全文获取类型
收费全文 | 1306篇 |
免费 | 31篇 |
国内免费 | 36篇 |
专业分类
安全科学 | 73篇 |
废物处理 | 3篇 |
环保管理 | 307篇 |
综合类 | 504篇 |
基础理论 | 201篇 |
环境理论 | 1篇 |
污染及防治 | 78篇 |
评价与监测 | 140篇 |
社会与环境 | 50篇 |
灾害及防治 | 16篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 12篇 |
2021年 | 30篇 |
2020年 | 58篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 33篇 |
2016年 | 43篇 |
2015年 | 31篇 |
2014年 | 55篇 |
2013年 | 49篇 |
2012年 | 45篇 |
2011年 | 84篇 |
2010年 | 49篇 |
2009年 | 102篇 |
2008年 | 80篇 |
2007年 | 78篇 |
2006年 | 72篇 |
2005年 | 50篇 |
2004年 | 41篇 |
2003年 | 60篇 |
2002年 | 47篇 |
2001年 | 34篇 |
2000年 | 46篇 |
1999年 | 40篇 |
1998年 | 28篇 |
1997年 | 18篇 |
1996年 | 17篇 |
1995年 | 22篇 |
1994年 | 13篇 |
1993年 | 20篇 |
1992年 | 16篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有1373条查询结果,搜索用时 15 毫秒
881.
Jessica Unda-Calvo Miren Martínez-Santos Estilita Ruiz-Romer Juan Luis Lechuga-Crespo 《环境科学学报(英文版)》2019,31(1):255-268
A better understanding of the effects of a number of environmental factors on denitrification is vital for analyzing its role as nitrogen sink and providing deeper knowledge about the ecological status of a nitrate-rich ecosystem. Since few studies have addressed the occurrence and implications of denitrification in river sediments, and complexity of interactions among all these environmental factors makes comprehension of the process difficult, the potential of sediments from the Deba River to attenuate nitrate excess through denitrification was investigated. For this purpose, we adapted an in vitro method to measure activities of two enzymes contributing to the entire multiple-step nitrate reduction: Nitrate Reductase and Nitrite Reductase. The environmental features that influence both or single enzymatic activities were identified as oxygen availability, regulated directly by the moisture content or indirectly through the aerobic respiration, organic matter and nitrate content of sediments, and electrical conductivity and exchangeable sodium percentage of water. Additionally, our results showed that Nitrate Reductase catalyzes the principal limiting step of denitrification in sediments. Therefore, taking this enzymatic activity as an indicator, the southern part of the Deba River catchment presented low potential to denitrify but nitrate-limited sediments, whereas the middle and northern parts were characterized by high denitrification potential but nitrate-rich sediments. In general, this study on denitrifying enzymatic activities in sediments evaluates the suitability of the management of the effluents from wastewater treatment plants and municipal sewages to ensure a good ecological status of the Deba River. 相似文献
882.
《Environmental Communication: A Journal of Nature and Culture》2013,7(4):411-427
Citizen participation is a recurrent and democratically important issue in the ongoing debate about climate change. However, different meanings are ascribed to citizen participation in different contexts, ranging from top-down involvement to bottom-up engagement, thus creating tension between conflicting ideals. Focusing on public engagement and its construal in different situational contexts, we explore how citizens are discursively included or excluded from participation, as various climate change discourses unfold in two forums where local needs and global concerns interact. Furthermore, we address some opportunities and barriers regarding citizen participation in climate change issues. 相似文献
883.
长荡湖生态环境现状及防治对策 总被引:5,自引:0,他引:5
长荡湖是太湖流域的重要湖泊之一,分析了引起该湖生态环境恶化的主要原因,提出控制污染源,减少污染物进入湖体的关键措施,采取压缩网网养殖规模,推广轮牧式养殖工艺,实施全年封草并培植沉水植物,防止长荡湖由草型湖泊向藻型湖泊的转变,逐步恢复长荡湖的生态环境。 相似文献
884.
885.
