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   986篇
  免费   47篇
  国内免费   322篇
安全科学   46篇
废物处理   61篇
环保管理   64篇
综合类   545篇
基础理论   192篇
污染及防治   336篇
评价与监测   48篇
社会与环境   36篇
灾害及防治   27篇
  2023年   12篇
  2022年   55篇
  2021年   33篇
  2020年   23篇
  2019年   22篇
  2018年   27篇
  2017年   54篇
  2016年   43篇
  2015年   42篇
  2014年   77篇
  2013年   100篇
  2012年   96篇
  2011年   75篇
  2010年   52篇
  2009年   66篇
  2008年   87篇
  2007年   58篇
  2006年   70篇
  2005年   28篇
  2004年   23篇
  2003年   28篇
  2002年   29篇
  2001年   24篇
  2000年   25篇
  1999年   34篇
  1998年   26篇
  1997年   23篇
  1996年   18篇
  1995年   26篇
  1994年   11篇
  1993年   16篇
  1992年   18篇
  1991年   11篇
  1990年   6篇
  1989年   3篇
  1988年   5篇
  1987年   1篇
  1986年   1篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
排序方式: 共有1355条查询结果,搜索用时 140 毫秒
991.
不同pH控制策略下剩余污泥中NH+4-N、PO3-4-P、COD溶出研究   总被引:3,自引:1,他引:2  
污水处理厂的剩余污泥中富含氮、磷、COD,在其水解酸化过程中对pH条件进行控制,使污泥中的氮、磷、COD溶出到上清液中并进行回收利用是可行的。在22~25℃的温度条件下,1#反应器中剩余污泥先调节为酸性(pH=3),在实验第8 d氨氮、磷酸盐溶出量最多后调节为碱性(pH=10);3#反应器中剩余污泥先调节为碱性(pH=10),在实验第8 d COD溶出量最多后调节为酸性(pH=3); 2#反应器为对照实验,pH不进行调节。结果表明:若要以回收污泥中的氨氮、磷酸盐为主,剩余污泥由碱性(pH=10)调节为酸性(pH=3)优于由酸性(pH=3)调节为碱性(pH=10);若要回收污泥上清液中的COD为主,剩余污泥由酸性(pH=3)调节为碱性(pH=10)优于由碱性(pH=10)调节为酸性(pH=3)。  相似文献   
992.
才佳 《油气田环境保护》2012,22(2):22-24,75,76
文章介绍热电冷联供系统的设备组成及其设计注意事项;介绍以燃气轮机为发电机组的热电冷联供系统案例。在热电冷联供系统中配置溴化锂吸收式制冷机,可充分发挥其利用低品位能源的优势;设计热电冷联供系统前,应进行必要的经济性分析,合理确定设备配置方案和配置容量;以燃气轮机发电机组和烟气型溴化锂吸收式冷热水机组为主要设备组成的热电冷联供系统,烟气系统的设计和安装连接是关键。文章可为燃气轮机热电冷联供系统的设计和建造提供技术参考。  相似文献   
993.
Guo H  Yao J  Cai M  Qian Y  Guo Y  Richnow HH  Blake RE  Doni S  Ceccanti B 《Chemosphere》2012,87(11):1273-1280
The influence of petroleum contamination on soil microbial activities was investigated in 13 soil samples from sites around an injection water well (Iw-1, 2, 3, 4) (total petroleum hydrocarbons (TPH): 7.5-78 mg kg−1), an oil production well (Op-1, 2, 3, 4, 5) (TPH: 149-1110 mg kg−1), and an oil spill accident well (Os-1, 2, 3, 4) (TPH: 4500-34 600 mg kg−1). The growth rate constant (μ) of glucose stimulated organisms, determined by microcalorimetry, was higher in Iw soil samples than in Op and Os samples. Total cultivable bacteria and fungi and urease activity also decreased with increasing concentration of TPH. Total heat produced demonstrated that TPH at concentrations less than about 1 g kg−1 soil stimulated anaerobic respiration. A positive correlation between TPH and soil organic matter (OM) and stimulation of fungi-bacteria-urease at low TPH doses suggested that TPH is bound to soil OM and slowly metabolized in Iw soils during OM consumption. These methods can be used to evaluate the potential of polluted soils to carry out self-bioremediation by metabolizing TPH.  相似文献   
994.
Hong Q  Wang Y  Luo X  Chen S  Chen J  Cai M  Cai M  Mai B 《Chemosphere》2012,88(11):1340-1345
The spatial distribution and potential source of polychlorinated biphenyls (PCBs) in surface sediments from Bering Sea, Chukchi Sea, and Canada Basin and the relationship between PCBs and sedimentary properties including grain size, water content, loss on ignition, total organic carbon, and black carbon were explored. ΣPCBs (the sum of the detected PCB congeners) concentrations fluctuated in the study area, ranging from 22-150, 60-640 and 24-600 pg g(-1) dry weight for the Bering Sea, Chukchi Sea, and Canada Basin. A similar homologue pattern was observed at different locations, with tri-chlorinated PCBs being the dominant homologue, implying that the PCBs came mainly from the atmospheric transportation and deposition and ocean current transportation. No apparent co-relationships between PCB concentrations and sediment properties were obtained, indicating that the distribution of PCBs was not only controlled by their source, but also by the multi-factors such as atmospheric transport and depositing, mixing, partitioning and sorption in the water column and sediments.  相似文献   
995.
