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41.
The effects of the ellagic acid on the in vitro and in vivo acetylation of 2‐aminofluorene were investigated in male Sprague‐Dawley rats. For in vitro examination, cytosols with or without ellagic acid co‐treatment showed different percentage of 2‐aminofluorene acetylation. For in vivo examination, pre‐treatment of male rats with ellagic acid (10 mg/kg) 24h prior to the administration of 2‐aminofluorene (50 mg/kg) resulted in a 26% and 29%, respectively, decrease in the urinary and fecal recovery of N‐acetyl‐2‐aminofluorene, and a 37% decrease in the metabolic clearance of 2‐aminofluorene to N‐acetyl‐2‐aminofluorene. This is the first demonstration that ellagic acid decrease the N‐acetylation of carcinogens in vitro and in vivo. 相似文献
42.
Abstract Distributions of 210Pb and 7Be in the aerosol particles of different size fractions were measured around Taiwan offshore areas from October, 1994 to October, 1995. the size distribution and abundance of the aerosol particles showed both spatial and temporal variations. the particle concentrations off northwestern Taiwan were more than twice as those off northeastern Taiwan both in November and March, and the values were much higher in November than in March for both areas. the measured particle concentrations, except for one sample with an unusually high value, ranged from 10 to 83 μOgm ?3 in the study areas. the 210Pb concentrations in the aerosol particles filtered from the air mass varied between 20 × 10?3 and 72 × 10?3 dpm m?3 (1dpm = 0.45 pCi). the 210Pb concentrations in the area off southwestern Taiwan appeared somewhat higher than in other areas and were probably contributed by the land air from Taiwan which contains higher 210Pb in winter. the 210Pb concentrations off northern Taiwan were low in November when the aerosol concentrations were high, but they were high in March when the aerosol concentrations were low. Based on the 7Be monitoring records of 20 years on the aerosol particles of the island by the Taiwan Radiation Monitoring Center, the mean settling rate averaged 0.91, 0.79 and 0.68 cm s?1, respectively, in northern, central and southern Taiwan. with these values and the 210Pb concentrations in the aerosols, the 210Pb flux was determined to be between 0.58 and 2.30 dpm cm?2y?1, with an average of 1.19 dpm cm?2y?1. Excluding the highest value due to its extremely high 210Pb and aerosol concentrations, the average is reduced to 1.05 dpm cm?2y?1. the activity median diameters (AMD) for 210Pb in the study areas were between 0.69 and < 0.49 μM with a mean of 0.5 öm based on 210Pb distributions in different particle size fractions. Thus, 210Pb was preferentially adsorbed on to the submicron particles. 7Be in the study areas showed a good correlation with 210Pb in total activity although the two nucides had different sources. 相似文献
43.
Hwang SJ Kim HS Park JH Kim BH 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(4):483-488
We compared filtering rates (FR) and mortalities between freshwater filter-feeding bivalve Corbicula leana acclimatized (AM) and non-acclimatized (NAM) to an cyanobacterial bloom (mainly Microcystis aeruginosa) over seven days. Both mussel populations were simultaneously stocked into mesocosms constructed in littoral zones of a eutrophic lake at a density of 740 ind. m(-2) for 16 days. NAMs decreased the concentration of chlorophyll-a 50% less than AMs. For the first seven days, the FRs (0.46-0.61) and mortality rate (slope = -30.2, r = -0.95) of NAMs were higher than those of AMs, possibly due to a sudden increase in unselective filtering. From the eighth day NAM mortality decreased rapidly and then stabilized, becoming similar to that of AMs through the end of the experiment. Stocking both AMs and NAMs increased the NH4-N concentration in the water, and the mortality rates of both mussel populations were correlated with NH4-N. In contrast, other nutrients and microcystin concentrations were not significantly associated with mussel mortality. These results indicate that although a sudden introduction of non-acclimatized C. leana may partially control phytoplankton biomass fora short period, previous short-term acclimatization is needed to minimize mussel mortality. 相似文献
44.
