首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   103篇
  免费   1篇
  国内免费   1篇
安全科学   4篇
废物处理   5篇
环保管理   8篇
综合类   13篇
基础理论   21篇
污染及防治   38篇
评价与监测   9篇
社会与环境   6篇
灾害及防治   1篇
  2023年   3篇
  2022年   4篇
  2021年   1篇
  2019年   3篇
  2018年   3篇
  2017年   3篇
  2016年   3篇
  2015年   3篇
  2014年   5篇
  2013年   11篇
  2012年   7篇
  2011年   11篇
  2010年   2篇
  2009年   7篇
  2008年   7篇
  2007年   3篇
  2006年   10篇
  2005年   3篇
  2004年   2篇
  2003年   4篇
  2002年   4篇
  1996年   1篇
  1995年   1篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
排序方式: 共有105条查询结果,搜索用时 140 毫秒
91.
92.
Aluminum is one of the most abundant metals in the earth's crust. Although it shows no known biological function, it is recognized as an adjuvant in vaccines for human and veterinary uses. This study aims to evaluate the role of lifestyle and environment in the promotion of chronic disease. In it, we associated two factors: chronic exposure to aluminum and high‐fat diets. Thus, we aimed to determine whether the association of long‐term exposure to aluminum and high‐fat diets affects the NTPDase and 5′‐nucleotidase activities in the blood platelets and lymphocytes obtained from the mesenteric lymph nodes of young rats. In fact, the ectonucleotidase activities were shown to be upregulated upon exposure to aluminum plus high‐fat diets. As a result, we can suggest that the progressive upregulation of ectonucleotidase activities that we observed could be controlling the extent of inflammation and immune response.  相似文献   
93.
Zooplankton represents a key contributor to the ocean biological pump through its consumption of sinking and suspended carbon. A specific and highly sensitive method to evaluate zooplankton carbon requirement from the sinking flux is through the estimation of the activity of the electron transport system. The present study was carried out from samplings in 2006, and it was focused on the spatial 200–0?m zooplankton carbon demand across 24 sampling stations, along the Mediterranean Sea, from the island of Crete to the Strait of Gibraltar. Its potential day/night variability was evaluated. The zooplankton composition, abundance and biomass were investigated. The carbon demand per unit zooplankton biomass indicates geographical and diel differences among the sampling stations. A higher mean carbon demand was seen for the western Mediterranean with respect to the eastern Mediterranean, which can be justified through the observed ratio of gelatinous:crustacean taxa and the water temperatures recorded. Higher carbon demand was measured in samples collected during the dark hours. The relation to the presence and abundance of actively migrating euphausiids and copepods was discussed. A comparison with data from another of our study carried out in the same study area but in another seasonal period was done.  相似文献   
94.
This study determined concentrations and speciation of arsenic (As) in rice samples obtained from the cities of Akure, Ore, Ondo and Ikare in Ondo State, south-western Nigeria. The estimated dietary intake of As from rice consumption for total As and the identified As species were compared with the As benchmark dose lower confidence limit. Analyses of rice from the four cities identified three As species: inorganic As, monomethylarsonic, acid and dimethylarsinic acid. Concentrations of total As and the As species differed significantly across the sampling locations (by a factor of 2.5 for total As). Mean levels (±S.D.) were 58.8 ± 0.7 µg/kg total As, 47.0 ± 0.6 µg/kg inorganic As, 0.33 ± 0.03 µg/kg monomethylarsonic acid, and 11.5 ± 0.1 µg/kg dimethylarsinic acid. The estimated mean dietary intakes were 4.1 µg/d total As, 3.3 µg/d inorganic As, 0.02 µg/d monomethylarsonic acid, and 0.8 µg/d dimethylarsinic acid. These values are below the benchmark dose lower confidence limit and comparable to, or lower than, those reported for other countries. Thus, consumption of rice cultivated in south-western Nigeria does not appear to have inherent As-associated health risks.  相似文献   
95.
The occurrence of diseases in cultivars has caused significant losses in global food production. The advancement of nanobiotechnology makes it possible to obtain new products to be used in the control of pathogens in cultivars. Silver nanoparticles can be synthesized by microalgae and are widely known for their antimicrobial activity. In addition, the biomass produced in microalgal culture for the biosynthesis of the nanoparticles also demonstrates antimicrobial properties, as it can increase the antibacterial and antifungal potential of the silver nanoparticles. In this context, this article addresses the use of microalgae to biosynthesize silver nanoparticles simultaneously with biomass production. In addition, we demonstrate the antimicrobial potential of these nanomaterials, as well as of the microalgal biomass produced in biosynthesis, to use in the control of pathogens in agriculture.  相似文献   
96.

