全文获取类型
收费全文 | 536篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 5篇 |
环保管理 | 132篇 |
综合类 | 44篇 |
基础理论 | 161篇 |
污染及防治 | 112篇 |
评价与监测 | 51篇 |
社会与环境 | 14篇 |
灾害及防治 | 11篇 |
出版年
2022年 | 5篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 23篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 55篇 |
2012年 | 17篇 |
2011年 | 28篇 |
2010年 | 15篇 |
2009年 | 28篇 |
2008年 | 26篇 |
2007年 | 27篇 |
2006年 | 30篇 |
2005年 | 13篇 |
2004年 | 25篇 |
2003年 | 21篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 11篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1974年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1962年 | 3篇 |
1954年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有544条查询结果,搜索用时 218 毫秒
91.
Phytophagous insects commonly interact through shared host plants. These interactions, however, do not occur in accordance with traditional paradigms of competition, and competition in phytophagous insects is still being defined. It remains unclear, for example, if particular guilds of insects are superior competitors or important players in structuring insect communities. Gall-forming insects are likely candidates for such superior competitors because of their ability to manipulate host plants, but their role as competitors is understudied. We investigate the effect of invasive populations of an oak gall wasp, Neuroterus saltatorius, on a native specialist butterfly, Erynnis propertius, as mediated by their shared host plant, Quercus garryana. This gall wasp occurs at high densities in its introduced range, where we stocked enclosures with caterpillars on trees that varied in gall wasp density. Biomass production of butterflies was lower in enclosures on high-density than on low-density trees because overwintering caterpillars were smaller, and fewer of them eclosed into adults the following spring. To see if the gall wasp induced changes in foliar quality, we measured host plant quality before and after gall induction on 30 trees each at two sites. We found a positive relationship between gall wasp density and the percentage change in foliar C:N, a negative relationship between gall wasp density and the percentage change in foliar water at one site, and no relationship between the percentage change in protein-binding capacity (i.e., phenolics) and gall-wasp density. Additionally, there was a negative relationship between foliar quality and butterfly performance. Our results provide evidence for a plant-mediated impact of an invasive oak gall wasp on a native butterfly and suggest that gall wasps could act as superior competitors, especially when they occur at high densities. 相似文献
92.
Kirstin Dow Benjamin K. Haywood Nathan P. Kettle Kirsten Lackstrom 《Regional Environmental Change》2013,13(6):1235-1244
To examine the factors that support adaptation within a regional and sectoral context, this article explores five climate-sensitive sectors in North and South Carolina (Forestry, Government Administration, Tourism, Water Management, and Wildlife Management) and the role of partnerships, collaborations, and networks in facilitating climate adaptation and related activities. Drawing from 117 online questionnaires and interviews with sector leaders across the Carolinas, the article highlights several key functions of networks in regard to supporting adaptation—intra-sector information sharing; monitoring, data collection, and research; and education and outreach. Furthermore, the analysis examines how climate networks in the region have facilitated the development of bonding, bridging, and linking social capital while also noting factors that have constrained the growth and success of both intra- and cross-sector collaboration. Although no formal, or discrete, state or regional cross-sector climate change network exists in the Carolinas, climate adaptations and capacity-building efforts have been supported by ad hoc and decentralized networks, emerging collegial partnerships within and across sectors, and collaborative efforts to pool expertise and resources. The role of different forms of social capital within these networks is discussed in the context of a contentious political environment where support for activities designed to address climate change is limited. These findings enhance our understanding of the social factors and relational processes that shape and influence capacity to adapt to climate change. 相似文献
93.
Bera M Radcliffe DE Cabrera ML Vencill WK Thompson A Hassan S 《Journal of environmental quality》2011,40(6):1983-1990
17β-estradiol and testosterone are naturally occurring steroids that co-occur in poultry litter. The effects of litter on sorption of these hormones to soil are not known. Sorption isotherms were developed for C-labeled testosterone and H-labeled estradiol in a Cecil sandy clay loam with and without poultry litter addition. The effect of applying the hormones alone (single-sorbate) or together (multisorbate) was also investigated. C-testosterone sorption in soil increased from 2 to 48 h and remained relatively constant thereafter. H-estradiol sorption in soil was relatively constant from 2 to 24 h and then decreased to 72 h. These differences may reflect transformation of the parent hormones to products with different solid-phase affinity. The maximum sorption coefficient () in soil for C-testosterone (20.2 mL g) was similar to that for H-estradiol (19.6 mL g) in single-sorbate experiments. When hormones were applied together, sorption of both hormones in soil decreased, but the C-testosterone (12.5 mL g) was nearly twice as large as the H-estradiol (7.4 mL g). We propose this resulted from competition between the hormones and their transformation products for sorption sites, with C-testosterone and its expected transformation product (androstenedione) being better competitors than H-estradiol and its expected transformation product (estrone). When poultry litter was mixed with soil, sorption increased for H-estradiol but decreased for C-testosterone. This may have been because poultry litter slowed the transformation of parent hormones. Our results show that poultry litter could have important effects on the mobility of estradiol and testosterone. 相似文献
94.
