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91.
To assess the health of aquatic organisms, biomarkers that measure changes at the biochemical level have been used as effective early warning tools in ecological risk assessment. In order to develop an integrated risk assessment strategy for the south coast of Portugal, mussels Mytilus galloprovincialis were collected from six sites along the coast with different organic contaminant characteristics. Additionally, an active biomonitoring approach was followed by transplanting indigenous mussels from site 4 to 6 and vice versa (from site 6 to 4) for 28 days. PAHs and PCBs contents were measured and the associated responses of phase I and phase II detoxification mechanisms evaluated by measuring cytochrome P450 and GST activities. GST activity was also determined on different tissues (gills, digestive gland, foot, mantle and gonads) of M. galloprovincialis and the impact of abiotic parameters (temperature, salinity, pH, conductivity and dissolved oxygen) on the GST activity assessed. Results indicate that CYP 450 follow the same pattern of PAHs and a direct relationship exist between CYP 450 and PAH levels from the different sites. Although there is a decrease between GST and PAHs concentrations it was not significant. The majority of the GST activity was in the gills and the digestive gland (around of 75% of the activity measured in all tissues) followed in decreasing order by the mantle, gonads. An inverse relationship between GST activity and salinity was detected along with temperature although not significant. These two biomarkers respond to changes of these two groups of compounds and to salinity especially for GST. In conclusion CYP 450 in mussels gives a reliable response as biomarker for organic contaminants in risk assessment in the South Coast of Portugal.  相似文献   
92.
Radionuclides from past uranium mining in rivers of Portugal   总被引:2,自引:0,他引:2  
During several decades and until a few years ago, uranium mines were exploited in the Centre of Portugal and wastewaters from uranium ore milling facilities were discharged into river basins. To investigate enhancement of radioactivity in freshwater ecosystems, radionuclides of uranium and thorium series were measured in water, sediments, suspended matter, and fish samples from the rivers Vouga, D?o, Távora and Mondego. The results show that these rivers carry sediments with relatively high naturally occurring radioactivity, and display relatively high concentrations of radon dissolved in water, which is typical of a uranium rich region. Riverbed sediments show enhanced concentrations of radionuclides in the mid-section of the Mondego River, a sign of past wastewater discharges from mining and milling works at Urgeiri?a confirmed by the enhanced values of (238)U/(232)Th radionuclide ratios in sediments. Radionuclide concentrations in water, suspended matter and freshwater fish from that section of Mondego are also enhanced in comparison with concentrations measured in other rivers. Based on current radionuclide concentrations in fish, regular consumption of freshwater species by local populations would add 0.032 mSv a(-1) of dose equivalent (1%) to the average background radiation dose. Therefore, it is concluded that current levels of enhanced radioactivity do not pose a significant radiological risk either to aquatic fauna or to freshwater fish consumers.  相似文献   
93.
94.
Fetal echocardiography was performed during the third trimester in a normal primigravida. The fetal heart was severely affected with the typical cardiac manifestations of Marfan syndrome. The medical history of the father was investigated and a mild form of the syndrome was diagnosed. The neonate died at 2 months of age of congestive heart failure.  相似文献   
95.

The high pollutant load of sanitary landfill leachates poses a huge challenge in the search for efficient and environment friendly solutions for their treatment. The objective of this work was to study an integrated solution of environmentally friendly technologies — immediate one-step lime precipitation (IOSLP), carbonation (CB), and phytoremediation (Phyt) — to treat a sanitary landfill leachate. In the leachate sample treatment by IOSLP, the influence of CaO concentration (18.2–33.3 gCaO L?1) and stirring time (2–60 min) on the sludge sedimentability and pollutant removal was studied. Organic load and ammonia nitrogen (AN) removal increases with CaO added, as well as sludge volume. Stirring time has a small influence on organic load and AN removal, presenting a minimum for sludge volume. Thus, the best operational conditions were chosen as 27.6 gCaO L?1, and 40-min stirring time, with 64% chemical oxygen demand (COD) removal. Sludge humidity was 2.1%, making dewatering needless. IOSLP supernatant was submitted to CB by atmospheric CO2, and 100% removals in AN and hardness were attained. Effluents from IOSLP and IOSLP?+?CB were utilized in Phyt tests, with Vetiver (Chrysopogon zizanioides (L.) Roberty). The best COD removal (37%) during Phyt was attained for the samples treated by IOSLP?+?CB.

