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   9032篇
  免费   575篇
  国内免费   335篇
安全科学   1970篇
废物处理   145篇
环保管理   3157篇
综合类   2349篇
基础理论   883篇
环境理论   10篇
污染及防治   335篇
评价与监测   378篇
社会与环境   377篇
灾害及防治   338篇
  2023年   119篇
  2022年   143篇
  2021年   238篇
  2020年   298篇
  2019年   211篇
  2018年   177篇
  2017年   249篇
  2016年   347篇
  2015年   302篇
  2014年   356篇
  2013年   534篇
  2012年   489篇
  2011年   647篇
  2010年   402篇
  2009年   551篇
  2008年   419篇
  2007年   518篇
  2006年   492篇
  2005年   392篇
  2004年   418篇
  2003年   335篇
  2002年   302篇
  2001年   285篇
  2000年   280篇
  1999年   219篇
  1998年   140篇
  1997年   146篇
  1996年   119篇
  1995年   111篇
  1994年   56篇
  1993年   76篇
  1992年   64篇
  1991年   49篇
  1990年   36篇
  1989年   29篇
  1988年   35篇
  1987年   38篇
  1986年   30篇
  1985年   25篇
  1984年   28篇
  1983年   18篇
  1982年   22篇
  1981年   24篇
  1980年   25篇
  1979年   33篇
  1978年   21篇
  1975年   14篇
  1973年   14篇
  1972年   16篇
  1971年   14篇
排序方式: 共有9942条查询结果,搜索用时 0 毫秒
971.
根据国家及行业协会的有关规定要求,环境污染治理设施运营资质认定的管理方式实行改革,资质证书管理已完成了从行政许可到行业自律管理的过渡。阐述了资质证书管理方式转变的意义和重要性,以及具体实行中需要注意的问题和对策。  相似文献   
972.
In this study, a recourse‐based interval fuzzy programming (RIFP) model is developed for tackling uncertainties expressed as fuzzy, interval, and/or probabilistic forms in an effluent trading program. It can incorporate preregulated water‐pollution control policies directly into its optimization process, such that an effective linkage between environmental regulations and economic implications (i.e., penalties) caused by improper policies due to uncertainty existence can be provided. The RIFP model is applied to point‐nonpoint source effluent trading of the Xiangxi River in China. The efficiency of trading efforts between water quality improvement and net system benefit under different degrees of satisfying discharge limits is analyzed. The results are able to help support (1) formulation of water‐pollution control strategies under various economic objectives and system‐reliability constraints, (2) selection of the desired effluent trading pattern for point and nonpoint sources, and (3) generation of tradeoffs among system benefit, satisfaction degree, and pollutant mitigation under multiple uncertainties. Compared with the traditional regulatory approaches, the results demonstrate that the water‐pollution control program can be performed more cost‐effectively through trading than nontrading.  相似文献   
973.
针对我国目前非正常死亡长期据高不下现状,分析了小尺度环境安全问题成因特点,提出用加强城市环境风险管理作为对策,并具体讨论了环境安全标准、环境安全责任、环境安全立法、环境安全经济、环境安全管理、环境安全科研等相关问题。  相似文献   
974.
Despite long-standing knowledge of the benefits of riparian buffers for mitigating nonpoint source pollution, many streams are unprotected by buffers. Even landowners who understand ecological values of buffers mow riparian vegetation to the streambank. Do trends in rural riparian conditions reflect the development of riparian forest science? What motivates residential riparian management actions? Using high-resolution orthoimagery, we quantified riparian conditions and trends between 1998 and 2015 in the rural upper Little Tennessee River basin in Macon County, North Carolina and explored how landowners view riparian zone management and riparian restoration programs. Buffer composition in 2015 was as follows: no buffer (32.5%), narrow (19.3%), forested (26.7%), shrub (7.2%), and intermediate (7.0%). Relative to 1998, the greatest decrease occurred in the no buffer class (−17.7%, 46 km) and the largest increases occurred in the shrub (+72.5%, 20 km) and narrow (12.6%, 14 km) classes. Forested buffer marginally increased. Semi-structured interview data suggest that landowners prioritize recreational and scenic aspects of riparian buffers over ecological functions such as filtration and bank stabilization. Riparian restoration programs might be made more enticing to non-adopters if outreach language appealed to landowner priorities, design elements demonstrated intentional management, and program managers highlighted areas where ecological goals and landowner values align.  相似文献   
975.