Background, aim, and scope  

Fishery wastewater treatment can be compromised due to seasonal production. The use of sequencing batch reactors is not completely successful, despite flexibility being one of the principal advantages. Most research on activated sludge is performed using synthetic wastewater to ensure a stable and constant feed. The current work compared biomass morphology and settling ability using image analysis of synthetic and real fishery wastewaters, with and without NaCl addition.  相似文献   
97.
Within the initiatives for poliomyelitis eradication by WHO, Italy activated an environmental surveillance (ES) in 2005. ES complements clinical Acute Flaccid Paralysis (AFP) surveillance for possible polio cases, detects poliovirus circulation in environmental sewage, and is used to monitor transmission in communities. In addition to polioviruses, the analyses comprised: (i) the monitoring of the presence of non-polio enteroviruses in sewage samples and (ii) the temporal and geographical distribution of the detected viruses. From 2009 to 2015, 2880 sewage samples were collected from eight cities participating in the surveillance. Overall, 1479 samples resulted positive for enteroviruses. No wild-type polioviruses were found, although four Sabin-like polioviruses were detected. The low degree of mutation found in the genomes of these four isolates suggests that these viruses have had a limited circulation in the population. All non-polio enteroviruses belonged to species B and the most frequent serotype was CV-B5, followed by CV-B4, E-11, E-6, E-7, CV-B3, and CV-B2. Variations in the frequency of different serotypes were also observed in different seasons and/or Italian areas. Environmental surveillance in Italy, as part of the ‘WHO global polio eradication program’, is a powerful tool to augment the polio surveillance and to investigate the silent circulation or the re-emergence of enteroviruses in the population.  相似文献   
98.
An Eco-balance of a Recycling Plant for Spent Lead–Acid Batteries   总被引:2,自引:0,他引:2  
This study applies Life Cycle Assessment (LCA) methodology to present an eco-balance of a recycling plant that treats spent lead–acid batteries. The recycling plant uses pyrometallurgical treatment to obtain lead from spent batteries. The application of LCA methodology (ISO 14040 series) enabled us to assess the potential environmental impacts arising from the recycling plants operations. Thus, net emissions of greenhouse gases as well as other major environmental consequences were examined and hot spots inside the recycling plant were identified. A sensitivity analysis was also performed on certain variables to evaluate their effect on the LCA study. The LCA of a recycling plant for spent lead–acid batteries presented shows that this methodology allows all of the major environmental consequences associated with lead recycling using the pyrometallurgical process to be examined. The study highlights areas in which environmental improvements are easily achievable by a business, providing a basis for suggestions to minimize the environmental impact of its production phases, improving process and company performance in environmental terms.  相似文献   
99.
The conventional (hot pressing or HP) and the novel (spark plasma sintering or SPS) consolidation techniques were compared when processing Ti–Al2O3–TiC powders obtained by self-propagating high-temperature synthesis (SHS). It was found that the two different methods are able to produce similar materials, in some cases (Vickers hardness and wear rate) slightly better for SPSed samples. However, SPS does not need sintering temperatures as high as HP to obtain fully dense products. Most significantly, processing times were strongly reduced when adopting the SPS technique instead of HP, i.e. 4–7 min and about 5 h, respectively. Finally, when the total energies required during each SPS or HP experiment were compared, it was found that the use of the SPS technology allowed for an energy saving in the order of 90–95%. This fact makes SPS significantly advantageous from environmental and economical points of view compared to HP.  相似文献   
100.
In diverse taxa, offspring solicit parental care using complex displays, which may evolve as reliable signals of condition or as mechanisms to manipulate parental investment. Differential sex allocation may therefore result from adaptive parental decisions or sex-related variation in competitive ability or because of sex-related asymmetries in kin selection. Under normal food provisioning, female barn swallow (Hirundo rustica) nestlings begged more loudly but did not receive more food than male nestlings. After food deprivation, begging call loudness of males but not females increased. Begging loudness positively predicted the number of feedings received by the nestlings, and males gained more mass than females after food deprivation. Male nestlings are more severely affected by chronic food reduction and may therefore accrue a larger benefit compared to females by increasing their food intake under short-term conditions of food scarcity. These results suggest that either females do not increase begging intensity to favour male broodmates which are more vulnerable to prolonged food stress, or that males prevail in scramble competition despite being similar in size to females.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号