全文获取类型
收费全文 | 1167篇 |
免费 | 24篇 |
国内免费 | 12篇 |
专业分类
安全科学 | 78篇 |
废物处理 | 58篇 |
环保管理 | 235篇 |
综合类 | 104篇 |
基础理论 | 368篇 |
环境理论 | 2篇 |
污染及防治 | 222篇 |
评价与监测 | 93篇 |
社会与环境 | 39篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 27篇 |
2014年 | 32篇 |
2013年 | 103篇 |
2012年 | 43篇 |
2011年 | 78篇 |
2010年 | 48篇 |
2009年 | 46篇 |
2008年 | 54篇 |
2007年 | 64篇 |
2006年 | 76篇 |
2005年 | 29篇 |
2004年 | 35篇 |
2003年 | 40篇 |
2002年 | 42篇 |
2001年 | 33篇 |
2000年 | 31篇 |
1999年 | 20篇 |
1998年 | 22篇 |
1997年 | 15篇 |
1996年 | 18篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 15篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1973年 | 6篇 |
排序方式: 共有1203条查询结果,搜索用时 15 毫秒
881.
This article identifies and compares meanings of wildfire risk mitigation for stakeholders in the Front Range of Colorado, USA. We examine the case of a collaborative partnership sponsored by government agencies and directed to decrease hazardous fuels in interface areas. Data were collected by way of key informant interviews and focus groups. The analysis is guided by the Circuit of Culture model in communication research. We found both shared and differing meanings between members of this partnership (the "producers") and other stakeholders not formally in the partnership (the "consumers"). We conclude that those promoting the partnership's project to mitigate risk are primarily aligned with a discourse of scientific management. Stakeholders outside the partnership follow a discourse of community. We argue that failure to recognize and account for differences in the way risk mitigation is framed and related power dynamics could hamper the communicational efforts of the collaborative partnership and impact goals for fuels reduction. We recommend ways that both groups can capitalize on shared meanings and how agency managers and decision makers can build better working relationships with interface communities and other external stakeholders. 相似文献
882.
Many beach management practices focus on creating an attractive environment for tourists, but can detrimentally affect long-term
dune integrity. One such practice is mechanical beach raking in which the wrack line is removed from the beach front. In Texas,
Sargassum fluitans and natans, types of brown alga, are the main components of wrack and may provide a subsidy to the ecosystem. In this study, we used
greenhouse studies to test the hypothesis that the addition of sargassum can increase soil nutrients and produce increased
growth in dune plants. We also conducted an analysis of the nutrients in the sargassum to determine the mechanisms responsible
for any growth enhancement. Panicum amarum showed significant enhancement of growth with the addition of sargassum, and while Helianthus debilis, Ipomoea stolonifera, Sporobolus virginicus, and Uniola paniculata responded slightly differently to the specific treatments, none were impaired by the addition of sargassum. In general, plants
seemed to respond well to unwashed sargassum and multiple additions of sargassum, indicating that plants may have adapted
to capitalize on the subsidy in its natural state directly from the ocean. For coastal managers, the use of sargassum as a
fertilizer could be a positive, natural, and efficient method of dealing with the accumulation of wrack on the beach. 相似文献
883.
Elizabeth A. Jones J. Michael Wright Glenn Rice Brian T. Buckley Melina S. Magsumbol Dana B. Barr Bryan L. Williams 《Environment international》2010,36(7):649-654
ObjectivesWe measured concentrations of lead (Pb), manganese (Mn), chromium (Cr), and copper (Cu) in umbilical cord whole blood and examined sources of environmental Pb exposures in a predominantly African-American population.MethodsBetween April and July 2006, we collected reproductive histories, questionnaires, and blood samples from 102 women, aged 16–45 years, who delivered at a Memphis, TN hospital.ResultsThe prevalence of preeclampsia and low birth weight infancy in the study population was 11% and 10%, respectively. Twenty-eight percent of mothers reported living near a potential Pb-contaminated area, while 43% lived in a residence built before 1978. Geometric mean (GM) concentrations for umbilical cord blood in the study population were 1.3, 3.5, 9.0, and 52.0 µg/dL for Pb, Mn, Cr, and Cu, respectively. Six neonates had cord blood Pb (CBL) concentrations above 10 µg/dL, while 20 had CBL concentrations ≥ 2 µg/dL. GM umbilical CBL levels were higher in neonates born to women living near a potential Pb-contaminated area (2.2 vs. 1.1 µg/dL) and those with friends, family or household members exposed to lead products (1.6 vs. 1.1 μg/dL). Some evidence of an exposure–response relationship was also detected between all four metal concentrations and an increasing number of maternal lead exposures. After adjustment for confounding, proximity to a Pb-contaminated area was the strongest environmental determinant of CBL levels among neonates with CBL concentrations of ≥ 2 µg/dL (odds ratio = 5.1; 95% CI = 1.6, 16.7).ConclusionsMetal concentrations were elevated in this population, and CBL levels were associated with proximity to Pb-contaminated areas. 相似文献
884.
