全文获取类型
收费全文 | 94483篇 |
免费 | 1229篇 |
国内免费 | 1118篇 |
专业分类
安全科学 | 3810篇 |
废物处理 | 3403篇 |
环保管理 | 14496篇 |
综合类 | 21301篇 |
基础理论 | 26922篇 |
环境理论 | 73篇 |
污染及防治 | 16737篇 |
评价与监测 | 5633篇 |
社会与环境 | 3871篇 |
灾害及防治 | 584篇 |
出版年
2022年 | 801篇 |
2021年 | 799篇 |
2020年 | 654篇 |
2019年 | 871篇 |
2018年 | 1182篇 |
2017年 | 1225篇 |
2016年 | 2205篇 |
2015年 | 1848篇 |
2014年 | 2592篇 |
2013年 | 9264篇 |
2012年 | 2342篇 |
2011年 | 2761篇 |
2010年 | 3317篇 |
2009年 | 3460篇 |
2008年 | 2359篇 |
2007年 | 2245篇 |
2006年 | 2538篇 |
2005年 | 2461篇 |
2004年 | 2791篇 |
2003年 | 2613篇 |
2002年 | 2194篇 |
2001年 | 2613篇 |
2000年 | 2168篇 |
1999年 | 1578篇 |
1998年 | 1402篇 |
1997年 | 1396篇 |
1996年 | 1522篇 |
1995年 | 1604篇 |
1994年 | 1506篇 |
1993年 | 1348篇 |
1992年 | 1345篇 |
1991年 | 1317篇 |
1990年 | 1259篇 |
1989年 | 1237篇 |
1988年 | 1083篇 |
1987年 | 1002篇 |
1986年 | 1004篇 |
1985年 | 1081篇 |
1984年 | 1171篇 |
1983年 | 1183篇 |
1982年 | 1182篇 |
1981年 | 1104篇 |
1980年 | 951篇 |
1979年 | 937篇 |
1978年 | 833篇 |
1977年 | 729篇 |
1976年 | 658篇 |
1974年 | 630篇 |
1973年 | 656篇 |
1972年 | 671篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
651.
Sánchez López FJ Gil García MD Martínez Vidal JL Aguilera PA Garrido Frenich A 《Environmental monitoring and assessment》2004,93(1-3):17-29
Water quality assessment in the Aznalcollar area was attempted using multivariate methods based on heavy metal concentrations in red swamp crayfish (Procamburus clarkii). Trace levels of four heavy metals, copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), were detected in crayfish from eleven different stations. Principal component analysis (PCA) highlighted a gradient of contamination between the sampling stations. Cluster analysis (CA) distinguished three groups of stations. Discriminant analysis also differentiated three groups. The group centroids of the first discriminant function were used to devise an index that varies according to the source of the crayfish. These standardized values are proposed for use as a water quality index. The ability of this index to successfully predict environmental quality was proved with random samples. 相似文献
652.
van Wijk D Thompson RS De Rooij C Garny V Lecloux A Kanne R 《Environmental monitoring and assessment》2004,97(1-3):69-86
This risk assessment on monochlorobenzene was carried out for the marine environment, following methodology given in the EU risk assessment Regulation (1488/94) and Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). Data from analytical monitoring programmes in large rivers and estuaries in the North Sea area were collected and evaluated for effects and environmental concentrations. Risk is indicated by the ratio of predicted environmental concentration (PEC) to predicted no-effect concentration (PNEC) for the marine aquatic environment. In total, 27 data for fish, 24 data for invertebrates and 13 data for algae were evaluated. Acute and chronic toxicity studies were taken into account and appropriate assessment factors used to define a final PNEC value of 32 micro/l. Recent monitoring data indicate that monochlorobenzene levels in surface waters are below determination limits of 0.1, 0.2, 0.5 microg/l used in monitoring programs. Assuming that half of the lowest determination (0.1 microg/l) is typical, a PEC of 0.05 microg/l was derived. A worst case of 0.5 microg/l is assumed. PEC/PNEC ratios give safety factors of 60 to over 500, taking no account of dilution in the sea. Monochlorobenzene is not a 'toxic, persistent and liable to bioaccumulate' substance sensu the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC) criteria. Environmental fate and effects data indicate that current use of monochlorobenzene poses no unacceptable risk to the aquatic environment. 相似文献
653.
