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   491篇
  免费   2篇
  国内免费   23篇
安全科学   12篇
废物处理   54篇
环保管理   48篇
综合类   43篇
基础理论   62篇
环境理论   1篇
污染及防治   193篇
评价与监测   69篇
社会与环境   31篇
灾害及防治   3篇
  2023年   16篇
  2022年   76篇
  2021年   53篇
  2020年   21篇
  2019年   14篇
  2018年   21篇
  2017年   25篇
  2016年   23篇
  2015年   16篇
  2014年   23篇
  2013年   45篇
  2012年   30篇
  2011年   31篇
  2010年   24篇
  2009年   23篇
  2008年   10篇
  2007年   13篇
  2006年   10篇
  2005年   5篇
  2004年   8篇
  2003年   5篇
  2002年   3篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1987年   1篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1977年   1篇
  1972年   1篇
  1964年   1篇
  1963年   2篇
排序方式: 共有516条查询结果,搜索用时 859 毫秒
451.
452.
Methane (CH4) is one of the most relevant greenhouse gases and it has a global warming potential 25 times greater than that of carbon dioxide (CO2), risking human health and the environment. Microbial CH4 oxidation in landfill cover soils may constitute a means of controlling CH4 emissions. The study was intended to quantify CH4 and CO2 emissions rates at the Sungai Sedu open dumping landfill during the dry season, characterize their spatial and temporal variations, and measure the CH4 oxidation associated with the landfill cover soil using a homemade static flux chamber. Concentrations of the gases were analyzed by a Micro-GC CP-4900. Two methods, kriging values and inverse distance weighting (IDW), were found almost identical. The findings of the proposed method show that the ratio of CH4 to CO2 emissions was 25.4 %, indicating higher CO2 emissions than CH4 emissions. Also, the average CH4 oxidation in the landfill cover soil was 52.5 %. The CH4 and CO2 emissions did not show fixed-pattern temporal variation based on daytime measurements. Statistically, a negative relationship was found between CH4 emissions and oxidation (R 2?=?0.46). It can be concluded that the variation in the CH4 oxidation was mainly attributed to the properties of the landfill cover soil.  相似文献   
453.
454.
Environment, Development and Sustainability - Crop production is highly sensitive to climate. It is affected by long-term trends in average rainfall and temperature, inter-annual climate...  相似文献   
455.
Environment, Development and Sustainability - Greenhouse gases (GHGs) are one of the leading causes of global warming. Therefore, accuracy estimates for greenhouse gases (GHGs) emissions are a key...  相似文献   
456.
Salicylic acid to decrease plant stress   总被引:2,自引:0,他引:2  
Pollution and climate change degrade plant health. Plant stress can be decreased by application of salicylic acid, an hormone involved in plant signaling. Salicylic acid indeed initiates pathogenesis-related gene expression and synthesis of defensive compounds involved in local resistance and systemic acquired resistance. Salicylic acid may thus be used against pathogen virulence, heavy metal stresses, salt stress, and toxicities of other elements. Applied salicylic acid improves photosynthesis, growth, and various other physiological and biochemical characteristics in stressed plants. Salicylic acid antagonizes the oxidative damaging effect of metal toxicity directly by acting as an antioxidant to scavenge the reactive oxygen species and by activating the antioxidant systems of plants and indirectly by reducing uptake of metals from their medium of growth. We review here the use of exogenous salicylic acid in alleviating bacterial, fungal, and viral diseases, heavy metal toxicity, toxicity of essential micronutrients, and salt stress.  相似文献   
457.
Environmental Science and Pollution Research - No-till wheat is gaining popularity in rice-based cropping system as it provides a better chance for timely planting of wheat, management of crop...  相似文献   
458.
Environmental Science and Pollution Research - This study examines the impact of economic growth, corruption, health, and poverty on environmental degradation for three countries from ASEAN, namely...  相似文献   
459.
Biofuel blends produced from Jatropha (Jatropha curcas) and Karanja (Pongamia pinnata) oil were evaluated for their combustion properties. Two kinds of blends (regular diesel with Jatropha and Karanja oil) were prepared at 20% volume to the diesel and tested as alternative fuels in single cylinder (vertical), water-cooled, direct injection diesel engine at the rated speed of 1500 rpm. The performance of the engine in terms of thermal efficiency at full load for diesel was 30%. For Jatropha and Karanja biodiesel blends, the thermal efficiencies were 29.0% and 28.6%, respectively. The maximum cylinder pressure and ignition delay for biodiesel fuel blends are very close to that of regular diesel. Prolonged combustion was observed for Karanja oil blend in comparison to Jatropha oil blend. The combustion pattern also reveals the slow burning characteristics of vegetable oils and this study indicates that the blended biofuels have combustion characteristics that are similar to regular diesel fuels.  相似文献   
460.
In the present study, the tube well water quality and the associated health risks, emphasizing on arsenic contamination, were investigated in rural and urban samples from Tehsil Mailsi located in Punjab, Pakistan. Arsenic concentrations (μg/L) were ranged from 12 to 448.5 and which exceeded the WHO recommended limit (10 μg/L) in all cases. The calculated average daily dose (3.3 × 10?0.4 to 1.2 × 10?0.2 mg/kg day) and hazard quotient (1.1–40) reflected the potential health risk to local population due to tube well water consumption as drinking purpose. Sodium percent (Na%), sodium absorption ratio, residual sodium carbonate, Kelly’s index and magnesium absorption ratio were also determined to assess the suitability of tube well water for irrigation purpose. The resulting piper plot revealed the Na–Ca–HCO3 type water chemistry of the area and generally alkaline environment. The spatial distribution of arsenic in the tube well waters pinpoints the significant contribution of anthropogenic activities to arsenic pollution. Nevertheless, different statistical tools, including principal component analysis, hierarchical cluster analysis and correlation matrices, revealed the contribution of both natural and anthropogenic activities and alkaline type of aquifers toward the high level of arsenic contamination.  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