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   77篇
  免费   0篇
  国内免费   1篇
安全科学   3篇
废物处理   2篇
环保管理   16篇
综合类   24篇
基础理论   6篇
污染及防治   20篇
评价与监测   4篇
社会与环境   3篇
  2023年   1篇
  2019年   2篇
  2017年   4篇
  2016年   3篇
  2014年   2篇
  2013年   5篇
  2012年   1篇
  2011年   2篇
  2010年   2篇
  2009年   5篇
  2008年   4篇
  2007年   1篇
  2006年   5篇
  2005年   3篇
  2004年   4篇
  2002年   2篇
  2001年   4篇
  2000年   1篇
  1999年   2篇
  1998年   3篇
  1992年   1篇
  1988年   2篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1975年   1篇
  1972年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1965年   1篇
  1964年   1篇
  1959年   1篇
  1952年   1篇
  1950年   1篇
  1936年   1篇
排序方式: 共有78条查询结果,搜索用时 15 毫秒
31.
32.
33.
The paper differentiates approaches in technology (end-of-pipe, cleaner production, industrial ecology, zero emission and eco-social-tech) and compares them in respect to the problem solving capacity on the ecological as well as social dimension by showing the eco-impact reduction and job creation. Eco-social-tech represents the approach with highest problem solution as it is based on "eco-social market economy", which will the replace free market economy. The deep background of these innovations is "ecosophy", the wisdom of nature, which serves as guideline for eco-restructuring the world.  相似文献   
34.
Moser GA  McLachlan MS 《Chemosphere》2001,45(2):201-211
The gastrointestinal exchange of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs) as well as hexachlorobenzene was measured in five volunteers. The dietary intake and the fecal excretion of the chemicals were quantified and the net absorption/net excretion was calculated as the difference between these two fluxes. Experiments were conducted using an elevated dietary intake and a reduced dietary intake of chemical, and the results were compared with the absorption during normal dietary intake. The net absorption varied widely with the dietary intake for those compounds which bioaccumulate in humans; high dietary intake of chemical resulted in absorption approaching 100% of intake, while low dietary intake resulted in a net excretion several times greater than the dietary intake. In contrast to net absorption, the chemical flux in the feces was largely independent of the dietary intake of chemical for a given individual. Good agreement was found between the feces/blood distribution coefficients measured in this study and in a study with contaminated workers whose blood concentrations were several orders of magnitude higher, indicating that fecal excretion of chemical is linearly proportional to the blood concentration. The results suggest that gastrointestinal exchange can be viewed as two processes operating simultaneously: absorption of contaminant from the diet, and excretion of contaminant from the body's reservoirs via the feces. By subtracting that component of the fecal flux originating from the body, the maximum dietary absorption could be calculated. This was >95% for most of the compounds, decreasing to a minimum of 50-60% for the octachlorinated dioxins and furans. The maximum dietary absorption showed a Kow dependency consistent with the two film model of gastrointestinal absorption of persistent organic chemicals.  相似文献   
35.
Dyestuffs generally do not readily undergo aerobic biodegradation during sewage treatment processes and for new products an assessment of their bioaccumulation in fish is a requirement under certain environmental chemicals legislation. The results presented in this paper show that the partition coefficient in n-octanol/water is a useful indicator of the bioaccumulation tendency of dyestuffs, thus supporting its use as a screening test for bioaccumulation as proposed by the OECD Chemicals Testing Programme.  相似文献   
36.
Plasmalogen biosynthesis and phytanic acid oxidation activity were measured in cultured chorionic villus samples or amniocytes from four pregnancies at risk for the rhizomelic form of chondrodysplasia punctata (RCDP). Normal results were obtained in three of the samples and post-natal examination or fetal ultrasound studies confirmed that the fetuses were unaffected. Chorionic villus culture in one case demonstrated defective plasmalogen biosynthesis and lack of phytanic acid oxidation. Pregnancy was interrupted at 10 weeks. Immunoblot studies of post-mortem fetal tissues showed thatperoxisomal 3-oxoacyl-coenzyme A thiolase was present in the unprocessed form, a finding we had previously demonstrated in RCDP. These results establish that RCDP can be identified prenatally.  相似文献   
37.
. Water Reservoir Systems were investigated for urban areas as an alternative or complement to storm water drainage systems for flood control which could provide benefits in water conservation and reduce drainage system costs. The study consisted of: (1) gathering of engineering data on the topographical, hydrological, and precipitation characteristics of the area and urban development and economic statistics  相似文献   
38.