Recent targets for reduced amounts of waste to landfills in Sweden will result in a large increase in waste incineration with recovery of energy, used primarily for district heating. The aim of this study is to investigate what changes in the usage of other fuels and technologies for district heat production would be caused by this increase. A questionnaire was sent out to the largest district heating companies, and simulations in an energy systems model were carried out. The analysis shows that increased waste incineration reduces the demand for other fuels, especially biomass, for district heat production. The effects include reductions in operating hours as well as the avoidance or postponement of investments in new plants for district heat production. Increased waste incineration will also lead to a greater use of district heating in Sweden.  相似文献   
976.
随着公众环保意识的不断增强,上市公司环境行为日益受到关注,对上市公司的环境管理水平也提出了新要求。上市公司应配备专业环境管理队伍,完善并实施企业环境管理制度,在日常环境管理中应注意环境影响评价和“三同时”手续的办理,及时进行排污申报并办理排污许可证,制定并执行环境监测计划,保证环保设施稳定运行,确保污染物达标排放,妥善处理生产过程中产生的一般固废和危险废物,做好事故应急预案,避免出现环境污染事件,并根据相关要求开展清洁生产审核,进行环境信息公开。  相似文献   
977.
Polycyclic aromatic hydrocarbons(PAHs), as persistent toxic substances(PTS), have been widely monitored in coastal environment, including seawater and sediment. However, scientific monitoring methods, like ecological risk assessment and integrated biomarker response, still need massive researches to verify their availabilities. This study was performed in March, May, August and October of 2018 at eight sites, Yellow River estuary(S1), Guangli Port(S2), Xiaying(S3), Laizhou(S4), Inner Bay(S5), Ou...  相似文献   
978.
介绍呼和浩特市城市生活垃圾的管理体制和垃圾处理、处置的现状,分析了管理中存在的问题,并对今后的管理提出相关的解决措施和建议。  相似文献   
979.
Abstract: Conserving the watershed can help to preserve ground water recharge. Preventing overuse of available water through pricing reforms can also substantially increase the value of an aquifer. Inasmuch as users are accustomed to low prices, efficiency pricing may be politically infeasible, and watershed conservation may be considered as an alternative. We estimate and compare welfare gains from pricing reform and watershed conservation for a water management district in Oahu that obtains its water supply from the Pearl Harbor aquifer. We find that pricing reform is welfare superior to watershed conservation unless the latter is able to prevent very large recharge losses. Watershed conservation that yields net gains in combination with pricing reform may cause net losses without the pricing reform. If adoption of watershed conservation delays the implementation of pricing reform, the benefits of the latter are significantly reduced.  相似文献   
980.
Monitoring communities of fish is important for the management and sustainability of fisheries and marine ecosystems. Baited remote underwater video systems (BRUVs) are among the most effective nondestructive techniques for sampling bony fishes and elasmobranchs (sharks, rays, and skates). However, BRUVs sample visually conspicuous biota; hence, some taxa are undersampled or not recorded at all. We compared the diversity of fishes characterized using BRUVs with diversity detected via environmental DNA (eDNA) metabarcoding. We sampled seawater and captured BRUVs imagery at 48 locales that included reef and seagrass beds inside and outside a marine reserve (Jurien Bay in Western Australia). Eighty-two fish genera from 13 orders were detected, and the community of fishes described using eDNA and BRUVs combined yielded >30% more generic richness than when either method was used alone. Rather than detecting a homogenous genetic signature, the eDNA assemblages mirrored the BRUVs’ spatial explicitness; differentiation of taxa between seagrass and reef was clear despite the relatively small geographical scale of the study site (∼35 km2). Taxa that were not sampled by one approach, due to limitations and biases intrinsic to the method, were often detected with the other. Therefore, using BRUVs and eDNA in concert provides a more holistic view of vertebrate marine communities across habitats. Both methods are noninvasive, which enhances their potential for widespread implementation in the surveillance of marine ecosystems.  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