全文获取类型
收费全文 | 5837篇 |
免费 | 178篇 |
国内免费 | 196篇 |
专业分类
安全科学 | 373篇 |
废物处理 | 51篇 |
环保管理 | 1251篇 |
综合类 | 2624篇 |
基础理论 | 389篇 |
环境理论 | 20篇 |
污染及防治 | 382篇 |
评价与监测 | 773篇 |
社会与环境 | 303篇 |
灾害及防治 | 45篇 |
出版年
2024年 | 2篇 |
2023年 | 35篇 |
2022年 | 54篇 |
2021年 | 104篇 |
2020年 | 212篇 |
2019年 | 83篇 |
2018年 | 82篇 |
2017年 | 152篇 |
2016年 | 188篇 |
2015年 | 149篇 |
2014年 | 241篇 |
2013年 | 327篇 |
2012年 | 241篇 |
2011年 | 428篇 |
2010年 | 206篇 |
2009年 | 361篇 |
2008年 | 289篇 |
2007年 | 301篇 |
2006年 | 293篇 |
2005年 | 163篇 |
2004年 | 186篇 |
2003年 | 238篇 |
2002年 | 225篇 |
2001年 | 200篇 |
2000年 | 233篇 |
1999年 | 206篇 |
1998年 | 190篇 |
1997年 | 176篇 |
1996年 | 112篇 |
1995年 | 89篇 |
1994年 | 108篇 |
1993年 | 87篇 |
1992年 | 65篇 |
1991年 | 36篇 |
1990年 | 16篇 |
1989年 | 19篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 16篇 |
1985年 | 14篇 |
1984年 | 14篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1974年 | 1篇 |
1973年 | 4篇 |
排序方式: 共有6211条查询结果,搜索用时 187 毫秒
1.
Cultural heritage is being addressed by a number of charters and conventions and it is clear that its consideration within decision-making processes is progressively becoming a real challenge, both for developers and public authorities. Against this background, this paper reviews the environmental assessment framework developed by the European Community, as this should increasingly influence decision making about cultural heritage in an urban setting. The legislative framework for access to environmental information is also reviewed because of its relevance to the decision-making process.The Directives on Environmental Impact Assessment and Strategic Environmental Assessment both require a consideration of cultural heritage in decision making. This requirement can go some way to addressing the paradox in the European Community's position whereby the community wishes to conserve and enhance its own cultural identity whilst, at the same time, cultural heritage is usually defined at a local level. The present paper suggests that, given their flexibility, the two European Community directives on environmental assessment constitute a promising opportunity to address this seeming paradox, but that there is a significant gap between legal obligations and the methodological tools to meet them. 相似文献
2.
Evolution of environmental impact assessment as applied to watershed modification projects in Canada
Herman J. Dirschl Nicholas S. Novakowski M. Husain Sadar 《Environmental management》1993,17(4):545-555
This article reviews the application of environmental impact assessment (EIA) procedures and practices to three watershed
modification projects situaled in western Canada. These ventures were justified for accelerating regional economic development,
and cover the period during which public concerns for protecting the environment rapidly made their way into the national
political agenda. An historical account and analysis of the situation, therefore, seems desirable in order to understand the
development of EIA processes, practices, and methodologies since the start of construction of the first project in 1961. This
study concludes that there has been good progress in predicting and evaluating environmental and related social impacts of
watershed modification proposals. However, a number of obstacles need to be overcome before EIA can firmly establish itself
as an effective planning tool. These difficulties include jurisdictional confusions and conflicts, division of authority and
responsibility in designing and implementing appropriate mitigative and monitoring measures, lack of tested EIA methodologies,
and limited availability of qualified human resources. A number of conclusions and suggestions are offered so that future
watershed modification proposals may be planned and implemented in a more environmentally sustainable fashion. These include:
(1) EIA processes must be completed before irrevocable decisions are made. (2) Any major intrusion into a watershed is likely
to impact on some major components of the ecosystem(s). (3) Mitigation costs must form part of the benefit-cost analysis of
any project proposal. (4) Interjurisdictional cooperation is imperative where watersheds cross political boundaries. (5) The
EIA process is a public process, hence public concerns must be dealt with fairly. (6) The role of science in the EIA process
must be at arms length from project proponents and regulators, and allowed to function in the interest of the protection of
the environment and public health and safety.