Sang Tae Chung Yi Yoon Hye Jeong Park 《Journal of Loss Prevention in the Process Industries》2013,26(6):1679-1684
Improvised explosive devices (IEDs) have become an alternative method for terrorists or criminals who face difficulties in obtaining traditional explosives as threatening tools. The ease of obtaining precursor materials from commodity chemicals in the free market and the ease of generating bombs through the hands of novices have created problems. Controlling the potential precursors to defeat illegal acquisition is not trivial due to their widespread use as common merchandise among chemical industries and consumers. However, efforts to identify the potential precursors may be the first step for devising appropriate control measures. In this study, we proposed a systematic screening method for identifying potential IED precursors (IEDPs) from commodity chemicals, which are regulated by Korean controls. We identified 25 potential IEDPs from 3980 candidate chemicals that can be diverted into IEDs or homemade bombs but are not likely to be solely used as an IED. We also developed a methodology of prioritizing the potential precursor chemicals to assess the urgency of controls using a scoring system with four criteria: previous listing as an official precursor; past record of being encountered in criminal use; volume of commercial circulation, which denotes the probability of exposure to individuals; and the degree of regulatory counter-measures against illegal acquisitions that are currently effective in Korea. 相似文献
45.
In the Ag(II)/Ag(I) redox mediator integrated scrubber system, NO reacts with the Ag(II) ions produced by the electrochemical oxidation of Ag(I) in an electrochemical cell present in the scrubbing solution (aqueous HNO3 acid) to form NO2. This NO2 is then absorbed into the scrubbing solution and degraded to nitrate. Numerous experimental runs were carried out to evaluate the feasibility of the integrated system to treat industrial waste gases containing high NOx levels. The results showed that the levels of NO and NOx removal increased with increasing Ag(II) loading and contact time. Under optimized conditions, 93.5% and 73.3% of the NO and NOx, respectively, were removed by a single stage gas scrubber with 1.62 g L?1 Ag(II) operating at 25 °C and atmospheric pressure. 相似文献
46.
Chiang CT Chang TK Hwang YH Su CC Tsai KY Yuan TH Lian IeB 《Environmental geochemistry and health》2011,33(5):469-476
The growing incidence of oral cancer (OC) in Taiwan has become a crucial public health concern. In particular, Changhua, a
county in central Taiwan, carries persistently high OC incidence rate, with an alarmingly high male/female ratio of OC incidence.
Previous epidemiological studies had found that the incidence is spatially correlated with the level of soil content to certain
heavy metals in the central Taiwan area. Soil and the human body both intake environmental heavy metals, which can be absorbed
through various ways. The soil metal concentration is an index of possible environmental exposure to heavy metal, and the
blood metal concentration somewhat reflects the level of the exposure on the human body. Metallic carcinogen is likely to
generate free radicals and play a role in many cancers, and many studies had reported that environmental exposure to heavy
metals is an important risk factor for developing cancer. Studies on animals showed that chronic intake of chromium (Cr) could
induce OC. This study aims to explore the association between the Cr concentration in the farm soil and in the blood of OC
patients. We recruited 79 OC patients from Changhua County, with their lifestyle being adjusted in regression analysis. The
results showed that the Cr concentration in the blood of OC patients is significantly higher than the background value, and
is positively associated with the Cr concentration in the soil surrounding their residence (p-value < 0.023). Because Changhua County is only with moderate prevalence of the known OC habitual risk factors, an environmental
factor related to heavy metal Cr exposure is suspected. Future investigations may verify the causal relation between Cr and
OC. 相似文献
47.
Effects of oceanic and terrestrial sediment suspensions on the behavioral traits activity, colony expansion, and mucus formation
of the gorgonian octocoral Subergorgia suberosa (Pallas, 1766) were studied in the laboratory. Increased sediment concentration significantly changed the logits of activity
indices (as colony expansion) and was correlated with decreased activity. For both sources of sediments, the activity index
decreased as the concentration of sediment increased. The level of decrease was more significance for terrestrial sediments.
The activity index showed no clear time pattern for the control group, but a decrease over time occurred in both sediment
treatment groups. Activity change was linearly correlated with exposure time and concentration of terrestrial and ocean sediments.
The activity indices of polyps were negatively correlated with the formation of mucus sheets (correlation = −0.536, p = 0.048). For both sources of sediments, the frequency of mucus sheet formation (MSF) increased with sediment concentration.
