全文获取类型
收费全文 | 156篇 |
免费 | 8篇 |
国内免费 | 42篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 8篇 |
环保管理 | 32篇 |
综合类 | 96篇 |
基础理论 | 31篇 |
污染及防治 | 8篇 |
评价与监测 | 5篇 |
社会与环境 | 21篇 |
灾害及防治 | 3篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 10篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 15篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有206条查询结果,搜索用时 15 毫秒
61.
A Method for Improving the Management of Controversial Wetland 总被引:3,自引:0,他引:3
Merot P Hubert-Moy L Gascuel-Odoux C Clement B Durand P Baudry J Thenail C 《Environmental management》2006,37(2):258-270
Valley bottom wetlands in agricultural landscapes often are neglected in national and regional wetland inventories. Although
these areas are small, located in the bottomlands of the headwater catchments, and scattered in the rural landscape, they
strongly influence hydrology, water quality, and biodiversity over the whole catchment area. Valley bottom wetlands often
are considered as controversial wetlands. Awareness of the functional role of wetlands is increasing, in parallel with their
progressive disappearance in intensive farming landscapes. The need to improve tools for controlling wetland management is
a primary consideration for decision makers and land users. This article proposes a method for the inventory of valley bottom
wetlands. The method is based on the functional analysis of potential, existing, and efficient valley bottom wetlands (the
PEEW approach). Several indicators are proposed for checking the validity of such an approach. Potential wetlands are delineated
by means of a topographic index using topographic and pedoclimatic criteria computed from a Digital Elevation Model and easily
accessible databases. Existing wetlands are identified from observed surface moisture, the presence of specific wetland vegetation,
or soil feature criteria. Efficient wetlands are defined through a given function, such as flow or pollutant regulation or
biodiversity control. An analysis of areas at the limits between potential, existing, and efficient wetlands highlights land
cultivated or drained in the past, which currently represents negotiating areas in which rehabilitation and other intended
management actions can be implemented. 相似文献
62.
硫酸参与喀斯特流域(北盘江)风化过程的碳同位素证据 总被引:1,自引:0,他引:1
在碳酸盐岩地区,流域侵蚀过程中硫酸是否参与,对于我们正确理解流域化学风化速率,以及流域侵蚀对大气CO2的消耗和全球碳循环等都有重要的意义。本工作在前期工作(乌江)的基础上,对贵州喀斯特地区的河流(北盘江)和支流的水化学特征以及水体溶解无机碳同位素组成进行了初步研究,研究结果证实硫酸参与了该喀斯特流域岩石/土壤化学风化过程。 相似文献
63.
枯水期赣江流域氮磷的分布特征 总被引:1,自引:1,他引:0
于2006年1月对赣江流域地表水进行了系统采集,分析研究了水体中各形态氮磷含量分布特征,结果表明,赣江水体中主要的氮素形式是NO3--N,支流中以袁水NO3--N(2.57 mg/L)和TN(3.32 mg/L)含量最高,赣江中支NH4+-N(1.26 mg/L)和TP(0.07 mg/L)含量为全流域最大值。沿水流方向赣江主干流TN开始呈现明显下降趋势,而后又呈上升趋势。赣江流域从上游至下游NO3--N、TN有明显的上升趋势,NH4+-N变化趋势不是很明显,TP在中游处最低,下游比上游高。赣江水中三态无机氮处于较稳定的热力学平衡状态。 相似文献
64.
This paper invokes the theory of planned behavior (TPB) as a diagnostic tool to explain an existing public education program's limited success at improving river water quality in the City of Perth, Western Australia. A reflective, client-driven research approach was used. A facilitated expert workshop defined an environmental problem (excess nutrients leaving gardens and entering waterways) and a desired behavior (residents purchasing environmentally sensitive fertilizer) to address the problem. A TPB-based belief elicitation survey captured respondents' beliefs regarding the desired behavior. The findings suggest respondents were aware of the links between purchasing environmentally sensitive fertilizer and river water quality. However, this behavior is compromised by the challenges in identifying appropriate products, product quality concerns, and cost. Viewing the content of a public education program through the lens of the TPB reveals insights into how and why the program fell short in achieving one of its key behavioral change goals. 相似文献
65.