Private domestic gardens contribute substantially to the biodiversity of urban areas and benefit human health and well-being.
We previously reported a study of 267 gardens across five cities in the United Kingdom in which variation in geographical
and climatic factors had little bearing on the richness, diversity and composition of plant species. We therefore hypothesise
that garden management is an important factor in determining garden characteristics. Here, from the same sample of gardens,
we investigate potential associations between the uses to which people put their gardens, the types of management activities
they undertake, and the characteristics of those gardens. Householders (n = 265) completed a questionnaire detailing various aspects of garden use and management activities. The majority of respondents
used their gardens chiefly for relaxation, recreation, and eating. Fewer than one fifth included “gardening” amongst their
garden uses even though all performed some garden management, suggesting that not all management activity resulted from an
interest in gardening. Garden-watering and lawn-mowing were the most prevalent activities and were predictors of other types
of management including weeding, vegetation-cutting, leaf-collection, and dead-heading flowers. A number of these activities
were associated with one another, the richness and composition of plant species, and the number of land uses in gardens. However,
relationships between management activities and the amount of tall vegetation were less consistent, and garden management
appeared to be independent of garden area. More species of amphibians, birds, and mammals were observed in gardens with ponds
and in which efforts were made to attract wildlife, particularly by providing drinking water. This study supports the hypothesis
that garden use and management is associated with garden characteristics. 相似文献
95.
Donald B. Thompson 《Journal of Agricultural and Environmental Ethics》2011,24(2):165-194
The term natural is effective in the marketing of a wide variety of foods. This ambiguous term carries important meaning in Western culture.
To challenge an uncritical understanding of natural with respect to food and to explore the ambiguity of the term, the development of Western ideas of nature is first discussed. Personification and hypostasization of nature are given special emphasis. Leo Marx’s idea of the pastoral
design in literature is then used to explore the meaning of natural as applied to food, emphasizing Marx’s distinction between
a sentimental and a complex pastoral. The latter is applied to natural as a means of collapsing a dichotomy of man and nature to the idea of second nature. From this perspective an understanding of the industrialization of the food system and the importance of local and organic
food are considered. The extent to which processed foods might properly be considered natural is raised and discussed for
several common foods. Although marketing of natural foods might make us think that we consume nature, I suggest that what
is consumed is more appropriately second nature. I suggest that in order to maintain a critical perspective about one’s relationship
to the natural world, everyone should make an attempt to experience the complex pastoral with respect to at least something
that is consumed as food. When nature is understood as second nature in the context of a complex pastoral, the question of
whether a food or ingredient is to be considered natural is replaced by deliberative thought based on our best knowledge and
judgment, and the result will be less constrained by ideology. 相似文献
96.
Assessments of watershed condition for aquatic and riparian species often have to rely on expert opinion because of the complexity of establishing statistical relationships among the many factors involved. Such expert-based assessments can be difficult to document and apply consistently over time and space. We describe and reflect on the process of developing a computer-based decision support application from expert judgments for assessing aquatic and riparian conditions over the 100,000?km2 managed by the US federal government under the Northwest Forest Plan. The decision support system helped structure and document the assessment process and provided consistency and transparency to the evaluation methodology. However, many decisions and trade-offs were required in the expert engagement and model-building processes. Knowledge elicitation in an interactive group had a number of benefits over nominal group or Delphi processes, but efficient knowledge capture required considerable planning and expertise in the subject matter and modeling process. Communicating model results for validation was problematic and only effectively accomplished via in-person workshops. The choice to use different expert groups for each biophysical province provided more opportunities for participation and promoted greater ownership in the assessment, but it also led to increased variation among the resulting model structures. We propose three possible approaches for better managing the consistency of assessment models when multiple expert groups are involved. 相似文献
97.