Work-contingent self-esteem (WCSE; the degree to which workers' self-esteem is based on workplace performance) has positive consequences for performance, yet less is known about its consequences for well-being. In this paper, we contribute to the literature on WCSE by examining the mechanisms through which it impacts well-being at work and outside of work. We challenge contingent self-esteem (CSE) theory (Crocker & Park, 2004), which argues that CSE negatively impacts well-being by fostering internally controlled (introjected) motivation and diminishing autonomous motivation, by suggesting that WCSE fosters autonomous and internally controlled motivation and thus has both beneficial and harmful effects on well-being. We also expand CSE theory by suggesting that WCSE can negatively impact well-being outcomes by causing work–nonwork conflict. Results from a time-separated design in a sample of full-time employees supported our arguments, revealing that WCSE impacted well-being at work through both autonomous and internally controlled work motivations. WCSE also had negative effects on well-being at and outside of work through work–nonwork conflict. The beneficial effects of WCSE outweighed its harmful effects on job satisfaction and neutralized its harmful effects for all other outcomes. We discuss theoretical implications for CSE theory, self-determination theory, and work–nonwork issues and note important practical implications. 相似文献
885.
Survey of arsenic and its speciation in rice products such as breakfast cereals, rice crackers and Japanese rice condiments 总被引:1,自引:0,他引:1
Sun GX Williams PN Zhu YG Deacon C Carey AM Raab A Feldmann J Meharg AA 《Environment international》2009,35(3):473-475
Rice has been demonstrated to be one of the major contributors to arsenic (As) in human diets in addition to drinking water, but little is known about rice products as an additional source of As exposure. Rice products were analyzed for total As and a subset of samples were measured for arsenic speciation using high performance liquid chromatography interfaced with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). A wide range of rice products had total and inorganic arsenic levels that typified those found in rice grain including, crisped rice, puffed rice, rice crackers, rice noodles and a range of Japanese rice condiments as well as rice products targeted at the macrobiotic, vegan, lactose intolerant and gluten intolerance food market. Most As in rice products are inorganic As (75.2-90.1%). This study provides a wider appreciation of how inorganic arsenic derived from rice products enters the human diet. 相似文献
886.
This article will briefly outline the origins, structure and functions of United Nations Environment Program and the Commission on Sustainable Development in the context of the goals of ecologically sustainable development (ESD). Economic development, social development and environmental protection form the three interconnected parts of ESD. The achievements of the key UN environmental institutions and programs in opening up the global system to civil society, the private sector and a diversity of actors and interests, promoting the role of poverty alleviation as part of ESD through the Millennium Development Goals, and facilitating important Multilateral Environmental Agreements should be recognized. However, with these notable exceptions, organizations such as United Nations Environment Program and the Commission on Sustainable Development have become weak in scientific and technical leadership, global policy, co-ordination (inside and outside the UN) and has few achievements in the inter- national and national implementation of obligations and standards in Global Environmental Governance - including enforcement, compliance and effectiveness. This article will outline the key reasons for this inadequacy. Attention will also be focused on the way forward through of a new United Nations Environment Organization. This will require a clarification of purpose and function (within the UN system and as part of global governance structures) as well as consideration of whether it depends on system-wide UN reform. It is recommended that medium and long term strategies for reform are necessary. 相似文献
887.