Biodiesel from waste cooking oil (WCO) requires antioxidants to meet oxidation stability specifications set forth in ASTM D6751 or EN 14214. In contrast, unrefined cottonseed oil (CSO), containing tocopherols and gossypol, produces biodiesel of higher oxidation stability. However, only a portion of these CSO endogenous antioxidants are suspected to be retained in biodiesel. Because the economics of biodiesel manufacturing rely upon inexpensive sources of triglycerides, emphasis was placed on developing improved alternative processing methods where WCO was the main source of methyl esters (WCOME) and CSO was used as a supplemental source of triglycerides and antioxidants in a 4:1 ratio. This study compared four processing methods for their ability to produce biodiesel of increased oxidative stability prepared from a 4:1 ratio of WCO:CSO. Two novel processing methods developed for this study utilise solvent properties of fatty acid methyl esters and glycerol to avoid additional chemical inventory for biodiesel processors. This study concludes that the two new processing methods resulted in biodiesel that had statistically significant improved oxidation stability when compared to two common industrial processing methods. Another significant finding is that high-shear homogenisation during transesterification reduced reaction time from the published one hour to 16 minutes.  相似文献   
39.
Understanding patterns, dynamics, and drivers of land use is crucial for improving our ability to cope with sustainability challenges. The human appropriation of net primary production (HANPP) framework provides a set of integrated socio-ecological indicators that quantify how land use alters energy flows in ecosystems via land conversions and biomass harvest. Thus, HANPP enables researchers to systematically and consistently assess the outcome of changes in land cover and land-use intensity across spatio-temporal scales. Yet, fine-scale HANPP assessments are so far missing, an information important to address site-specific ecological implications of land use. Here, we provide such an assessment for Europe at a 1-km scale for the years 1990, 2000, and 2006. The assessment was based on a consistent land-use/biomass flow dataset derived from statistical data, remote sensing maps, and a dynamic global vegetation model. We find that HANPP in Europe amounted to ~43 % of potential productivity, well above the global average of ~25 %, with little variation in the European average since 1990. HANPP was highest in Central Europe and lower in Northern and Southern Europe. At the regional level, distinct changes in land-use intensity were observed, most importantly the decline of cropland areas and yields following the breakdown of socialism in Eastern Europe and the subsequent recovery after 2000, or strong dynamics related to storm events that resulted in massive salvage loggings. In sum, however, these local dynamics cancelled each other out at the aggregate level. We conclude that this finding warrants further research into aspects of the scale-dependency of dynamics and stability of land use.  相似文献   
40.
Dutch elm disease (DED) is a destructive vascular wilt disease of elm (Ulmus) trees caused by the introduced Ascomycete fungus Ophiostoma novo-ulmi. In Europe, this DED pathogen is transmitted by elm bark beetles in the genus Scolytus. These insects carry phoretic mites to new, suitable habitats. The aim of this study was to record and quantify conidia and ascospores of O. novo-ulmi on phoretic mites on the three elm bark beetle species Scolytus multistriatus, Scolytus pygmaeus, and Scolytus scolytus. Spores of O. novo-ulmi were found on four of the ten mite species phoretic on Scolytus spp. These included Elattoma fraxini, Proctolaelaps scolyti, Pseudotarsonemoides eccoptogasteri, and Tarsonemus crassus. All four species had spores attached externally to their body surfaces. However, T. crassus carried most spores within its sporothecae, two paired pocket-like structures adapted for fungal transmission. Individuals of Pr. scolyti also had O. novo-ulmi conidia and ascospores frequently in their digestive system, where they may remain viable. While E. fraxini and P. eccoptogasteri rarely had spores attached to their bodies, large portions of Pr. scolyti and T. crassus carried significant numbers of conidia and/or ascospores of O. novo-ulmi. P. scolyti and T. crassus, which likely are fungivores, may thus contribute to the transmission of O. novo-ulmi, by increasing the spore loads of individual Scolytus beetles during their maturation feeding on twigs of healthy elm trees, enhancing the chance for successful infection with the pathogen. Only S. scolytus, which is the most efficient vector of O. novo-ulmi in Europe, carried high numbers of Pr. scolyti and T. crassus, in contrast to S. multistriatus and S. pygmaeus, which are known as less efficient vectors. The high efficiency of S. scolytus in spreading Dutch elm disease may be partly due to its association with these two mites and the hyperphoretic spores of O. novo-ulmi they carry.  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