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   965篇
  免费   52篇
  国内免费   342篇
安全科学   54篇
废物处理   67篇
环保管理   98篇
综合类   511篇
基础理论   149篇
污染及防治   343篇
评价与监测   50篇
社会与环境   50篇
灾害及防治   37篇
  2024年   2篇
  2023年   18篇
  2022年   50篇
  2021年   38篇
  2020年   37篇
  2019年   36篇
  2018年   44篇
  2017年   48篇
  2016年   49篇
  2015年   42篇
  2014年   58篇
  2013年   96篇
  2012年   69篇
  2011年   88篇
  2010年   67篇
  2009年   58篇
  2008年   60篇
  2007年   62篇
  2006年   47篇
  2005年   46篇
  2004年   29篇
  2003年   33篇
  2002年   31篇
  2001年   21篇
  2000年   37篇
  1999年   24篇
  1998年   27篇
  1997年   26篇
  1996年   24篇
  1995年   14篇
  1994年   15篇
  1993年   6篇
  1992年   13篇
  1991年   11篇
  1990年   15篇
  1989年   4篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
排序方式: 共有1359条查询结果,搜索用时 15 毫秒
991.
为有效控制防污漆中杀生物活性物质给海洋环境带来的不利影响,亟需开展活性物质的环境风险评估研究,为筛选环境友好型活性物质提供依据。以25种国产防污漆中的铜为评估对象,采用防污漆活性物质环境风险评估的针对性方法,分步进行暴露评估、危害性评估和风险表征。暴露评估采用海洋防污剂预测环境浓度模型(MAMPEC)中的港口、码头和开阔海域等典型暴露场景;危害性评估基于铜对淡水和海水水生生物的慢性毒性数据,采用物种敏感度分布法和评估因子法;风险表征采用熵值法。结果表明,铜对全部水生生物和海水生物的预测无效应浓度分别为2.8和2.3μg·L~(-1),藻类对铜最为敏感。除1种配方外,其余24种防污漆配方中铜的风险熵均小于1,可判定铜为"相对低风险"类活性物质,使用上述防污漆时铜对生态环境造成的风险较小。铜在不同暴露场景中的环境风险分析表明其对水流交换较弱海域的码头造成的风险最大,其次是默认港口和码头,对于公海造成的风险最小。根据现有的评估结果,设计含铜型防污漆配方时,应使铜的释放速率不大于33.5μg·cm~(-2)·d~(-1),以避免对较封闭海域的生态环境造成不可忽视的风险。  相似文献   
992.
ABSTRACT

Land use in China has changed remarkably over the past centuries with manifold implications for sustainable development. Investigation and projection of the land-use and land-cover changes (LUCC) have therefore become critical to promote the understanding of the LUCC process and the interactions with human societies. Scientists had devoted great efforts to create, process, and interpret comprehensive historical land-use/cover datasets, and to simulate future land-use systems under different scenarios. We synthesize the literature on the historical trajectories of LUCC in China, and summarize existing efforts of scenario developments for the projection of spatially explicit LUCC. Our review therefore provides salient suggestions for future land-use change analysis.  相似文献   
993.
994.
臭氧催化氧化法是结合了臭氧的强氧化性和催化剂特性的一种高级氧化技术,在处理含酚废水方面具有明显的技术优势。系统研究了臭氧催化氧化技术处理含酚废水的国内外研究进展,探讨了不同反应体系的优缺点,并指出改进的建议和发展方向。  相似文献   
995.
Using sequence variation in the mitochondrial cytochrome oxidase I locus, we estimated the population structure and phylogeography of the intertidal acorn barnacle, Chthamalus anisopoma, and its gastropod predator, Mexacanthina lugubris angelica. Both are endemic to the Gulf of California, being derived from taxa on the Pacific coast of the Baja peninsula, and both exhibit phenotypic plasticity for traits affecting their coevolutionary interactions. Consistent with expectations based on differences in dispersal, C. anisopoma populations generally lack geographic structure, while those of M. l. angelica are more strongly structured. However, the variable degree of differentiation in both species suggests that the extent of reciprocal selection and local adaptation in the species will vary geographically, a result consistent with the concept of a geographic mosaic of coevolution. The pattern of variation in C. anisopoma shows clear evidence of recent spatial expansion, possibly due to increased habitat availability following the last glacial maximum. Phylogeographic analyses suggest that M. l. angelica diversified into three distinct clades after the colonization of the Gulf. Overall, our results illustrate how dispersal potential, geological and climatic events, and recent population growth have impacted the pattern of sequence variation in the two species.  相似文献   
996.
