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   1431篇
  免费   141篇
  国内免费   185篇
安全科学   56篇
废物处理   12篇
环保管理   294篇
综合类   726篇
基础理论   329篇
污染及防治   64篇
评价与监测   84篇
社会与环境   145篇
灾害及防治   47篇
  2024年   9篇
  2023年   21篇
  2022年   51篇
  2021年   81篇
  2020年   50篇
  2019年   60篇
  2018年   41篇
  2017年   57篇
  2016年   68篇
  2015年   60篇
  2014年   81篇
  2013年   112篇
  2012年   95篇
  2011年   108篇
  2010年   95篇
  2009年   85篇
  2008年   72篇
  2007年   97篇
  2006年   64篇
  2005年   71篇
  2004年   55篇
  2003年   48篇
  2002年   39篇
  2001年   34篇
  2000年   35篇
  1999年   16篇
  1998年   24篇
  1997年   29篇
  1996年   28篇
  1995年   11篇
  1994年   16篇
  1993年   7篇
  1992年   10篇
  1991年   3篇
  1990年   3篇
  1989年   6篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1978年   2篇
  1977年   3篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
排序方式: 共有1757条查询结果,搜索用时 31 毫秒
861.
Marine protected areas (MPAs) are a primary tool for the stewardship, conservation, and restoration of marine ecosystems, yet 69% of global MPAs are only partially protected (i.e., are open to some form of fishing). Although fully protected areas have well-documented outcomes, including increased fish diversity and biomass, the effectiveness of partially protected areas is contested. Partially protected areas may provide benefits in some contexts and may be warranted for social reasons, yet social outcomes often depend on MPAs achieving their ecological goals to distinguish them from open areas and justify the cost of protection. We assessed the social perceptions and ecological effectiveness of 18 partially protected areas and 19 fully protected areas compared with 19 open areas along 7000 km of coast of southern Australia. We used mixed methods, gathering data via semistructured interviews, site surveys, and Reef Life (underwater visual census) surveys. We analyzed qualitative data in accordance with grounded theory and quantitative data with multivariate and univariate linear mixed-effects models. We found no social or ecological benefits for partially protected areas relative to open areas in our study. Partially protected areas had no more fish, invertebrates, or algae than open areas; were poorly understood by coastal users; were not more attractive than open areas; and were not perceived to have better marine life than open areas. These findings provide an important counterpoint to some large-scale meta-analyses that conclude partially protected areas can be ecologically effective but that draw this conclusion based on narrower measures. We argue that partially protected areas act as red herrings in marine conservation because they create an illusion of protection and consume scarce conservation resources yet provide little or no social or ecological gain over open areas. Fully protected areas, by contrast, have more fish species and biomass and are well understood, supported, and valued by the public. They are perceived to have better marine life and be improving over time in keeping with actual ecological results. Conservation outcomes can be improved by upgrading partially protected areas to higher levels of protection including conversion to fully protected areas.  相似文献   
862.
Urban growth is a major threat to biodiversity conservation at the global scale. Its impacts are expected to be especially detrimental when it sprawls into the landscape and reaches sites of high conservation value due to the species and ecosystems they host, such as protected areas. I analyzed the degree of urbanization (i.e., urban cover and growth rate) from 2006 to 2015 in protected sites in the Natura 2000 network, which, according to the Habitats and Birds Directives, harbor species and habitats of high conservation concern in Europe. I used data on the degree of land imperviousness from COPERNICUS to calculate and compare urban covers and growth rates inside and outside Natura 2000. I also analyzed the relationships of urban cover and growth rates with a set of characteristics of Natura sites. Urban cover inside Natura 2000 was 10 times lower than outside (0.4% vs. 4%) throughout the European Union. However, the rates of urban growth were slightly higher inside than outside Natura 2000 (4.8% vs. 3.9%), which indicates an incipient urban sprawl inside the network. In general, Natura sites affected most by urbanization were those surrounded by densely populated areas (i.e., urban clusters) that had a low number of species or habitats of conservation concern, albeit some member states had high urban cover or growth rate or both in protected sites with a large number of species or habitats of high conservation value. Small Natura sites had more urban cover than large sites, but urban growth rates were highest in large Natura sites. Natura 2000 is protected against urbanization to some extent, but there is room for improvement. Member states must enact stricter legal protection and control law enforcement to halt urban sprawl into protected areas under the greatest pressure from urban sprawl (i.e., close to urban clusters). Such actions are particularly needed in Natura sites with high urban cover and growth rates and areas where urbanization is affecting small Natura sites of high conservation value, which are especially vulnerable and concentrated in the Mediterranean region.  相似文献   
863.
