全文获取类型
收费全文 | 17477篇 |
免费 | 282篇 |
国内免费 | 380篇 |
专业分类
安全科学 | 613篇 |
废物处理 | 737篇 |
环保管理 | 2591篇 |
综合类 | 2971篇 |
基础理论 | 4481篇 |
环境理论 | 7篇 |
污染及防治 | 4607篇 |
评价与监测 | 991篇 |
社会与环境 | 1016篇 |
灾害及防治 | 125篇 |
出版年
2023年 | 95篇 |
2022年 | 171篇 |
2021年 | 168篇 |
2020年 | 189篇 |
2019年 | 151篇 |
2018年 | 284篇 |
2017年 | 268篇 |
2016年 | 413篇 |
2015年 | 334篇 |
2014年 | 445篇 |
2013年 | 1408篇 |
2012年 | 614篇 |
2011年 | 885篇 |
2010年 | 669篇 |
2009年 | 759篇 |
2008年 | 824篇 |
2007年 | 868篇 |
2006年 | 716篇 |
2005年 | 603篇 |
2004年 | 621篇 |
2003年 | 563篇 |
2002年 | 536篇 |
2001年 | 642篇 |
2000年 | 518篇 |
1999年 | 315篇 |
1998年 | 209篇 |
1997年 | 228篇 |
1996年 | 221篇 |
1995年 | 266篇 |
1994年 | 209篇 |
1993年 | 208篇 |
1992年 | 174篇 |
1991年 | 182篇 |
1990年 | 178篇 |
1989年 | 180篇 |
1988年 | 153篇 |
1987年 | 133篇 |
1986年 | 156篇 |
1985年 | 143篇 |
1984年 | 190篇 |
1983年 | 147篇 |
1982年 | 171篇 |
1981年 | 157篇 |
1980年 | 130篇 |
1979年 | 149篇 |
1978年 | 94篇 |
1977年 | 98篇 |
1975年 | 88篇 |
1974年 | 93篇 |
1972年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
401.
J.M. Logue K.E. Huff-Hartz A.T. Lambe N.M. Donahue A.L. Robinson 《Atmospheric environment (Oxford, England : 1994)》2009,43(39):6205-6217
High time-resolved (HTR) measurements can provide significant insight into sources and exposures of air pollution. In this study, an automated instrument was developed and deployed to measure hourly concentrations of 18 gas-phase organic air toxics and 6 volatile organic compounds (VOCs) at three sites in and around Pittsburgh, Pennsylvania. The sites represent different source regimes: a site with substantial mobile-source emissions; a residential site adjacent to a heavily industrialized zone; and an urban background site. Despite the close proximity of the sites (less than 13 km apart), the temporal characteristic of outdoor concentrations varied widely. Most of the compounds measured were characterized by short periods of elevated concentrations or plume events, but the duration, magnitude and composition of these events varied from site to site. The HTR data underscored the strong role of emissions from local sources on exposure to most air toxics. Plume events contributed more than 50% of the study average concentrations for all pollutants except chloroform, 1,2-dichloroethane, and carbon tetrachloride. Wind directional dependence of air toxic concentrations revealed that emissions from large industrial facilities affected concentrations at all of the sites. Diurnal patterns and weekend/weekday variations indicated the effects of the mixing layer, point source emissions patterns, and mobile source air toxics (MSATs) on concentrations. Concentrations of many air toxics were temporally correlated, especially MSATs, indicating that they are likely co-emitted. It was also shown that correlations of the HTR data were greater than lower time resolution data (24-h measurements). This difference was most pronounced for the chlorinated pollutants. The stronger correlations in HTR measurements underscore their value for source apportionment studies. 相似文献
402.
This paper considers liberal and nationalist economic policy approaches to the ownership and development of Australian energy resources (oil, gas, coal and uranium). In the two decades prior to 1983, Australia pursued economic policies in relation to its energy resources which could broadly be described as ‘nationalist’. Governments of the day intervened in development decisions in an effort to enhance the ‘national interest’. From 1983, along with the deregulation of the Australian economy as a whole, policy relating to energy resources was liberalised. Development of energy reserves henceforth occurred according to the dictates of the market. This paper argues that recent Australian energy policy initiatives reflect an increase in nationalist influences and a retreat from the liberalisation agenda that dominated energy policy making in the 1980s and 1990s. Three examples are discussed where policy has been influenced by a nationalist framework: (1) the domestic gas reservation policy in Western Australia; (2) Australian government efforts to promote a ‘value adding’ nuclear processing industry and (3) Australian Labor Party policy giving preferential financial incentives for gas to liquids projects. The re-emergence of nationalism in Australia is occurring either because policy makers now favour it as a path to energy security or in some cases because they believe that appeals to nationalism will generate political support. 相似文献
403.
