全文获取类型
收费全文 | 469篇 |
免费 | 2篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 5篇 |
环保管理 | 29篇 |
综合类 | 165篇 |
基础理论 | 144篇 |
污染及防治 | 112篇 |
评价与监测 | 12篇 |
社会与环境 | 14篇 |
出版年
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 23篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 15篇 |
2008年 | 20篇 |
2007年 | 24篇 |
2006年 | 32篇 |
2005年 | 21篇 |
2004年 | 9篇 |
2003年 | 16篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 19篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1991年 | 4篇 |
1989年 | 5篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1983年 | 6篇 |
1969年 | 3篇 |
1967年 | 2篇 |
1966年 | 7篇 |
1965年 | 4篇 |
1964年 | 8篇 |
1963年 | 7篇 |
1962年 | 2篇 |
1961年 | 5篇 |
1960年 | 6篇 |
1959年 | 3篇 |
1958年 | 3篇 |
1957年 | 6篇 |
1956年 | 3篇 |
1955年 | 5篇 |
1954年 | 4篇 |
1953年 | 7篇 |
1951年 | 2篇 |
1950年 | 2篇 |
1938年 | 2篇 |
1934年 | 2篇 |
排序方式: 共有489条查询结果,搜索用时 328 毫秒
381.
Anne?Marijke?SchelEmail author Klaus?Zuberbühler 《Behavioral ecology and sociobiology》2012,66(3):361-373
Dawn chorusing by guereza black-and-white colobus monkeys is one of the most impressive spectacles of African rainforests.
This vocal behaviour is highly contagious, travelling from one neighbouring group to the next, until a wide forest area is
covered by calling monkeys. Chorusing usually occurs up to 2 h before dawn, sometimes more than once, unless the preceding
night was cold and wet. We conducted a series of playback experiments, which showed that guerezas’ chorusing was difficult
to elicit experimentally, suggesting that callers took several variables into account before responding to other monkeys’
predawn calls. Acoustic analyses showed that morning calls were individually distinct, but we found no evidence that callers
took individual identity into account in their decision to participate in chorusing. The only way to reliably elicit chorusing
in our study area was to broadcast recordings of morning choruses for longer than 30 s and at a time when a chorus simultaneously
emerged in a distant part of the forest. 相似文献
382.
Josefine Norman Per-Erik Jansson Neda Farahbakhshazad Klaus Butterbach-Bahl Changsheng Li Leif Klemedtsson 《Ecological modelling》2008
The amount of nitrogen gases (N2O, NO and N2) emitted from forest soils depends on interactions between soil properties, climatic factors and soil management. To increase the understanding of nitrogen processes in soil ecosystems, two dynamic models, CoupModel (coupled heat and mass transfer model for soil–plant–atmosphere systems) and the denitrification–decomposition (DNDC) model were selected. Both are dynamic models with different submodels for soil, vegetation, hydrology and climate system. CoupModel has a higher degree of detail on soil physical and abiotic components, whereas the DNDC model contains details of microbiological processes involved in production of nitrogen gases. To improve the previous simple submodel of nitrogen emission in CoupModel, we included a submodel corresponding to the forest version of DNDC containing photosynthesis/evapotranspiration-nitrogen (PnET-N-DNDC model). 相似文献
383.
Pharmaceuticals and contrast media have been detected in hospital effluents, sewage treatment plants, surface water, and ground water. Only little is known about their elimination during sewage treatment and effects of possible biotransformation products against bacteria. The modified Zahn-Wellens test (ZWT, OECD 302 B) and a test simulating biological sewage treatment (modified OECD 303 A test) were used to assess the biodegradability of the widely used ionic iodinated contrast agent diatrizoic acid (diatrizoate). Effects against sewage sludge bacteria were studied in the two test systems by monitoring the biomarkers quinones, polyamines, phospholipids and adenosine triphosphate. Diatrizoate was biotransformed into 2,4,6-triiodo-3,5-diamino-benzoic acid in the ZWT. 2,4,6-Triiodo-3,5-diamino-benzoic acid was stable under the test conditions of the ZWT. Diatrizoate was not eliminated in the OECD 303 A simulation test. It was not adsorbed by the sewage sludge. No effects of the test compound or its aerobic transformation products against the bacteria present in the sewage sludge were detected using phospholipids, quinones, polyamines, and adenosine triphosphate as biomarkers. 相似文献
384.
Klaus Kabelitz 《生态毒理学报》1999,21(1)
志愿协议(VAs)正在作为环境政策的一种新手段出现,因为它们有超过传统政策措施的优势.具体地说,它们是经济上效率更高的.德国工业界涉及众多工业协会、大概是世界上最昂贵的1996年志愿气候保护协议,是以到2005年显著削减CO2为目标的.这项志愿协议的实施是由一个独立机构按年度监测的.从全球来说,志愿协议应当与联合实施和排放交易相互联系,从而使国际气候保护政策更加灵活和成本有效. 相似文献
385.
The synthesis of eleven environmentally relevant mono-, di- and trichlorodibenzothiophenes (2) by photochemical ring-closure of polychlorodiphenylsulfides (1) is described. All monochlorodibenzothiophenes were additionally synthesized starting with a chlorothiophenol in a three-step reaction adapted from the synthesis of methyldibenzothiophenes. 相似文献
386.
387.
