全文获取类型
收费全文 | 1571篇 |
免费 | 5篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 71篇 |
环保管理 | 80篇 |
综合类 | 522篇 |
基础理论 | 362篇 |
污染及防治 | 362篇 |
评价与监测 | 97篇 |
社会与环境 | 68篇 |
灾害及防治 | 10篇 |
出版年
2017年 | 14篇 |
2016年 | 20篇 |
2014年 | 21篇 |
2013年 | 69篇 |
2012年 | 22篇 |
2011年 | 45篇 |
2010年 | 44篇 |
2009年 | 48篇 |
2008年 | 66篇 |
2007年 | 51篇 |
2006年 | 46篇 |
2005年 | 45篇 |
2004年 | 41篇 |
2003年 | 37篇 |
2002年 | 48篇 |
2001年 | 59篇 |
2000年 | 54篇 |
1999年 | 34篇 |
1998年 | 20篇 |
1997年 | 30篇 |
1996年 | 28篇 |
1995年 | 30篇 |
1994年 | 28篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 36篇 |
1990年 | 50篇 |
1989年 | 23篇 |
1988年 | 27篇 |
1987年 | 20篇 |
1985年 | 21篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 30篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1974年 | 17篇 |
1972年 | 17篇 |
1971年 | 12篇 |
1969年 | 11篇 |
1968年 | 12篇 |
1967年 | 23篇 |
1966年 | 19篇 |
1965年 | 13篇 |
1964年 | 12篇 |
1962年 | 13篇 |
1958年 | 14篇 |
1957年 | 12篇 |
排序方式: 共有1582条查询结果,搜索用时 15 毫秒
941.
Ammophila arenaria (marram or European beach grass) for dune stabilization in South Africa in the past and present, its present distribution
in South Africa, and the perceptions of coastal management agencies and the public about its further use. The planting of
A. arenaria became the most important means of dune stabilization, by human intervention, along the South African Cape coast in this
century. Its modern distribution from the semiarid west coast to the subtropical shores of the Eastern Cape extends through
various climatic zones. Although historical data are missing for some areas, there is no indication of its unaided spread.
A. arenaria occurs at most sites because of its prior planting. The South African climate appears to affect its vigor. However, concern
about the use of the alien grass has been raised since it has proved to be a highly invasive species in other parts of the
world, particularly along the North American west coast and in Tasmania. While the CSIR (Council of Scientific and Industrial
Research) promotes its use, CNC (Cape Nature Conservation) follows a policy that restricts the use of any alien plant, including
A. arenaria, and requests further research on its invasive properties. Although a questionnaire survey shows that stabilization sites
featuring large areas of A. arenaria are accepted by the South African public, current coastal management practices need to be analyzed critically. A thorough
investigation of the potential invasiveness of A. arenaria on South African coastal dunes will be essential and shed new light on the American A. arenaria problem. 相似文献
942.
Evaluation of a respirometric test method to determine the heterotrophic yield coefficient of activated sludge bacteria 总被引:1,自引:0,他引:1
The heterotrophic yield coefficient of activated sludge bacteria is an important parameter in the field of wastewater degradation kinetics and the determination of degradation kinetics of defined chemicals. With the help of easily biodegradable organic compounds like glucose and acetate the respiration kinetics of degrading activated sludge bacteria was studied. The results of the respiration analysis were transformed to examine the degradation and respiration kinetics of municipal wastewaters at different food to microorganism ratios (F/M ratios). It was proved that the heterotrophic yield coefficient of aerobically degrading activated sludge bacteria could reliably be determined and that the heterotrophic yield coefficient was independent of the F/M ratio over a wide range. 相似文献
943.
Ringed seal (Phoca hispida) and bearded seal (Erignathus barbatus) are the main prey of polar bears (Ursus maritimus), and information on organochlorines (OCs) in these pinniped species is important to understand the transport, fate and effects of persistent organic pollutants in the Arctic ecosystem. Thus, OCs were analysed in blood samples of bearded and ringed seals from the coastal ecosystem of the north-western Svalbard archipelago (Kongsfjorden, 78.55degrees N). The relative contribution of OCs could be ranked as follows: Ringed seal females: sigmaPCB > sigma DDT > sigma CHL > sigma HCH > HCB > Mirex. Ringed seal males: sigma PCB > or = sigma DDT > sigma CHL > sigma HCH > or = HCB > Mirex. Bearded seal females: sigma PCB > sigma HCH > or = sigma CHL > sigma DDT > Mirex > HCB. Bearded seal males: sigma PCB > sigma DDT > or = sigma CHL > sigma HCH > Mirex > or = HCB. The concentrations of sigmaPCB and sigma DDT were higher in ringed seals than in bearded seals, whereas sigma HCH was higher in bearded than in ringed seals. In ringed seal females and males sigma PCB was 337 +/- 95 ng/g (n= 6) and 625 +/- 443 ng/g (n=6), whereas sigma DDT was 165 +/- 47 ng/g (n=6) and 621 +/- 559 ng/g (n = 6), respectively. In bearded seal females and males, sigmaPCB was 159 +/- 132 ng/g (n = 6) and 248 +/- 93 ng/g (n = 5), whereas sigmaDDT was 46 +/- 41 ng/g (n = 6) and 161 +/- 71 ng/g (n = 5), respectively. The inter-species differences are caused by a higher trophic position of ringed seals in the Svalbard ecosystem compared to bearded seals. OC levels in ringed seals at Svalbard are similar to those reported from the North-American Arctic and in the lower range compared to previously reported data from Svalbard. 相似文献
944.