The effects and associated toxicological mechanisms of five phthalate esters (PAEs) on abalone embryonic development were investigated by exposing the embryos to a range of PAEs concentrations (0.05, 0.2, 2 and 10 μg/mL). The results showed that PAEs could significantly reduce embryo hatchability, increase developmental malformations, and suppress the metamorphosis of abalone larvae. The possible toxicological mechanisms of PAEs to abalone embryos included, affecting the Na+-K+-pump and Ca2+-Mg2+-pump activities, altering the peroxidase (POD) level and the malondialdehyde (MDA) production, damaging the extraembryonic membranes structure, as well as disrupting endocrine-related genes (gpx, cyp3a, and 17β-hsd 12) expression properties. Taken together, this work showed that PAEs adversely affected the embryonic ontogeny of abalone. The abilities of PAEs affecting the osmoregulation, inducing oxidative stress, damaging embryo envelope structure, and causing physiological homeostasis disorder, are likely to be a part of the common mechanisms responsible for their embryonic toxicity.  相似文献   
996.
7种水生植物去除城市生活污水氮磷效果的研究   总被引:3,自引:0,他引:3  
在对南方地区水生植物全面了解的基础上,选择凤眼莲、长鬃蓼、美人蕉、短叶茳芏、鸭趾草、空心莲子草和风车草7种南方地区最常见的水生植物作为研究对象,分别从7种水生植物对城市生活污水中NH3-N、TN和TP等污染的净化效果进行研究,结果表明,7种植物对生活污水中的NH3-N、TN和TP等污染成分都有一定的去除效果,其中凤眼莲...  相似文献   
997.
催化型微粒捕集器的再生与压降数值研究   总被引:1,自引:0,他引:1  
采用新的再生机理对催化型微粒捕集器(CPF)深床捕集微粒的氧化再生过程进行了建模,并将微粒捕集器中的压降分成5个部分分别计算,对其压降特性进行了数值研究。结果表明,新模型对深床捕集微粒的氧化再生计算与实验值吻合良好,比原模型更能反映微粒沉积的实际过程,深床捕集微粒的压降计算值也更精确。在排气流量大、温度高的工况下,深床捕集微粒的压降先迅速增大再减小的现象明显。研究结果能为工程应用提供验证手段,为CPF的优化设计提供依据。  相似文献   
998.
Water shortage is a common problem around the world, especially in developing countries. Water shortage is closely linked to natural and social conditions, but the linkages between these natural and social conditions and their underlying temporal and spatial variation are less well explored. This paper details an application of the Driving‐Force‐Pressure‐State‐Impact‐Response (DPSIR) model, a holistic and sustainable tool for resources planning and management, and uses comprehensive weights to evaluate the water poverty (wp) in China from 1997 to 2014. This study applies the Kernel density estimation model to analyze the temporal variation trend and uses the least square error model to analyze the spatial pattern of wp. The results show the level of wp is gradually declining over time and the improvements in the coastal and inland wp situation are not spatially harmonious, and there are four primary types of wp in China based on drivers and causal mechanisms: D‐P‐I, D‐P‐I‐R, D‐P‐S‐I, and D‐P‐S‐I‐R. Furthermore, we analyze the main causes of spatial difference of wp and put forward corresponding countermeasures. The research findings are intended to provide a new insight for the evaluation of wp in the context of sustainable development, breaking past limitations that arise in simplified analyses using a single method, and to provide a strategy for regional water resources management to relieve wp.  相似文献   
999.
电凝并式空气净化单元对颗粒物和甲醛净化效果的实验   总被引:2,自引:0,他引:2  
研究一种新型电凝并式空气净化单元对室内空气中颗粒物和甲醛的净化效果.实验结果表明,高压高频(HV-HF)电凝并装置能促使小粒子相互凝并为较大的电中性的粒子团,这些具有较高比表面积的电中性粒子团进入室内空间,能继续粘附空气中及物体表面上的颗粒,形成更大的粒子团,从而易于被净化单元中的中效过滤器捕集,而且该净化单元对于大粒子(粒径>0.7μm)浓度较高的场所净化效果更加明显.另外,室内空气中吸附在颗粒物表面的甲醛也随之被高效去除.该净化单元的投入使用,起到了提高过滤效率、去除气溶胶小粒子、降低能耗、进一步改善室内空气品质等多重功效.  相似文献   
1000.
沸石生物联合吸附再生工艺参数优化研究   总被引:2,自引:1,他引:1  
简述了沸石生物联合吸附再生工艺(ZCS工艺)的工艺原理,选取了影响沸石生物联合吸附再生工艺污水处理效果的影响因素,通过正交实验,优化了工艺的运行参数.在优化结果为泥龄(SRT)40 d、沸石投加量16.8 g/L、外回流比(R)1、内回流比(r)1、A池碳源投加比(m)0、吸附池溶解氧(DO吸)1 mh/L和O池溶解氧(DOO)2 mg/L的条件下稳定运行后,出水水质达到《城镇污水处理厂污染物排放标准》(GB18918-2002)中一级B标准的要求.  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