Kelley L. Arbogast Brian C.P. Kane Jeffrey L. Kirwan Bradley R. Hertel 《Journal of environmental psychology》2009
Empirical and anecdotal evidence suggests that landscapes with more vegetation have a positive impact on children's focus, attention, and cognitive development. In school, children are able to regain focus, suppress impulses, and pay attention in class longer after exposure to natural settings. Because children spend much of their time in school, the amount and types of vegetation on school grounds may influence their development. Public elementary schools in the Commonwealth of Virginia (N = 988) were surveyed to examine correlations between school ground vegetation and outside recess. The number of trees on school grounds, the size of the school grounds, and the presence of sports fields were modestly correlated with greater outside recess time. These correlations support common sense because sports fields facilitate supervised play and larger school grounds provide space for sports fields and playgrounds and additional opportunities for free play. More trees on school grounds provide a welcoming environment for students and teachers, and encourage outside play. These results may help school personnel design and maintain school grounds that increase outdoor recess time. 相似文献
404.
How organizational motives and communications affect public trust in organizations: The case of carbon dioxide capture and storage 总被引:1,自引:0,他引:1
Bart W. Terwel Fieke Harinck Naomi Ellemers Dancker D.L. Daamen 《Journal of environmental psychology》2009,29(2):290-299
Preventing climate change is among the greatest environmental challenges facing the world today. Recently developed carbon dioxide capture and storage (CCS) technology is an important strategy to mitigate climate change. Public trust in organizations involved in CCS technology is important for successful implementation of this technology. This work adresses how inferred organizational motives and organizational communications affect public trust in these organizations. Study 1 (N = 264) showed that Dutch citizens generally have less trust in the industrial organizations than in the environmental NGOs involved in CCS. As predicted, inferred organizational motives (organization-serving motives versus public-serving motives) accounted for this difference. In Study 2 (N = 78) and Study 3 (N = 51) we used experimental designs. Both experiments showed that organizations that communicated arguments incongruent with inferred organizational motives instigated less trust than organizations that communicated arguments congruent with inferred organizational motives. Study 3 additionally showed that communicating an incongruent and a congruent argument together diminished the negative effects of the incongruent argument. In both Study 2 and Study 3 the effect of congruency on trust was mediated by perceived honesty of the organizations. 相似文献
405.
F. Boukhoubza A. Jail F. Korchi L. Loukili Idrissi H. Hannache J.C. Duarte L. Hassani A. Nejmeddine 《Journal of environmental management》2009,91(1):124-132
The application of hypochlorite for the removal of soluble COD, phenolic and polyphenolic like compounds, and other organic compounds responsible for the olive mill wastewater (OOWW) colour has been experimentally studied. After the OOWW filtration on a sand column, the effluent was subjected to a fast liming under optimal conditions. Lime application reduced polyphenols, COD and SS contents to half of their initial values but an important blackening of the treated OOWW was observed, especially when adding high concentrations of lime (10% (W/V) and 15% (W/V)).A second stage of treatment was applied using calcium hypochlorite. In this stage, removal of the studied compounds reached as much as 95% at higher concentrations, and particularly the colouring of OOWW which is generally difficult to eliminate was greatly reduced. The OOWW hypochloration acted through coagulation–flocculation and a rapid oxidation of the organic matter proceeded from the first 5 min. The kinetic study of the degradation of the waste polluting compounds from liming showed that Ca(ClO)2 reacts similarly in the elimination of organic compounds, polyphenols, SS and colouration. The analysis of the organochloride compounds generated by the reaction between hypochlorite and the organic compounds showed that DDD, DDT and the heptachlor contents exceeded the values recommended by the International and European drinking water standards. 相似文献
406.