Kriech AJ Osborn LV Wissel HL Kurek JT Sweeney BJ Peregrine CJ 《Journal of environmental monitoring : JEM》2004,6(10):827-833
Exposure to asphalt fumes has a threshold limit value (TLV of 0.5 mg m(-3) (benzene extractable inhalable particulate) as recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). This reflects a recent change (2000) whereby two variables are different from the previous recommendation. First is a 10-fold reduction in quantity from 5 mg m(-3) to 0.5 mg m(-3). Secondly, the new TLV specifies the "inhalable" fraction as compared to what is presumed to be total particulate. To assess the impact of these changes, this study compares the differences between measurements of paving asphalt fume exposure in the field using an "inhalable" instrument versus the historically used 'total' sampler. Particle size is also examined to assist in the understanding of the aerodynamic collection differences as related to asphalt fumes and confounders. Results show that when exposures are limited to asphalt fumes, a 1:1 relationship exists between samplers, showing no statistically significant differences in benzene soluble matter (BSM). This means that for the asphalt fume ACGIH TLV, the 'total' 37-mm sampler is an equivalent method to the "inhalable" method, referred to as IOM (Institute of Occupational Medicine), and should be acceptable for use against the TLV. However, the study found that when confounders (dust or old asphalt millings) are present in the workplace, there can be significant differences between the two samplers' reported exposure. The ratio of IOM/Total was 1.37 for milling asphalt sites, 1.41 for asphalt paving over granular base, and 1.02 for asphalt over asphalt pavements. 相似文献
654.
A. Haurie J.J.E. Kübler A. Clappier H. van den Bergh 《Environmental Modeling and Assessment》2004,9(1):1-12
A method is proposed to build integrated models (also called Metamodels) aimed at quantifying the economic efficiency of air quality policies. This Metamodeling approach is based on the coupling of two complementary models, that operate at different scales in space and time, and which represent the economic and the physical and chemical processes, respectively. The joint consideration of the physico-chemical and techno-economic structure of the pollution control problems permits a comprehensive evaluation of air pollution abatement strategies. The motivating pollution control problems include urban-regional air quality management through efficient energy and traffic control policies. A pilot study, exploiting data collected in the Geneva canton (Switzerland), is used to demonstrate the potential of the approach. 相似文献
655.
Gary W. Heinke 《Environmental monitoring and assessment》1997,44(1-3):155-171
The challenges of urban growth for mega-cities in Asia, now and over the next few decades, are examined with particular reference to the ability or inability of those in charge of cities, elected officials and administrators, to provide for the legitimate demands of citizens. Issues such as population growth, industrialization, urbanization, financing, employment, health care, social services, public safety, transportation, water supply, waste disposal, and cultural and recreational facilities are included. While sustainable development of cities is advocated strongly by environmentalists and administrators, the past history of urban growth is quite often the opposite. Why? This paper examines the severe constraints that urban developments are subjected to, and might be possible to change in order to create a better future, with particular emphasis on Asia. Finally, the important contributions made by environmental scientists and engineers towards more sustainable development are placed in context with the reality of urban growth. The approach taken is my personal view, having lived for over a period of 62 years in Europe, North America and now Asia, and having practised as an engineer and educator for almost 40 years. 相似文献
656.
J. Franzaring 《Environmental monitoring and assessment》1997,46(3):209-220
Up to now only very few studies in biomonitoring of organic air pollutants have been published taking into account the strong influence mean temperatures have on the accumulation process into plants during the course of the exposition. Temperature governed sorption as well as the plants vitality pose a major source of uncertainty making inter-study comparisons difficult. Different surface-to-volume ratios of plant foliage lead to strongly varying concentration effects in different plant species. Moreover a plants content of waxes and lipids must be considered in order to relate xenobiotic concentrations to the compounds being most efficient in the bioaccumulation process. Some of these factors are evaluated in regard to the use of plants as biomonitors for organic air pollutants. Another aim is to deduce the mean ambient gas phase concentrations from PAH concentrations determined in the biomonitor plants using vegetation-air partitioning coefficients which have been corrected for temperature dependent sorption as well as the plants lipid content. Restrictions of such approaches and methods of biomonitoring in general are discussed. 相似文献
657.
