全文获取类型
收费全文 | 13722篇 |
免费 | 197篇 |
国内免费 | 143篇 |
专业分类
安全科学 | 522篇 |
废物处理 | 602篇 |
环保管理 | 2050篇 |
综合类 | 1653篇 |
基础理论 | 3627篇 |
环境理论 | 5篇 |
污染及防治 | 3680篇 |
评价与监测 | 1000篇 |
社会与环境 | 833篇 |
灾害及防治 | 90篇 |
出版年
2023年 | 66篇 |
2022年 | 137篇 |
2021年 | 119篇 |
2020年 | 121篇 |
2019年 | 134篇 |
2018年 | 226篇 |
2017年 | 255篇 |
2016年 | 363篇 |
2015年 | 266篇 |
2014年 | 357篇 |
2013年 | 1069篇 |
2012年 | 475篇 |
2011年 | 671篇 |
2010年 | 537篇 |
2009年 | 592篇 |
2008年 | 668篇 |
2007年 | 687篇 |
2006年 | 613篇 |
2005年 | 535篇 |
2004年 | 474篇 |
2003年 | 502篇 |
2002年 | 460篇 |
2001年 | 596篇 |
2000年 | 400篇 |
1999年 | 253篇 |
1998年 | 184篇 |
1997年 | 196篇 |
1996年 | 190篇 |
1995年 | 217篇 |
1994年 | 184篇 |
1993年 | 149篇 |
1992年 | 165篇 |
1991年 | 149篇 |
1990年 | 159篇 |
1989年 | 159篇 |
1988年 | 116篇 |
1987年 | 103篇 |
1986年 | 82篇 |
1985年 | 113篇 |
1984年 | 106篇 |
1983年 | 113篇 |
1982年 | 106篇 |
1981年 | 106篇 |
1980年 | 79篇 |
1979年 | 87篇 |
1978年 | 59篇 |
1977年 | 58篇 |
1976年 | 54篇 |
1975年 | 59篇 |
1973年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
681.
Miqdam?T.?ChaichanEmail author Hussien?A.?Kazem Talib?A.?Abed 《Environment, Development and Sustainability》2018,20(2):589-603
In Iraq, the number of passenger cars, trucks and buses, local generators, and heavy construction equipment rose to a considerable extent since 2003, causing high environmental problems. Many types of pollutants were monitored and recorded for 24 h during March 2016. The study attempts to explore and establish a relationship between the volume of activity and the movement of motor vehicles of various compounds and contaminants resulting from their exhaust pipes, such as sulfur dioxide, particulate matters, oxides of nitrogen, VOCs, and unburned hydrocarbons. The study focused in and around Mohammad Al-Qasim highway adjacent to the University of Technology, Baghdad. The results showed the need for urgent treatments addressed by the environmental authorities in the city. The study results demonstrated that these contaminants are increased during periods of the beginning and end of working hours for government departments. Some types of sulfur compounds (H2S and SO2) concentrations were at serious health-threatening levels, which is a result of the high sulfur content in the Iraqi fuel. The concentrations of NOx and VOC were high, also, which could make the studied area vulnerable to the risk of smog formation. The Iraqi government should make greater efforts to protect the environment and human in this country from the transportation pollution risks. 相似文献
682.
Soininen H. Manskinen K. Ranta T. 《Journal of Material Cycles and Waste Management》2018,20(3):1832-1841
Journal of Material Cycles and Waste Management - The amount of biomass-derived ashes is expected to rise in the EU due to targets to increase the use of renewable energy resources. To promote the... 相似文献
683.