Government administered protected areas (PAs) have dominated conservation strategies, discourse, and research, yet private actors are increasingly managing land for conservation. Little is known about the social and environmental outcomes of these privately protected areas (PPAs). We searched the global literature in English on PPAs and their environmental and social outcomes and identified 412 articles suitable for inclusion. Research on PPAs was geographically skewed; more studies occurred in the United States. Environmental outcomes of PPAs were mostly positive (89%), but social outcomes of PPAs were reported less (12% of all studies), and these outcomes were more mixed (65% positive). Private protected areas increased the number or extent of ecosystems, ecoregions, or species covered by PAs (representativeness) and PA network connectivity and effectively reduced deforestation and restored degraded lands. Few PPA owners reported negative social outcomes, experienced improved social capital, increased property value, or a reduction in taxes. Local communities benefited from increased employment, training, and community-wide development (e.g., building of schools), but they reported reduced social capital and no significant difference to household income. The causal mechanisms through which PPAs influence social and environmental outcomes remain unclear, as does how political, economic, and social contexts shape these mechanisms. Future research should widen the geographical scope and diversify the types of PPAs studied and focus on determining the casual mechanisms through which PPA outcomes occur in different contexts. We propose an assessment framework that could be adopted to facilitate this process.  相似文献   
864.
Expansion of the global protected-area network has been proposed as a strategy to address threats from accelerating climate change and species extinction. A key step in increasing the effectiveness of such expansion is understanding how novel threats to biodiversity from climate change alter concepts such as rewilding, which have underpinned many proposals for large interconnected reserves. We reviewed potential challenges that climate change poses to rewilding and found that the conservation value of large protected areas persists under climate change. Nevertheless, more attention should be given to protection of microrefugia, macrorefugia, complete environmental gradients, and areas that connect current and future suitable climates and to maintaining ecosystem processes and stabilizing feedbacks via conservation strategies that are resilient to uncertainty regarding climate trends. Because a major element of the threat from climate change stems from its novel geographic patterns, we examined, as an example, the implications for climate-adaptation planning of latitudinal, longitudinal (continental to maritime), and elevational gradients in climate-change exposure across the Yellowstone-to-Yukon region, the locus of an iconic conservation proposal initially designed to conserve wide-ranging carnivore species. In addition to a continued emphasis on conserving intact landscapes, restoration of degraded low-elevation areas within the region is needed to capture sites important for landscape-level climate resilience. Extreme climate exposure projected for boreal North America suggests the need for ambitious goals for expansion of the protected-area network there to include refugia created by topography and ecological features, such as peatlands, whose conservation can also reduce emissions from carbon stored in soil. Qualitative understanding of underlying reserve design rules and the geography of climate-change exposure can strengthen the outcomes of inclusive regional planning processes that identify specific sites for protection.  相似文献   
865.
绿色服务作为促进绿色产业专业化、高端化、规范化发展的综合性服务业,是保障绿色产业持续健康发展的重要支撑。本文以《绿色产业指导目录》为依据,全面梳理1986年以来我国中央政府颁布的各类绿色服务政策,从政策演进、政策主体关系、文本类型、政策工具结构等方面对我国绿色服务政策进行量化分析。研究发现:(1)我国中央政府颁布的绿色服务政策数量及总力度都越来越大,绿色服务政策的制定已经渡过探索期,进入高质量发展的政策体系全面形成阶段;(2)政策主体牵涉广泛,部际合作现象明显且合作模式较为固定,整体上部际合作增强但又呈现出阶段性的发展特征;(3)政策类型多种多样,但不同形式的政策文件分布不均,多通知、公告类低效力文件,缺乏高效力文件;(4)政策客体结构较为完整,但行业分布不平衡;(5)总体上政策工具类型逐渐多样化,但过度重视管理,供给型、环境型、需求型三大政策工具间存在一定程度的失衡,具体表现为重环境,轻供给和需求。本文建议,应进一步加强部际协调和有效合作,平衡政策工具结构和政策的行业分布,完成绿色服务政策由量到质的升级发展。  相似文献   
866.
