全文获取类型
收费全文 | 105篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 1篇 |
环保管理 | 22篇 |
综合类 | 15篇 |
基础理论 | 26篇 |
污染及防治 | 33篇 |
评价与监测 | 9篇 |
社会与环境 | 1篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2014年 | 5篇 |
2013年 | 13篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 10篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有111条查询结果,搜索用时 15 毫秒
41.
Pregitzer KS Zak DR Talhelm AF Burton AJ Eikenberry JR 《Ecology》2010,91(12):3456-62; discussion 3503-14
In order to better understand the nitrogen (N) cycle, a pulse of 15NO3- was applied in 1998 to a sugar maple (Acer saccharum) dominated northern hardwood forest receiving long-term (1994-2008) simulated atmospheric N deposition. Sugar maple leaf litter and live fine-root 15N were quantified for four years prior to labeling and for 11 subsequent years. Continuous sampling of 15N following addition of the tracer enabled calculation of leaf litter and fine-root N pool turnover utilizing an exponential decay function. Fine-root 15N recovery peaked at 3.7% +/- 1.7% the year the tracer was applied, while leaf litter 15N recovery peaked in the two years following tracer application at approximately 8%. These results suggest shoots are primarily constructed from N taken up in previous years, while fine roots are constructed from new N. The residence time of N was 6.5 years in leaf litter and 3.1 years in fine roots. The longer residence time and higher recovery rate are evidence that leaves were a stronger sink for labeled N than fine roots, but the relatively short residence time of tracer N in both pools suggests that there is not tight intra-ecosystem cycling of N in this mature forest. 相似文献
42.
Genetic differentiation and reproductive incompatibility among Baja California populations of the copepod Tigriopus californicus 总被引:6,自引:0,他引:6
Populations of the harpacticoid copepod Tigriopus californicus were sampled from five sites from San Diego, California, to Playa Altamira, Baja California, Mexico. Allozyme analyses revealed that all the study populations are sharply differentiated genetically. At the extreme, two populations, Punta Baja and Playa Altamira, have no alleles in common at the seven allozyme loci studied. All pairwise interpopulation crosses successfully produced F2 hybrids except those involving the Playa Altamira population. All crosses using Playa Altamira females failed to produce F1 hybrids, while Playa Altamira males successfully produced F1 progeny with females from all other sites. These F1 offspring, however, were completely sterile (with San Diego and Punta Banda females) or only occasionally produced F2 offspring (with Punta Morro and Punta Baja females). These results suggest that allopatric differentiation among Baja populations has resulted in exceptionally high levels of genetic divergence and nearly complete reproductive isolation of the Playa Altamira population, which should now be recognized at the semispecies (or perhaps sibling species) level. 相似文献
43.
The incidence of haemangiomas was ascertained by questionnaire in infants born to 578 consecutive CVS patients and 445 consecutive mid-trimester amniocentesis patients seen at a single institution between 1 January 1989 and 31 May 1991. The incidence of 7·4 per cent reported in the amniocentesis group was comparable to previous estimates of the incidence of haemangiomas in the general population. In contrast, a 21·1 per cent incidence, three-fold higher than that observed in the amniocentesis group, was observed among CVS-exposed infants (P<0·001). This increased incidence was largely confined to patients undergoing a transcervical procedure. No correlation was observed between the incidence of haemangiomas and gestational age at sampling, sample size, number of sampling attempts, or a history of bleeding following the procedure. 相似文献
44.
45.
The Science of Adaptation: A Framework for Assessment 总被引:2,自引:0,他引:2
Smit B. Burton I. Klein R.J.T. Street R. 《Mitigation and Adaptation Strategies for Global Change》1999,4(3-4):199-213
Mitigation and Adaptation Strategies for Global Change - This paper outlines what is meant by "adaptation" to climate change, and how it might be addressed in the IPCC Assessments. Two... 相似文献
46.
47.
48.
Burton GA Greenberg MS Rowland CD Irvine CA Lavoie DR Brooker JA Moore L Raymer DF McWilliam RA 《Environmental pollution (Barking, Essex : 1987)》2005,134(1):133-144
An in situ toxicity and bioaccumulation assessment approach is described to assess stressor exposure and effects in surface waters (low and high flow), the sediment-water interface, surficial sediments and pore waters (including groundwater upwellings). This approach can be used for exposing species, representing major functional and taxonomic groups. Pimephales promelas, Daphnia magna, Ceriodaphnia dubia, Hyalella azteca, Hyalella sp., Chironomus tentans, Lumbriculus variegatus, Hydra attenuatta, Hexagenia sp. and Baetis tibialis were successfully used to measure effects on survival, growth, feeding, and/or uptake. Stressors identified included chemical toxicants, suspended solids, photo-induced toxicity, indigenous predators, and flow. Responses varied between laboratory and in situ exposures in many cases and were attributed to differing exposure dynamics and sample-processing artifacts. These in situ exposure approaches provide unique assessment information that is complementary to traditional laboratory-based toxicity and bioaccumulation testing and reduce the uncertainties of extrapolating from the laboratory to field responses. 相似文献
49.
Iain C. Field Corey J. A. Bradshaw John van den Hoff Harry R. Burton Mark A. Hindell 《Marine Biology》2007,150(6):1441-1452
Southern elephant seals are important apex predators in a highly variable and unpredictable marine environment. In the presence
of resource limitation, foraging behaviours evolve to reduce intra-specific competition increasing a species’ overall probability
of successful foraging. We examined the diet of 141 (aged 1–3 years) juvenile southern elephant seals to test the hypotheses
that differences between ages, sexes and seasons in diet structure occur. We described prey species composition for common
squid and fish species and the mean size of cephalopod prey items for these age groups. Three cephalopod species dominated
the stomach samples, Alluroteuthis antarcticus, Histioteuthis eltaninae and Slosarczykovia circumantarcticus. We found age-related differences in both species composition and size of larger prey species that probably relate to ontogenetic
changes in diving ability and haul-out behaviour and prey availability. These changes in foraging behaviour and diet are hypothesised
to reduce intra-specific food competition concomitant with the increase in foraging niche of growing juveniles. 相似文献
50.
Turner C Williams SM Burton CH Cumby TR Wilkinson PJ Farrent JW 《Journal of environmental science and health. Part. B》1999,34(6):989-1007
This paper describes a pilot scale treatment plant that has been designed and built for the thermal inactivation in pig slurry of two viruses that infect pigs--African swine fever virus (ASFV) and swine vesicular disease virus (SVDV). The plant treats pig slurry continuously at a rate of up to 100 litres/hour and functions by heating the slurry, maintaining at least 99.99% of the slurry at the required temperature for a minimum period of 5 minutes, and then recovering the heat to raise the temperature of the incoming slurry. Results obtained indicated that SVDV was inactivated in pig slurry to below detectable levels with an alkaline pH (pH 7.5 to 8, as is usually the case) at a temperature of between 50 and 55 degrees C. In acidified slurry (pH 6.4), inactivation occurred between 55 and 60 degrees C. The difference in inactivation temperatures was probably due to the presence of free ammonia in the unacidified slurry. ASFV was inactivated by operating the plant at a temperature of 53 degrees C at a pH of 8. 相似文献