全文获取类型
收费全文 | 19330篇 |
免费 | 229篇 |
国内免费 | 150篇 |
专业分类
安全科学 | 513篇 |
废物处理 | 811篇 |
环保管理 | 2458篇 |
综合类 | 3462篇 |
基础理论 | 4676篇 |
环境理论 | 16篇 |
污染及防治 | 5168篇 |
评价与监测 | 1297篇 |
社会与环境 | 1173篇 |
灾害及防治 | 135篇 |
出版年
2023年 | 105篇 |
2022年 | 216篇 |
2021年 | 273篇 |
2020年 | 162篇 |
2019年 | 195篇 |
2018年 | 325篇 |
2017年 | 367篇 |
2016年 | 525篇 |
2015年 | 384篇 |
2014年 | 573篇 |
2013年 | 1647篇 |
2012年 | 708篇 |
2011年 | 893篇 |
2010年 | 698篇 |
2009年 | 704篇 |
2008年 | 839篇 |
2007年 | 883篇 |
2006年 | 772篇 |
2005年 | 632篇 |
2004年 | 591篇 |
2003年 | 571篇 |
2002年 | 507篇 |
2001年 | 577篇 |
2000年 | 453篇 |
1999年 | 261篇 |
1998年 | 213篇 |
1997年 | 198篇 |
1996年 | 216篇 |
1995年 | 227篇 |
1994年 | 219篇 |
1993年 | 211篇 |
1992年 | 218篇 |
1991年 | 207篇 |
1990年 | 208篇 |
1989年 | 176篇 |
1988年 | 153篇 |
1987年 | 133篇 |
1986年 | 158篇 |
1985年 | 162篇 |
1984年 | 160篇 |
1983年 | 163篇 |
1982年 | 158篇 |
1981年 | 163篇 |
1980年 | 152篇 |
1979年 | 145篇 |
1978年 | 109篇 |
1977年 | 121篇 |
1974年 | 109篇 |
1973年 | 91篇 |
1972年 | 107篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
M. E. Berlyand N. Sh. Volberg R. F. Lavrinenko E. N. Rusina 《Environmental monitoring and assessment》1982,2(4):393-402
- The Air Polluttion Monitoring System has got a significant development of late, which is in direct relation with a considerable extention and improvement of the observation network in cities and industrial areas, with creation of a new network for assessing regional and global background of the atmosphere pollution, as well as with the wide involvement of meteorologists to monitoring organization.
- While developing a new global monitoring system, it is necessary to take into account its relationship with the local monitoring within the region of air pollution sources, i.e. at the \lsimpact\rs level. The need in such an account is dictated first of all by the physics of pollutant spreading that states: changes in air pollution over large territories must be in a certain agreement with greater changes in the vicinity of emission sources. Methods applied in the global and local monitoring have also a number of common peculiarities. White organizing regional network for observations of the background pollution of the atmosphere twin stations (one of the pair of stations located outside the city boundaries in a small community, and the other, in the nearest city with the population of 200–400 thousand inhabitants) were established in the U.S.S.R. and in a number of socialist countries in Europe.
- Implementation of the twin-station principles in the U.S.S.R. has contributed to data interpretation and representativity assessment as well as to correction of the station location. Observation results from the Soviet background stations and those abroad have been compared by now according to a number of indices.
- The correlation of monitoring systems of various scales tells positively both on mutual improvement and completion of observational methods. The methods of obtaining integral characteristics of air pollution were used for the global monitoring, in particular spectral actinometric observations and chemical analysis of the precipitation composition. Now they find still wider employment. Thus methods of spectral actinometric measurements and data processing were used to estimate the degree of aerosol pollution of a number of industrial centres. The theory of solar radiation spreading and aerosol contents determination in urban atmosphere has also been developed. It is a generalization of an earlier developed theory, used to estimate global atmosphere pollution basing on actinometric data. The organization of precipitation collection and analysis on a network of stations around Leningrad and in Donbass area enables us to compare the admixture content in precipitations falling in industrial and agricultural areas.
- A considerable increase of possibilities to measure microconcentrations of sulphur dioxide, nitrogen oxides and of a number of other pollutants is connected with the use of solid solvents for sampling. Their use will allow to avoid establishment of special laboratories at background stations and only send samples by post for their analysis in centralized laboratories.
92.
Peter A. Beedlow Don S. Daly Michael E. Thiede 《Environmental monitoring and assessment》1986,6(3):277-282
An electrical device capable of continuously measuring micronsized changes in stem diameter of woody and herbaceous plants is described. Fumigation of sunflowers with automotive exhaust was used to test the ability of the device to detect short-term plant responses. 相似文献
93.
An attempt was made to explain ambient air quality violations in the vicinity of industrial plants. Micrometeorology, diffusion calculaations, ambient readings, and plant engineering data are all taken into consideration to ascertain whether the plant is or is not the principal offender.Scrutiny of hi-vol filters using scanning electron microscopy for particle size analysis and particle chemical make-up as an assessment technique is also described.Case histories using the above analytical techniques are discussed.Presented at the 16th National Conference on Energy and the Environment, May 23, 1979 相似文献
94.
95.
