全文获取类型
收费全文 | 234篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 29篇 |
废物处理 | 6篇 |
环保管理 | 76篇 |
综合类 | 31篇 |
基础理论 | 43篇 |
环境理论 | 1篇 |
污染及防治 | 29篇 |
评价与监测 | 15篇 |
社会与环境 | 4篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 14篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 7篇 |
2009年 | 14篇 |
2008年 | 15篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有238条查询结果,搜索用时 492 毫秒
121.
Differential Assessment of Designations of Wetland Status Using Two Delineation Methods 总被引:1,自引:0,他引:1
Two different methods are commonly used to delineate and characterize wetlands. The U.S. Army Corps of Engineers (ACOE) delineation method uses field observation of hydrology, soils, and vegetation. The U.S. Fish and Wildlife Service’s National Wetland Inventory Program (NWI) relies on remote sensing and photointerpretation. This study compared designations of wetland status at selected study sites using both methods. Twenty wetlands from the Wetland Boundaries Map of the Ausable–Boquet River Basin (created using the revised NWI method) in the Ausable River watershed in Essex and Clinton Counties, NY, were selected for this study. Sampling sites within and beyond the NWI wetland boundaries were selected. During the summers of 2008 and 2009, wetland hydrology, soils, and vegetation were examined for wetland indicators following the methods described in the ACOE delineation manual. The study shows that the two methods agree at 78 % of the sampling sites and disagree at 22 % of the sites. Ninety percent of the sampling locations within the wetland boundaries on the NWI maps were categorized as ACOE wetlands with all three ACOE wetland indicators present. A binary linear logistic regression model analyzed the relationship between the designations of the two methods. The outcome of the model indicates that 83 % of the time, the two wetland designation methods agree. When discrepancies are found, it is the presence or absence of wetland hydrology and vegetation that causes the differences in delineation. 相似文献
122.
123.
Clausen CA 《Waste management (New York, N.Y.)》2004,24(4):407-411
Remediation processes for recovery and reuse of chromated-copper-arsenate- (CCA) treated wood are not gaining wide acceptance because they are more expensive than landfill disposal. One reason is the high cost of the nutrient medium used to culture the metal-tolerant bacterium, Bacillus licheniformis, which removes 70-100% of the copper, chromium, and arsenic from CCA-treated southern yellow pine (CCA-SYP) in a two-step process involving oxalic acid extraction and bacterial culture. To reduce this cost, the nutrient concentration in the culture medium and the ratio of wood to nutrient medium were optimized. Maximum metal removal occurred when B. licheniformis was cultured in 1.0% nutrient medium and at a wood to nutrient medium ratio of 1:10. Also, malted barley, an abundant by-product of brewing, was evaluated as an alternative nutrient medium. Tests were done to determine absorption of metals by barley, and the results indicate that the barley acted as a biosorbent, removing heavy metals from the liquid culture after their release from CCA to SYP. For comparison, tests were also performed with no nutrient medium. Following bacterial remediation, 17% copper and 15% arsenic were removed from an aqueous slurry of CCA-SYP (no medium). When oxalic acid extraction preceded the aqueous bacterial culture, 21% copper, 54% chromium, and 63% arsenic were removed. The two-step process (oxalic acid extraction and bacterial culture with nutrient medium) appears to be an effective, yet costly, way to remove metals. 相似文献
124.
The use of seaweed as an agricultural soil conditioner gives rise to a potential pathway for the transfer of Technetium-99 ((99)Tc) from marine to terrestrial ecosystems and thence to man. However, to date there is little information on the extent of the release of (99)Tc from seaweed into soil and the mechanisms involved. This pot experiment has shown that (99)Tc is released fairly rapidly from Fucus vesiculosus into a sandy coastal soil. Despite low temperature conditions, 60% of the (99)Tc added with the seaweed had accumulated in the soil 15 weeks after addition. Concurrent CO(2) monitoring (used as a measure of microbial decomposition or catabolism) suggested that the initial (99)Tc release (up to 40% in the first 8 weeks) was due to leaching from the seaweed and that microbial decomposition was responsible for the release of the remaining (99)Tc in the latter phase (12-15 weeks). 相似文献
125.
126.
Thomas E. Croley Carol L. Luukkonen 《Journal of the American Water Resources Association》2003,39(1):149-163
ABSTRACT: Computer simulations involving general circulation models, a hydrologic modeling system, and a ground water flow model indicate potential impacts of selected climate change projections on ground water levels in the Lansing, Michigan, area. General circulation models developed by the Canadian Climate Centre and the Hadley Centre generated meteorology estimates for 1961 through 1990 (as a reference condition) and for the 20 years centered on 2030 (as a changed climate condition). Using these meteorology estimates, the Great Lakes Environmental Research Laboratory's hydrologic modeling system produced corresponding period streamflow simulations. Ground water recharge was estimated from the streamflow simulations and from variables derived from the general circulation models. The U.S. Geological Survey developed a numerical ground water flow model of the Saginaw and glacial aquifers in the Tri‐County region surrounding Lansing, Michigan. Model simulations, using the ground water recharge estimates, indicate changes in ground water levels. Within the Lansing area, simulated ground water levels in the Saginaw aquifer declined under the Canadian predictions and increased under the Hadley. 相似文献
127.
128.
129.
Carol A. Bloomgarden 《Environmental management》1995,19(5):641-648
Anthropogenic climate climate change presents a unique challenge for endangered species policy and an opportunity for policy
makers to develop a more predictive and robust approach to preserving the nation's biological resources. Biological and ecological
reactions to shifting climate conditions and the potential feedbacks and synergistic effects of such changes may threaten
the well-being of many species, particularly of those already in jeopardy of extinction. The United States Endangered Species
Act of 1973 will fail to keep pace with increasing numbers of species needing protection as long as it remains focused on
protecting species individually. The actmust not be abandoned, however; it holds tremendous promise for preserving biological diversity through a more proactive, anticipatory
perspective. The current Endangered Species Act should be reinforced and improved by better integration of scientific expertise
into habitat and community preservation listing decisions and recovery plan devlopment. Given the uncertainties surrounding
long-term environmental consequences of human activities and resource use, a longer-term perspective must be integrated into
all efforts to protect our biotic resources.
Under appointment from the Graduate Fellowships for Global Change administered by the Oak Ridge Institute for Science and
Ecducation for the US Department of Energy. 相似文献
130.
Quality control is a crucial aspect of database management, particularly for physicochemical parameters that are widely used
in modeling environmental fate processes. Complete rechecking of original studies to verify environmental fate parameters
is time consuming and difficult. This paper evaluates an alternative, more efficient approach to identifying database errors.
The approach focuses verification efforts on a targeted subset of entries by making use of the relationship between water
solubility (S) and soil organic carbon partition coefficient (K
oc
). Two regression equations, one selected from the literature and one calculated from entries in the database, were used to
evaluate the reasonableness of (S, K
oc
) pairs among control compared to the targeted outlier group from a total of 59 pesticides. Our hypothesis was that (S, K
oc
) pairs that lay far from the regression line were more likely to be in error than those that fit the regression. Database
values were checked against original studies.
Identified errors in the database included coding mistakes, miscalculations, and incorrect chemical identification codes.
The error rate in outlier (S, K
oc
) pairs was about twice that of pairs that conformed to the regression equation; however, the error rate differential was
probably not large enough to justify the use of this quality control method. Through our close scrutiny of database entries
we were able to identify administrative practices that led to mistakes in the data base. Resolution of these problems will
significantly decrease the number of future mistakes. 相似文献