We coupled rainfall–runoff and instream water quality models to evaluate total suspended solids (TSS) in Wissahickon Creek, a mid‐sized urban stream near Philadelphia, Pennsylvania. Using stormwater runoff and instream field data, we calibrated the model at a subdaily scale and focused on storm responses. We demonstrate that treating event mean concentrations as a calibration parameter rather than a fixed input can substantially improve model performance. Urban stormwater TSS concentrations vary widely in time and space and are difficult to represent simply. Suspended and deposited sediment pose independent stressors to stream biota and model results suggest that both currently impair stream health in Wissahickon Creek. Retrofitting existing detention basins to prioritize infiltration reduced instream TSS loads by 20%, suggesting that infiltration mitigates sediment more effectively than detention. Infiltrating stormwater from 30% of the watershed reduced instream TSS loads by 47% and cut the frequency of TSS exceeding 100 mg/L by half. Settled loads and the frequency of high TSS values were reduced by a smaller fraction than suspended loads and duration at high TSS values. A widely distributed network of infiltration‐focused projects is an effective stormwater management strategy to mitigate sediment stress. Coupling rainfall–runoff and water quality models is an important way to integrate watershed‐wide impacts and evaluate how management directly affects urban stream health.  相似文献   
867.
采用超高效液相色谱-串联质谱仪分析了辽宁典型海域表层海水中14种在用化学农药(current use pesticides,CUPs)浓度水平,探讨了CUPs的可能来源,并评估其潜在生态风险.结果表明,辽宁典型海域表层海水中共检出7种CUPs,总浓度水平范围为16.7~176.1 ng·L-1,高值区域主要位于河流入海口,辽东湾西部海域CUPs检出浓度普遍高于黄海东北部海域.除草剂阿特拉津(atrazine)和杀菌剂三唑醇(triadimenol)在检出7种CUPs中占比最高,贡献率分别为56.0%和34.5%.源解析表明,6种CUPs可能来源于农田退水等径流输入和生产化学农药的工厂废水排放等,水果种植业则可能是单一组分乙草胺(acetochlor)的重要贡献源.除草剂阿特拉津和乙草胺对研究海域微藻存在中等-高风险,7种CUPs对无脊椎动物和鱼类的风险均处于较低水平.  相似文献   
868.
京津冀及周边大气污染综合立体观测网制定了38项观测标准技术规范,开展了高效的综合立体观测,解决了原有站点不足、观测零散、标准不一、要素不全、数据可比性差等问题;注重业务和科研相结合,提升了京津冀及周边地区(“2+26”城市)重污染过程中大气污染化学成分的快速监控能力,对区域空气质量宏观和中、微观演变特征进行动态监测与追踪.区域大气环境综合监测数据库和共享应用平台解决了多源大气环境数据缺乏归一质控、管理、分析和图形影像显示技术,缺乏统一、安全、稳定的数据采集、传输、核验、存储和共享业务化平台的问题,为生态环境部、地方政府和科研机构及研究人员提供全方位数据共享.   相似文献   
869.
分析了胜利浅海油田海洋环境保护的现状和存在的问题,并提出了加强海洋环保工作的对策.  相似文献   
870.
The aim of this work was to validate in the field certain measurement of the heart rate alterations of the bioindicator organism Mytilus galloprovicialis as a tool for ecotoxicological biomonitoring and assessment applications related to coastal and marine environment. The latter was determined by testing the mussels according to the method of functional loading (1-hour lowered salinity stress-exposure). The time of heart rate (HR) recovery (Trec) and the coefficient of HR variation (CVHR) in a group of tested animals were used as biomarkers for the assessment of their physiological state. It was found that the values of the biomarkers in mussels from our reference location were 1.3-1.5 times lower than in mussels from differently polluted coastal areas of the Bay. The study also included an investigation of the relationship between the mussel’s cardiac rhythm characteristics and the bioaccumulation of trace elements in their soft tissues, caused by chronic pollution. The conclusion was drawn that this approach to the physiological testing of mussels could be useful in developing a rapid and low-cost method for the assessment of the health of coastal 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