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111.
Food Security in the Face of Climate Change,Population Growth,and Resource Constraints: Implications for Bangladesh 总被引:1,自引:0,他引:1
Ensuring food security has been one of the major national priorities of Bangladesh since its independence in 1971. Now, this national priority is facing new challenges from the possible impacts of climate change in addition to the already existing threats from rapid population growth, declining availability of cultivable land, and inadequate access to water in the dry season. In this backdrop, this paper has examined the nature and magnitude of these threats for the benchmark years of 2030 and 2050. It has been shown that the overall impact of climate change on the production of food grains in Bangladesh would probably be small in 2030. This is due to the strong positive impact of CO2 fertilization that would compensate for the negative impacts of higher temperature and sea level rise. In 2050, the negative impacts of climate change might become noticeable: production of rice and wheat might drop by 8% and 32%, respectively. However, rice would be less affected by climate change compared to wheat, which is more sensitive to a change in temperature. Based on the population projections and analysis of future agronomic innovations, this study further shows that the availability of cultivable land alone would not be a constraint for achieving food self-sufficiency, provided that the productivity of rice and wheat grows at a rate of 10% or more per decade. However, the situation would be more critical in terms of water availability. If the dry season water availability does not decline from the 1990 level of about 100 Bm3, there would be just enough water in 2030 for meeting both the agricultural and nonagricultural needs. In 2050, the demand for irrigation water to maintain food self-sufficiency would be about 40% to 50% of the dry season water availability. Meeting such a high agricultural water demand might cause significant negative impacts on the domestic and commercial water supply, fisheries, ecosystems, navigation, and salinity management. 相似文献
112.
The results of analyses for polychlorodibenzofuran (PCDF) content in two samples of polychlorobiphenyl (PCB) from used electrical transformers are presented and discussed. In neither sample was there evidence for enhanced PCDF concentrations even though one of them had been subjected to overheating while in service. 相似文献
113.
Results of analyses of eight samples of technical pentachlorophenol conducted by three different analytical methods are presented and discussed. 相似文献
114.
M. Masudul Hassan M. Rabiul Islam Mubarak A. Khan 《Journal of Polymers and the Environment》2002,10(4):139-145
The jute yarn was grafted with acrylamide monomer (AA) under ultraviolet (UV) radiation to modify its mechanical and degradable properties. A number of AA solutions of different concentrations in methanol (MeOH) along with photoinitiator Irgacure 907 [2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone-1] were prepared. The monomer concentration and irradiation time were optimized. Jute yarn grafted with 30% AA under UV radiation for 60 min showed of the highest polymer loading (PL) value of 22% with a enhanced tensile strength (TS) value of 195% and elongation at break (Eb) value of 256% compared to untreated jute yarn. To further improve the properties of jute yarn, a number of additives (1%) such as urea, polyvinylpyrrolidone, urethane acrylate, and urethane diacrylate were used in the AA (30%) solution. Among all the additives used, urea significantly influenced the PL (27%), TS (230%), and Eb (264%) values of the treated jute yarns. Water uptake and the degradation properties of treated and untreated jute yarn caused by simulated weathering and in soil (25% water) were also studied. The rate of degradation of grafted sample is lower then that of untreated sample. DSC studies showed the thermal stability of the AA plus urea grafted sample. 相似文献
115.
Biswas SK Tarafdar SA Islam A Khaliquzzaman M Tervahattu H Kupiainen K 《Journal of the Air & Waste Management Association (1995)》2003,53(11):1355-1362
Airborne particulate matter (APM) samples collected at a semiresidential area in Dhaka, Bangladesh, during the periods of 1994 and 1997-2000 have been studied to assess the impact of the use of unleaded gasoline in Bangladesh. According to scanning electron microscopy/ energy-dispersive X-ray microanalyzer studies, lead (Pb) was found as Pb sulfates and Pb halides in motor-vehicle exhaust particles, whose diameters were some hundreds of nanometers. No significant changes in the annual averages of APM mass and black carbon concentrations have been observed over the period. The yearly average Pb concentration reached a maximum value of 370 ng/m3 in the particulate matter with an aerodynamic diameter < 2.5 microm fraction in 1998. In 2000, the concentration decreased to approximately one-third (106 ng/m3) of the high earlier values after the introduction of unleaded gasoline in 1999. A significant lowering of the blood Pb level of the population over next few years is expected as a result of this great decrease in Pb concentration. 相似文献
116.
A pot experiment was conducted to explore a more effective approach to enhancing vegetable uptake of soil iodine, with the
ultimate goal of using agricultural fortification as a measure to prevent iodine deficiency disorders in local communities.