Lam N Nicas M Ruiz-Mercado I Thompson LM Romero C Smith KR 《Journal of environmental monitoring : JEM》2011,13(8):2172-2181
The use of wood-fired steam baths, or temazcales, is a potentially dangerous source of CO exposure in Guatemalan Highland communities where adults and children use them regularly for bathing, relaxation, and healing purposes. Physical characteristics of children predispose them to absorb CO faster than adults, placing them at greater exposure and health risks. Efforts to quantify temazcal exposures across all age groups, however, have been hampered by the limitations in exposure measurement methods. In this pilot study we measured COHb levels in children and adults following use of the temazcal using three field-based, non-invasive CO measurement methods: CO-oximetry, exhaled breath, and by estimation of COHb using micro-environmental concentrations and time diaries. We then performed a brief comparison of methods. Average CO concentrations measured during temazcal use were 661 ± 503 ppm, approximately 10 times the 15 min WHO guideline. Average COHb levels for all participants ranged from 12-14% (max of 30%, min 2%), depending on the method. COHb levels measured in children were not significantly different from adults despite the fact that they spent 66% less time exposed. COHb measured by CO-oximetry and exhaled breath had good agreement, but precision of the former was affected substantially by random instrument error. The version of the field CO-oximeter device used in this pilot could be useful in screening for acute CO exposure events in children but may lack the precision for monitoring the burden from less extreme, but more day-to-day CO exposures (e.g. indoor solid fuel use). In urban settings, health effects in children and adults have been associated with chronic exposure to ambient CO concentrations much lower than measured in this study. Future research should focus on reducing exposure from temazcales through culturally appropriate modifications to their design and practices, and targeted efforts to educate communities on the health risks they pose and actions they can take to reduce this risk. 相似文献
98.
Christopher James Lemieux Jessica Thompson D. Scott Slocombe Rudy Schuster 《Journal of Environmental Planning and Management》2015,58(4):654-677
It has been argued that regional collaboration can facilitate adaptation to climate change impacts through integrated planning and management. In an attempt to understand the underlying institutional factors that either support or contest this assumption, this paper explores the institutional factors influencing adaptation to climate change at the regional scale, where multiple public land and natural resource management jurisdictions are involved. Insights from two mid-western US case studies reveal that several challenges to collaboration persist and prevent fully integrative multi-jurisdictional adaptation planning at a regional scale. We propose that some of these challenges, such as lack of adequate time, funding and communication channels, be reframed as opportunities to build interdependence, identify issue-linkages and collaboratively explore the nature and extent of organisational trade-offs with respect to regional climate change adaptation efforts. Such a reframing can better facilitate multi-jurisdictional adaptation planning and management of shared biophysical resources generally while simultaneously enhancing organisational capacity to mitigate negative effects and take advantage of potentially favourable future conditions in an era characterised by rapid climate change. 相似文献
99.
Hasti Daraei Kimia Toolabian Ian Thompson Guanglei Qiu 《Frontiers of Environmental Science & Engineering》2022,16(2):19
100.
Christine E. Thacker Andrew R. Thompson Dawn M. Roje Emily Y. Shaw 《Marine Biology》2008,153(3):375-385
Species of the reef goby genus Gnatholepis exhibit enormous geographic ranges with little evidence of population segregation detectable based on mitochondrial DNA.
To determine if genetic differentiation is evident with more rapidly evolving markers, seven microsatellite loci were screened
from the species Gnatholepis anjerensis and G. scapulostigma and population segregation was tested among fish from across the South Pacific. Both AMOVA and pairwise F
ST analyses showed that, in concordance with previous mitochondrial results, most genetic variance occurs within individual
populations, as population differentiation is evident only over the largest distances (>3,700 km). This result is contrasted
with previous studies demonstrating that despite their relatively long larval periods, some gobiid fishes exhibit population
differentiation on small (<100 km) geographic scales. Coalescence analysis showed that current Pacific populations of these
species originated in the Pleistocene, presumably related to sea level fluctuations associated with episodes of glaciation.
However, rate analysis based on a phylogeny of Gnatholepis species indicates that the species themselves are much older, consistent with a complex history of rapid, short-term population
contractions and expansions, with corresponding rapid dispersal. 相似文献