-MS with respect
to the type and amount of identified compounds. Three types of LDPE films containing photosensitising additives according
to the Scott-Gilead patents and pure LDPE were used as model substances. The polyethylene films were thermally aged at 80‡C
after the induction period was surpassed by subjecting the materials to 100 h of UV radiation. The new SPME method was developed
using nonpolar poly(dimethylsiloxane) and polar carbowax fibers to extract the low molecular weight products formed in the
polyethylene films during aging. Many more products were identified after SPME followed by GC-MS than after direct headspace-GC-MS
of the samples. The SPME method allowed the identification of homologous series of carboxylic acids, ketones, and furanones,
while direct headspace-GC-MS identified only a few carboxylic acids (C1-C6) and small amounts of some ketones and furanones.
In general, SPME was more effective in extracting less volatile products, and in particular, the polar carbowax fiber identified
also C7-C12 carboxylic acids and 4-oxopentanoic acid. By SEC and FTIR we confirmed that the number and amount of former degradation
products correlated well with the decrease in molecular weights and the amount of formed carbonyl compounds. 相似文献
449.
成都市春季大气飘尘目标变换因子分析 总被引:10,自引:0,他引:10
对成都市大气飘尘(SMP〈10μm)用目标变换因子分析(TTFA)作源解析。结果表明,主要排放源及其贡献为,道路交通尘(16.8%),冶金尘(19.2%),垃圾与草木焚烧烟尘(24.8%),燃煤飞灰(54.3%),大气尘污染以煤烟为主。 相似文献
450.
固相微萃取-毛细管气相色谱法快速分析水中酚类化合物 总被引:10,自引:4,他引:10
固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点.本工作用固相微萃取富集水中酚类化合物,毛细管气相色谱分离分析,整个分析过程只需45min,检出限可达1.0~10.0μg/L,已用于地面水、海水、工厂废水中酚类化合物含量的测定. 相似文献