全文获取类型
收费全文 | 17267篇 |
免费 | 173篇 |
国内免费 | 120篇 |
专业分类
安全科学 | 438篇 |
废物处理 | 511篇 |
环保管理 | 2203篇 |
综合类 | 4580篇 |
基础理论 | 3977篇 |
环境理论 | 14篇 |
污染及防治 | 4424篇 |
评价与监测 | 790篇 |
社会与环境 | 549篇 |
灾害及防治 | 74篇 |
出版年
2018年 | 219篇 |
2017年 | 222篇 |
2016年 | 295篇 |
2015年 | 260篇 |
2014年 | 321篇 |
2013年 | 1160篇 |
2012年 | 418篇 |
2011年 | 632篇 |
2010年 | 435篇 |
2009年 | 543篇 |
2008年 | 665篇 |
2007年 | 670篇 |
2006年 | 594篇 |
2005年 | 451篇 |
2004年 | 476篇 |
2003年 | 483篇 |
2002年 | 461篇 |
2001年 | 560篇 |
2000年 | 397篇 |
1999年 | 267篇 |
1998年 | 196篇 |
1997年 | 192篇 |
1996年 | 228篇 |
1995年 | 228篇 |
1994年 | 250篇 |
1993年 | 207篇 |
1992年 | 222篇 |
1991年 | 216篇 |
1990年 | 237篇 |
1989年 | 216篇 |
1988年 | 188篇 |
1987年 | 182篇 |
1986年 | 173篇 |
1985年 | 184篇 |
1984年 | 170篇 |
1983年 | 176篇 |
1982年 | 186篇 |
1981年 | 190篇 |
1980年 | 167篇 |
1979年 | 162篇 |
1978年 | 161篇 |
1977年 | 150篇 |
1976年 | 165篇 |
1975年 | 126篇 |
1974年 | 157篇 |
1973年 | 148篇 |
1972年 | 140篇 |
1971年 | 125篇 |
1967年 | 144篇 |
1965年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
951.
Björn Hassler 《Journal of Environmental Policy & Planning》2017,19(4):408-422
While scholars have showed a long-standing interest for how to design effective environmental treaties and other international agreements, less interest has been paid to implementation phases of these agreements. This article takes the Eutrophication Segment in the Baltic Sea Action Plan as an example of a regional effort to reduce nutrient leakages, where national reporting of adopted strategies has been a key mechanism to improve implementation effectiveness. It is shown that although transnational collective action theory is a powerful tool to analyse underlying drivers and priorities in state implementation policies, a deeper analysis of domestic and external constraints can shed additional light on observed implementation gaps. Varying views among countries on, for example, the role of stakeholder participation, legitimacy and top-down governing versus multi-stakeholder governance approaches may comprise domestic constraints that make effective and efficient implementation problematic. In terms of external constraints, states’ balancing of action plan objectives versus other international commitments, such as other environmental treaties and EU Directives, is shown to potentially reduce implementation efficiency as well. 相似文献
952.
Cecilia Sundberg Dan Yu Ingrid Franke-Whittle Sari Kauppi Sven Smårs Heribert Insam Martin Romantschuk Håkan Jönsson 《Waste management (New York, N.Y.)》2013,33(1):204-211
A major problem for composting plants is odour emission. Slow decomposition during prolonged low-pH conditions is a frequent process problem in food waste composting. The aim was to investigate correlations between low pH, odour and microbial composition during food waste composting. Samples from laboratory composting experiments and two large scale composting plants were analysed for odour by olfactometry, as well as physico-chemical and microbial composition. There was large variation in odour, and samples clustered in two groups, one with low odour and high pH (above 6.5), the other with high odour and low pH (below 6.0). The low-odour samples were significantly drier, had lower nitrate and TVOC concentrations and no detectable organic acids. Samples of both groups were dominated by Bacillales or Actinobacteria, organisms which are often indicative of well-functioning composting processes, but the high-odour group DNA sequences were similar to those of anaerobic or facultatively anaerobic species, not to typical thermophilic composting species. High-odour samples also contained Lactobacteria and Clostridia, known to produce odorous substances. A proposed odour reduction strategy is to rapidly overcome the low pH phase, through high initial aeration rates and the use of additives such as recycled compost. 相似文献
953.
Evaluation of heavy metal content in digestate from batch anaerobic co-digestion of sunflower hulls and poultry manure 总被引:1,自引:0,他引:1
Burak Demirel Nefise Pınar Göl Turgut Tüzün Onay 《Journal of Material Cycles and Waste Management》2013,15(2):242-246
In this experimental study, the biogas digestate from mesophilic batch anaerobic co-digestion of poultry manure and an agricultural residue, sunflower hulls, was characterized, particularly in terms of heavy metal content, in order to evaluate whether the biogas digestate was suitable for land applications. Ni, Zn, Cu, Pb, Cr, Cd, and Hg were detected in the biogas digestate in each trial, however, their concentrations were always lower than the limit values stated in Turkish regulations. The main source of heavy metals in the biogas digestate seemed to be the poultry manure, not the agricultural residue. The commercial feedstuffs that are frequently supplemented with various essential elements to promote optimum nutrient supply and optimum growth rates may have contributed to heavy metals presence in the biogas digestate. The results indicated that the biogas digestate from anaerobic co-digestion of manure and agricultural residue could be utilized as fertilizer in agricultural applications. 相似文献
954.