采用Fenton试剂氧化—曝气生物滤池组合工艺对某制药厂常规生化处理后的废水进行深度处理.实验结果表明,Fenton试剂氧化的适宜操作条件为pH=5,ρ(H2O2)∶COD=1.5、n(H2O2)∶n(Fe2+)=2,反应时间为60min.经氧化处理后的废水再进入曝气生物滤池进行生化处理,最终出水COD小于80 mg/L,色度小于10倍,处理效果良好.  相似文献   
997.
食品、医药和化妆品等行业大量使用含有对羟基苯甲酸丙酯(propylparaben,PrP)的防腐剂导致其广泛分布于河流、空气和土壤等自然环境中.为探究PrP对鱼类的毒性作用,以食蚊鱼(Gambusia affinis)为模式生物,分别开展了急性毒性实验和K+流速检测实验.急性毒性实验中设置8种不同浓度的PrP溶液得到9...  相似文献   
998.
硝化褐煤对铬离子溶液的吸附研究   总被引:13,自引:0,他引:13  
利用硝酸与龙口褐煤反应制得硝化褐煤,使其有效吸附质腐植酸含量提高。用该湖化褐煤对铬离子进行吸附试验,研究吸附剂的吸附量、吸附动力学、吸附模型和溶液的pH值对吸附的影响。结果表明:硝化褐煤对铬离子具有良好的吸附特性,其静态等温吸附符合Langmuir等温议程。  相似文献   
999.
As the backland of the Qinghai-Tibet Plateau, the river source region is highly sensitive to changes in global climate. Air temperature estimation using remote sensing satellite provides a new way of conducting studies in the field of climate change study. A geographically weighted regression model was applied to estimate synchronic air temperature from 2001 to 2015 using Moderate-Resolution Imaging Spectroradiometry (MODIS) data. The results were R2?=?0.913 and RMSE?=?2.47 °C, which confirmed the feasibility of the estimation. The spatial distribution and variation characteristics of the average annual and seasonal air temperature were analyzed. The findings are as follows: (1) the distribution of average annual air temperature has significant terrain characteristics. The reduction in average annual air temperature along the elevation of the region is 0.19 °C/km, whereas the reduction in the average annual air temperature along the latitude is 0.04 °C/degree. (2) The average annual air temperature increase in the region is 0.37 °C/decade. The average air temperature increase could be arranged in the following decreasing order: Yangtze River Basin > Mekong River Basin > Nujiang River Basin > Yarlung Zangbo River Basin > Yellow River Basin. The fastest, namely, Yangtze River Basin, is 0.47 °C/decade. (3) The average air temperature rise in spring, summer, and winter generally increases with higher altitude. The average annual air temperature in different types of lands following a decreasing order is as follows: wetland > construction land > bare land glacier > shrub grassland > arable land > forest land > water body and that of the fastest one, wetland, is 0.13 °C/year.  相似文献   
1000.
Surface ozone and some meteorological parameters were continuously measured from June 2003 to May 2004 at urban Jinan, China. The levels and variations of surface ozone were studied and the influences of meteorological parameters on ozone were analyzed. Annual and diurnal ozone variation patterns in Jinan both show a typical pattern for polluted urban areas. Daytime ozone concentrations in summer were the highest in the four seasons. However, during nighttime from 2100 to 0600 hours ozone concentrations in spring was higher than that in summer. Daily averaged ozone showed negative correlation with pressure and relative humidity and positive correlation with temperature, total solar radiation, sunshine duration and wind speed during the study period. Further studies show that, solar radiation is a primary influence factor for the daytime variations of ozone concentrations at this site; transport of pollutants by wind could enhance the pollution at this site; precipitation has a significant influence on decreasing surface ozone. A multi-day ozone episode from 16 to 21 June 2003 was observed at this site. Surface meteorological data analysis and backward trajectory computation show that the episode is associated with the influence of typhoon Soudelor, attributing to both local photochemical processes and transport of air pollutants from southeastern coastal region, especially Yangtze River Delta region.  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