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   401篇
  免费   17篇
  国内免费   145篇
安全科学   37篇
废物处理   18篇
环保管理   30篇
综合类   205篇
基础理论   70篇
污染及防治   151篇
评价与监测   18篇
社会与环境   22篇
灾害及防治   12篇
  2024年   1篇
  2023年   10篇
  2022年   27篇
  2021年   15篇
  2020年   12篇
  2019年   19篇
  2018年   12篇
  2017年   15篇
  2016年   28篇
  2015年   19篇
  2014年   23篇
  2013年   50篇
  2012年   30篇
  2011年   31篇
  2010年   33篇
  2009年   32篇
  2008年   24篇
  2007年   25篇
  2006年   37篇
  2005年   15篇
  2004年   10篇
  2003年   14篇
  2002年   10篇
  2001年   8篇
  2000年   16篇
  1999年   13篇
  1998年   8篇
  1997年   2篇
  1996年   2篇
  1995年   5篇
  1994年   6篇
  1993年   1篇
  1992年   1篇
  1991年   6篇
  1990年   1篇
  1989年   1篇
  1986年   1篇
排序方式: 共有563条查询结果,搜索用时 0 毫秒
41.
本文比较全面地阐述了近年来我国海洋环境保护工作所取得的主要成就,并针对未来沿海经济的迅速发展将给海洋环境带来的压力,探讨深入开展海洋环境保护工作。  相似文献   
42.
以2010年8月湘江干流株洲段代表性断面水质与底泥监测资料以及其他资料为基础,采用WASP7模型模拟该江段丰水期镉浓度,并进行镉污染负荷测算与分配。研究结果表明,WASP7模型较好地重现了镉浓度的变化规律,8月份该河段上游镉入流量2 446.33 kg,下游出流量3 076.44 kg,区间增量630.12 kg,其中点源负荷量241.67 kg,占38.4%,面源负荷量304.49 kg,占48.3%,内源负荷量为83.96 kg,占13.3%。  相似文献   
43.
SBR亚硝化快速启动过程中影响因子研究   总被引:5,自引:5,他引:5  
李冬  陶晓晓  李占  王俊安  张杰 《环境科学》2011,32(8):2317-2322
在低DO条件下对SBR反应器实现快速亚硝化的途径及影响因素进行研究.控制反应器主要参数为:DO 0.15~0.40mg/L,pH值7.52~8.30,温度22.3~27.1℃,曝气时间为8 h.通过高、低氨氮浓度(245.28 mg/L与58.08 mg/L)交替进水的方式,经过57个周期(36 d)的稳定运行成功实现...  相似文献   
44.
催化剂含氨氮污水治理技术的探讨   总被引:3,自引:0,他引:3  
对高浓度氨氮污水的处理技术进行比较,结合兰州石化公司催化剂污水排放的实际和目前开展的治理研究,提出了综合治理催化剂含氨氮污水的设想。  相似文献   
45.
Atrazine is one of the most widely applied and persistent herbicides in the world. In view of limited information on the regional contamination of atrazine in soils in China, this study investigated the spatial distribution and environmental impacts of atrazine in agricultural soils collected from the Yangtze River Delta (YRD) as an illustrative analysis of rapidly developing regions in the country. The results showed that the concentrations of atrazine in the YRD agricultural soils ranged from <1.0 to 113 ng/g dry weight, with a mean of 5.7 ng/g, and a detection rate of 57.7 % in soils. Pesticide factory might be a major source for the elevated levels of atrazine in Zhejiang Province. The contamination of atrazine was closely associated with land use types. The concentrations and detection rates of atrazine were higher in corn fields and mulberry fields than in rice paddy fields. There was no significant difference in compositions of soil microbial phospholipids fatty acids among the areas with different atrazine levels. Positive relationship (R = 0.417, p < 0.05, n = 30) was observed between atrazine and total microbial biomass. However, other factors, such as soil type and land management practice, might have stronger influences on soil microbial communities. Human health risks via exposure to atrazine in soils were estimated according to the methods recommended by the US EPA. Atrazine by itself in all the soil samples imposed very low carcinogenic risks (<10?6) and minimal non-cancer risks (hazard index <1) to adults and children.  相似文献   
46.