Biogeochemical C and N cycles in urban soils 总被引:8,自引:0,他引:8
The percentage of urban population is projected to increase drastically. In 2030, 50.7 to 86.7% of the total population in Africa and Northern America may live in urban areas, respectively. The effects of the attendant increases in urban land uses on biogeochemical C and N cycles are, however, largely unknown. Biogeochemical cycles in urban ecosystems are altered directly and indirectly by human activities. Direct effects include changes in the biological, chemical and physical soil properties and processes in urban soils. Indirect effects of urban environments on biogeochemical cycles may be attributed to the introductions of exotic plant and animal species and atmospheric deposition of pollutants. Urbanization may also affect the regional and global atmospheric climate by the urban heat island and pollution island effect. On the other hand, urban soils have the potential to store large amounts of soil organic carbon (SOC) and, thus, contribute to mitigating increases in atmospheric CO(2) concentrations. However, the amount of SOC stored in urban soils is highly variable in space and time, and depends among others on soil parent material and land use. The SOC pool in 0.3-m depth may range between 16 and 232 Mg ha(-1), and between 15 and 285 Mg ha(-1) in 1-m depth. Thus, depending on the soil replaced or disturbed, urban soils may have higher or lower SOC pools, but very little is known. This review provides an overview of the biogeochemical cycling of C and N in urban soils, with a focus on the effects of urban land use and management on soil organic matter (SOM). In view of the increase in atmospheric CO(2) and reactive N concentrations as a result of urbanization, urban land use planning must also include strategies to sequester C in soil, and also enhance the N sink in urban soils and vegetation. This will strengthen soil ecological functions such as retention of nutrients, hazardous compounds and water, and also improve urban ecosystem services by promoting soil fertility. 相似文献
388.
Chunyan Liu Jirko Holst Zhisheng Yao Nicolas Brüggemann Klaus Butterbach-Bahl Shenghui Han Xingguo Han Bart Tas Andreas Susenbeth Xunhua Zheng 《Atmospheric environment (Oxford, England : 1994)》2009,43(19):3086-3095
We present a methane (CH4) budget for the area of the Baiyinxile Livestock Farm, which comprises approximately 1/3 of the Xilin river catchment in central Inner Mongolia, P.R. China. The budget calculations comprise the contributions of natural sources and sinks as well as sources related to the main land-use in this region (non-nomadic pastoralism) during the growing season (May–September). We identified as important CH4 sources floodplains (mean 1.55 ± 0.97 mg CH4–C m?2 h?1) and domestic ruminants, which are mainly sheep in this area. Within the floodplain significant differences between investigated positions were detected, whereby only positions close-by the river or bayous emitted large amounts of CH4 (mean up to 6.21 ± 1.83 mg CH4–C m?2 h?1). Further CH4 sources were sheepfolds (0.08–0.91 mg CH4–C m?2 h?1) and pasture faeces (1.34 ± 0.22 mg CH4–C g?1 faeces dry weight), but they did not play a significant role for the CH4 budget. In contrast, dung heaps were not a net source of CH4 (0.0 ± 0.2 for an old and 0.0 ± 0.3 μg CH4–C kg?1 h?1 for a new dung heap). Trace gas measurements along two landscape transects (volcano, hill slope) revealed expectedly a mean CH4 uptake (volcano: 76.5 ± 4.3; hill: 28.3 ± 5.3 μg CH4–C m?2 h?1), which is typical for the aerobic soils in this and other steppe ecosystems. The observed fluxes were rarely influenced by topography.The CH4 emissions from the floodplain and the sheep were not compensated by the CH4 oxidation of aerobic steppe soils and thus, this managed semi-arid grassland did not serve as a terrestrial sink, but as a source for this globally important greenhouse gas. The source strength amounted to 1.5–3.6 kg CH4–C ha?1 during the growing season, corresponding to 3.5–8.7 kg C ha?1 yr?1. 相似文献
389.
Synthetic nanoparticles have already been detected in the aquatic environment. Therefore, knowledge on their biodegradability is of utmost importance for risk assessment but such information is currently not available. Therefore, the biodegradability of fullerenes, single, double, multi-walled as well as COOH functionalized carbon nanotubes and cellulose and starch nanocrystals in aqueous environment has been investigated according to OECD standards. The biodegradability of starch and cellulose nanoparticles was also compared with the biodegradability of their macroscopic counterparts. Fullerenes and all carbon nanotubes did not biodegrade at all, while starch and cellulose nanoparticles biodegrade to similar levels as their macroscopic counterparts. However, neither comfortably met the criterion for ready biodegradability (60% after 28 days). The cellulose and starch nanoparticles were also found to degrade faster than their macroscopic counterparts due to their higher surface area. These findings are the first report of biodegradability of organic nanoparticles in the aquatic environment, an important accumulation environment for manmade compounds. 相似文献
390.
Estimating the extent of intraspecific variation in sensitivity to contaminant exposure is important in order to explain variation in the outcome of toxicity tests and to predict the effects of chemical stress on natural populations of plants and animals. However, only few studies provide evident data concerning intraspecific variation in life-history traits caused by a differential response to chemical stress. In this study, we compared the life-history response of six laboratory strains of the midge Chironomus riparius to cadmium exposure in a full life-cycle assay. In addition, the level of genetic variation in all strains was measured at five variable microsatellite loci. Several significant differences in life-history traits among the strains were observed in controls and cadmium treatments. The extent of variation among strains was largest at moderate cadmium concentration (0.42 mg Cd/kg dw). At increased Cd concentrations all strains showed similar levels of high mortality and reduced reproductive success. All strains exhibited considerable levels of genetic impoverishment compared to field populations. Strains with low genetic variation showed reduced fitness in the controls and were more susceptible to Cd exposure. For instance, no reproductive success in the lowest Cd treatment was observed for the strain with the lowest level of genetic diversity. In contrast, this Cd concentration had no negative effects on life-history traits of more variable strains. These results confirm recent findings, that inbreeding and reduced genetic variation influence the reaction of populations towards environmental stress. In addition, we show that the level of genetic variation and inbreeding directly influences the outcome of toxicity tests and contributes to the lack of reproducibility of test results among laboratories. 相似文献