Davies TD Pierce CE Robinson HJ Dorling SR 《Environmental pollution (Barking, Essex : 1987)》1992,75(2):111-119
The EMEP precipitation composition network is used to examine relationships between non-marine SO4(2-), NO3-, NH4+, H+ concentrations and precipitation amount and a local zonal pressure index (an index of the atmospheric circulation). The pattern of the relationships changes across Europe with the zonal pressure gradient explaining more of the variance in ion concentrations in the west, and precipitation amount explaining relatively more of the variance in the east. There is some predictive capability for precipitation composition in the zonal pressure gradient for restricted regions in Europe; R2 values are up to 40% on a daily basis but in some seasons/months attain >60%. The zonal pressure gradient is an index which appears to include pertinent information on transport and wet removal. Preliminary analysis indicates that this approach can be useful in assessing the contributions of changing atmospheric circulation to time-trends of wet acidic deposition in an area stretching from the UK over the North Sea to Denmark. The zonal pressure gradient is known to have varied on time-scales of decades, and the simple index may be one appropriate approach to assessing future deposition patterns from future climate projections. 相似文献
684.
Günter Gunkel Florian Selge Jonas Keitel Debora Lima Silvana Calado Maria Sobral Maricela Rodriguez Elena Matta Reinhard Hinkelmann Peter Casper Michael Hupfer 《Regional Environmental Change》2018,18(7):1913-1925
Reservoirs have a wide variety of uses that have led to frequent conflicts over ecological conservation and contamination, especially as land management has intensified. Oligotrophication must be implemented in numerous tropical reservoirs that experience advanced eutrophication to maintain aquatic ecosystem functions. To quantify impacts on ecosystem functions and to develop an adaptive management policy, multiple studies have been conducted on the Itaparica Reservoir, São Francisco River, in the semi-arid north-eastern region of Brazil. Here, we add to that existing body of knowledge through investigating how nutrient accumulation is affected by water exchange between the main river flow and Icó-Mandantes Bay. Operational water-level fluctuations in the reservoir create large desiccated littoral areas that release high amounts of nutrients when they are rewetted. In particular, water-level variation promotes proliferation of Egeria densa, a noxious weed, thus elevating trophic levels of the Itaparica Reservoir and Icó-Mandantes Bay. Analysis with a P efficiency model determined 25 μg P L?1 to be the critical concentration and further indicated that the critical load in both bodies of water have been exceeded. Moreover, intensive fish aquaculture using net cages has led to further overtaxing of the reservoir. We conclude that an effective ecological reservoir management policy must involve oligotrophication, harvesting of noxious water weeds for use as soil amendment in agriculture or biogas production, “blue” aquaculture, and limiting hydroelectric power production based on current water availability. 相似文献
685.
Cattle vaccination records question the impact of recent zero-deforestation agreements in the Amazon
Regional Environmental Change - In the late 2000s, slaughterhouses across the Amazon entered into a series of agreements designed to reduce the environmental impact of the local cattle sector. In... 相似文献
686.
Kristin K. Runge Dominique Brossard Michael A. Xenos 《Environmental Communication: A Journal of Nature and Culture》2018,12(8):1023-1045
ABSTRACTThis study demonstrates a post-hoc segmentation that is effective in creating distinct and robust segments of interest for researchers and practitioners in science communication. We use agglomerative hierarchical clustering to classify survey respondents based on answers to a short, five-item battery of questions drawn from variables that are frequently used in science communication. Resulting segments demonstrate strong differences in regards to demographics, issue-specific science knowledge, attention to media, sentiment toward media, and social networking site use. We assess the utility of the segments through a series of regression analyses in order to determine differences among segments with regards to intent to seek information about three science issues: fracking, nanotechnology, and synthetic biology. 相似文献
687.
Mark DeLaurier Michael Salvador 《Environmental Communication: A Journal of Nature and Culture》2018,12(3):387-401
This paper responds to recent calls for alternative approaches to the analysis of environmental communication that uncover overlooked voices in the discussion of environmental issues. Borrowing core principles from critical rhetoric, it suggests a way to categorize media messages according to how human–nature relationships are constructed in media discourse. The paper illustrates how, in presenting contrasting and often oppositional constructions of human–nature relationships, the media messages examined articulate three recurrent (but not equal) discourses on global warming. These discourses include (1) nature-as-out-of-reach discourse, (2) nature-as-antagonist discourse, and (3) nature-as-co-present discourse. By juxtaposing these discourses, the paper shows how environmental communication scholars can engage in critical realism and political advocacy to illuminate latent public discourse that holds the potential to champion marginalized voices of nature and accentuate the interconnectedness of humans and the environment. 相似文献
688.
