全文获取类型
收费全文 | 9650篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 767篇 |
环保管理 | 1207篇 |
综合类 | 937篇 |
基础理论 | 3109篇 |
污染及防治 | 1728篇 |
评价与监测 | 1008篇 |
社会与环境 | 894篇 |
出版年
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1474篇 |
2017年 | 1373篇 |
2016年 | 1197篇 |
2015年 | 124篇 |
2014年 | 13篇 |
2013年 | 7篇 |
2012年 | 459篇 |
2011年 | 1340篇 |
2010年 | 690篇 |
2009年 | 597篇 |
2008年 | 877篇 |
2007年 | 1225篇 |
2006年 | 1篇 |
2005年 | 18篇 |
2004年 | 33篇 |
2003年 | 61篇 |
2002年 | 97篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 9篇 |
1991年 | 1篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1935年 | 2篇 |
排序方式: 共有9651条查询结果,搜索用时 15 毫秒
391.
Kuselah Mae M. Tayaban Katherine L. Pintor Pierangeli G. Vital 《Environment, Development and Sustainability》2018,20(3):1311-1328
Prawn aquaculture industry is one of the developing economic activities in the Philippines. Generally, a wide range of microalgae typically grow and proliferate in many aquaculture ponds. However, certain species of microalgae have the ability to form harmful algal blooms (HABs) which often bring damaging consequences to the aquaculture industry, food safety, and the environment. The study aims to identify and characterize the composition of microalgae (particularly Cyanophyta) that are capable of forming HABs in selected freshwater prawn culture ponds in Central Luzon, Philippines, using morphological, ultrastructural, and molecular characterizations. From water samples collected in ten selected ponds across Central Luzon (Bulacan, Nueva Ecija, Pampanga, Tarlac, and Zambales), potential HAB formers such as Oscillatoria agardhii, O. princeps, Microcystis aeruginosa, and M. wesenbergii were observed to have occurred mostly, while Anabaena circinalis was only observed in one site. Both morphological and ultrastructural methods brought upon some challenges and limitations while molecular methods using 16S rRNA gene and phylogenetic analysis which were optimized in this study offered better and more efficient ways of identification and were helpful in resolving genus-level and species-level relationships. The influence of physicochemical properties of pond water, especially nutrient levels (nitrate, nitrite, and orthophosphate) on the occurrence of these cyanobacteria was also analyzed. As a pioneering study on freshwater HABs in aquaculture ponds in the country, results of the study can provide information to improve the knowledge in bloom occurrence and prediction, and to develop freshwater HAB prevention and control methods. 相似文献
392.
Martyn N. Futter Lars Högbom Salar Valinia Ryan A. Sponseller Hjalmar Laudon 《Ambio》2016,45(2):188-202
We present a framework for evaluating and communicating effects of human activity on water quality in managed forests. The framework is based on the following processes: atmospheric deposition, weathering, accumulation, recirculation and flux. Impairments to water quality are characterized in terms of their extent, longevity and frequency. Impacts are communicated using a “traffic lights” metaphor for characterizing severity of water quality impairments arising from forestry and other anthropogenic pressures. The most serious impairments to water quality in managed boreal forests include (i) forestry activities causing excessive sediment mobilization and extirpation of aquatic species and (ii) other anthropogenic pressures caused by long-range transport of mercury and acidifying pollutants. The framework and tool presented here can help evaluate, summarize and communicate the most important issues in circumstances where land management and other anthropogenic pressures combine to impair water quality and may also assist in implementing the “polluter pays” principle. 相似文献
393.
Positive plant–animal interactions are important in community ecology, but relatively little attention has been paid to their
effect on the production of mangroves, dominant halophytic trees in tropical coastal marshes. Here, the role of fiddler crab
(Uca spp.) burrowing on the growth and production of the white mangrove, Laguncularia racemosa (<2 years old), was examined in a restored marsh in Tampa Bay, Florida (27°41.65 N, 82°30.34 W) with manipulative experiments
from June 2006 to May 2007. Fiddler crab burrowing significantly increased mangrove height by 27%, trunk diameter by 25%,
and leaf production by 15%, compared to mangroves in crab exclusion enclosures. Additionally, the exclusion of fiddler crabs
significantly increased interstitial water salinity from 32.4 to 44.2, and decreased the oxidation–reduction potential of
the low organic sediments, but did not affect soil pH or sulfide concentration. Mangrove height, trunk diameter, and leaf
production along a transect that varied in crab burrow density were positively associated with the number of crab burrows.