Michael U. Ben-Eli 《Sustainability Science》2018,13(5):1337-1343
A systems perspective is used to discuss the concept of sustainability. From this perspective, it is argued, sustainability can be regarded as a system state that is mediated by specific structures. This is fundamentally different from regarding sustainability merely as a normative goal, as it is presently regarded by most. Insight into the kinds of structures which mediate a system’s state open the door to proactive design of new structures and mechanisms, which are necessary for yielding effective change: in this case, promoting the sustainability agenda. The kind of change required to transform the prevailing trajectory of human affairs is presented as a second order change: a change that requires a major shift, and a complete transformation of the system itself, not only in a few aspects of its behavior. A new definition of sustainability is offered, anchored in the interaction of a population and the carrying capacity of its environment. From this definition, five core sustainability principles are derived, along with their respective policy and operational implications. Together, these principles prescribe the conditions that must be met to attain sustainability as an enduring state. The principles themselves form an integrated, systemic set, which requires them to be acted on simultaneously. A piecemeal approach—focusing on one aspect while neglecting others—is not likely to yield effective results for the whole. 相似文献
945.
Terleph Thomas A. Malaivijitnond S. Reichard U. H. 《Behavioral ecology and sociobiology》2018,72(1):1-21
Behavioral Ecology and Sociobiology - In recent years, research on insect motor behaviour―locomotion in particular―has provided a number of important new insights, many of which became... 相似文献
946.
Banajarani?Panda S.?Chidambaram N.?Ganesh V.?S.?Adithya K.?Pradeep U.?Vasudevan A.?L.?Ramanathan Shyam?Ranjan M.?V.?PrasannaEmail author K.?Paramaguru 《Environment, Development and Sustainability》2018,20(5):2243-2259
Mountain front recharge (MFR) is the contribution of mountains to recharge the aquifers in the adjacent basins. The estimation of MFR is essential to obtain a detailed investigation of recharge of the groundwater at the mountain front. This study summarises the current understanding of recharge processes by comparing daily groundwater fluctuation to daily rainfall and identifies the recharge rates. The recharge rates vary with time due to difference in water table depth and travel time. Thus to understand the MFR along the foothills of Courtallam, a total of 14 surface water, rainwater and groundwater samples were collected and measured for stable isotopes. The isotopic data were used to investigate the recharge process and to identify the elevations to recharge. The study findings also suggest that predominantly rainfall along the foothills contributes recharge to the riparian zone (basin block region), whereas foothill regions receive recharge from rainfall over mountain block. 相似文献
947.
Migration and reclamation in Northeast China in response to climatic disasters in North China over the past 300?years 总被引:5,自引:0,他引:5
Climatic disaster-induced migration and its effects on land exploitation of new settlements is a crucial topic that needs
to be researched to better understand the impact of climate change and human adaptation. This paper focuses on the process
and mechanism of migrant–reclamation in Northeast China in response to climatic disasters over the past 300 years. The research
used comparative analysis of key interlinked factors in this response involving drought/flood events, population, cropland
area, farmer revolts, administrations establishment, and land reclamation policies. It draws the following conclusions: (1)
seven peaks of migrants–reclamation in Northeast China were evident, most likely when frequent climatic disasters happened
in North China, such as the drought–flood in 1851–1859, drought in 1875–1877, and drought 1927–1929; (2) six instances of
policy transformation adopted to cope with extreme climatic events, including distinctive examples like changing to a firm
policy prohibiting migration in 1740 and a subsequent lifting of that prohibition in 1860; and (3) the fast expansion of the
northern agricultural boundary since the middle of the nineteenth century in this area benefited from a climate change trend
from a cold period into a warm period. Altogether, over the past 300 years, extreme climatic disasters in North China have
deepened the contradiction between the limited land resources and the rapidly increasing population and have resulted in migration
and reclamation in Northeast China. Climate, policy, and reclamation constructed an organic chain of response that dominated
the land use/cover change process of Northeast China. 相似文献
948.