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96.
Regional Environmental Change - Shrimps are an important and valuable fishing resource, being increasingly exploited worldwide, demanding appropriate management. However, factors such as how...  相似文献   
97.
Tropical coastal lagoons are highly productive environments exhibiting high biodiversity. However, the use of these ecosystems by local communities is of concern, since this generally leads to environmental degradation. The Imboassica coastal lagoon, located in Macaé city, in Northern Rio de Janeiro, is an important ecosystem in the state, however, already displaying signs of anthropogenic impacts. Carnivorous fish Hoplias malabaricus specimens were sampled from this impacted site, as well as from a reference area. Fish from Imboassica Lagoon presented lower condition factor, lower cholinesterase activity, and higher percentage of erythrocyte micronuclei when compared to fish from the reference site. Metals in fish from Imboassica Lagoon were always higher than Encantada Lagoon, with some seasonal differences, where some metals were higher in the rainy season compared to the dry season in muscle tissue, with the exception of Cu, Fe, Sr, and Zn; and in the liver, except for Ba, Cd, Cr, Ni, and Sr. Cr and Mn in the edible muscle portion of the fish were higher than the limits established by Brazilian and International legislations as permissible for human consumption, thus leading to concerns regarding public health risks for the local population that use fish as their main protein source.  相似文献   
98.
Environmental Science and Pollution Research - Perovskite oxides BaFeyTi1-yO3, with y = 0, 0.6, 0.8 and 1, were prepared by ceramic (CM) and complex polymerization methods (CPM) and utilized in...  相似文献   
99.
A study was conducted at three sampling regions along the Rio Negro and surrounding Puraquequara Lake, Amazonas, Brazil. The aim was to determine the influence of the local effects of climatic and hydrological variables on new malaria cases. Data was gathered on the river level, precipitation, air temperature, and the number of new cases of autochthonous malaria between January 2003 and December 2013. Monthly averages, time series decompositions, cross-correlations, and multiple regressions revealed different relationships at each location. The sampling region in the upper Rio Negro indicated no statistically significant results. However, monthly averages suggest that precipitation and air temperature correlate positively with the occurrence of new cases of malaria. In the mid Rio Negro and Puraquequara Lake, the river level positively correlated, and temperature negatively correlated with new transmissions, while precipitation correlated negatively in the mid Rio Negro and positively on the lake. Overall, the river level is a key variable affecting the formation of breeding sites, while precipitation may either develop or damage them. A negative temperature correlation is associated with the occurrence of new annual post-peak cases of malaria, when the monthly average exceeds 28.5 °C. This suggests that several factors contribute to the occurrence of new malaria cases as higher temperatures are reached at the same time as precipitation and the river levels are lowest. Differences between signals and correlation lags indicate that local characteristics have an impact on how different variables influence the disease vector’s life cycle, pathogens, and consequently, new cases of malaria.  相似文献   
100.
This work constitutes the first assessment of tributyltin (TBT) pollution levels in the Republic of Cabo Verde (Africa) and proposes the marine gastropod Gemophos viverratus (Kiener, 1834) as a new bioindicator of TBT pollution in the Macaronesia and west coast of Africa. Specimens were collected between August and October 2012 along a gradient of naval traffic in São Vicente Island. The results clearly indicate an increase of imposex levels (percentage of females affected with imposex, 0–100 %; vas deferens sequence index, 0–4.1; relative penis length index, 0–54.6 %) and female TBT contamination (from 5 to 37 ngSn g?1 dry weight (dw)) from outside to inside the harbour of Porto Grande Bay and identify this area as the focus of TBT pollution in the island. The butyltin degradation index for G. viverratus tissues ranged between 1.3 and 2.2, which being above 1 suggests that a considerable part of TBT inputs to the bay may not be very recent. Sterile females were found inside the harbour with an incidence up to 21.4 %. Considering the existence of a planktonic veliger stage in the life cycle of G. viverratus, it is expected that recruitment of newborn individuals can be supplied from unaffected breeding females inside and outside the Porto Grande Bay, resulting in a reduced impact of TBT pollution on population abundance. G. viverratus is very promising to be used as a simple, inexpensive and efficient novel tool for TBT pollution biomonitoring in the Macaronesia and west coast of Africa, a region for which there is an astonishing lack of information concerning levels and ecological impacts of TBT pollution.  相似文献   
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