全文获取类型
收费全文 | 3649篇 |
免费 | 532篇 |
国内免费 | 2009篇 |
专业分类
安全科学 | 150篇 |
废物处理 | 208篇 |
环保管理 | 418篇 |
综合类 | 3525篇 |
基础理论 | 659篇 |
环境理论 | 4篇 |
污染及防治 | 708篇 |
评价与监测 | 137篇 |
社会与环境 | 373篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 34篇 |
2023年 | 166篇 |
2022年 | 253篇 |
2021年 | 225篇 |
2020年 | 203篇 |
2019年 | 221篇 |
2018年 | 227篇 |
2017年 | 252篇 |
2016年 | 293篇 |
2015年 | 319篇 |
2014年 | 313篇 |
2013年 | 521篇 |
2012年 | 522篇 |
2011年 | 491篇 |
2010年 | 315篇 |
2009年 | 262篇 |
2008年 | 207篇 |
2007年 | 241篇 |
2006年 | 257篇 |
2005年 | 144篇 |
2004年 | 106篇 |
2003年 | 104篇 |
2002年 | 84篇 |
2001年 | 76篇 |
2000年 | 71篇 |
1999年 | 55篇 |
1998年 | 45篇 |
1997年 | 35篇 |
1996年 | 37篇 |
1995年 | 21篇 |
1994年 | 27篇 |
1993年 | 20篇 |
1992年 | 20篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有6190条查询结果,搜索用时 281 毫秒
131.
132.
133.
134.
以黄浦江水源水厂的滤后水为试验对象,进行饮用水O3-BAC深度处理工艺影响因素的中试研完。针对进水水质的试验结果表明,最优臭氧投加量为3mg/L左右,空床停留时间为15min左右。试验结果可为工程设计提供有益的参考。 相似文献
135.
136.
Black liquor gasification–combined cycle (BLGCC) is a new technology that has the potential to increase electricity production of a chemical pulping mill. Increased electricity generation in combination with the potential to use biomass (e.g. bark, hog fuel) more efficiently can result in increased power output compared to the conventional Tomlinson-boiler. Because the BLGCC enables an integrated pulp and paper mill to produce excess power, it can offset electricity produced by power plants. This may lead to reduction of the net-CO2 emissions. The impact of BLGCC to offset CO2 emissions from the pulp and paper industry is studied. We focus on two different plant designs and compare the situation in Sweden and the US. The CO2 emissions are studied as function of the share of recycled fibre used to make the paper. The study shows that under specific conditions the production of “CO2-free paper” is possible. First, energy efficiency in pulp and paper mills needs to be improved to allow the export of sufficient power to offset emissions from fossil fuels used in boilers and other equipment. Secondly, the net-CO2 emission per ton of paper depends strongly on the emission reduction credits for electricity export, and hence on the country or grid to which the paper mill is connected. Thirdly, supplemental use of biomass to replace fossil fuel inputs is important to reduce the overall emissions of the pulp and paper industry. 相似文献
137.
138.
139.
采用改性活性炭粉末对用纯净水加氟化钠配制而成的含氟水溶液进行动态电吸附去除实验.研究不同电压、电吸附时间,以及Cl-和SO2-4对氟离子去除的影响,并探讨吸附动力学和吸附方程.实验结果表明:活性炭对氟离子的吸附等温方程符合Freundlich方程,吸附动力学符合一级动力学方程;活性炭对氟离子去除与所施加的电位、吸附时间等因素有关,施加的电位越大,去除效果越好;随着吸附去除时间的延长,氟离子浓度下降趋缓;Cl-对氟离子去除影响很小,而SO2-4对氟离子去除有显著的不利影响. 相似文献
140.
Loss of grassland species resulting from activities such as off-road vehicle use increases the need for models that predict
effects of anthropogenic disturbance. The relationship of disturbance by military training to plant species richness and composition
on two soils (Foard and Lawton) in a mixed prairie area was investigated. Track cover (cover of vehicle disturbance to the
soil) and soil organic carbon were selected as measures of short- and long-term disturbance, respectively. Soil and vegetation
data, collected in 1-m2 quadrats, were analyzed at three spatial scales (60, 10, and 1 m2). Plant species richness peaked at intermediate levels of soil organic carbon at the 10-m2 and 1-m2 spatial scales on both the Lawton and Foard soils, and at intermediate levels of track cover at all three spatial scales
on the Foard soil. Species composition differed across the disturbance gradient on the Foard soil but not on the Lawton soil.
Disturbance increased total plant species richness on the Foard soil. The authors conclude that disturbance up to intermediate
levels can be used to maintain biodiversity by enriching the plant species pool. 相似文献