The views expressed here are the authors’ own and do not necessarily reflect those of FEARO and/or other government agencies
and officials involved in the review of these projects. 相似文献
3.
三峡库区中低产土壤重金属含量及其与小麦吸收的关系 总被引:3,自引:0,他引:3
三峡库区中低产土壤的Hg,As,Cr,Pb,Cu五个重金属含量(除渝北区外),均在国家土壤环境质量标准内,属自然背景值一级标准。Cd和Zn高于全国土壤中的平均含量和背景值含量,属二级标准。土壤的重金属含量与土壤母质类型,pH值,阳离子交换量,有机质,无定形铁和物理性粘粒有关,同时存在一定的地域分布。重庆近郊的土壤所有重金属含量相对较高。土壤重金属的可给态或有效性含量极低,锌和铜不是过量,而是不足。小麦籽粒中As,Cr,Pb,Zn,Cu含量低于国家食品对重金属限量标准和小麦籽粒背景值标准,Hg,Cd含量高于国家规定标准。籽粒中的Cu,Zn含量是小麦茎叶中的2.0-2.2倍,而茎叶中的Hg,Pb,As,Cr,Cd含量明显高于籽粒。 相似文献
4.
Mikael Skou Andersen 《Sustainability Science》2007,2(1):133-140
This paper provides an introduction to some of the fundamental principles and approaches in environmental economics which
are of significance to achieving an integrated sustainability science. The concept of a circular economy, introduced by the
late David Pearce in 1990, addresses the interlinkages of the four economic functions of the environment. The environment
not only provides amenity values, in addition to being a resource base and a sink for economic activities, it is also a fundamental
life-support system. Environmental economists have suggested that, taking these four functions as an analytical starting point,
unpriced or underpriced services should be internalised in the economy. In Europe significant advances have been achieved
in the pricing of externalities by means of truly interdisciplinary analysis which accounts in detail for the environmental
consequences. The monetary estimates reached as a result of such interdisciplinary research are gradually being applied to
the economic analysis of environmental policy priorities. Although such figures provide only a partial and incomplete picture
of the environmental costs at stake, they support and inform the analysis of the virtues of a circular economy for individual
resources as well as for sustainability as a future trajectory. 相似文献
5.
Dynamics and Causation of Environmental Equity, Locally Unwanted Land Uses, and Neighborhood Changes
Feng Liu 《Environmental management》1997,21(5):643-656
/ Why are some environmental risks distributed disproportionately in the neighborhoods of the minorities and the poor? A hypothesis was proposed in a recent study that market dynamics contributed to the current environmental inequity. That is, locally unwanted land uses (LULUs) make the host communities home to more poor people and people of color. This hypothesis was allegedly supported by a Houston case study, whereby its author analyzed the postsiting changes of the socioeconomic characteristics of the neighborhoods surrounding solid waste facilities. I argue that such an analysis of postsiting changes alone is insufficient to test the causation hypothesis. Instead, I propose a conceptual framework for analysis of environmental equity dynamics and causation. I suggest that the presiting neighborhood dynamics and the characteristics of control neighborhoods be analyzed as the first test for the causation hypothesis. Furthermore, I present theories of neighborhood change and then examine alternative hypotheses that these theories offer for explaining neighborhood changes and for the roles of LULUs in neighborhood changes. These alternative hypotheses should be examined when analyzing the relationship between LULUs and neighborhood changes in a metropolitan area. Using this framework of analysis, I revisited the Houston case. First, I found no evidence that provided support for the hypothesis that the presence of LULUs made the neighborhoods home to more blacks and poor people, contrary to the conclusion made by the previous study. Second, I examined alternative hypotheses for explaining neighborhood changes-invasion-succession, other push forces, and neighborhood life-cycle; the former two might offer better explanation.KEY WORDS: Environmental equity and justice; Locally unwanted lane uses; Siting; Market dynamics; Invasion-succession; Neighborhood changes 相似文献
6.