Further, the density of sympatric Spartina alterniflora shoots was positively correlated with crab burrow density along the transect. As in temperate marshes, fiddler crabs can
have significant ecological effects on mangrove communities, serving as ecological engineers by modulating the amount of resources
available to marsh plants, and by altering the physical, chemical, and biological state of these soft sediment communities.
In restored coastal systems that typically have very poor sediment quality, techniques such as soil amendment could be used
to facilitate a more natural interaction between crabs and mangroves in ecosystem development. 相似文献
394.
We performed male attraction experiments and staged courtship sequences to test for non-random mating with respect to social
behavioral phenotype in the comb-footed spider, Anelosimus studiosus. While asocial behavior is the dominant phenotype in all A. studiosus populations examined to date, a social phenotype approaches a frequency of 15% in colder environments. We collected test
subjects from higher latitude polymorphic populations and scored all individuals as to their behavioral phenotype prior to
their use in these trials. Males of both phenotypes differentially approached and courted social females over asocial females
and no-spider controls. By offering males different numbers of females of one type vs. the other in subsequent trials, we
determined that the difference in attractiveness between the two phenotypes social/asocial is 1.5/1. Both the web produced
by a female and a female that has been removed from its web attract males. We suggest that the male attracting pheromone is
present on females and is also attached to silk threads. Staged encounters completed between males and females of the respective
phenotypes demonstrated that courting males suffer significantly less pre-copulatory sexual cannibalism with social females
than with asocial ones, and thus, female social tendency is phenotypically linked to sexual aggression. We propose that the
male preference for social females is adaptive because of the observed asymmetry in courtship success. 相似文献
395.
Marianne Robert Laurent Dagorn Jean Louis Deneubourg David Itano Kim Holland 《Marine Biology》2012,159(4):907-914
Several lines of evidence indicate that aggregations of yellowfin tuna associated with floating objects are more frequently
composed of small animals than larger ones. Also, the diet of small yellowfin tuna caught at anchored fish aggregating devices
(FADs) around Oahu, Hawaii, was found to shift quite rapidly when these fish reached approximately 50 cm FL. In order to test
for ontogenetic changes in aggregation behavior, we tagged and released two distinct size classes of yellowfin tuna in an
array of anchored FADs around Oahu, Hawaii. Twenty-four yellowfin tuna 30–39 cm FL and 16 yellowfin tuna 63–83 cm FL were
tagged with acoustic transmitters and released near anchored FADs equipped with automated acoustic receivers. Fish in the
smaller size class stayed about 2.5 times longer at individual FADs than the larger fish (mean 4.05 days vs. 1.65 days) and
displayed larger horizontal movements within the array. However, the durations of unassociated phases, residence times in
the entire FAD array, percentage of time spent associated with FADs and numbers of movements between FADs did not show any
difference between the two size groups. The observed size-dependent behavior is discussed in terms of physiological abilities,
diet segregation and anti-predator behavior. 相似文献
396.
Robin Warner Mary Kaidonis Olivia Dun Kerrylee Rogers Yubing Shi Thang T. X. Nguyen Colin D. Woodroffe 《Sustainability Science》2016,11(4):661-677
Increasing value is attributed to mangroves due to their considerable capacity to sequester carbon, known as ‘blue carbon’. Assessments of opportunities and challenges associated with estimating the significance of carbon sequestered by mangroves need to consider a range of disciplinary perspectives, including the bio-physical science mangroves, social and economic issues of land use, local and international law, and the role of public and private finance. We undertook an interdisciplinary review based on available literature and fieldwork focused on parts of the Mekong River Delta (MRD). Preliminary estimates indicate mangrove biomass may be 70–150 t ha?1, but considerably larger storage of carbon occurs in sediments beneath mangroves. These natural stores of carbon are compromised when mangroves are removed to accommodate anthropogenic activities. Mangroves are an important resource in the MRD that supplies multiple goods and services, and conservation or re-establishment of mangroves provides many benefits. International law and within-country environmental frameworks offer increasing scope to recognize the role that mangrove forests play through carbon sequestration, in order that these might lead to funding opportunities, both in public and private sectors. Such schemes need to have positive rather than negative impacts on the livelihoods of the many people living within and adjacent to these wetlands. Nevertheless, many challenges remain and it will require further targeted and coordinated scientific research, development of economic and social incentives to protect and restore mangroves, supportive law and policy mechanisms at global and national levels, and establishment of long-term financing for such endeavours. 相似文献
397.
