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   9708篇
  免费   6篇
  国内免费   2篇
安全科学   4篇
废物处理   770篇
环保管理   1224篇
综合类   939篇
基础理论   3135篇
污染及防治   1741篇
评价与监测   1004篇
社会与环境   897篇
灾害及防治   2篇
  2023年   2篇
  2022年   4篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1474篇
  2017年   1374篇
  2016年   1196篇
  2015年   129篇
  2014年   14篇
  2013年   11篇
  2012年   464篇
  2011年   1341篇
  2010年   693篇
  2009年   597篇
  2008年   878篇
  2007年   1232篇
  2006年   6篇
  2005年   23篇
  2004年   34篇
  2003年   66篇
  2002年   101篇
  2001年   16篇
  2000年   11篇
  1999年   3篇
  1998年   13篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1991年   1篇
  1988年   1篇
  1984年   11篇
  1983年   9篇
  1969年   1篇
  1935年   2篇
排序方式: 共有9716条查询结果,搜索用时 15 毫秒
981.
Assmuth T 《Ambio》2011,40(2):158-169
Policy and research issues in the framing and qualities of uncertainties in risks are analyzed, based on the assessments of dioxin-like compounds (DLCs) and other ingredients in Baltic Sea fish, a high-profile case of governance. Risks are framed broadly, to then focus on dioxins and beneficial fatty acids, fish consumption, human health, and science-management links. Hierarchies of uncertainty (data, model, decision rule, and epistemic) and ambiguity (of values) are used to identify issues of scientific and policy contestation and opportunities for resolving them. The associated complexity of risks is illustrated by risk–benefit analyses of fish consumption and by evaluations of guideline values, highlighting value contents and policy factors in presumably scientific decision criteria, and arguments used in multi-dimensional risk and benefit comparisons. These comparisons pose challenges to narrow assessments centered, for e.g., on toxicants or on food benefits, and to more many-sided and balanced risk communication and management. It is shown that structured and contextualized treatment of uncertainties and ambiguities in a reflexive approach can inform balances between wide and narrow focus, detail and generality, and evidence and precaution.  相似文献   
982.
983.
Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic Sweden. We recorded the change in coverage of shrub and tree species over a 32– to 34-year period, in three 50 × 50 m plots; in the alpine-tree-line ecotone. The cover of shrubs and trees (<3.5 cm diameter at breast height) were estimated during 2009–2010 and compared with historical documentation from 1976 to 1977. Similarly, all tree stems (≥3.5 cm) were noted and positions determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory.  相似文献   
984.
This study was conducted in the Swedish sub-Arctic, near Abisko, in order to assess the direction and scale of possible vegetation changes in the alpine–birch forest ecotone. We have re-surveyed shrub, tree and vegetation data at 549 plots grouped into 61 clusters. The plots were originally surveyed in 1997 and re-surveyed in 2010. Our study is unique for the area as we have quantitatively estimated a 19% increase in tree biomass mainly within the existing birch forest. We also found significant increases in the cover of two vegetation types—“birch forest-heath with mosses” and “meadow with low herbs”, while the cover of snowbed vegetation decreased significantly. The vegetation changes might be caused by climate, herbivory and past human impact but irrespective of the causes, the observed transition of the vegetation will have substantial effects on the mountain ecosystems.  相似文献   
985.

Introduction  

Effluent organic matter from biological wastewater treatment plants is composed of degradation products and soluble microbial products (SMP). Protein, polysaccharide, humic acid, and DNA were major biomolecules of SMP. Little is known about the effects of SMP as microbially derived precursors on disinfection byproduct formation and speciation in biologically treated wastewater. In addition, there has never been any attempt to directly chlorinate the major biomolecules of SMP.  相似文献   
986.

Introduction  

The present study was part of a comprehensive weight-of-evidence approach with the goal of identifying potential causes for the declines in fish populations, which have been observed during the past decades in the Upper Danube River.  相似文献   
987.

Purpose  

Birds have been used successfully for biomonitoring of the levels and effects of persistent organic pollutants (POPs) in the environments; however, there is exceedingly little data on organochlorinated pesticide (OCPs) and polychlorinated biphenyls (PCBs) residues in bird inhabiting in China. In the present study, we detected the concentrations of PCBs, dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorocyclohexanes (HCHs) in muscle, liver and kidney of birds that inhabit in an e-waste recycling site. Associated with the stable isotope ratio (δ 15N), we investigated the effect of trophic level on the body burdens of persistent contaminants in birds. The tissue distributions of contaminants in these birds were examined, and a preliminary risk assessment was also conducted.  相似文献   
988.

Introduction  

A Microcoleus sp. consortium, obtained from the Ebro delta microbial mat, was maintained under different conditions including uncontaminated, lead-contaminated, and acidic conditions.  相似文献   
989.

Purpose  

The dyes and dye stuffs present in effluents released from textile dyeing industries are potentially mutagenic and carcinogenic. Phytoremediation technology can be used for remediating sites contaminated with such textile dyeing effluents. The purpose of the work was to explore the potential of Glandularia pulchella (Sweet) Tronc. to decolorize different textile dyes, textile dyeing effluent, and synthetic mixture of dyes.  相似文献   
990.

Purpose  

Chitosan membranes (non-crosslinked, crosslinked, and modified with l-cysteine) were evaluated as sorbents prior to electrothermal atomic absorption spectrometry (ETAAS) determination of total dissolved metal content in surface water samples.  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