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   31247篇
  免费   1433篇
  国内免费   7578篇
安全科学   1899篇
废物处理   2052篇
环保管理   3023篇
综合类   13984篇
基础理论   6327篇
环境理论   2篇
污染及防治   8229篇
评价与监测   2012篇
社会与环境   1760篇
灾害及防治   970篇
  2024年   36篇
  2023年   363篇
  2022年   1105篇
  2021年   1037篇
  2020年   896篇
  2019年   731篇
  2018年   2275篇
  2017年   2300篇
  2016年   2100篇
  2015年   1375篇
  2014年   1754篇
  2013年   2248篇
  2012年   2363篇
  2011年   3245篇
  2010年   2243篇
  2009年   2128篇
  2008年   2510篇
  2007年   2630篇
  2006年   1330篇
  2005年   896篇
  2004年   703篇
  2003年   804篇
  2002年   760篇
  2001年   525篇
  2000年   607篇
  1999年   555篇
  1998年   469篇
  1997年   479篇
  1996年   411篇
  1995年   309篇
  1994年   268篇
  1993年   206篇
  1992年   175篇
  1991年   108篇
  1990年   88篇
  1989年   43篇
  1988年   38篇
  1987年   28篇
  1986年   21篇
  1985年   12篇
  1984年   23篇
  1983年   21篇
  1982年   17篇
  1981年   12篇
  1978年   2篇
  1976年   1篇
  1975年   1篇
  1958年   1篇
  1957年   1篇
  1935年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
典型地区农用地污染调查及风险管控标准探讨   总被引:2,自引:0,他引:2  
针对《土壤污染风险管控标准——农用地土壤污染风险管控标准》(GB 15618—2018),提出以土壤中全量浓度筛选值和管控值作为衡量农用地土壤污染风险管控的标准,对湖南省部分稻田农用地土壤及点对点稻米样品中镉、铅、砷、汞的总量和有效态浓度及稻米中含量进行监测,根据重金属总量浓度分为低风险、中风险、高风险3组。结果显示:(1)土壤及稻米中镉含量基本为随着风险级别的升高而增加,铅、砷在土壤和稻米中含量无规律性结果,汞监测结果均为未检出。(2)低风险组稻米镉超标率为12. 0%,高风险组稻米镉达标率为33. 3%,表明利用总量浓度对农用地土壤潜在风险进行分组存在一定的局限性。(3)依据4种重金属在土壤中总量及稻米(早稻)中含量情况,对风险级别进行调整并综合判断:有58个样品为低风险组,占样品总数的68. 2%,超标率为零;有15个样品为中风险组,占样品总数的17. 7%,超标率为80. 0%;有12个样品为高风险组,占样品总数的14. 1%,超标率为100. 0%。调整后评价结果与上述标准的划分目标更接近,能够提高上述标准的准确性和实用性。  相似文献   
2.

The continuous increase in waste generation warrants global management of waste to reduce the adverse economic, social, and environmental impact of waste while achieving goals for sustainability. The complexity of waste management systems due to different waste management practices renders such systems difficult to analyze. System dynamics (SD) approach aids in conceptualizing and analyzing the structure, interactions, and mode of behavior of the complex systems. The impact of the underlying components can therefore be assessed in an integrated way while the impact of possible policies on the system can be studied to implement appropriate decisions. This review summarizes various applications of SD pertinent to the waste management practices in different countries. Practices may include waste generation, reduction, reuse/recovery, recycling, and disposal. Each study supports regional-demanding targets in environmental, social, and economic scopes such as expanding landfill life span, implementing proper disposal fee, global warming mitigation, energy generation/saving, etc. The interacting variables in the WMS are specifically determined based on the defined problem, ultimate goal, and the type of waste. Generally, population and gross domestic product can increase the waste generation. An increase in waste reduction, source separation, and recycling rate could decrease the environmental impact, but it is not necessarily profitable from an economic perspective. Incentives to separate waste and knowledge about waste management are variables that always have a positive impact on the entire system.

  相似文献   
3.
Environmental Science and Pollution Research - A mechanical harvesting technology based on coupling flocculation with a rotary drum filter (RDF, 35-μm) was applied to remove cyanobacterial...  相似文献   
4.
Environmental Science and Pollution Research - Buildings account for nearly 2/5ths of global energy expenditure. Due to this figure, the 90s witnessed the rise of green buildings (GBs) that were...  相似文献   
5.
Environmental Science and Pollution Research - Growing environmental pressure urges China to develop in a sustainable and low carbon way, and thus China strives to achieve a carbon peak by 2030 and...  相似文献   
6.
Environmental Science and Pollution Research - At present, the contradiction between survival and ecology necessitates the integration of crop planting, chemical fertilizer application, and...  相似文献   
7.
Zhu  Rong  Wang  Shixin  Srinivasakannan  C.  Li  Shiwei  Yin  Shaohua  Zhang  Libo  Jiang  Xiaobin  Zhou  Guoli  Zhang  Ning 《Environmental Chemistry Letters》2023,21(3):1611-1626
Environmental Chemistry Letters - The demand for lithium is growing rapidly with the increase in electric vehicles, batteries and electronic equipments. Lithium can be extracted from brines, yet...  相似文献   
8.
Environmental Science and Pollution Research - Hydrothermal liquefaction (HTL) of biomass used HTL reaction under high temperature and pressure to produce bio-oil. This technology is considered as...  相似文献   
9.
Journal of Material Cycles and Waste Management - The iron ore tailing (IOT) is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the...  相似文献   
10.
This paper investigates the effects of the incorporation of lignin and small quantities of epoxidized natural rubber (ENR) as an impact modifying agent on blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL). The addition of lignin resulted in a slight improvement of flexural strength and modulus of the ternary blending system. Incorporation of ENR into the blend resulted in an increase in notched Izod impact strength from 40 to 135% depending on the concentration of ENR. The addition of lignin into the blend resulted in an improvement of thermal stability of the ternary blend system. Morphological analysis showed a good dispersion of PHBV phases and lignin within the PCL matrix. Rheological characterization revealed that the presence of lignin resulted in increased storage modulus of the bioblend.  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