Lisa A. Baron Tom L. Ashwood Bradley E. Sample Christopher Welsh 《Environmental monitoring and assessment》1997,47(2):153-165
The belted kingfisher (Ceryle alcyon), acommon piscivore in the eastern United States, hasbecome a common endpoint in ecological riskassessments (ERA) because of their high consumptionof potentially contaminated aquatic prey. Whilebioaccumulation data and biosurveys may be used tosupport conclusions of ERAs for kingfishers, thereare currently no published data on contaminantconcentrations in kingfishers. Additionally,methods available for collecting biological samples(e.g., feathers, eggs, food debris, etc.) fromkingfisher burrows can be detrimental to thereproductive success of the birds. We present amethod for obtaining samples from burrows during orfollowing the nesting season. The method wasapplied to kingfisher burrows on the Oak RidgeReservation (ORR) in eastern Tennessee. Feathers,eggshells, and nestlings were collected from burrows and analyzed. In addition, carcasses ofthree adult kingfishers found dead on the ORR wereanalyzed. Metals and radionuclides were accumulatedby both juvenile and adult birds. Body burdens ofcadmium, lead, and cesium-137 in adult birds were belowlevels associated with toxicity. Concentrations of selenium and mercury were observed at potentiallytoxic levels. Contaminants in eggshells andnestling feathers indicate exposure, however, thereis insufficient information to evaluate thetoxicological significance of this contamination.National Laboratory Oak Ridge National Laboratory is managed for the U.S. Department of Energy by Lockheed Martin Energy Research Corp. under contract DE-AC05-96OR22464 相似文献
658.
Brock B. Bernstein Rainer Hoenicke Catherine Tyrell 《Environmental monitoring and assessment》1997,48(3):297-306
We present a planning framework that structures thelarge amount of interrelated information involved indeveloping regional monitoring programs. By regionalwe mean programs that recognize the importance ofprocesses that occur on larger geographic scales andthat cut across more than one ecosystem component. Theframework helps visualize functional relationshipsamong qualitative ingredients such as public concernsand more concrete details such as individual dataelements. It portrays the flow of information amongthe components of a regional program and ties eachaspect of the program to management decision-makingneeds. This makes it easier, during the planningprocess, to ensure that monitoring will actuallyproduce useful information. Further, the frameworksnovel, graphically oriented, and readily accessibleformat makes key information equally available to thewide range of participants (regulators, scientists,managers, public) whose input and support arenecessary for program success. 相似文献
659.
Andrew D. Kennedy 《Environmental monitoring and assessment》1997,48(2):173-192
Identifying process from pattern is one of the most vexing tasks inenvironmental monitoring. Given information on the distribution of speciesin a pre-defined area, together with comprehensive data on how environmentalconditions in that area have altered through time, is it possible toidentify the factors controlling the species‘ layout? Here, the practicalsignificance of this quandary is demonstrated using a series ofenvironmentally-degraded coastal lagoons in New South Wales. The TuggerahLakes (33°17′S,151°30′E) have over the last 50 yearsexperienced significant changes in species‘ distributions. Seagrasses,macroalgae, phytoplankton, molluscs, prawns and the jellyfish Catostylus mosaicus have altered in spatial pattern. Two human activitieshave been blamed for these perturbations: (1) agricultural clearance ofnative vegetation from the catchment, with associated input of top-soil andnutrients; (2) the commissioning of a coal-fired power station in 1967, withmassive uptake and recirculation of lake water for cooling purposes. In thispaper, spatial changes in macrophyte distributions over the last 50 yearsare reviewed in an attempt to identify the true source(s) of perturbation.The model adopted assumes that the power station is a point source of impactwhile nutrient inputs from the catchment are a diffuse source of impact;changes in species distributions can hypothetically be related back to thesesources according to whether they are localised or widespread. However,after a comprehensive analysis of available macrophyte data derived frominterviews, aerial photography and line transect methodologyies theconclusion is reached that changes in biogeographical pattern around theTuggerah Lakes cannot be attributed to specific anthropogenic pressures atanything beyond the coarsest of levels. This is considered to be the normfor most coastal management situations where natural background variation(’noise‘) and the complexity of linkages between physical, chemical andbiological components confounds the identification of causal relationships.The practical implications of this conclusion are discussed in the contextof litigation and remedial management design. Emphasis is placed on theneed to adopt an adaptive approach to estuarine management, incorporatingexplicit recognition of the limitations of available data, and to developnew techniques for identifying cause-effect relationships. 相似文献
660.
D. Hart L. Stone A. Stern D. Straile U. Gaedke 《Environmental Modeling and Assessment》1997,2(1-2):23-28
We describe a general computer program which employs novel techniques to analyze carbon (energy) and nutrient flows in complex food webs. The program uses estimates of metabolic/physiological parameters and ecosystem fluxes to simultaneously calculate the most likely balanced flux charts for carbon and a nutrient. We give an example of how the model can explore the theoretical issues involved with nutrient limitation and recycling. 相似文献