Jonathan M. H. Green Gemma R. Cranston William J. Sutherland Hannah R. Tranter Sarah J. Bell Tim G. Benton Eva Blixt Colm Bowe Sarah Broadley Andrew Brown Chris Brown Neil Burns David Butler Hannah Collins Helen Crowley Justin DeKoszmovszky Les G. Firbank Brett Fulford Toby A. Gardner Rosemary S. Hails Sharla Halvorson Michael Jack Ben Kerrison Lenny S. C. Koh Steven C. Lang Emily J. McKenzie Pablo Monsivais Timothy O’Riordan Jeremy Osborn Stephen Oswald Emma Price Thomas David Raffaelli Belinda Reyers Jagjit S. Srai Bernardo B. N. Strassburg David Webster Ruth Welters Gail Whiteman James Wilsdon Bhaskar Vira 《Sustainability Science》2017,12(2):319-331
Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation. 相似文献
689.
Fine particulate matter (\(\hbox {PM}_{2.5}\)) events negatively affect the health of numerous persons globally each year. Previous works have described the association between air pollution and surface-level meteorological conditions; however, there has been less focus on the task of linking air pollution events with meteorological conditions at higher levels of the atmosphere. Working within the functional data framework, we develop a penalized functional quantile regression (PFQR) procedure to model conditional quantiles of a continuous response based on a functional covariate, with the ability to penalize selected derivatives of the estimated coefficient function. Our aim is to investigate the relationship between atmospheric profile variables (APVs), assumed to be functional, and key quantiles of the conditional distribution of surface-level \(\hbox {PM}_{2.5}\). Via a simulation study, we find that the performance of our PFQR procedure compares favorably to other related approaches. We conclude with an analysis of \(\hbox {PM}_{2.5}\) data at two Southeastern US locations, Columbia, SC and Tampa, FL, where we estimate the coefficient functions for the APVs corresponding to both ‘typical’ and ‘high’ \(\hbox {PM}_{2.5}\) events. As we believe that the true coefficient functions are smooth and may be exactly zero over subsets of their domains, we impose penalties on the 0th and 2nd derivatives. Our analysis indicates that the corresponding atmospheric conditions differ between the two locations, and that the conditions differ seasonally within location. 相似文献
690.
Peter Bacopoulos Ethan J. Kubatko Scott C. Hagen Andrew T. Cox Teddy Mulamba 《Environmental Fluid Mechanics》2017,17(2):323-353
Continuous data of vertical-profile salinity were analyzed for four stations located successively upriver in a macrotidal estuary, the lower St. Johns River (Northeast Florida, USA). The data analysis confirmed well-mixed salinity conditions in the river with at most 1.3 ppt of vertical variability at Dames Point (river km 20), where the main variations of salinity are along the longitudinal axis of the river. Given the well-mixed salinity conditions and dominant horizontal structure of salinity variations in the river, we present and apply a barotropic, two-dimensional modeling approach for hydrodynamic-salinity transport simulation in the lower St. Johns River. When properly forced by offshore surge, high-resolution wind fields and freshwater river inflows, the model replicated the salinity measurements remarkably well, including the separation into tidal and sub-tidal components. The data and model results show that, at times, offshore winds and surge can be more influential on longitudinal salinity variations than local winds over the river. We demonstrate the importance of using proper boundary conditions to force the model relative to the minimal sensitivity of the model to parameter adjustment of horizontal mixing and uncertainty-based perturbation of wind and inflow forcings. 相似文献