Weicheng Zhang Bingyu Ning Caiyun Sun Ke Song Xin Xu Tao Fang Lunguang Yao 《环境科学学报(英文版)》2020,32(3):180-193
Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials, and thus, the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag+ ratios. Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays, and shifts to both Ag particles and released Ag+ in 48 hr bioassays. Herein, as a continued study, the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically. The cytotoxicity and mechanisms of nano-Ag colloids are dynamic throughout exposure and are derived from both Ag ions and particles. Ag accumulation by E. coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure, and thereafter mainly from intracellular Ag ions. Fe3+ accelerates the oxidative dissolution of nano-Ag colloids, which results in decreasing amounts of Ag particles and particle-related toxicity. Na+ stabilizes nano-Ag colloids, thereby decreasing the bioavailability of Ag particles and particle-related toxicity. Humic acid (HA) binds Ag+ to form Ag+-HA, decreasing ion-related toxicity and binding to the E. coli surface, decreasing particle-related toxicity. HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na+ or Fe3+. The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors, and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments. 相似文献
7.
以武陵山片区42个国家级贫困县(市、区)为案例地,综合运用SBM模型、改进的熵值法与耦合协调模型,揭示产业结构转型升级水平与旅游扶贫效率耦合协调关系的时空演化特征。结果表明:(1)武陵山片区整体及各分片区产业结构转型升级指数均呈波浪式变化,湖北片区、重庆片区以及武陵山片区整体的旅游扶贫效率呈上升态势,而湖南片区和贵州片区略有下降;(2)产业结构转型升级水平与旅游扶贫效率不耦合、不协调的县域单元主要集中在武陵山片区中部,数量逐年减少,实现耦合和协调的县域数量显著增加并向边缘地带形成集聚态势;(3)不耦合失调(类型1)向耦合协调(类型2)转变是核心转变路径,促使类型2的地区数量显著增多,并逐渐在研究区域边缘形成带状分布。研究可为集中连片特困地区产业结构优化升级和跨越贫困陷阱提供参考借鉴。 相似文献
8.
北山地区大气降水中水化学及稳定同位素特征 总被引:1,自引:0,他引:1
为揭示甘肃北山地区大气降水的水化学及同位素特征,利用2012~2019年度采集的97件大气降水样品,采用相关性分析,富集因子,气团后向轨迹分析等多种方法对北山地区稳定同位素变化特征及其影响因素,降水中主要离子变化特征,不同离子来源及贡献,水汽来源进行了分析.结果表明,北山地区区域降水线的斜率与截距均高于张掖地区大气降水线;该区降水中稳定同位素比率明显受季节性,温度和高程效应的影响,在年尺度下,降雨量效应不明显;该区降水中氘盈余变化较大,雨季降水中氘盈余显著小于旱季降水中氘盈余值;北山地区大气降水的水化学型主要为HCO3·SO4-Ca和HCO3-Ca型,降水中离子浓度具有明显的季节性变化,降雨量的增加对离子浓度具有一定的稀释作用;Na+受海源和陆源物质的双重影响;绝大部分的Ca2+,K+,HCO3-和部分Mg2+来源于陆源,SO42-与NO3-的主要来自于人类活动输入;区内冬夏季水汽来源基本一致,来源于西北方向的季风源是北山地区最主要的水汽来源.研究成果可为我国高放废物地质处置库选址和性能评价以及未来地下处置库建设提供依据,也有助于丰富西北干旱区的水文循环过程研究. 相似文献
9.
对环境监测中的数据、统计、有效数字、修约,以及计量单位、结果表达、原始数据的记录等既平常又十分重要易被忽略的重要问题作了概述,这些问题的解决才能保证监测结果的准确性和可靠性. 相似文献
10.