全文获取类型
收费全文 | 562篇 |
免费 | 70篇 |
国内免费 | 199篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 6篇 |
环保管理 | 73篇 |
综合类 | 547篇 |
基础理论 | 89篇 |
污染及防治 | 24篇 |
评价与监测 | 56篇 |
社会与环境 | 25篇 |
灾害及防治 | 9篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 23篇 |
2018年 | 21篇 |
2017年 | 16篇 |
2016年 | 21篇 |
2015年 | 28篇 |
2014年 | 29篇 |
2013年 | 57篇 |
2012年 | 64篇 |
2011年 | 65篇 |
2010年 | 47篇 |
2009年 | 45篇 |
2008年 | 36篇 |
2007年 | 53篇 |
2006年 | 50篇 |
2005年 | 29篇 |
2004年 | 35篇 |
2003年 | 28篇 |
2002年 | 19篇 |
2001年 | 17篇 |
2000年 | 11篇 |
1999年 | 16篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有831条查询结果,搜索用时 31 毫秒
81.
胶州湾入海污染物总量控制研究 总被引:5,自引:3,他引:5
在胶州湾水质数值模拟的基础上,建立了污染物总量控制模型.计算了各个点源的响应系数,分担率及环境容量.结果表明,胶州湾内COD各入海污染源均有余量,不需要削减.胶州湾东北部N、P污染较严重,污染物入海总量已经超过海域的环境容量.研究结果将为胶州湾污水排海、海域水质管理、总量控制规划编制提供科学依据. 相似文献
82.
83.
84.
85.
Quantifying and Evaluating Ecosystem Health: A Case Study from Moreton Bay, Australia 总被引:1,自引:0,他引:1
As part of the program monitoring the ecosystem health of Moreton Bay, Queensland, Australia, we developed a means for assessing
ecosystem health that allows quantitative evaluation and spatial representations of the assessments. The management objectives
for achieving ecosystem health were grouped into ecosystem objectives, water quality objectives, and human health objectives.
For the first two groups, aspects of the ecosystem (e.g., trophic status) were identified, and an indicator was chosen for
each aspect. Reference values for each indicator were derived from management objectives and compared with the mapped survey
values. Subregions for which the indicator statistic was equal to or better than the assigned reference value are referred
to as “compliant zones.” High-resolution surface maps were created from spatial predictions on a fine hexagonal grid for each
of the indicators. Eight reporting subregions were established based on the depth and predicted residence times of the water.
Within each reporting subregion, the proportion that was compliant was calculated. These results then were averaged to create
an integrated ecosystem health index. The ratings by a team of ecosystem experts and the calculated ecosystem health indices
had good correspondence, providing assurance that the approach was internally consistent, and that the management objectives
covered the relevant biologic issues for the region. This method of calculating and mapping ecosystem health, relating it
directly to management objectives, may have widespread applicability for ecosystem assessment. 相似文献
86.
Environmental changes in Sepetiba Bay,SE Brazil 总被引:2,自引:0,他引:2
M.?M.?Molisani R.?V.?Marins W.?Machado H.?H.?M.?Paraquetti E.?D.?Bidone L.?D.?LacerdaEmail author 《Regional Environmental Change》2004,4(1):17-27
Sepetiba Bay is an example of an aquatic environment that has been severely impacted by human occupation and industrial activities in its basin. Some 400 industries including metallurgical, petrochemical and pyrometallurgical smelters, which emitted pollutants to air, soil and water, were established in Sepetiba Basin during the past 30 years. Apart from these point sources, changes in land use have also resulted in a large remobilization of pollutant deposition on Sepetiba Bay Basin. Studies have pointed out significant changes in sedimentation rates, concentrations of inorganic pollutants (Zn, Cd, Pb and Hg) and more recently, eutrophication, pointing to this area as an example of an impacted coastal zone. Notwithstanding local sources, Sepetiba Bay also suffers environmental impacts caused by diversion of river waters from adjacent basins, with some 30% of the total Hg flux to Sepetiba Bay and a 10-fold increase in water and sediment fluxes resulting from this. Decreasing environmental quality compromises both the large biodiversity and the potential economic uses of Sepetiba Bay, including fisheries and tourism. Monitoring of heavy metal levels in organisms (algae, mollusks, crustaceans and oysters) often shows concentrations well above the limits allowed following Brazilian legislation for food quality. Historical evolution of these concentrations suggests a worsening of the situation. Failure to monitor the effect of land-based activities, including those from other basins artificially associated with Sepetiba Bay has resulted in poor scenario construction and proper management planning. 相似文献
87.
Monitoring of eutrophication and nutrient limitation in the Izmir Bay (Turkey) before and after Wastewater Treatment Plant 总被引:3,自引:0,他引:3
The distribution of inorganic nutrients and phytoplankton chlorophyll-a was investigated and N/P ratios were determined in Izmir Bay during 1996-2001. The average concentrations showed ranges of 0.01-0.19 and 0.01-10 microM for phosphate-phosphorus; 0.11-1.8 and 0.13-27 microM for (nitrate+nitrite)-nitrogen, 0.30-4.1 and 0.50-39 microM for silicate and 0.02-4.3 and 0.10-26 microg l(-1) for chlorophyll-a in the outer and middle-inner bays, respectively. The results are compared with the values obtained from the relatively unpolluted waters of the Aegean Sea. The N/P ratio is significantly lower than the assimilatory optimal (N/P=15:1) in conformity with Redfield's ratio N/P=16:1. Nitrogen is the limiting element in the Izmir Bay. Phosphate, which originates from detergents, is an important source for eutrophication in the bay, especially in the inner bay. In early 2000, a Wastewater Treatment Plant (WTP) began to treat domestic and industrial wastes. This plant treats the wastes about 60% capacity between 2000 and 2001. The sampling periods cover before and after treatment plant. Although the capacity of wastewater plant is sufficient for removal of nitrogen from the wastes, it is inadequate for removal of phosphate. This is also in accordance with the decreasing N/P ratios observed during 2000-2001 (after WTP) in the middle-inner bays. 相似文献
88.
89.
90.