全文获取类型
收费全文 | 3856篇 |
免费 | 77篇 |
国内免费 | 357篇 |
专业分类
安全科学 | 156篇 |
废物处理 | 228篇 |
环保管理 | 339篇 |
综合类 | 940篇 |
基础理论 | 851篇 |
环境理论 | 2篇 |
污染及防治 | 1252篇 |
评价与监测 | 267篇 |
社会与环境 | 207篇 |
灾害及防治 | 48篇 |
出版年
2023年 | 28篇 |
2022年 | 101篇 |
2021年 | 65篇 |
2020年 | 47篇 |
2019年 | 66篇 |
2018年 | 144篇 |
2017年 | 78篇 |
2016年 | 109篇 |
2015年 | 124篇 |
2014年 | 138篇 |
2013年 | 327篇 |
2012年 | 140篇 |
2011年 | 216篇 |
2010年 | 180篇 |
2009年 | 194篇 |
2008年 | 208篇 |
2007年 | 219篇 |
2006年 | 167篇 |
2005年 | 132篇 |
2004年 | 152篇 |
2003年 | 155篇 |
2002年 | 132篇 |
2001年 | 251篇 |
2000年 | 152篇 |
1999年 | 77篇 |
1998年 | 50篇 |
1997年 | 51篇 |
1996年 | 36篇 |
1995年 | 43篇 |
1994年 | 45篇 |
1993年 | 42篇 |
1992年 | 31篇 |
1991年 | 37篇 |
1990年 | 29篇 |
1989年 | 32篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 18篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 12篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有4290条查询结果,搜索用时 15 毫秒
41.
Land use as a mitigation strategy for the water-quality impacts of global warming: a scenario analysis on two watersheds in the Ohio River Basin 总被引:4,自引:0,他引:4
This study uses an integrative approach to study the water-quality impacts of future global climate and land-use changes. In this study, changing land-use types was used as a mitigation strategy to reduce the adverse impacts of global climate change on water resources. The climate scenarios were based on projections made by the Intergovernmental Panel on Climate Change (IPCC) and the United Kingdom Hadley Centre's climate model (HadCM2). The Thornthwaite water-balance model was coupled with a land-use model (L-THIA) to investigate the hydrologic effects of future climate and land-use changes in the Ohio River Basin. The land-use model is based on the Soil Conservation Service's curve-number method. It uses the curve number, an index of land use and soil type, to calculate runoff volume and depth. The ArcView programming language, Avenue, was used to integrate the two models into a geographic information system (GIS). An output of the water-balance model, daily precipitation values adjusted for potential evapotranspiration, served as one of the inputs into the land-use model. Two watersheds were used in the present study: one containing the city of Cincinnati on the main stem of the Ohio River, and one containing the city of Columbus on a tributary of the Ohio River. These cities represent two major metropolitan areas in the Ohio River Basin with different land uses experiencing different rates of population growth. The projected hypothetical land-use changes were based on linear extrapolations of current population data. Results of the analyses indicate that conversion from agricultural land use to low-density residential land use may decrease the amount of surface runoff. The land-use practices which generate the least amount of runoff are forest, low-density residential, and agriculture; whereas high-density residential and commercial land-use types produce the highest runoff. The hydrologic soil type present was also an important factor in determining the amount of runoff and non-point-source pollution. A runoff-depth matrix and total nitrogen matrix were created for Cincinnati and Columbus to describe possible land-use mitigation measures in response to global climate change. The differences in Cincinnati and Columbus were due to differences in geographic location, air temperature, and total runoff. The results of this study may be useful to planners and policy makers for defining the possible impacts of future global climate and land-use changes on water resources. 相似文献
42.
采用水解酸化厌氧好氧混凝吸附工艺处理洁霉素生产丁提高浓度有机废水,工程实践表明,CODCr和BOD5去除率在99%以上,所排废水各项指标达到国家排放标准。 相似文献
43.
This study investigated the influence of cat urine odour in suppressing development and fertility in Campbell's hamster males.
Exposure to this odour from postnatal day 11 until day 45 (sexual maturation) resulted in reduced sex organ weights, reduced
testosterone levels and in an increase in abnormalities of the synaptonemal complex in both sex chromosomes and autosomes.
Subsequent breeding experiments revealed a significant decrease in litter size. All these data indicate a severe effect of
predator odour on the breeding success of potential prey species. It is assumed that these effects are caused by the sulphurous
compounds in the urine; however, the underlying mechanisms are not yet known.
Received: 31 January 2000 / Accepted in revised form: 6 June 2000 相似文献
44.
Laperdina T. G. Melnikova M. V. Koval A. T. Sidorov Y. F. Nagorny V. A. Ostapchuk V. I. 《环境科学学报(英文版)》2000,(Z1)
IntroductionSiberiaandtheFarEastaretheoldestandtherichestgold miningareasofRussia .Intensivegold miningherestartedinthebeginningofthe 19thcentury(Vyazelshchikov ,1963) .Forthemostpartgold bearingoresandsandswereprocessedwiththeuseofamalgamationmethodforgolde… 相似文献
45.
本文综合分析了以环境保护法为基本法的环境保护法律的体系,试图从环境法律关系和法律责任等方面对环境法进行法律属性的分析,得学我国环境管理体制实质上就是环境行政管理体制的结论,环境行政管理必须在法制的轨道上运行,这样才会从根本上解决环境保护的问题,才会使我们的生存环境更加美好。 相似文献
46.
稻、土及田水中锐劲特残留量分析方法 总被引:10,自引:0,他引:10
建立了新型杀虫剂锐劲特及其代谢物在水稻、土壤、田水中的气相色谱毛细管柱残留分析方法。该方法对锐劲特及其代谢物MB46513、MB45950、MB46136、RPA200766等,在水稻中的最低检出浓度依次为:0.002,0.001,0.001,0.004,0.01mg/kg;在土壤中这几种组分最低检出浓度为水稻中的1/3;在田水中最低检出浓度为水稻中的1/25。加标回收率83.4%-97.7%。变异系数1.86%-7.07%。 相似文献
47.
48.
生物膜反应器处理洗涤污水的试验 总被引:1,自引:0,他引:1
介绍了采用生物膜反应器处理洗涤污水的试验研究方法,研究了COD、LAS和NH3-N的去除效果。试验结果表明:整个系统出水稳定,水质良好(COD〈38.7mg/L、NH3-N〈1.1mg/L、LAS〈0.9mg/L,且无色无味、无SS),符合国家建设部生活杂用水回用水质标准,且具有较强的抗冲击负荷能力。在生物膜反应器中,微生物对污染物的去除起主要作用,而中空纤维膜对维持系统的稳定出水起重要作用。 相似文献
49.
50.