Two types of iodine fertilizers were added separately to pot soil samples at various dosages. The fortified soil in each of
the flower pots was seeded with one of four test crops (pakchoi, celery, pepper, and radish) in an effort to examine the effect
of vegetable cultivation. The fate and residual levels of the exogenous iodine in the fortified soil samples were then monitored
and quantified. The data showed that the soil iodine contents decreased with time (and hence with plant growth as well). At
the second cutting, iodine from the inorganic form (KI) as the exogenous source was reduced to approximately 50% (41.6–61.0%)
of the applied dose, whereas that in soil fortified with the seaweed fertilizer was down to approximately 60% (53.9–71.5%).
The abilities of the edible portion of the four vegetables in accumulating the soil iodine were as follows: pakchoi > celery > radish > pepper.
On the whole, iodine residues were found less in soil cultivated with vegetables. Vegetable cultivation appeared to have enhanced
the soil content of the water-soluble form of iodine somewhat, especially in soil fortified with the inorganic forms. There
also appeared to be a significant negative correlation between the residual iodine and its dissolution rate in soil. Overall,
the results of the present study pointed toward the direction that the seaweed fertilizer tends to be a (more) preferred source
of agricultural fortification in promoting human iodine nutrition. 相似文献
117.
Md. Kawser Ahmed Elora Parvin Md. Monirul Islam Mosammat Salma Akter Shahneawz Khan Md. Habibullah Al-Mamun 《Chemistry and Ecology》2014,30(6):532-540
The objective of this study was to examine the toxicological effect of two major heavy metal pollutants, lead chloride (PbCl2) and cadmium chloride (CdCl2), in the freshwater climbing perch, Anabas testudineus. Fish were exposed to 1.0 and 2.0 mg/L both metals and histopathological changes in gill, kidney and liver tissues were studied. Major changes observed in gill tissue were epithelial lifting, proliferation of epithelial cells, fusion of secondary lamellae, hyperplasia and hypertrophy of mucous cells, and necrosis of epithelial cells. Cell necrosis, degenerated kidney tubules, congestion, lymphocytic infiltration and vacuolation were the major abnormalities observed in kidney tissue. The most conspicuous changes in liver were darker nucleoli, irregularly shaped hepatocytes with dilated blood capillaries, and focal as well as single necrosis. Fish specimens exposed to PbCl2 exhibited pronounced changes in all tissues examined compared with those exposed to CdCl2. It is evident from this study that heavy metals can cause significant histopathological changes in fish tissue. 相似文献
118.
Islam Muhammad Saiful Hasan Md. Rashed Islam Zahidul 《Environmental science and pollution research international》2023,30(8):19994-20005
Environmental Science and Pollution Research - Microplastics (MPs), together with microfibers, have emerged as a contaminant of concern all around the globe. MPs have been detected in freshwater,... 相似文献
119.
Previous research showed a regional Cu enrichment of 6 mg kg−1 in the top soil of the Ypres war zone (Belgium), caused by corrosion of WWI shell fragments. Further research was required
since in addition to Cu, also As, Pb, and Zn were used during the manufacturing of ammunition. Therefore, an additional data
collection was conducted in which the initial Cu data set was tripled to 731 data points and extended to eight heavy metals
(As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) which permitted (1) to evaluate the environmental impact of the heavy metals at a regional
scale and (2) to assess their regional spatial occurrence by performing an optimized geostatistical modeling. The results
showed no pollution at a regional scale, but sometimes locally concentrations exceeded the soil sanitation threshold, especially
for Cu, Pb, and Zn. The spatial patterns of Ni and Cr were related to variations in soil texture whereas the occurrences of
Cu and Pb were clearly linked to WWI activities. This difference in spatial behavior was confirmed by an analysis of coregionalization. 相似文献
120.
Islam MR Joardder MU Hasan SM Takai K Haniu H 《Waste management (New York, N.Y.)》2011,31(9-10):2142-2149
In this study on the basis of lab data and available resources in Bangladesh, feasibility study has been carried out for pyrolysis process converting solid tire wastes into pyrolysis oils, solid char and gases. The process considered for detailed analysis was fixed-bed fire-tube heating pyrolysis reactor system. The comparative techno-economic assessment was carried out in US$ for three different sizes plants: medium commercial scale (144 tons/day), small commercial scale (36 tons/day), pilot scale (3.6 tons/day). The assessment showed that medium commercial scale plant was economically feasible, with the lowest unit production cost than small commercial and pilot scale plants for the production of crude pyrolysis oil that could be used as boiler fuel oil and for the production of upgraded liquid-products. 相似文献