Increases in terrestrial sediment loads resulted in more striking effects. The probability for MSF under different sediment
groups at different concentrations over time was modeled by regressions. Frequency of polyp activity is suggested as a suitable
biomarker to monitor the effects of sedimentation stress. 相似文献
48.
Chung-Yi Chung Jen-Jeng Chen Chang-Gai Lee Chun-Yen Chiu Wen-Liang Lai Shao-Wei Liao 《Environmental monitoring and assessment》2011,173(1-4):499-517
This work investigated sediment samples collected from Dapeng Bay and three neighboring rivers (Kaoping River, Tungkang River, and Lingbeng River) in southwestern Taiwan, Republic of China. Multivariate statistical analysis techniques, i.e., factor analysis, cluster analysis, and canonical discriminant analysis were used for the evaluation of spatial variations to determine the types of pollution and to identify pollutant sources from neighboring rivers. Factor analysis results showed that the most important latent factors in Dapeng Bay are soil texture, heavy metals, organic matter, and nutrients factors. Contour maps incorporating the factor scores showed heavy metals accumulate along the lakesides, especially on the southeastern banks of the lakes. A cluster analysis was performed using factor scores computed from these latent factors. We then classified these areas into five distinct classes using sampling stations, and we illustrate that in the three river classes, the sediment properties are influenced by industrial and domestic wastewater and agricultural activities (including livestock rearing and farm activities). However, in Dapeng Bay, the rivers were influenced more by complicated biogeochemical processes; these could be identified as a type of pollution. Canonical discriminant analysis illustrated that two constructed discriminant functions made a marked contribution to most of the discriminant variables, and the significant parameters of porosity and Cd, Cr, Al, and Pb content were combined as the ??heavy metal factor??. The recognition capacities of the two discriminant functions were 82.6% and 17.4%, respectively. It is also likely that the annual mean of the water exchange rate is insufficient (taking about 7 days to eliminate pollutants) and therefore has significantly influenced the carbon and nutrient biogeochemical processes and budgets in the semi-enclosed ecosystem. Thus, the sediment properties are not similar between the lagoon and the neighboring rivers. Our results yield useful information concerning estuary recovery and water resources management and may be applicable to other basins with similar characteristics that are experiencing similar coastal environmental issues. 相似文献
49.
Chung-Yi Chung Pei-Ling Chung Shao-Wei Liao 《Environmental monitoring and assessment》2011,173(1-4):701-707
In the land ecosystem, the forest can absorb the carbon dioxide (CO2) in the atmosphere and turn the CO2 into organic carbon to store it in the plant body. About 2 × 1011 tons of CO2 changes through photosynthesis into organic matter by plant annually. In this research, ten kinds of woody plants were selected for assessing the carbon fixation ability influenced by sulfur dioxide (SO2). The tested trees were put into a fumigation chamber for 210 days in a 40-ppb SO2 environment. The results of this study showed that there was no clear symptom of tested trees under a 40-ppb SO2 environment. The tested trees could tolerate this polluted environment, but it will impact their CO2 absorption ability. The carbon fixation ability will reduce as the polluted period lengthens. The carbon fixation potential of tested trees ranged from 2.1 to 15.5 g·CO2/m2·d with an average of 7.7 g·CO2/m2·d. The changes in CO2 absorption volume for Messerschmidia argentea were more stable during the fumigation period with a variation of 102%. Among the tested trees, Diospyros morrisiana had the best carbon fixation potential of 9.19 g·CO2/m2·d and M. argentea had the least with 2.54 g·CO2/m2·d. 相似文献
50.
Low-level liquid borate wastes have been immobilized with paraffin wax using a concentrate waste drying system (CWDS) in Korean nuclear power plants. The possibility for improving chemical durability of paraffin waste form was suggested in this study. A small amount of low density polyethylene (LDPE) was added to increase the leaching resistance of the existing paraffin waste form. The influence of LDPE on the leaching behavior of waste form was investigated by performing leaching test according to ANSI/ANS-16.1 procedure during 325 days. It was observed that the leaching of nuclides immobilized within paraffin waste form made a marked reduction although little content of LDPE was added to waste form. The acceptance criteria of paraffin waste form associated with leachability index (LI) and compressive strength after the leaching test were fully satisfied with the help of LDPE. 相似文献