Enforced institutional settings such as penitentiaries provide environments to raise awareness, carry out research, and implement
and assess practices for sustainable living. Institutions where residence is enforced due to health, recreational, military,
or legal reasons (e.g., assisted living centers, summer camps, army bases, prisons) house people who may lack scientific training
but have time and need for intellectual stimulation that can be filled by supervised research. These institutions have stable
populations, structured social organization, and measurable inputs and outputs of materials and energy to carry out sustainable
practices in tasks that affect regional resources such as groundwater quality and landfill use. We report on three examples
at a corrections center resulting from partnerships among visiting academic ecology researchers, sustainability practitioners,
corrections administrators, and prisoners: (1) research on how to sustainably “farm” moss for the horticulture trade to reduce
harvesting pressure on wild moss populations; (2) a vermiculture and thermophilic composting system to reduce the kitchen
waste; and (3) a monthly seminar series at the prison. Over 26 months: (1) participants developed methods to optimize moss
growth; (2) landfill-bound waste and particulate flow rate destined for wastewater treatment decreased by 50%, to less than
50% of permit limits; (3) resulting compost (ca. 5000 kg) fertilized institutional vegetable gardens; (4) water quality improved
so that the prison could return funds allocated to upgrade the prison’s water quality. The lectures encouraged intellectual
exchange among researchers, convicts, and guards. Researchers derived new perspectives and broader impacts for their work.
This can be a model for other correctional facilities and other enforced residential institutions (ERIs).
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
888.
Educational tools to assist the public in recognizing impacts of water policy in a realistic context are not generally available. This project developed systems with modeling-based educational decision support simulation tools to satisfy this need. The goal of this model is to teach undergraduate students and the general public about the implications of common water management alternatives so that they can better understand or become involved in water policy and make more knowledgeable personal or community decisions. The model is based on Powersim, a dynamic simulation software package capable of producing web-accessible, intuitive, graphic, user-friendly interfaces. Modules are included to represent residential, agricultural, industrial, and turf uses, as well as non-market values, water quality, reservoir, flow, and climate conditions. Supplementary materials emphasize important concepts and lead learners through the model, culminating in an open-ended water management project. The model is used in a University of Arizona undergraduate class and within the Arizona Master Watershed Stewards Program. Evaluation results demonstrated improved understanding of concepts and system interactions, fulfilling the project's objectives. 相似文献
889.
Cheng-Yuan Xu Kevin L. Griffin Elizabeth C. Craig Sanpisa Sritrairat Marco J. Castaldi 《Environmental pollution (Barking, Essex : 1987)》2009,157(7):2118-2125
Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO2 that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO2] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 μmol mol−1 [CO2] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 μmol mol−1 [CO2], but declined when [CO2] rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO2 and NO2) significantly offset the CO2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO2 from the power plant emissions to optimize growth in commercial green house could be viable. 相似文献
890.
Jonathan Thornburg Charles E. Rodes Phillip A. Lawless Ron Williams 《Atmospheric environment (Oxford, England : 1994)》2009,43(28):4251-4258
The Detroit Exposure and Aerosol Research Study (DEARS) provided data to compare outdoor residential coarse particulate matter (PM10–2.5) concentrations in six different areas of Detroit with data from a central monitoring site. Daily and seasonal influences on the spatial distribution of PM10–2.5 during Summer 2006 and Winter 2007 were investigated using data collected with the newly developed coarse particle exposure monitor (CPEM). These data allowed the representativeness of the community monitoring site to be assessed for the greater Detroit metro area. Multiple CPEMs collocated with a dichotomous sampler determined the precision and accuracy of the CPEM PM10–2.5 and PM2.5 data.CPEM PM2.5 concentrations agreed well with the dichotomous sampler data. The slope was 0.97 and the R2 was 0.91. CPEM concentrations had an average 23% negative bias and R2 of 0.81. The directional nature of the CPEM sampling efficiency due to bluff body effects probably caused the negative CPEM concentration bias.PM10–2.5 was observed to vary spatially and temporally across Detroit, reflecting the seasonal impact of local sources. Summer PM10–2.5 was 5 μg m?3 higher in the two industrial areas near downtown than the average concentrations in other areas of Detroit. An area impacted by vehicular traffic had concentrations 8 μg m?3 higher than the average concentrations in other parts of Detroit in the winter due to the suspected suspension of road salt. PM10–2.5 Pearson Correlation Coefficients between monitoring locations varied from 0.03 to 0.76. All summer PM10–2.5 correlations were greater than 0.28 and statistically significant (p-value < 0.05). Winter PM10–2.5 correlations greater than 0.33 were statistically significant (p-value < 0.05). The PM10–2.5 correlations found to be insignificant were associated with the area impacted by mobile sources during the winter. The suspected suspension of road salt from the Southfield Freeway, combined with a very stable atmosphere, caused concentrations to be greater in this area compared to other areas of Detroit. These findings indicated that PM10–2.5, although correlated in some instances, varies sufficiently across a complex urban airshed that that a central monitoring site may not adequately represent the population's exposure to PM10–2.5. 相似文献