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61.
This work has been developed to examine the level of non-dioxin-like (ndl) PCBs (28, 52, 101, 138, 153 and 180) in (a) ten different freshwater fish species from the Danube river, (b) two sampling points: up and downstream of the industrial zone of the city of Pancevo (ecological hot spot in Serbia) and (c) two time points i.e., in 2001 and 2006. Obtained results would serve to analyse spatial, temporal and congener profile characteristics of ndl PCBs cumulated in fish tissues due to environmental pollution. Sixty-four samples of the following species were collected: wels (Silirus glanus), pike (Esox lucius), bream (Abramis brama), crucian carp (Carassius carassius), pike pearch (Stizostedion lucioperca), barbel (Barbus barbus), tench (Tinca tinca), sterlet (Acipenser ruthenus L.), common carp (Cyprinus carpio) and bighead carp (Hypophthalmichthys nobilis). Gas chromatography coupled with electron capture detector was used for analysis of ndl PCBs. Total ndl PCBs content in upstream samples ranged from 2.7 to 98.1 ng/g and from 4.9 to 68.3 ng/g in 2001 and 2006, respectively. During the 5 years, ndl PCBs content increased significantly in downstream samples i.e., ndl PCBs varied from 13.7 to 46.1 ng/g and from 14.4 to 107.2 ng/g in 2001 and 2006, respectively. PCBs 138 and 180 were predominant congeners in 2001, while in 2006 the most abundant PCB congeners were 138 and 153. In 2006, the presence of PCB 28 and PCB 52 has indicated a recent contamination event. Data on continual monitoring of PCBs in all relevant environmental compartments together with appropriate biomonitoring data are expected to give comprehensive insight into the fate and behaviour profile of these contaminants.  相似文献   
62.
We analyzed bulk UV absorbance of methanolic extracts and levels of five UV-absorbing compounds (hydroxycinnamic acid derivatives) in 135 herbarium samples of the liverwort Jungermannia exsertifolia subsp. cordifolia from northern Europe. Samples had been collected in 1850–2006 (96% in June–August). Both UV absorbance and compound levels were correlated positively with collection year. p-Coumaroylmalic acid (C1) was the only compound showing a significant (and negative) correlation with stratospheric ozone and UV irradiance in the period that real data of these variables existed. Stratospheric ozone reconstruction (1850–2006) based on C1 showed higher values in June than in July and August, which coincides with the normal monthly variation of ozone. Combining all the data, there was no long-term temporal trend from 1850 to 2006. Reconstructed UV showed higher values in June–July than in August, but again no temporal trend was detected in 1918–2006 using the joint data. This agrees with previous UV reconstructions.  相似文献   
63.
Since the performance of algal treatment for pulp mill effluent decreases with increasing color intensity and AOX content, which mainly originate from the chlorine bleaching of Kraft pulp, the separated CEH bleaching effluent was pre-treated by both the conventional and the heterogeneous catalytic ozonation processes. An increase in the BOD(5)/COD ratio from 0.11 to 0.28 and 87% color abatement in terms of Pt-Co were achieved by catalytic ozonation, which had the best treatment performance. Biodegradability enhancement of the CEH effluent correlated well with a decrease in toxicity, high-molecular-weight-compound content, and AOX abatement. By the pre-treatment of the CEH bleaching effluent, the overall efficiencies of algal treatment of the combined pulp mill effluent in terms of the fractional removal of COD and color were increased from 76% and 53% to 86-90% and 96-99%, respectively. Effects of both the conventional and the catalytic ozonation pre-treatments on subsequent biological treatment were close to each other and they reduced the filling period of the Sequential Batch Reactor (SBR) cycle from 8 to 5 days.  相似文献   
64.
65.
介绍了生物修复、生物强化和生物刺激的基本概念。综述了基于生物强化和生物刺激技术处理石油污染海岸线的研究进展,并指出不同处理技术的优势与不足。分析了影响溢油污染海岸线生物修复的重要因素,包括石油类型、波浪和水流能量、温度、盐度、氧气含量等。对今后研究的主要方向进行了展望。  相似文献   
66.
一种湿度试验中计算露点温度的方法   总被引:1,自引:1,他引:0  
陈晓晨  张倩  吴飒 《装备环境工程》2016,13(2):88-91,122
目的研究在气候环境试验中如何把露点温度作为控制目标的方法。方法选择干湿球温度表作为测量湿度的传感器,饱和水汽压是计算湿度量的一个重要参数,探究出便于在微控制器上应用的计算饱和水汽压的公式,然后建立露点温度计算模型,得出水汽压与露点温度的关系式。结果通过0~100℃的100组样本值的验证,与《湿度查算手册》值比较,平均误差较小。结论该公式适用于湿度试验箱中微控制器中露点温度的处理问题。  相似文献   
67.
