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   28763篇
  免费   2681篇
  国内免费   6709篇
安全科学   3105篇
废物处理   745篇
环保管理   4748篇
综合类   19113篇
基础理论   3159篇
环境理论   18篇
污染及防治   2501篇
评价与监测   1866篇
社会与环境   1810篇
灾害及防治   1088篇
  2024年   87篇
  2023年   582篇
  2022年   958篇
  2021年   1184篇
  2020年   1178篇
  2019年   1003篇
  2018年   884篇
  2017年   1154篇
  2016年   1298篇
  2015年   1437篇
  2014年   1544篇
  2013年   2087篇
  2012年   2243篇
  2011年   2420篇
  2010年   1710篇
  2009年   1738篇
  2008年   1349篇
  2007年   1967篇
  2006年   1993篇
  2005年   1564篇
  2004年   1369篇
  2003年   1347篇
  2002年   1149篇
  2001年   1020篇
  2000年   936篇
  1999年   810篇
  1998年   571篇
  1997年   492篇
  1996年   371篇
  1995年   333篇
  1994年   298篇
  1993年   261篇
  1992年   184篇
  1991年   122篇
  1990年   85篇
  1989年   43篇
  1988年   39篇
  1987年   43篇
  1986年   23篇
  1985年   23篇
  1984年   27篇
  1983年   19篇
  1982年   28篇
  1981年   25篇
  1980年   29篇
  1979年   24篇
  1978年   19篇
  1973年   16篇
  1972年   13篇
  1971年   20篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
11.
针对蓝藻资源化问题,概述国内外利用蓝藻制备有机肥、提取高纯度藻蓝蛋白、制备活性炭和藻粉这4种利用方式的特点、现状及应用进展。提出,应从高温好氧堆肥技术、藻蓝蛋白提取技术和藻水分离技术这3个方面,解决其关键技术问题并进行进一步研究开发。  相似文献   
12.
采用臭氧氧化—湿式钙法吸收工艺对模拟烟气进行同时脱硫脱硝处理。O3于150 ℃下具有较高的热稳定性,可将NO氧化为高价态氮氧化物,且NO氧化率随n(O3)∶n(NO)的增大而逐渐提高。烟气中SO2和H2O的存在对NO氧化率的影响不大。O3对SO2的氧化率较低,约为5%。3%(w)石灰石浆液对SO2的吸收率接近100%,NOx吸收率随n(O3)∶n(NO)的增大而逐渐提高,当n(O3)∶n(NO)为1.6时NOx吸收率可达约65%。SO2能促进吸收液对NOx的脱除。石灰石浆液中加入0.2%(w)的(NH42SO3或Na2SO3后NOx吸收率可达约85%或82%,且吸收率随添加剂加入量的增加而提高,添加(NH42SO3的NOx吸收率略高于添加Na2SO3。  相似文献   
13.
In order to enhance Chinese workers’ occupational safety awareness, it is essential to learn from developed countries’ experiences. This article investigates thoroughly occupational safety and health (OSH) in China and the UK; moreover, the article performs a comparison of Chinese and British OSH training-related laws, regulations and education system. The following conclusions are drawn: China’s work safety continues to improve, but there is still a large gap compared with the UK. In China a relatively complete vocational education and training (VET) system has been established. However, there exist some defects in OSH. In the UK, the employer will not only pay attention to employees’ physiological health, but also to their mental health. The UK’s VET is characterized by classification and grading management, which helps integrate OSH into the whole education system. China can learn from the UK in the development of policies, VET and OSH training.  相似文献   
14.
分析了汽车及零部件行业VOCs的主要来源和危害,阐述了我国现阶段汽车及零部件行业VOCs的污染现状。建议采取以源头削减和过程控制为重点、兼顾末端治理的全过程综合防治措施,控制汽车及零部件行业的VOCs排放。  相似文献   
15.
李楠  王鹏  宋伦  邵泽伟  赵海勃 《化工环保》2018,38(3):300-304
以颗粒活性炭(GAC)为载体、铜为活性组分、铈为助剂组分、草酸钠为沉淀剂,采用浸渍焙烧法制得CuO_x-CeO_2/GAC催化剂。以H_2O_2为氧化剂,微波强化催化湿式过氧化氢氧化(CWPO)处理二甲亚砜(DMSO)初始质量浓度为1 000 mg/L的废水,处理3 min后DMSO去除率达93.8%。催化剂第7次使用时DMSO去除率仍保持在75%以上。初始废水pH在3~9范围内,DMSO去除率均在85%以上。助剂Ce的加入提高了催化剂表面活性组分的分散性和稳定性,使催化剂的活性稳定性和使用寿命显著提高。  相似文献   
16.