Policy and practice in Myanmar's protected area system 总被引:1,自引:0,他引:1
Myint Aung U 《Journal of environmental management》2007,84(2):188-203
Myanmar's protected area (PA) system began nearly 150 years ago under royal patronage. Park policies and practices, embodied in 19 pieces of legislation developed sporadically during and after the colonial period. As a result of the FAO-UNDP's Nature Conservation and National Parks Project (1981-1985) the government established the Nature & Wildlife Conservation Division and placed it within the Forest Department as the agency responsible for PA management. As a consequence the number of parks increased from 14 to 33. Myanmar's median park size is less than 50 km(2), but only five parks (15%) are larger than 1000 km(2). Most parks conserve terrestrial habitats; parks encompassing inland wetlands, mangrove, and marine habitats are limited in number and size. Existing PAs unequally represent Myanmar's ecosystems; the Malay Transition, Burmese coast, Burmese Transition and Cardamom Mountains bio-units are under-represented within the system. The effective total PA size (i.e., area of all parks less the area of 13 paper parks) is currently about 2.1%. Budgetary support for parks increased 11% since 1996, but is insufficient to address park needs, particularly in remote parks that are understaffed. Limited education and training of PA staff is a major factor limiting effective park management. Fifty-eight percent of park wardens are educated as foresters, and 42% have university degrees. The average posting in a park is 4 years, which is less than ideal for management continuity. Recommended actions to secure Myanmar's PAs include evaluation and reformulation of policies, increasing representation of Myanmar's habitats within the PA system, management planning, and standardizing protocols for anti-poaching patrols and other forms of law enforcement. Improved leadership training for wardens and range forest officers can also improve park management. Funding for community relations and more integrated management of parks and people can reduce conflicts, while environmental education and outreach activities can provide some needed services. Finally, new ways and means are needed to support these activities. Myanmar's PAs need creative and sustainable means of support, including partnerships with non-government organizations to supplement traditional means of support. 相似文献
949.
Interactions between environment, species traits, and human uses describe patterns of plant invasions 总被引:2,自引:0,他引:2
Although invasive alien species (IAS) are a major threat to biodiversity, human health, and economy, our understanding of the factors controlling their distribution and abundance is limited. Here, we determine how environmental factors, land use, life-history traits of the invaders, residence time, origin, and human usage interact to shape the spatial pattern of invasive alien plant species in South Africa. Relationships between the environmental factors and the extrinsic and intrinsic attributes of species were investigated using RLQ analysis, a multivariate method for relating a species-attribute table to an environmental table by way of a species presence/absence table. We then clustered species according to their position on the RLQ axes, and tested these groups for phylogenetic independence. The first three axes of the RLQ explained 99% of the variation and were strongly related to the species attributes. The clustering showed that, after accounting for environmental factors, the spatial pattern of IAS in South Africa was driven by human uses, life forms, and reproductive traits. The seven clusters of species strongly reflected geographical distribution, but also intrinsic species attributes and patterns of human use. Two of the clusters, centered on the genera Acacia and Opuntia, were phylogenetically non-independent. The remaining clusters comprised species of diverse taxonomic affinities, but sharing traits facilitating invasion in particular habitats. This information is useful for assessing the extent to which the potential spread of recent introductions can be predicted by considering the interaction of their biological attributes, region of origin, and human use. 相似文献
950.
Life cycle assessment of municipal solid waste management methods: Ankara case study 总被引:1,自引:0,他引:1
Different solid waste management system scenarios were developed and compared for the Municipal Solid Waste Management System of Ankara by using the life cycle assessment (LCA) methodology. The solid waste management methods considered in the scenarios were collection and transportation of wastes, source reduction, Material Recovery Facility (MRF)/Transfer Stations (TS), incineration, anaerobic digestion and landfilling. The goal of the study was to determine the most environmentally friendly option of MSWM system for Ankara. The functional unit of the study was the amount of solid waste generated in the system area of concern, which are the districts of Ankara. The life cycle inventory analysis was carried out by IWM Model-1. The inputs and outputs of each management stage were defined and the inventory emissions calculated by the model were classified in to impact categories; non-renewable energy sources exhausting potential, final solid waste as hazardous and non-hazardous, global warming, acidification, eutrophication and human toxicity. The impacts were quantified with the weighing factors of each category to develop the environmental profiles of each scenario. In most of the categories, Source Reduction Scenario was found to be the most feasible management method, except the global warming category. The lowest contribution to GWP was calculated for the anaerobic digestion process. In the interpretation and improvement assessment stage, the results were further evaluated and recommendations were made to improve the current solid waste management system of Ankara. 相似文献