全文获取类型
收费全文 | 94篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 3篇 |
环保管理 | 10篇 |
综合类 | 22篇 |
基础理论 | 16篇 |
污染及防治 | 29篇 |
评价与监测 | 10篇 |
社会与环境 | 2篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 2篇 |
1996年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有96条查询结果,搜索用时 0 毫秒
91.
Tina M Petersen Monica P Suarez Hanadi S Rifai Paul Jensen Yu-Chun Su Ron Stein 《Water environment research》2006,78(12):2340-2355
This paper examines bacterial levels and their causes in two Houston bayous (Texas). Buffalo and Whiteoak bayous are two of the most contaminated water bodies in Texas for indicator bacteria, based on the frequency and magnitude of contact recreation water quality exceedances. Examination of historical data indicates frequent exceedances, although some improvement has been made since the 1970s. Statistical analyses showed some correlation between in-stream fecal coliform concentrations and rainfall and with land use. Differences in fecal coliform concentrations were found between high- and low-flow conditions in Whiteoak Bayou, while reservoir releases confounded this relationship in Buffalo Bayou. Wastewater treatment plant effluent was found to make up two-thirds to three-fourths of the median flow in both bayous. Effluent sampling was conducted at 72 of the approximately 140 wastewater treatment plants (WWTPs) in the watersheds, providing evidence that WWTP effluent could act to maintain low-flow concentrations of fecal coliform in the bayous. 相似文献
92.
Tina Kiefer 《组织行为杂志》2005,26(8):875-897
This paper examines how and why ongoing organizational change is experienced emotionally on an everyday basis and identifies important consequences of such emotional experiences. Three main antecedents to negative emotions in ongoing change are proposed: perceptions of an insecure future; perceptions of inadequate working conditions; and perceptions of inadequate treatment by the organization. Two outcome variables are identified: trust in the organization and withdrawal from the organization. The model is tested with cross‐sectional and follow‐up data from a field study. Regression and path analysis reveal that: a) ongoing changes are associated with negative emotions; b) this relationship between ongoing changes and emotions is mediated by the three proposed antecedents; and c) negative emotions predict employee lack of trust and employee withdrawal, both immediately and one month later. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
93.
Tina Fredsted Mikkel H. Schierup Linn F. Groeneveld Peter M. Kappeler 《Behavioral ecology and sociobiology》2007,61(6):943-954
Mating system and dispersal patterns influence the spatio-genetic structure within and between populations. Among mammals,
monogamy is rare, and its socio-genetic consequences have not been studied in detail before. The goal of our study was to
investigate population history, demographic structure, and dispersal patterns in a population of pair-living fat-tailed dwarf
lemurs, Cheirogaleus medius, a small, nocturnal primate from western Madagascar, and to infer their underlying behavioral mechanisms. Tissue samples
for DNA extraction were obtained from a total of 140 individuals that were captured in two subpopulations about 3 km apart.
Analyses of mtDNA variability at the population level revealed very low levels of genetic variability combined with high haplotype
diversity, which is indicative of a recent population bottleneck. We found no evidence for spatial clustering of same-sexed
individuals with identical haplotypes within each of two subpopulations but significant clustering between them. Thus, a high
level of local subpopulation differentiation was observed (F
ST = 0.230). The sexes showed equal variances in the number of individuals representing each haplotype, as well as equal levels
of aggregation of identical haplotypes. Hence, both sexes disperse from their natal area, one pattern expected in a pair-living
mammal. There is a possibility of behavioral and social flexibility in this species, however, because we documented pronounced
differences in density and sex ratio between the two subpopulations, suggesting that single study sites or populations may
not be representative of a given local population or even species. 相似文献
94.
95.