Summary. We adapted a four-arm olfactometer (55 × 55 × 5.5 cm) for bioassays of large insects and its usefulness was evaluated by testing the responses of three beetles, the palm weevil Rhynchophorus palmarum (L.) (Coleoptera: Curculionidea) and two Dynast scarabs Strategus aloeus (L.) and Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae) to plant odours and aggregation pheromones. This olfactometer was coupled to a volatile delivery system dispensing highly volatile semiochemicals at constant concentrations. We materialized airflows in the olfactometer by discolouring sensitive papers with acid vapours under various conditions (air straighten by stainless steel grids in inputs and output, 500 ml/min per arm) to visualize air turbulence and to test air-tightness. The volatile delivery system can be used to mix and dispense a broad range of concentrations of semiochemicals in air from diluted aqueous solutions. It was calibrated by measuring the release of the pheromone using solid phase-microextraction (SPME). Dose-response curves to synthetic pheromone were obtained for O. rhinoceros of both sexes. Coupling the volatile delivery system to the fourarm olfactometer provided a system with which the responses of R. palmarum and S. aloeus to their synthetic aggregation pheromones and to natural plant volatiles could be readily observed and studied.  相似文献   
68.
In order to understand the relationships between the dynamics of phytoplankton populations in the surface microlayer (MIL) and in the water column below (SSW), this study used high-performance liquid chromatography-derived pigment markers in samples from a coastal lagoon of Baja California (Estero de Punta Banda, EPB) under summer (October 2003) and winter (December 2003) conditions. Photosynthetic pigment signatures of phytoplankton at the air–sea interface (phytoneuston) and subsurface measurements were related to bottom-up (temperature, salinity, nutrient concentrations) and top-down factors (zooplankton abundance). Slicks and scum layers were observed in the inner part of the lagoon and coincided with greater stratification of layers just below the sea surface and lower wind intensities. In general, spatial variability in pigment markers and ancillary data was very high and resulted in non-significant differences between MIL and subsurface samples when different regions of EPB or sampling dates were compared. However, different patterns were found between pigments and environmental factors of MIL and SSW samples when the relative numbers of stations with positive and negative differences (ΔX = X MILX SSW) were computed. For each survey, pigment markers of phytoneuston and phytoplankton samples were not necessarily correlated. Further analysis revealed that those markers (19′-butanoyloxyfucoxanthin, prasinoxanthin, divinil-chlorophyll a) corresponded to picophytoplankton groups (haptophyte, prasinophyte, and prochlorophyte). On both dates, the MIL was enriched in 19′-hexanoyloxyfucoxanthin (a marker for a type 4 haptophyte) and fucoxanthin (marker for bacillariophytes, haptophytes, and crysophytes) and depleted in peridinin (marker for dinophytes). Different zooplankton grazers accumulated in the MIL (loricate tintinnids) and in SSW (copepod nauplii).  相似文献   
69.
Two different types of hydroponic cultures, "water culture" and "perlite system", were compared using white lupin plants (Lupinus albus L., cv. Marta) under different Cd treatments: 0, 0.2, 0.6, 2, 4, 6, 13, 20, 40 and 60 microM (water culture) and 0.2, 2, 20, 60 and 150 microM (moistened perlite). Fresh weight, shoot and root length, and total Cd concentration in the plants were measured. Moreover, a batch experiment was carried out to study the ability of perlite to adsorb and desorb Cd from nutrient solution. Lupin plants under Cd treatments in "water culture" showed a higher growth inhibition than those grown on perlite. A high positive correlation between Cd concentration in the plant and Cd supply was obtained regardless of the substrate used. Moreover, a high positive correlation between Cd doses with the "perlite system" and their equivalent Cd doses estimated for the "water culture" system was observed. Thus, the "water culture-equivalent" Cd doses were 14 times lower than the Cd doses in the perlite system. On the other hand, desorbed Cd concentrations were calculated giving values 12 times lower than the tested Cd doses.  相似文献   
70.
2018年12月1日实施的《环境影响评价技术导则大气环境》(HJ 2.2—2018),对建设项目环境影响评价中二次PM_(2.5)影响预测问题给出了模型模拟法和系数法两种解决方案。在详细介绍模型模拟法和系数法的基础上,对两种方法预测同一项目时预测结果的差异性进行了比较分析。差异性比较分析结果表明,就二次PM_(2.5)日均浓度和年均浓度,AERMOD系数法计算结果较CALPUFF模型模拟法计算结果偏保守;两种方法在预测二次PM_(2.5)日均浓度时比值范围为0.08~5.16,均值为2.35;在预测二次PM_(2.5)年均浓度时比值范围为0.89~26.22,均值为10.71;两种方法在预测二次PM_(2.5)日均浓度时差异较小。  相似文献   
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