易成豪  秦伟  陈湛  文湘华 《环境科学》2019,40(9):4143-4151
以可生物降解聚合物聚己内酯(PCL)和聚羟基丁酸戊酸酯(PHBV)作为反硝化缓释碳源和微生物载体,利用清水释碳和批式反硝化试验选出适用于再生水反硝化深度脱氮生物滤池的可生物降解碳源滤料,通过比较与分析碳源滤料的表面形态及物质特性和附着微生物的群落特征揭示其性能优越的原因.结果表明,PHBV反硝化启动时间短,反硝化速率高,剩余有机物浓度低,相比PCL具有更稳定持续的反硝化效果.原因是其表面粗糙,且含有大量C—O和CO等亲水性基团,易于微生物附着和降解利用;其表面附着的微生物种类多样,其中发硫菌属(Thiothrix)、假单胞属(Pseudomonas)、菌胶团属(Zoogloea)、黄杆菌属(Flavobacterium)和脱氯菌属(Dechloromonas)等优势菌属均具有异养反硝化功能.因此,PHBV更适合作为再生水反硝化深度脱氮生物滤池的碳源滤料.  相似文献   
47.
随着城市化的进程,垃圾处理设施成为影响城市化质量的重要指标。依据人们实际所关注的垃圾处理设施的总成本和负效应两个因素,在前人研究的基础上,建立了垃圾收运多目标模型,使得总成本和负效应最优化。根据模型设计了粒子群算法,该算法属于智能算法,且精度高,收敛快,在许多领域也得到广泛应用。用设计的粒子群算法并结合案例求出了Pareto最优解,给出三种决策方案,验证了模型和算法的有效性和可行性,为决策者提供了一种理论参考。  相似文献   
48.
To assess the responses of the soil microbial community to chronic ozone (O3), wheat seedlings (Triticum aestivum Linn.) were planted in the field and exposed to elevated O3 (eO3) concentration. Three treatments were employed: (1) Control treatment (CK), AOT40 = 0; (2) O3-1, AOT40 = 1.59 ppm•h; (3) O3-2, AOT40 = 9.17 ppm•h. Soil samples were collected for the assessment of microbial biomass C, community-level physiological profiles (CLPPs), and phospholipid fatty acids (PLFAs). EO3 concentration significantly reduced soil microbial carbon and changed microbial CLPPs in rhizosphere soil, but not in non-rhizosphere soil. The results of the PLFAs showed that eO3 concentrations had significant effects on soil community structure in both rhizosphere and non-rhizosphere soils. The relative abundances of fungal and actinomycetous indicator PLFAs decreased in both rhizosphere and non-rhizosphere soils, while those of bacterial PLFAs increased. Thus the results proved that eO3 concentration significantly changed the soil microbial community function and composition, which would influence the soil nutrient supply and carbon dynamics under O3 exposure.  相似文献   
49.
Sulfonamides (SAs) are one of the most widely used antibiotics and their residuals in the environment could cause some negative environmental issues. Advanced oxidation such as Fenton-like reaction has been widely applied in the treatment of SAs polluted water. Degradation rates of 95%-99.7% were achieved in this work for the tested 8 SAs, including sulfisomidine, sulfameter (SME), phthalylsulfathiazole, sulfamethoxypyridazine, sulfamonomethoxine, sulfisoxazole, sulfachloropyridazine, and sulfadimethoxine, in the Fe3O4/peroxodisulfate (PDS) oxidation system after the optimization of PDS concentration and pH. Meanwhile, it was found that a lot of unknown oxidation products were formed, which brought up the uncertainty of health risks to the environment, and the identification of these unknown products was critical. Therefore, SME was selected as the model compound, from which the oxidation products were never elucidated, to identify these intermediates/products. With liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS), 10 new products were identified, in which 2-amino-5-methoxypyrimidine (AMP) was confirmed by its standard. The investigation of the oxidation process of SME indicated that most of the products were not stable and the degradation pathways were very complicated as multiple reactions, such as oxidation of the amino group, SO2 extrusion, and potential cross-reaction occurred simultaneously. Though most of the products were not verified due to the lack of standards, our results could be helpful in the evaluation of the treatment performance of SAs containing wastewater.  相似文献   
50.
中国农业经历了多种策略阶段,可持续发展策略是新近出现的最先进、最适合现在和将来农业发展的策略。新策略带有系统性原理,其实质是发展与生态环境保护协调的农业。因此,可持续发展措施应同时重视解决农业经济发展与生态环境保护两方面的问题。据此,本文提出了六项措施。  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