全文获取类型
收费全文 | 120篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 3篇 |
环保管理 | 13篇 |
综合类 | 29篇 |
基础理论 | 24篇 |
环境理论 | 1篇 |
污染及防治 | 31篇 |
评价与监测 | 12篇 |
社会与环境 | 5篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1967年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有123条查询结果,搜索用时 580 毫秒
41.
Triantafyllou AG Kiros ES Evagelopoulos VG 《Journal of the Air & Waste Management Association (1995)》2002,52(3):287-296
Continuous data of the concentration measurements of respirable suspended particulates (PM10, particles with aerodynamic diameter smaller than or equal to 10 pm) were analyzed. These measurements were carried out at an urban and nearby industrial location in northern Greece for the 5-year period 1996-2000. The time series concentration trend was examined, the seasonal and diurnal variations were identified, and the lognormality of the daily mean concentration data sets was tested. Over the 5-year data-gathering period, the days on which the U.S. Environmental Protection Agency (EPA) 24-hr PM10 standard was exceeded (episode days) were identified and their relation to prevailing synoptic-scale meteorological conditions was studied. The analysis led to useful information concerning the air quality levels, the contribution of the main pollution sources in this area, as well as some of the mechanisms that influence the PM10 concentrations. It also was proved that the measured PM10 concentrations are a result of a combination of processes including local anthropogenic sources, mesoscale transport, and resuspension. A complex system of sources and meteorological conditions modulate the heavy particulate pollution in the area of interest. 相似文献
42.
Despite widespread recognition that intersexual interactions shape reproductive strategies, studies of male competition do
not typically include effects imposed by females. In cannibalistic redback spiders, escalated fighting between rival suitors
is predicted, as males are unlikely to mate with more than one female, and strong first-male sperm precedence favours mating
with virgins. In staged competitions for matings between size mismatched rivals, smaller males adopted an alternative sneaking
strategy. However, despite initial agonistic interactions, larger males did not pursue or incapacitate smaller males. When
inter-male competition occurred, females struck at males frequently, although strikes were rarely seen when males courted
in the absence of a rival. After minimal fighting, larger males engaged in significant courtship (3 h) rather than killing
inferior rivals. Prolonged courtship was favoured by female behaviour, as males that attempted rapid copulation (smaller,
sneaking males) were cannibalised before mating was completed. This premature cannibalism significantly decreases paternity
in redback spiders. Thus, significant features of male competitive behaviour (i.e. prolonged courtship by larger males) may
be predicted with consideration of the female’s response to male reproductive strategies. Although the effect of females may
be more subtle in systems without the extreme reversed size-dimorphism of redbacks, these results suggest that female interests
should be explicitly considered when studying inter-male interactions. 相似文献
43.
Overview of temporary ponds in the Mediterranean region: threats, management and conservation issues 总被引:4,自引:0,他引:4
Zacharias I Dimitriou E Dekker A Dorsman E 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(1):1-9
Mediterranean temporary ponds (MTPs) comprise an endangered habitat with several endemic species that can be found in many countries, mainly in the Mediterranean region but are disappearing at a high rate. For designing optimal conservation and management strategies for the particular ecosystems, appropriate characterization and classification of these ponds is necessary based on the different type of habitats and on their varying environmental conditions. This paper presents the current ecological status and the threats of Mediterranean temporary ponds and summarizes some management and conservation issues based on the existing experience on a regional level. Emphasis is given in the Greek MTPs with respect to their characteristics and the pressures received mainly from human activities such as agriculture and water overexploitation. Restoration practices should be commenced immediately aiming at the reestablishment of the ponds' hydroperiod and water quality at the natural levels. 相似文献
44.
Elias Isaksson 《环境政策》2017,26(3):553-555
45.