Dr. R. Harold Holbrook Jr Ann M. Krovoza Susan Schelley James E. Ferguson II 《黑龙江环境通报》1987,7(9):653-655
Anencephaly in twin B was accompanied by elevated amniotic fluid alpha-fetoprotein (AFP) and a positive acetylcholinesterase (AChE) band on gel electrophoresis in both twin sacs, although twin A was normal. AChE results did not help distinguish the false positive AFP in this set of twins, implying that AChE may diffuse transamniotically as has been previously postulated for AFP. In light of the low concordance rate for neural tube defects in twins, patient counselling in this situation must include the information that AFP and AChE may be falsely elevated in normal twin when the other twin has a neural tube defect. 相似文献
886.
Direct preparations and long-term cultures from a chorion villus biopsy, taken because of a known maternal additional marker chromosome, showed a 48,XX,+mar,+mar karyotype in all cells examined. The same karyotype was revealed in a subsequent amniotic fluid sample and in cord blood at delivery. Detailed examination of the child at delivery and at 1 year of age showed no evidence of phenotypic abnormality or developmental problems. 相似文献
887.
Preston BL 《Environmental management》2002,29(3):311-323
Understanding toxicant effects at higher levels of biological organization continues to be a challenge in ecotoxicology and
ecological risk assessment. This is due in part to a tradition in ecotoxicology of considering the direct effects of toxicants
on a limited number of model test species. However, the indirect effects of toxicity may be a significant factor influencing
the manner in which ecosystem structure and function respond to anthropogenic stressors. Subsequently, failure to incorporate
indirect effects into risk assessment paradigms may be a significant source of uncertainty in risk estimates. The current
paper addresses the importance of indirect effects in an ecotoxicological context. Laboratory, mesocosm, and whole ecosystem
research into indirect effects is reviewed. The implications of indirect effects for ecological risk assessment and potential
areas of profitable future research are also discussed. 相似文献
888.
Restoration,stewardship, environmental health,and policy: understanding stakeholders' perceptions 总被引:1,自引:0,他引:1
Burger J 《Environmental management》2002,30(5):0631-0640
In recent years there has been considerable interest in the health of humans and the environment, restoration of contaminated
or otherwise degraded lands, and in long-term stewardship of public lands. Unfortunately, it is unclear whether governmental
agencies and the public hold similar views about the meanings of these concepts, making policy decisions about restoration
and stewardship difficult. In this paper, I explore how the public conceptualizes restoration and stewardship by examining
the relative rating of several attributes of restoration, stewardship, environmental health, ecological health, environmental
restoration, and ecological restoration. People were interviewed in Santa Fe, New Mexico, USA, near the Department of Energy's
Los Alamos National Laboratory. The ratings of attributes of environmental health and ecological health reported in this paper
can be used to understand how the public understands these concepts. The attributes rated most highly by the subjects were
more similar to definitions in the scientific literature for these terms than they were to those used by the Department of
Energy. For environmental health, the highest rating related to human sanitation, while for ecological health the highest
rating was for maintaining functioning ecosystems. Reduction of exposure to hazardous substances was rated the second highest
for both environmental and ecological health. The wise use of natural resources, preservation of natural resources, and hazardous
waste site cleanup were rated the highest attributes of stewardship. These data suggest that both expert and nonexpert perceptions
about restoration and stewardship should be incorporated into environmental management decisions. 相似文献
889.
A procedure for incorporating spatial variability in ecological risk assessment of Dutch river floodplains 总被引:9,自引:0,他引:9
Floodplain soils along the river Rhine in the Netherlands show a large spatial variability in pollutant concentrations. For
an accurate ecological risk characterization of the river floodplains, this heterogeneity has to be included into the ecological
risk assessment. In this paper a procedure is presented that incorporates spatial components of exposure into the risk assessment
by linking geographical information systems (GIS) with models that estimate exposure for the most sensitive species of a floodplain.
The procedure uses readily available site-specific data and is applicable to a wide range of locations and floodplain management
scenarios. The procedure is applied to estimate exposure risks to metals for a typical foodweb in the Afferdensche and Deestsche
Waarden floodplain along the river Waal, the main branch of the Rhine in the Netherlands. Spatial variability of pollutants
is quantified by overlaying appropriate topographic and soil maps resulting in the definition of homogeneous pollution units.
Next to that, GIS is used to include foraging behavior of the exposed terrestrial organisms. Risk estimates from a probabilistic
exposure model were used to construct site-specific risk maps for the floodplain. Based on these maps, recommendations for
future management of the floodplain can be made that aim at both ecological rehabilitation and an optimal flood defense. 相似文献
890.