The hydrogeomorphic (HGM) approach to wetland classification and functional assessment is becoming more widespread in the
United States but its use has been limited by the length of time needed to develop appropriate data sets and functional assessment
models. One particularly difficult aspect is the transferability among geographic regions of specific models used to assess
wetland function. Sharing of models could considerably shorten development and implementation of HGM throughout the United
States and elsewhere. As hydrology is the driving force behind wetland functions, we assessed the comparability of hydrologic
characteristics of three HGM subclasses (slope, headwater floodplain, mainstem floodplain) using comparable long-term hydrologic
data sets from different regions of the United States (Ridge and Valley Province in Pennsylvania and the Willamette Valley
in Oregon). If hydrology by HGM subclass were similar between different geographic regions, it might be possible to more readily
transfer extant models between those regions. We found that slope wetlands (typically groundwater-driven) had similar hydrologic
characteristics, even though absolute details (such as depth of water) differed. We did not find the floodplain subclasses
to be comparable, likely due to effects of urbanization in Oregon, regional differences in soils and, perhaps, climate. Slight
differences in hydrology can shift wetland functions from those mediated by aerobic processes to those dominated by anaerobic
processes. Functions such as nutrient cycling can be noticeably altered as a result. Our data suggest considerable caution
in the application of models outside of the region for which they were developed. 相似文献
398.
Hydroponic root mats for wastewater treatment—a review 总被引:2,自引:0,他引:2
Zhongbing Chen Diego Paredes Cuervo Jochen A. Müller Arndt Wiessner Heinz Köser Jan Vymazal Matthias Kästner Peter Kuschk 《Environmental science and pollution research international》2016,23(16):15911-15928
Hydroponic root mats (HRMs) are ecotechnological wastewater treatment systems where aquatic vegetation forms buoyant filters by their dense interwoven roots and rhizomes, sometimes supported by rafts or other floating materials. A preferential hydraulic flow is created in the water zone between the plant root mat and the bottom of the treatment system. When the mat touches the bottom of the water body, such systems can also function as HRM filter; i.e. the hydraulic flow passes directly through the root zone. HRMs have been used for the treatment of various types of polluted water, including domestic wastewater; agricultural effluents; and polluted river, lake, stormwater and groundwater and even acid mine drainage. This article provides an overview on the concept of applying floating HRM and non-floating HRM filters for wastewater treatment. Exemplary performance data are presented, and the advantages and disadvantages of this technology are discussed in comparison to those of ponds, free-floating plant and soil-based constructed wetlands. Finally, suggestions are provided on the preferred scope of application of HRMs. 相似文献
399.
The impacts of the waterfront development in Iskandar Malaysia 总被引:1,自引:0,他引:1
Suk-Wah Woo Abdelnaser Omran Chee-Leong Lee Mohd Hanizun Hanafi 《Environment, Development and Sustainability》2017,19(4):1293-1306
The increasing number of waterfront projects shows that the concept of waterfront development has contributed to the advancement of the Malaysian construction industry. This study seeks to assess the impacts of the implementation of waterfront development in Iskandar Malaysia eliciting the perceived relative importance of these impacts. A comprehensive literature review has been conducted to collate the potential impacts of the waterfront development. A total of 363 sets of questionnaires were distributed to the contractors and developers registered under G7 category of the Construction Industry Development Board in Malaysia. Results show that the most significant influence of the waterfront development is related to economic benefits, while environmental impacts are not considered as a priority for this category of stakeholders. In addition, this study also indicates that the implementation of the waterfront projects has generated numerous job opportunities within the developed region. Moreover, exchanging knowledge in the planning and managing of the waterfront development is imperative to the development of the waterfront projects. Nevertheless, the shortcomings of these developments, such as the negative environmental impact on natural beaches and the coastline (i.e. pollution) as well as human-related issues (i.e. excessive human settlement), should not be taken lightly. This research confirms that the reclamation of land for waterfront development is closely correlated with the destruction of these natural structures. 相似文献
400.
MIRIAM MIRANDA CAREL DIEPERINK PIETER GLASBERGEN 《Environment, Development and Sustainability》2007,9(1):1-19
This article analyses the application of voluntary environmental agreements (VEAs) in watershed protection in Costa Rica.
Next to an involvement of private energy firms, the Costa Rican state, and farmers, the participation of NGOs is a remarkable
feature. From an analysis of these multi-stakeholder arrangements, it is concluded that these arrangements bring benefits
to all actors involved. VEAs have been able to grow as powerful policy instruments, generating positive environmental effects.
Essential is their embedded ness in a broader set of environmental policies, especially related to forest management
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献