Two different methods to predict biotic integrity were tested and compared in the present paper. The first one tries to predict the fish indices of biotic integrity (IBI) at the state or regional scale based on the most similar observations to a specific target site of interest using the simple to implement k-nearest neighbors (or kNN) method. Two different distance functions were considered to find the k-nearest neighbors: the Euclidean and the Mahalanobis. The second method was applied on the same datasets and consisted of a step-wise multiple regression. The two modeling approaches yielded similar results but kNN proved to be more time-efficient and very fast computationally for the given dataset sizes, which allowed applying a leave-one-out cross validation.In an attempt to reveal the importance of scale in the prediction of IBI, regression models were constructed at the state (or regional) scale and at the more refined cluster of sampling sites scale. Clusters of sites were extracted using Kohonen's self-organizing maps (SOM) followed by k-means clustering of the SOM neurons. Cluster-level regression models, constructed after site patterning, performed better in IBI prediction than global regression models constructed without any previous site patterning. The importance of identifying groups of sites with similar environmental characteristics affecting the IBI was revealed. The combined use of site patterning and regression modeling for IBI prediction also helped identifying important variables acting at the local scale which remain latent at the global scale. 相似文献
46.
Consistent effects of nitrogen fertilization on soil bacterial communities in contrasting systems 总被引:11,自引:0,他引:11
Ecosystems worldwide are receiving increasing amounts of reactive nitrogen (N) through anthropogenic activities. Although the effects of increased N inputs on plant communities have been reasonably well studied, few comparable studies have examined impacts on whole soil bacterial communities, though they play critical roles in ecosystem functioning. We sampled soils from two long-term ecological research (LTER) experimental N gradients, both of which have been amended with NH4NO3; a grassland at Cedar Creek (27 years of N additions) and an agricultural field at Kellogg Biological Station (8 years of N additions). By examining shifts in bacterial communities across these contrasting ecosystem types, we could test competing hypotheses about the direct and indirect factors that might drive bacterial responses to elevated N inputs. Bacterial community structure was highly responsive to N additions. We observed predictable and consistent changes in the structure of the bacterial communities across both ecosystem types. Our results suggest that bacterial communities across these gradients are more structured by N and/or soil carbon availability than by shifts in the plant community or soil pH associated with the elevated nitrogen inputs. In contrast to the pronounced shifts in bacterial community composition and in direct contrast to the patterns often observed in plant communities, increases in N availability did not have consistent effects on the richness and diversity of soil bacterial communities. 相似文献
47.
Brito Pedro Elias Marcos Silva-Neto Carlos Sujii Edison Silva Daniela Gonçalves Bruno Franceschinelli Edivani 《Environmental science and pollution research international》2020,27(31):38654-38661
Environmental Science and Pollution Research - The presence of Brazilian native bees can improve tomato production by increasing pollination effectiveness. However, the extensive use of pesticides... 相似文献
48.
Joris Koornneef Andrea Ramirez Toon van Harmelen Arjan van Horssen Wim Turkenburg Andre Faaij 《Atmospheric environment (Oxford, England : 1994)》2010,44(11):1369-1385
This study quantifies the trade-offs and synergies between climate and air quality policy objectives for the European power and heat (P&H) sector. An overview is presented of the expected performance data of CO2 capture systems implemented at P&H plants, and the expected emission of key air pollutants, being: SO2, NOX, NH3, volatile organic compounds (VOCs) and particulate matter (PM). The CO2 capture systems investigated include: post-combustion, oxyfuel combustion and pre-combustion capture.For all capture systems it was found that SO2, NOx and PM emissions are expected to be reduced or remain equal per unit of primary energy input compared to power plants without CO2 capture. Increase in primary energy input as a result of the energy penalty for CO2 capture may for some technologies and substances result in a net increase of emissions per kWh output. The emission of ammonia may increase by a factor of up to 45 per unit of primary energy input for post-combustion technologies. No data are available about the emission of VOCs from CO2 capture technologies.A simple model was developed and applied to analyse the impact of CO2 capture in the European P&H sector on the emission level of key air pollutants in 2030. Four scenarios were developed: one without CO2 capture and three with one dominantly implemented CO2 capture system, varying between: post-combustion, oxyfuel combustion and pre-combustion.The results showed a reduction in GHG emissions for the scenarios with CO2 capture compared to the baseline scenario between 12% and 20% in the EU 27 region in 2030. NOx emissions were 15% higher in the P&H sector in a scenario with predominantly post-combustion and lower when oxyfuel combustion (?16%) or pre-combustion (?20%) were implemented on a large scale. Large scale implementation of the post-combustion technology in 2030 may also result in significantly higher, i.e. increase by a factor of 28, NH3 emissions compared to scenarios with other CO2 capture options or without capture. SO2 emissions were very low for all scenarios that include large scale implementation of CO2 capture in 2030, i.e. a reduction varying between 27% and 41%. Particulate Matter emissions were found to be lower in the scenarios with CO2 capture. The scenario with implementation of the oxyfuel technology showed the lowest PM emissions followed by the scenario with a significant share allocated to pre-combustion, respectively ?59% and ?31%. The scenario with post-combustion capture resulted in PM emissions varying between 35% reduction and 26% increase. 相似文献
49.