Bridget N. Bero Margrit C. von Braun Charles R. Knowles John E. Hammel 《Environmental monitoring and assessment》1995,36(2):123-138
The sampling of carpeted surfaces to test for lead contamination primarily focuses upon vacuum techniques. Vacuum sampling techniques, however, require time-consuming, expensive laboratory analysis of the dusts obtained and are unable to determine total lead load on the carpet. X-ray fluorescence (XRF) analysis is an on-site, inexpensive, non-destructive, quick technique for predicting metals levels in a variety of media, such as water, soil, filter paper and painted surfaces. A 1992 study of the feasibility of XRF to analyze for lead and soil loadings on carpeted surfaces indicated that XRF can detect lead at a low enough level to warrant further study. This paper expands this earlier study and developes lead and soil loading calibration curves for three different carpet types based upon XRF lead L-beta peak areas and XRF iron and barium K-alpha peak and background areas. Results indicate that variation in the data can be reduced through modifications of the XRF analysis technique, thus reducing the statistically determined detection level, and that carpet type does affect the calibration. Detection levels of approximately 70 mg/m2 for lead and 5 g/m2 for soil were obtained. Overall, good agreement was found between results of this study and the earlier one. XRF shows excellent potential for quantitative analysis of lead on carpeted surfaces. 相似文献
96.
V. M. Artyomov E. M. Artyomov Sh. D. Fridman 《Environmental monitoring and assessment》1994,29(3):221-228
The paper considers the methodology and results of experimental determination of dry deposition and ammonia uptake by isolated plant leaves. Analytical expressions are proposed which allow a transition from rates obtained in an isolated chamber to dry ammonia deposition by standing crops leaves. 相似文献
97.
Alexandra E. Boekhold Sjoerd E. A. T. M. Van Der Zee 《Environmental monitoring and assessment》1994,29(1):1-15
CaCl2-extractable soil Cd and Zn contents have been suggested as a measure of bioavailability. To investigate the ability of this measure to reflect spatial patterns of Cd and Zn concentrations in barley (Hordeum vulgare L.) in an arable field, plant and soil samples were taken from a 0.5 ha area sandy soil contaminated with Cd and Zn. Cd and Zn contents in barley and yield were spatially variable. Yield was low, which may have been caused by Zn toxicity or atrazine turnover. For Cd, CaCl2-extractable soil contents explained only 17% of the variation in Cd contents in grain, and for Zn no significant correlation was observed. Nevertheless, surface plots of CaCl2-extractable soil contents and contents of barley grain illustrated their corresponding spatial patterns. Despite the poor linear correlation between CaCl2-extractable soil-Cd and grain-Cd, a stochastic model for long term behaviour of Cd in field soils predicted observed variability in Cd contents of barley grain well from spatial variability of soil pH and organic matter content. The probabilistic model predicted behaviour of Cd in terms of probability, and was more appropriate than the deterministic approach. 相似文献
98.
Patchy distributions: Optimising sample size 总被引:1,自引:0,他引:1
J. E. Hewitt G. B. Mcbride R. D. Pridmore S. F. Thrush 《Environmental monitoring and assessment》1993,27(2):95-105
A method for estimating sample size which does not require an a priori definition of desired precision, or the assumption that the population is normally distributed with constant variance, has recently been proposed. This paper discusses this method and presents five modifications which make the method easier to use and reduce the probability of estimating a larger sample size than is actually required. The method is extended and used to estimate the mean abundance of patchily distributed benthic organisms. The technique can be used to guide the design of any environmental sampling programme, be it physical, chemical or biological, where comparisons between times and/or locations are required. Trade-offs between numbers of replicates and numbers of levels/sites are discussed. 相似文献
99.
Le Roux SM Turner A Millward GE Ebdon L Appriou P 《Journal of environmental monitoring : JEM》2001,3(1):37-42
Radiochemical partitioning experiments using 203Hg have been undertaken with mixtures of river, seawater and sediment samples taken from three geochemically contrasting UK estuaries: the Plym, Beaulieu and Mersey. Species of dissolved Hg were determined using reversed-phase C18 chelating columns and particulate species were determined by sequential leaching with 1 M NH4OAc and 1 M HCl. Mercury had a high particle reactivity with partition coefficients, KDs, ranging from 10(4) to 5 x 10(5) ml g(-1), depending on salinity, the chemical composition of the end-member waters, and on the physico-chemical characteristics of the sediment. Dissolved organic matter present in the waters (humic substances and/or anthropogenic compounds) was found to be the main factor governing the forms of dissolved Hg and their reactivity. From the spiked 203Hg, up to 95% of the dissolved metal was retained on the C18 columns for the Mersey waters, whereas this fraction was < 60% in the Plym and Beaulieu waters. Quasi-irreversible adsorption of Hg onto particles from each estuary was observed over a time-scale of a few hours and < 20% of total particulate Hg was released by the sequential leach. In this paper, physico-chemical processes are proposed to explain the estuarine behaviour of Hg and the results are discussed in terms of Hg availability in estuarine systems. 相似文献
100.
Pacáková V Pockeviciute D Armalis S Stulík K Li J Veselý J 《Journal of environmental monitoring : JEM》2000,2(2):187-191
Experiments were carried out to monitor the equilibrium distribution of lead, cadmium and copper between an aqueous phase modelling natural water and a solid phase modelling natural sediment, under varying conditions. The aqueous phase was analysed using ETAAS and differential pulse anodic stripping voltammetry (DPASV), whereas XRD and FTIR were used to study the solid phase. Sorption isotherms at constant pH were measured. Conditional distribution constants were calculated as functions of the pH, the time of equilibration and the amount of solid material. The results obtained stress the need for standardization of the approaches to the study of water-sediment interactions in order to be able to evaluate and compare the extensive data from field measurements and to predict these interactions. 相似文献