Rudolf Brenneis Hubertus Wichmann Regina Sprenger Astrid Eickhoff Ralf Bock Tina Dettmer Burkhard Baeck Christian Reger Müfit Bahadir 《Environmental Sciences Europe》2006,18(2):95-101
Aims and Scope
Compared to mineral oil products, cooling lubricants based on fatty acid esters have technological advantages. Moreover, they are more environmentally compatible and make a contribution to a sustainable economy. Nevertheless, they are rarely applied in practice, because of their comparably high price, that is based on raw-material and synthesis costs. Alternatives concerning raw-materials and synthesis pathways are considered and properties of resulting ester products are compared.Methods
The investigations aimed at three fatty acid-2-ethyl-hexylesters that were synthesized in an enzymatic-catalytic routine based on peanut oil, suet, and waste edible fat and at esters that were conventionally produced from animal and plant fats and 2-ethyl-1-hexanol. Physical properties, fatty acid patterns, contents of free fatty acids, as well as oxidative and hydrolytic stabilities were determined. Thermolysis experiments were performed.Results
The physical properties of the seven esters, density, viscosity, pourpoint, and flash point, were comparable and gave reason for the assumption, that the products could be used as basis oils in lubricant formulations. Hydrolysis stabilities of the esters were high and thermal stress did not point at high potential of hazardous compounds formation. Especially the enzymatic-catalytically produced esters showed deficits concerning oxidation stabilities and free fatty acid contents.Outlook
For practice it will be necessary to define minimum qualities for raw-materials and resulting ester oils to be used as lubricant basis oils. Moreover, processes have to be developed, that yield high quality ester products from waste edible and animal fats without loosing the advantage of low-cost raw-materials by high production and refinement costs. Surely, one contribution is the further development of the energy-saving enzymtic alcoholysis for ester production. 相似文献96.
Tina L. Cheng Jonathan D. Reichard Jeremy T. H. Coleman Theodore J. Weller Wayne E. Thogmartin Brian E. Reichert Alyssa B. Bennett Hugh G. Broders Joshua Campbell Katherine Etchison Daniel J. Feller Richard Geboy Traci Hemberger Carl Herzog Alan C. Hicks Sandra Houghton Jessica Humber Joseph A. Kath R. Andrew King Susan C. Loeb Ariane Massé Katrina M. Morris Holly Niederriter Gerda Nordquist Roger W. Perry Richard J. Reynolds D. Blake Sasse Michael R. Scafini Richard C. Stark Craig W. Stihler Steven C. Thomas Gregory G. Turner Shevenell Webb Bradford J. Westrich Winifred F. Frick 《Conservation biology》2021,35(5):1586-1597
Assessing the scope and severity of threats is necessary for evaluating impacts on populations to inform conservation planning. Quantitative threat assessment often requires monitoring programs that provide reliable data over relevant spatial and temporal scales, yet such programs can be difficult to justify until there is an apparent stressor. Leveraging efforts of wildlife management agencies to record winter counts of hibernating bats, we collated data for 5 species from over 200 sites across 27 U.S. states and 2 Canadian provinces from 1995 to 2018 to determine the impact of white-nose syndrome (WNS), a deadly disease of hibernating bats. We estimated declines of winter counts of bat colonies at sites where the invasive fungus that causes WNS (Pseudogymnoascus destructans) had been detected to assess the threat impact of WNS. Three species undergoing species status assessment by the U.S. Fish and Wildlife Service (Myotis septentrionalis, Myotis lucifugus, and Perimyotis subflavus) declined by more than 90%, which warrants classifying the severity of the WNS threat as extreme based on criteria used by NatureServe. The scope of the WNS threat as defined by NatureServe criteria was large (36% of Myotis lucifugus range) to pervasive (79% of Myotis septentrionalis range) for these species. Declines for 2 other species (Myotis sodalis and Eptesicus fuscus) were less severe but still qualified as moderate to serious based on NatureServe criteria. Data-sharing across jurisdictions provided a comprehensive evaluation of scope and severity of the threat of WNS and indicated regional differences that can inform response efforts at international, national, and state or provincial jurisdictions. We assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs, such as the North American Bat Monitoring Program (NABat), for data-driven conservation assessments and planning. 相似文献