Vincent Bartolomei Matthias Sörgel Sasho Gligorovski Elena Gómez Alvarez Adrien Gandolfo Rafal Strekowski Etienne Quivet Andreas Held Cornelius Zetzsch Henri Wortham 《Environmental science and pollution research international》2014,21(15):9259-9269
Gaseous nitrogen dioxide (NO2) represents an oxidant that is present in relatively high concentrations in various indoor settings. Remarkably increased NO2 levels up to 1.5 ppm are associated with homes using gas stoves. The heterogeneous reactions of NO2 with adsorbed water on surfaces lead to the generation of nitrous acid (HONO). Here, we present a HONO source induced by heterogeneous reactions of NO2 with selected indoor paint surfaces in the presence of light (300 nm?<?λ?<?400 nm). We demonstrate that the formation of HONO is much more pronounced at elevated relative humidity. In the presence of light (5.5 W m?2), an increase of HONO production rate of up to 8.6?·?109 molecules cm?2 s?1 was observed at [NO2]?=?60 ppb and 50 % relative humidity (RH). At higher light intensity of 10.6 (W m?2), the HONO production rate increased to 2.1?·?1010 molecules cm?2 s?1. A high NO2 to HONO conversion yield of up to 84 % was observed. This result strongly suggests that a light-driven process of indoor HONO production is operational. This work highlights the potential of paint surfaces to generate HONO within indoor environments by light-induced NO2 heterogeneous reactions. 相似文献
955.
Eric M. Fujita David E. Campbell W. Patrick Arnott Ted Johnson Will Ollison 《Journal of the Air & Waste Management Association (1995)》2014,64(7):743-758
Human exposures to criteria and hazardous air pollutants (HAPs) in urban areas vary greatly due to temporal-spatial variations in emissions, changing meteorology, varying proximity to sources, as well as due to building, vehicle, and other environmental characteristics that influence the amounts of ambient pollutants that penetrate or infiltrate into these microenvironments. Consequently, the exposure estimates derived from central-site ambient measurements are uncertain and tend to underestimate actual exposures. The Exposure Classification Project (ECP) was conducted to measure pollutant concentrations for common urban microenvironments (MEs) for use in evaluating the results of regulatory human exposure models. Nearly 500 sets of measurements were made in three Los Angeles County communities during fall 2008, winter 2009, and summer 2009. MEs included in-vehicle, near-road, outdoor, and indoor locations accessible to the general public. Contemporaneous 1- to 15-min average personal breathing zone concentrations of carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), nitric oxide (NO), nitrogen oxides (NOx), particulate matter (<2.5 μm diameter; PM2.5) mass, ultrafine particle (UFP; <100 nm diameter) number, black carbon (BC), speciated HAPs (e.g., benzene, toluene, ethylbenzene, xylenes [BTEX], 1,3-butadiene), and ozone (O3) were measured continuously. In-vehicle and inside/outside measurements were made in various passenger vehicle types and in public buildings to estimate penetration or infiltration factors. A large fraction of the observed pollutant concentrations for on-road MEs, especially near diesel trucks, was unrelated to ambient measurements at nearby monitors. Comparisons of ME concentrations estimated using the median ME/ambient ratio versus regression slopes and intercepts indicate that the regression approach may be more accurate for on-road MEs. Ranges in the ME/ambient ratios among ME categories were generally greater than differences among the three communities for the same ME category, suggesting that the ME proximity factors may be more broadly applicable to urban MEs.
Implications:Estimates of population exposure to air pollutants extrapolated from ambient measurements at ambient fixed site monitors or exposure surrogates are prone to uncertainty. This study measured concentrations of mobile source air toxics (MSAT) and related criteria pollutants within in-vehicle, outdoor near-road, and indoor urban MEs to provide multipollutant ME measurements that can be used to calibrate regulatory exposure models. 相似文献
956.
