首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   709篇
  免费   7篇
  国内免费   33篇
安全科学   9篇
废物处理   39篇
环保管理   40篇
综合类   51篇
基础理论   101篇
污染及防治   409篇
评价与监测   56篇
社会与环境   40篇
灾害及防治   4篇
  2023年   28篇
  2022年   151篇
  2021年   142篇
  2020年   46篇
  2019年   45篇
  2018年   40篇
  2017年   54篇
  2016年   43篇
  2015年   25篇
  2014年   35篇
  2013年   36篇
  2012年   21篇
  2011年   19篇
  2010年   7篇
  2009年   9篇
  2008年   10篇
  2007年   9篇
  2006年   6篇
  2005年   6篇
  2004年   2篇
  2003年   3篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1985年   1篇
  1974年   1篇
排序方式: 共有749条查询结果,搜索用时 0 毫秒
81.
This study investigates the mercury (Hg) contaminations in soil and foodstuffs along the artisanal gold mining areas, Gilgit-Baltistan Province, Pakistan. For this purpose, soils were analyzed for Hg concentrations and evaluated for the enrichment/contamination using enrichment factor or contamination factors (CF). The CF values ranged from 18.9 to 153 showed multifold higher levels of Hg contamination as compared to background or reference site. Foodstuffs including vegetables, seeds or grains and fish muscles showed Hg accumulation. Results revealed that Hg concentrations in foodstuffs were higher than the critical human health value set by European Union. The Hg in foodstuffs was consumed and, therefore, evaluated for the risk assessment indices using the daily intake (DI) and health risk index (HRI) for the exposed human population both children and adults. Results of this study revealed that cumulative HRI values through foodstuffs consumption were <1 (within safe limit), but if the current practices continued, then the Hg contamination could pose potential threat to exposed population in near future.  相似文献   
82.
The use of higher dosage and repeated applications of conventional pesticides have led to the rapid development of insect resistance to pesticide and adverse effects on human health and environment. Accordingly, researchers are prompted to identify an alternative entomotoxic agent for crop protection. Nanocides are being considered as alternatives to conventional insecticides because they are expected to lessen the application rate and reduce the chances of resistance development in pests. In this study, we evaluated the entomotoxic effects of nanosilica on larvae of Plutella xylostella, in a laboratory by using dust spray, larva dipping, leaf dipping, and solution spray methods. Dust treatment showed a more highly significant effect than the other three treatments. The mortality percentage increased up to 58% and 85% at 24 and 72 h after treatment, respectively, when nanosilica was applied at a rate of 1 mg cm?2. In all four bioassays, mortality rate increased with both increased time after nanosilica exposure and increased concentration. Light microscopy and scanning electron microscopy images showed that larval death was due to desiccation, body wall abrasion, and spiracle blockage. These results suggested that nanosilica can be an alternative to conventional pesticides if dust formulation would be properly used.  相似文献   
83.
Environmental Fluid Mechanics - The principle theme of this study is to introduce a novel countermeasure to reduce the energy of the overflowing floodwater by utilization of a water cushion. For...  相似文献   
84.
Environmental Science and Pollution Research - COVID-19, declared by the World Health Organization (WHO) to be a pandemic, has affected greenhouse gas emissions and contributed to the uncertainty...  相似文献   
85.

The shrinkage of cement-based materials is a critical dimensional property that needs proper attention as it can influence the corresponding characteristics especially when the preparation of such cement-based material is done in hot weather. Studies have shown that the casting or curing conditions influence the performance of concrete. However, there is limited understanding of the combined role of casting temperature and curing conditions, especially for concrete made with unconventional binders. In this study, five supplementary cementitious materials (SCMs) were utilized as the substitute of the ordinary Portland cement (OPC) at different ratios to produce greener concrete and improve its characteristics and sustainability. The influence of four casting temperatures (i.e., 25 °C, 32 °C, 38 °C, and 45 °C) and two curing regimes (i.e., covering of samples using wet burlap and applying curing compound on the surface of samples) on the corresponding compressive strength and drying shrinkage at various ages was studied. The outcomes of this research revealed that the composition of the binders has a substantial impact on the characteristics of concrete. In addition, the casting temperature and curing regimes also have a huge role on the compressive strength of concrete produced with binary binders. For example, the compressive strength at 3 days of concrete made at 25 °C made with binary binders was reduced up to 31% compared to that made with only OPC as the binder when cured using wet burlap. Nonetheless, less than 38 ℃ was suitable to minimize the durability issues in the studied blended cement mixes.

  相似文献   
86.
Environmental Science and Pollution Research - Healthcare waste management is considered one of the biggest challenges that the world is going to face in the future. This threat is becoming reality...  相似文献   
87.
Environmental Science and Pollution Research - Plastics have become inevitable for human beings in their daily life. Million tons of plastic waste is entering in oceans, soil, freshwater, and...  相似文献   
88.
Environmental Science and Pollution Research - Continuous incorporation of microplastics (MPs) and their fragmented residues into the ecosystem has sparked significant scientific apprehensions...  相似文献   
89.
Environmental Science and Pollution Research - Developing countries have depleted their natural resources in economic interest to achieve high economic growth. Current urbanization patterns and...  相似文献   
90.
Water represents 71% of all earth area and about 97% of this water is salty water. So, only 3% of the overall world water quantity is freshwater. Human can benefit only from 1% of this water and the remaining 2% freeze at both poles of earth. Therefore, it is important to preserve the freshwater through increasing the plants consuming salty water. The future prosperity of feed resources in arid and semi-arid countries depends on economic use of alternative resources that have been marginalized for long periods of time, such as halophytic plants, which are one such potential future resource. Halophyte plants can grow in high salinity water and soil and to some extent during drought. The growth of these plants depends on the contact of the salted water with plant roots as in semi-desert saline water, mangrove swamps, marshes, and seashores. Halophyte plants need high levels of sodium chloride in the soil water for growth, and the soil water must also contain high levels of salts, as sodium hydroxide or magnesium sulfate. There are many uses for halophyte plants, including feed for animals, vegetables, drugs, sand dune stabilizers, wind shelter, soil cover, wetland cultivation, laundry detergents, and paper production. This paper will focus on the use of halophytes as a feed additive for animals. In spite of the good nutritional value of halophytes, some anti-nutritional factors as nitrates, nitrite complexes, tannins, glycosides, phenolic compounds, saponins, oxalates, and alkaloids may be present in some of them. The presence of such anti-nutritional agents makes halophytes unpalatable to animals, which tends to reduce feed intake and nutrient use. Therefore, the negative effects of these plants on animal performance are the only objection against using halophytes in animal feed diets. This review article highlights the beneficial impact of considering halophytes in animal feeding on saving freshwater and illustrates its nutritive value for livestock from different aspects.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号