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   3141篇
  免费   104篇
  国内免费   222篇
安全科学   131篇
废物处理   215篇
环保管理   217篇
综合类   743篇
基础理论   633篇
环境理论   2篇
污染及防治   999篇
评价与监测   305篇
社会与环境   187篇
灾害及防治   35篇
  2024年   4篇
  2023年   47篇
  2022年   123篇
  2021年   131篇
  2020年   87篇
  2019年   95篇
  2018年   116篇
  2017年   137篇
  2016年   171篇
  2015年   131篇
  2014年   175篇
  2013年   308篇
  2012年   204篇
  2011年   237篇
  2010年   155篇
  2009年   126篇
  2008年   199篇
  2007年   193篇
  2006年   148篇
  2005年   126篇
  2004年   93篇
  2003年   81篇
  2002年   82篇
  2001年   48篇
  2000年   29篇
  1999年   26篇
  1998年   11篇
  1997年   11篇
  1996年   7篇
  1995年   15篇
  1994年   10篇
  1993年   13篇
  1992年   6篇
  1991年   10篇
  1990年   11篇
  1989年   4篇
  1988年   8篇
  1987年   4篇
  1986年   3篇
  1983年   3篇
  1967年   5篇
  1964年   8篇
  1963年   7篇
  1962年   7篇
  1960年   5篇
  1958年   9篇
  1957年   3篇
  1956年   4篇
  1955年   2篇
  1943年   2篇
排序方式: 共有3467条查询结果,搜索用时 15 毫秒
51.

This article shows oily sawdust gasification research on countercurrent installation. Experimental research was on a laboratory scale. The main purpose of the experiment was combustible gas production with higher CH4 concentration. Gas concentrations like CO, CO2, CH4, H2, and CnHm determine syngas composition. The technological parameter’s value defines experimental conditions. Value of this was fuel to air ratio. With fuel to air ratio change, syngas composition was a differential phenomenon where it depended on the process parameters like temperature. Additionally, evaluation of methane formation from CO, H2, and CO2 was done. Methanization coefficients were based on CO and CO2 hydrogenation reactions. Component’s activity was in analogs way to syngas components changed.

  相似文献   
52.
Environmental Science and Pollution Research - This work proposed a novel mathematical framework for the sustainability assessment of sewage sludge to energy (SStE) scenarios, by resorting to fuzzy...  相似文献   
53.
Environmental Science and Pollution Research - The international community has generally recognized the key role of developing countries’ cities in reducing carbon emissions, an elemental way...  相似文献   
54.

To examine pesticide mixture toxicity to aqueous organisms, we assessed the single and combined toxicities of thiamethoxam and other four pesticides (chlorpyrifos, beta-cypermethrin, tetraconazole, and azoxystrobin) to the rare minnow (Gobiocypris rarus). Data from 96-h semi-static toxicity assays of various developmental phases (embryonic, larval, juvenile, and adult phases) showed that beta-cypermethrin, chlorpyrifos, and azoxystrobin had the highest toxicities to G. rarus, and their LC50 values ranged from 0.0031 to 0.86 mg a.i. L?1, from 0.016 to 6.38 mg a.i. L?1, and from 0.39 to 1.08 mg a.i. L?1, respectively. Tetraconazole displayed a comparatively high toxicity, and its LC50 values ranged from 3.48 to 16.73 mg a.i. L?1. By contrast, thiamethoxam exhibited the lowest toxic effect with LC50 values ranging from 37.85 to 351.9 mg a.i. L?1. Rare minnow larvae were more sensitive than embryos to all the pesticides tested. Our data showed that a pesticide mixture of thiamethoxam–tetraconazole elicited synergetic toxicity to G. rarus. Moreover, pesticide mixtures containing beta-cypermethrin in combination with chlorpyrifos or tetraconazole also had synergetic toxicities to fish. The majority of pesticides are presumed to have additive toxicity, while our data emphasized that the concurrent existence of some chemicals in the aqueous circumstance could cause synergetic toxic effect, leading to severe loss to the aqueous environments in comparison with their single toxicities. Thence, the synergetic impacts of chemical mixtures should be considered when assessing the ecological risk of chemicals.

  相似文献   
55.
Environmental Science and Pollution Research - With the increasingly serious pollution of plastics, biodegradable plastics (BDPs) have attracted attention as a new material that can replace...  相似文献   
56.
Environmental Science and Pollution Research - A theoretical physicochemical and thermodynamic investigation of the adsorption of heavy metals Zn2+, Cd2+, Ni2+, and Cu2+on carbon-based adsorbents...  相似文献   
57.
Environmental Science and Pollution Research - Phytoremediation techniques have been proposed as ecological methods to clean up contaminated sites. This study is aimed to evaluate the effect of the...  相似文献   
58.
美国市政污水处理排放标准制定对中国的启示   总被引:2,自引:1,他引:1  
在概述美国市政污水处理排放标准制度体系的基础上,介绍了其制定基于技术的排放限值和基于水质的排放限值的方法,阐述了其制定的科学性,并指出了中国市政污水处理排放标准中存在的相应问题。最后,根据美国制定排放标准限值的经验,对我国污水处理排放标准进行了思考,并提出了科学制定排放标准的方法和建议。  相似文献   
59.
The understanding of organic phosphorus(P) dynamics in sediments requires information on their species at the molecular level,but such information in sediment profiles is scarce.A sediment profile was selected from a large eutrophic lake,Lake Taihu(China),and organic P species in the sediments were detected using solution phosphorus-31 nuclear magnetic resonance spectroscopy(31 P NMR) following extraction of the sediments with a mixture of 0.25 mol/L NaOH and 50 mmol/L EDTA(NaOH-EDTA) solution.The results showed that P in the NaOH-EDTA extracts was mainly composed of orthophosphate,orthophosphate monoesters,phospholipids,DNA,and pyrophosphate.Concentrations of the major organic P compound groups and pyrophosphate showed a decreasing trend with the increase of depth.Their half-life times varied from 3 to 27 years,following the order of orthophosphate monoesters > phospholipids DNA > pyrophosphate.Principal component analysis revealed that the detected organic P species had binding phases similar to those of humic acid-associated organic P(NaOH-NRP HA),a labile organic P pool that tends to transform to recalcitrant organic P pools as the early diagenetic processes proceed.This demonstrated that the depth attenuation of the organic P species could be partly attributed to their increasing immobilization by the sediment solids,while their degradation rates should be significantly lower than what were suggested in previous studies.  相似文献   
60.
白音华一号露天矿工程施工建设过程中,将会造成大气污染、地表水污染、地下水疏干、噪声污染、排土场及工业场地占地等大量生态环境问题。因此,在工程施工之初开展环境监理工作,对加强环境保护“三同时”制度,落实污染物防治及生态保护措施具有十分重要的意义。  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