Changes in Forest Area Along Stream Networks in an Agricultural Catchment of the Great Barrier Reef Lagoon 总被引:2,自引:1,他引:1
Scenes from the series of multispectral sensors on the Landsat satellites were used to map recent changes (between 1972 and 2004) in forest cover within and adjacent to stream networks of an intensively farmed region of the southern Great Barrier Reef catchment (Australia). Unsupervised ISODATA classifications of Tasseled-Cap transformed data (at 57 m ground resolution) mapped forest and cleared areas within 150 m of Pisoneer catchment waterways with 72.2% overall accuracy (K(hat) = 0.469), when adjusted for the size of each class. Although the user's accuracy was higher for the forest class (82.1 +/- 8.4% at alpha = 0.05), large errors of commission (34.2 +/- 8.3%) substantially affected map accuracy for the cleared class. The main reasons for misclassification include: (1) failure to discriminate narrowly vegetated riparian strips; (2) misregistration of scenes; and (3) spectral similarity of ground cover. Error matrix probabilities were used to adjust the mapped area of classes, resulting in a decline of forest cover by 12.3% and increase of clearing by 18.5% (22.4 km(2) change; 95% confidence interval: 14.3-29.6 km(2)) between 1972 and 2004. Despite the mapping errors, Landsat data were able to identify broad patterns of land cover change that were verified from aerial photography. Most of the forest losses occurred in open forest to woodland habitat dominated by Eucalyptus, Corymbia, and Lophostemon species, which were largely replaced by sugarcane cropping. Melaleuca communities were similarly affected, though they have a much smaller distribution in the catchment. 相似文献
66.
67.
于桥水库周边农业小流域氮素流失浓度特征 总被引:6,自引:1,他引:6
选择天津市水源地于桥水库周边2个典型的农业小流域进行了长期的氮素流失研究.结果表明,地表径流的总氮浓度以村庄和果园为最高,平均浓度在20 mg·L-1左右;农田次之,山坡最低,平均浓度低于10 mg·L-1.亚表层流中氮素流失在不同地点和不同降雨事件中浓度有较大差异,总体趋势以果园最高,村庄中菜园次之,农田最低.在流域出口处.曹各庄流域地表径流总氮浓度达到18.5 m8·L-1,桃花寺流域出口处浓度为5.9 mg·L-1,流域内不同景观格局和迁移廊道地貌的差异是造成2个流域氮素流失浓度差异的主要原因.曹各庄流域中主要污染源村庄离水库较近(约200 m),且道路型季节性河流等性质特征对污染物的滞留能力较弱,增加了氮素流失到受纳水体的风险;桃花寺流域的污染源村庄和果园离受纳水体较远(约1500 m),氮素在季节性河流迁移过程中被小石坝、植被过滤带和干塘等"汇"型结构所滞留.从而降低了向水体迁移的风险. 相似文献
68.
Over-allocation of irrigation water has led to widespread environmental degradation in the Murray-Darling Basin (MDB) in Australia,
prompting discussions of the water efficiency performance of irrigated industries. There is increasing pressure for irrigators
to adopt water efficient practices in line with ecologically sustainable principles, especially with current drought conditions.
However, there is great uncertainty surrounding the available practices to improve irrigation efficiency from both ecological
and economic standpoints. This paper examines the economic and environmental impact of several possible water efficient practices
and government policies, using an interdisciplinary approach combining biophysical modelling and economic modelling. This
is done for the case-study of the Mooki catchment in the MDB, located in northern New South Wales, Australia. 相似文献
69.
Reduced emissions of acidifying pollutants have changed the acidification process, and as a result, forest soils and surface
waters are slowly recovering in Sweden. However, model calculations show that some areas may never recover completely unless
further measures, such as liming, are undertaken. Liming of surface waters (lakes, rivers and wetlands) has been successfully
practised in Sweden since the 1970s, but repeated treatments are necessary. A full recovery of acidified lakes and streams
without frequent liming is however not possible until soil acidification is reversed in the most strongly affected areas.
In this study, the recovery of acidified streams was examined using ‘the total catchment approach’ i.e. treatment of both
recharge and discharge areas. The aim was to compare the quantitative effect of different treatments on run off chemistry
and the recovery of brown trout. Catchments in southwest Sweden were treated with a combination of 2 tons of wood ash and
4, 6 or 12 tons of crushed limestone per hectare in 1998/1999. Treatment of both recharge and discharge areas resulted in
fast and significant changes in stream water quality, e.g. increased concentrations of calcium, higher pH and ANC and a decreased
concentration of inorganic aluminium. The initial changes were dependent on the distribution of the applied lime between discharge
and recharge areas rather than the average dose on the total catchment. Treatment of recharge areas only, resulted in smaller
but still significant effects on calcium, pH and ANC in stream water. Furthermore, there was an initial leaching of nitrate
but it was only minor compared with the elevated leaching that occurs after a clear-cut. As a result of the treatments, brown
trout is now successfully reproducing.
Olle Westling (deceased). 相似文献
70.
Analysis of the character and condition of each river style in Bega catchment, and their downstream patterns, are used to
provide a biophysical basis to prioritorize river management strategies. These reach-scale strategies are prioritorized within
an integrative catchment framework. Conserving near-intact sections of the catchment is the first priority. Second, those
parts of the catchment that have natural recovery potential are targeted. Finally, rehabilitation priorities are considered
for highly degraded reaches. At these sites, erosion and sedimentation problems may reflect irreversible changes to river
structure. 相似文献