J. Medellín-Azuara L.G. Mendoza-Espinosa J.R. Lund J.J. Harou R.E. Howitt 《Journal of environmental management》2009,90(11):3470-3478
This paper uses simple hydro-economic optimization to investigate a wide range of regional water system management options for northern Baja California, Mexico. Hydro-economic optimization models, even with parsimonious model formulations, enable investigation of promising water management portfolios for supplying water to agricultural, environmental and urban users. CALVIN, a generalized hydro-economic model, is used in a case study of Baja California. This drought-prone region faces significant challenges to supply water to agriculture and its fast growing border cities. Water management portfolios include water markets, wastewater reuse, seawater desalination and infrastructure expansions. Water markets provide the flexibility to meet future urban demands; however conveyance capacity limits their use. Wastewater reuse and conveyance expansions are economically promising. At current costs desalination is currently uneconomical for Baja California compared to other alternatives. Even simple hydro-economic models suggest ways to increase efficiency of water management in water scarce areas, and provide an economic basis for evaluating long-term water management solutions. 相似文献
407.
Chambers MK Ford MR White DM Barnes DL Schiewer S 《Journal of environmental management》2009,90(2):961-966
People living without piped water and sewer can be at increased risk for diseases transmitted via the fecal-oral route. One rural Alaskan community that relies on hauling water into homes and sewage from homes was studied to determine the pathways of fecal contamination of drinking water and the human environment so that barriers can be established to protect health. Samples were tested for the fecal indicator, Escherichia coli, and the less specific indicator group, total coliforms. Shoes transported fecal contamination from outside to floor material inside buildings. Contamination in puddles on the road, in conjunction with contamination found on all-terrain vehicle (ATV) tires, supports vehicle traffic as a mechanism for transporting contamination from the dumpsite or other source areas to the rest of the community. The abundance of fecal bacteria transported around the community on shoes and ATV tires suggests that centralized measures for waste disposal as well as shoe removal in buildings could improve sanitation and health in the community. 相似文献
408.
409.
Patrick L. Witmer Paul M. Stewart Christopher K. Metcalf 《Journal of the American Water Resources Association》2009,45(3):734-747
Abstract: Unpaved road‐stream crossings increase sediment yields in streams and alter channel morphology and stability. Before restoration and sedimentation reduction strategies can be implemented, a priority listing of unpaved road‐stream crossings must be created. The objectives of this study were to develop a sedimentation risk index (SRI) for unpaved road‐stream crossings and to prioritize 125 sites in the Choctawhatchee watershed (southeastern Alabama) using this model. Field surveys involved qualitative and quantitative observations of 73 metrics related to waterway conditions, crossing structures, road approaches, and roadside soil erosion. The road‐stream crossing risk analyses involved elimination of candidate metrics based on redundancy, skewness, lack of data, professional judgment, lack of nonzero values, unbalanced box plots, and limited ranges of values. A final selection of 12 metrics formed the SRI and weighed factors involving soil erodibility, road sedimentation abatement features, and stream morphology alteration. The SRI was organized into narrative categories (excellent, good, fair, poor, and very poor) based on the distribution of scores. No excellent sites (scores ≥55) were found in this study, 17 (20.7%) were good (low sedimentation risk), 37 (45.1%) were fair (moderate sedimentation risk), 26 (31.7%) were poor (high sedimentation risk), and two (2.5%) were very poor (high sedimentation risk). There was no significant difference in SRI scores among crossing structure type (round culverts, box culverts, and bridges) (H = 4.31, df = 2, p = 0.058). A future study of the Choctawhatchee watershed involving the same study sites could assess the success of restoration plans and activities based on site score improvement or decline. 相似文献
410.
Franck L. B. Meijboom Nina Cohen Elsbeth N. Stassen Frans W. A. Brom 《Journal of Agricultural and Environmental Ethics》2009,22(6):559-571
European animal disease policy seems to find its justification in a “harm to other” principle. Limiting the freedom of animal
keepers—e.g., by culling their animals—is justified by the aim to prevent harm, i.e., the spreading of the disease. The picture,
however, is more complicated. Both during the control of outbreaks and in the prevention of notifiable, animal diseases the
government is confronted with conflicting claims of stakeholders who anticipate running a risk to be harmed by each other, and who ask for government intervention. In this paper, we first argue that in a policy that
aims to prevent animal diseases, the focus shifts from limiting “harm” to weighing conflicting claims with respect to “risks
of harm.” Therefore, we claim that the harm principle is no longer a sufficient justification for governmental intervention
in animal disease prevention. A policy that has to deal with and distribute conflicting risks of harm needs additional value
assumptions that guide this process of assessment and distribution. We show that currently, policies are based on assumptions
that are mainly economic considerations. In order to show the limitations of these considerations, we use the interests and
position of keepers of backyard animals as an example. Based on the problems they faced during and after the recent outbreaks,
we defend the thesis that in order to develop a sustainable animal disease policy other than economic assumptions need to
be taken into account. 相似文献