Wetlands are sustaining large communities of people in Rwanda where 10 % of its land surface consists of many local wetlands. Sustainable future management of these numerous wetlands requires a reliable inventory of their location and a dynamic quantitative characterization that allows assessment of their climate change sensitivity. The aim of this study was to assess the importance of climatic factors for determining wetland location at different regional scales. Wetland locations were analyzed and statistically modeled using their location factors with logistic regression. Wetland location probability was determined using topographic (elevation, slope), hydrological (contributing area) and climatic (temperature and rainfall) location factors. A wetland location probability map was made that demonstrated a calibration accuracy of 87.9 % correct at national level compared to an existing inventory, displaying even better fits at subnational level (reaching up to 98 % correct). A validation accuracy of 86.2 % was obtained using an independently collected dataset. A sensitivity analysis was applied to the threshold values used as cutoff value between wetland/non-wetland, demonstrating a robust performance. The developed models were used in a sensitivity scenario analysis to assess future wetland location probability to changes in temperature and rainfall. In particular, wetlands in the central regions of Rwanda demonstrate a high sensitivity to changes in temperature (1 % increase causes a net probable wetland area decline by 12.4 %) and rainfall (+1 % causes a net increase by 1.6 %). This potentially significant impact on wetland number and location probability indicates that climate-sensitive future planning of wetland use is required in Rwanda. 相似文献
50.
Assessment of heavy metals in water samples and tissues of edible fish species from Awassa and Koka Rift Valley Lakes, Ethiopia 总被引:1,自引:0,他引:1
Larissa Dsikowitzky Mesfin Mengesha Elias Dadebo Carlos Eduardo Veiga de Carvalho Sven Sindern 《Environmental monitoring and assessment》2013,185(4):3117-3131
The Ethiopian Rift Valley Lakes host populations of edible fish species including Oreochromis niloticus, Labeobarbus intermedius and Clarias gariepinus, which are harvested also in other tropical countries. We investigated the occurrence of six heavy metals in tissues of these fish species as well as in the waters of Lake Koka and Lake Awassa. Both lakes are affected by industrial effluents in their catchments, making them ideal study sites. Mercury concentrations were very low in the water samples, but concentrations in the fish samples were relatively high, suggesting a particularly high bioaccumulation tendency as compared with the other investigated metals. Mercury was preferentially accumulated in the fish liver or muscle. It was the only metal with species-specific accumulation with highest levels found in the predatory species L. intermedius. Lower mercury concentrations in O. niloticus could be attributed to the lower trophic level, whereas mercury values in the predatory C. gariepinus were unexpectedly low. This probably relates to the high growth rate of this species resulting in biodilution of mercury. Accumulation of lead, selenium, chromium, arsenic and cadmium did not differ between species, indicating that these elements are not biomagnified in the food chain. Values of cadmium, selenium and arsenic were highest in fish livers, while lead and chromium levels were highest in the gills, which could be related to the uptake pathway. A significant impact of the industrial discharges on the occurrence of metals in the lakes could not be detected, and the respective concentrations in fish do not pose a public health hazard. 相似文献