Darrell B. Sonntag Richard W. Baldauf Catherine A. Yanca Carl R. Fulper 《Journal of the Air & Waste Management Association (1995)》2014,64(5):529-545
Representative profiles for particulate matter particles less than or equal to 2.5 µm (PM2.5) are developed from the Kansas City Light-Duty Vehicle Emissions Study for use in the U.S. Environmental Protection Agency (EPA) vehicle emission model, the Motor Vehicle Emission Simulator (MOVES), and for inclusion in the EPA SPECIATE database for speciation profiles. The profiles are compatible with the inputs of current photochemical air quality models, including the Community Multiscale Air Quality Aerosol Module Version 6 (AE6). The composition of light-duty gasoline PM2.5 emissions differs significantly between cold start and hot stabilized running emissions, and between older and newer vehicles, reflecting both impacts of aging/deterioration and changes in vehicle technology. Fleet-average PM2.5 profiles are estimated for cold start and hot stabilized running emission processes. Fleet-average profiles are calculated to include emissions from deteriorated high-emitting vehicles that are expected to continue to contribute disproportionately to the fleet-wide PM2.5 emissions into the future. The profiles are calculated using a weighted average of the PM2.5 composition according to the contribution of PM2.5 emissions from each class of vehicles in the on-road gasoline fleet in the Kansas City Metropolitan Statistical Area. The paper introduces methods to exclude insignificant measurements, correct for organic carbon positive artifact, and control for contamination from the testing infrastructure in developing speciation profiles. The uncertainty of the PM2.5 species fraction in each profile is quantified using sampling survey analysis methods. The primary use of the profiles is to develop PM2.5 emissions inventories for the United States, but the profiles may also be used in source apportionment, atmospheric modeling, and exposure assessment, and as a basis for light-duty gasoline emission profiles for countries with limited data.
Implications: PM2.5 speciation profiles were developed from a large sample of light-duty gasoline vehicles tested in the Kansas City area. Separate PM2.5 profiles represent cold start and hot stabilized running emission processes to distinguish important differences in chemical composition. Statistical analysis was used to construct profiles that represent PM2.5 emissions from the U.S. vehicle fleet based on vehicles tested from the 2005 calendar year Kansas City metropolitan area. The profiles have been incorporated into the EPA MOVES emissions model, as well as the EPA SPECIATE database, to improve emission inventories and provide the PM2.5 chemical characterization needed by CMAQv5.0 for atmospheric chemistry modeling. 相似文献
957.
René van der Wal Cheng Zeng Danny Heptinstall Kapila Ponnamperuma Chris Mellish Stuart Ben Advaith Siddharthan 《Ambio》2015,44(4):612-623
Analysis of satellite-telemetry data mostly occurs long after it has been collected, due to the time and effort needed to collate and interpret such material. Delayed reporting reduces the usefulness of such data for nature conservation where timely information about animal movements is required. To counter this problem, we present a novel approach which combines automated analysis of satellite-telemetry data with rapid communication of insights derived from such data. A relatively simple algorithm (based on radial and angular velocity calculated from fixes) allowed instantaneous detection of excursions away from settlement areas and automated calculation of home ranges on the remaining data. Automating the detection of both excursions and home-range calculations enabled us to disseminate ecological insights from satellite-tag data instantaneously through a dedicated web portal. The automated analysis, interpretation, and communication of satellite-tag and other ecological data offer clear benefits to nature conservation research and practice. 相似文献
958.
Scott Newey Paul Davidson Sajid Nazir Gorry Fairhurst Fabio Verdicchio R. Justin Irvine René van der Wal 《Ambio》2015,44(4):624-635
The availability of affordable ‘recreational’ camera traps has dramatically increased over the last decade. We present survey results which show that many conservation practitioners use cheaper ‘recreational’ units for research rather than more expensive ‘professional’ equipment. We present our perspective of using two popular models of ‘recreational’ camera trap for ecological field-based studies. The models used (for >2 years) presented us with a range of practical problems at all stages of their use including deployment, operation, and data management, which collectively crippled data collection and limited opportunities for quantification of key issues arising. Our experiences demonstrate that prospective users need to have a sufficient understanding of the limitations camera trap technology poses, dimensions we communicate here. While the merits of different camera traps will be study specific, the performance of more expensive ‘professional’ models may prove more cost-effective in the long-term when using camera traps for research. 相似文献
959.
Erik Andersson Björn Nykvist Rebecka Malinga Fernando Jaramillo Regina Lindborg 《Ambio》2015,44(1):102-112
In this exploratory study we use existing in situ qualitative and quantitative data on biophysical and social indicators to compare two contrasting Swedish farming systems (low intensity and high intensity) with regard to ecosystem service supply and demand of a broad suite of services. We show that the value (demand) placed on a service is not necessarily connected to the quantity (supply) of the service, most clearly shown for the services recreation, biodiversity, esthetic experience, identity, and cultural heritage. To better capture this complexity we argue for the need to develop portfolios of indicators for different ecosystem services and to further investigate the different aspects of supply and demand. The study indicates that available data are often ill-suited to answer questions about local delivery of services. If ecosystem services are to be included in policy, planning, and management, census data need to be formatted and scaled appropriately. 相似文献
960.
It has been hypothesized that climate warming will allow southern species to advance north and invade northern ecosystems. We review the changes in the Swedish mammal and bird community in boreal forest and alpine tundra since the nineteenth century, as well as suggested drivers of change. Observed changes include (1) range expansion and increased abundance in southern birds, ungulates, and carnivores; (2) range contraction and decline in northern birds and carnivores; and (3) abundance decline or periodically disrupted dynamics in cyclic populations of small and medium-sized mammals and birds. The first warm spell, 1930–1960, stands out as a period of substantial faunal change. However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors. We hypothesize all these drivers interacted, primarily favoring southern generalists. Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems. 相似文献