When accounting the CO2 emissions responsibility of the electricity sector at the provincial level in China,it is of great significance to consider the scope of both producers’ and the consumers’ responsibility,since this will promote fairness in defining emission responsibility and enhance cooperation in emission reduction among provinces.This paper proposes a new method for calculating carbon emissions from the power sector at the provincial level based on the shared responsibility principle and taking into account interregional power exchange.This method can not only be used to account the emission responsibility shared by both the electricity production side and the consumption side,but it is also applicable for calculating the corresponding emission responsibility undertaken by those provinces with net electricity outflow and inflow.This method has been used to account for the carbon emissions responsibilities of the power sector at the provincial level in China since 2011.The empirical results indicate that compared with the production-based accounting method,the carbon emissions of major power-generation provinces in China calculated by the shared responsibility accounting method are reduced by at least 10%,but those of other power-consumption provinces are increased by 20% or more.Secondly,based on the principle of shared responsibility accounting,Inner Mongolia has the highest carbon emissions from the power sector while Hainan has the lowest.Thirdly,four provinces,including Inner Mongolia,Shanxi,Hubei and Anhui,have the highest carbon emissions from net electricity outflow- 14 million t in 2011,accounting for 74.42% of total carbon emissions from net electricity outflow in China.Six provinces,including Hebei,Beijing,Guangdong,Liaoning,Shandong,and Jiangsu,have the highest carbon emissions from net electricity inflow- 11 million t in 2011,accounting for 71.44% of total carbon emissions from net electricity inflow in China.Lastly,this paper has estimated the emission factors of electricity consumption at the provincial level,which can avoid repeated calculations when accounting the emission responsibility of power consumption terminals(e.g.construction,automobile manufacturing and other industries).In addition,these emission factors can also be used to account the emission responsibilities of provincial power grids.  相似文献   
17.
Hull, a city in the East Riding of Yorkshire, United Kingdom, suffered severe flooding in June 2007, affecting some 8,600 households and most schools. Despite the potential for damage in such disasters, no studies of the effects of floods on teachers and schools in the UK appear to have been published previously. This study analysed the impacts of the floods on teachers in Hull in two stages: first through correspondence with Hull City Council and a mailed questionnaire to 91 head teachers of primary, secondary, and special schools; and second, through in‐depth interviews with head teachers from six flooded schools, representing different degrees of flood experience, and a questionnaire completed by eight teachers from the same schools. The findings reveal the importance and the complexity of the role of the school in the wider community in a time of crisis. The study highlights issues concerning preparedness for floods, support for schools, and flood protection for schools.  相似文献   
18.
采用活性炭吸附和两级Fenton氧化组合工艺对高盐度对氨基苯酚生产废水进行了处理实验研究。结果表明,p H值对活性炭去除有机物的影响较小。当活性炭投加量为4 g/L时,TOC去除率61%。分级加药可以有效提高Fenton氧化对有机物的去除效率。在温度为25℃、p H为3、30%H2O2投加量为3%(V/V)、Fe2+/H2O2摩尔比为0.05时,两级Fenton氧化处理后,出水TOC降至150 mg/L以下。此外,Fenton氧化后形成氢氧化铁污泥颗粒粒径为4.5μm,经过聚丙烯酰胺(PAM)絮凝之后,污泥的粒径明显增加,过滤特性改善。PAM絮凝效果依赖于溶液的p H值,当p H超过10后会失去作用,故在使用过程中需要严格控制溶液的p H值。  相似文献   
19.
为探讨Cu2+、p H和流速对固定化斜生栅藻去除畜禽废水中NH+4-N、TP效果的影响,在实验室条件下模拟实际污水处理过程,并采用正交实验方案对结果进行分析。结果表明低质量浓度Cu2+(0~0.05 mg/L)改善藻的净化效果,高质量浓度Cu2+(0.50~5.00 mg/L)抑制藻的净化效果;在p H较高的条件下(p H=9),固定化斜生栅藻的净化效果明显提高;流速对结果没有明显影响。通过正交实验,得出固定化斜生栅藻去除畜禽废水中NH+4-N、TP的优化条件如下:Cu2+质量浓度为0.05 mg/L,p H为9,流速为0.3 m/s。此时NH+4-N去除率为96.11%,TP去除率为97.53%。  相似文献   
20.
采用车载GC-MS技术,建立了顶空-GC-MS方法对CFCs产品组分及排污废水中三氯一氟甲烷、二氯二氟甲烷、四氯化碳等成分进行监测分析,实现了快速鉴定企业是否违规生产CFCs相关产品,对于判定企业是否违规提供技术依据。同时,采用顶空-GC/ECD方法对废水中的四氯化碳进行定量分析,以排查企业是否超标排污。  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