全文获取类型
收费全文 | 16259篇 |
免费 | 884篇 |
国内免费 | 5615篇 |
专业分类
安全科学 | 1276篇 |
废物处理 | 1016篇 |
环保管理 | 1353篇 |
综合类 | 9530篇 |
基础理论 | 2532篇 |
污染及防治 | 4980篇 |
评价与监测 | 754篇 |
社会与环境 | 627篇 |
灾害及防治 | 690篇 |
出版年
2024年 | 23篇 |
2023年 | 259篇 |
2022年 | 790篇 |
2021年 | 730篇 |
2020年 | 582篇 |
2019年 | 510篇 |
2018年 | 645篇 |
2017年 | 730篇 |
2016年 | 702篇 |
2015年 | 910篇 |
2014年 | 1310篇 |
2013年 | 1638篇 |
2012年 | 1398篇 |
2011年 | 1438篇 |
2010年 | 1190篇 |
2009年 | 1170篇 |
2008年 | 1265篇 |
2007年 | 1043篇 |
2006年 | 1028篇 |
2005年 | 665篇 |
2004年 | 496篇 |
2003年 | 552篇 |
2002年 | 507篇 |
2001年 | 370篇 |
2000年 | 446篇 |
1999年 | 399篇 |
1998年 | 322篇 |
1997年 | 360篇 |
1996年 | 294篇 |
1995年 | 227篇 |
1994年 | 179篇 |
1993年 | 151篇 |
1992年 | 136篇 |
1991年 | 78篇 |
1990年 | 68篇 |
1989年 | 28篇 |
1988年 | 30篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
大气中SO_2、NO_x、TSP和CO平行采样监测结果的统计分析表明,地面与楼顶采样的差异不显著,其浓度变化有随高度呈规律性的变化趋向,降雪具有明显的洗脱清除作用。 相似文献
93.
应用灰色系统GM(1,1)模型,对地下水中总硬度的变化作了预测.检验结果表明,该模型精度较高,是一种较好的预测方法. 相似文献
94.
Prohaska T Quétel CR Hennessy C Liesegang D Papadakis I Taylor PD Latkoczy C Hann S Stingeder G 《Journal of environmental monitoring : JEM》2000,2(6):613-620
Many fields in environmental analytical chemistry deal with very low limits and thresholds as set by governmental legislations or transnational regulations. The need for the accuracy, comparability and traceability of analytical measurements in environmental analytical chemistry has significantly increased and total uncertainties are even asked for by accreditation bodies of environmental laboratories. This paper addresses achieving these goals to guarantee accuracy, quality control, quality assurance or validation of a method by means of certified reference materials. The assessment of analytical results in certified reference materials must be as accurate as possible and every single step has to be fully evaluated. This paper presents the SI-traceable certification of Cu, Cr, Cd and Pb contents in geological and environmentally relevant matrices (three sediments and one fly ash sample). Certification was achieved using isotope dilution (ID) ICPMS as a primary method of measurement. In order to reduce significantly the number of analytical steps and intermediate samples a multiple spiking approach was developed. The full methodology is documented and total uncertainty budgets are calculated for all certified values. A non-element specific sample digestion process was optimised. All wet chemical digestion methods examined resulted in a more or less pronounced amount of precipitate. It is demonstrated that these precipitates originate mainly from secondary formation of fluorides (essentially CaF2) and that their formation takes place after isotopic equilibration. The contribution to the total uncertainty of the final values resulting from the formation of such precipitates was in general < 0.1% for all investigated elements. Other sources of uncertainty scrutinised included the moisture content determination, procedural blank determination, cross-contamination from the different spike materials, correction for spectral interferences, instrumental background and deadtime effects, as well as the use of either certified values or IUPAC data in the IDMS equation. The average elemental content in the sediment samples was 30-130 micrograms g-1 for Pb, 0.5-3 micrograms g-1 for Cd and 50-70 micrograms g-1 for Cu. Cr was measured in one sample and was about 60 micrograms g-1. The concentrations in the fly ash sample were up to 2 orders of magnitude higher. Expanded uncertainty for the investigated elements was about 3% (coverae factor k = 2) except for Cr, (measured by high resolution ICPMS), for which the expanded uncertainty was about 7% (k = 2). 相似文献
95.
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
96.
97.
98.
介绍液相化学发光分析法的原理和特点以及十年来在我国环境监测中的应用。收录1983年~1991年国内的应用论文50余篇,作了较为系统全面的评述。 相似文献
99.
多介质环境目标值的应用 总被引:1,自引:0,他引:1
本文概述了多介质目标德的SAM/Ⅰ的方法。多介质目标值包括环境目标值和排放目标值。点源分析包括SAM/ⅠA,SAM/ⅠB,SAM/Ⅰ,SAM/Ⅱ。在缺少环境质量标准的情况下,使用多介质环境目标值有较强的适用性,且具有省时、省力、经济等特点。本文将多介质目标值的SAM/ⅠA点源分析方法引入聚氯乙烯生产废水的环境评价中,取得较为满意的结果。 相似文献
100.
地震安全性评价工作在城市建设中起着非常重要的作用,为工程抗震提供精确的设计依据,提供科学合理的地震动参数,提出科学合理的设防要求,能够在一定程度上避免破坏性地震造成的损失,从而达到有效减灾的目的。 相似文献