全文获取类型
收费全文 | 2664篇 |
免费 | 195篇 |
国内免费 | 453篇 |
专业分类
安全科学 | 442篇 |
废物处理 | 105篇 |
环保管理 | 560篇 |
综合类 | 1041篇 |
基础理论 | 359篇 |
污染及防治 | 321篇 |
评价与监测 | 133篇 |
社会与环境 | 121篇 |
灾害及防治 | 230篇 |
出版年
2024年 | 5篇 |
2023年 | 26篇 |
2022年 | 54篇 |
2021年 | 80篇 |
2020年 | 90篇 |
2019年 | 61篇 |
2018年 | 59篇 |
2017年 | 90篇 |
2016年 | 111篇 |
2015年 | 135篇 |
2014年 | 140篇 |
2013年 | 168篇 |
2012年 | 165篇 |
2011年 | 214篇 |
2010年 | 168篇 |
2009年 | 183篇 |
2008年 | 131篇 |
2007年 | 178篇 |
2006年 | 153篇 |
2005年 | 154篇 |
2004年 | 102篇 |
2003年 | 104篇 |
2002年 | 105篇 |
2001年 | 93篇 |
2000年 | 95篇 |
1999年 | 66篇 |
1998年 | 35篇 |
1997年 | 41篇 |
1996年 | 24篇 |
1995年 | 38篇 |
1994年 | 24篇 |
1993年 | 29篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1972年 | 7篇 |
1971年 | 9篇 |
排序方式: 共有3312条查询结果,搜索用时 78 毫秒
61.
M. R. Theobald U. Dragosits C. J. Place J. U. Smith M. Sozanska L. Brown D. Scholefield A. Del Prado J. Webb P. G. Whitehead A. Angus I. D. Hodge D. Fowler M. A. Sutton 《Water, Air, & Soil Pollution: Focus》2004,4(6):135-142
The distribution and impacts of different nitrogen pollutants are inextricably linked. To understand the problem fully, the interactions between the different pollutants need to be taken into account. This is particularly important when it comes to abatement techniques, since measures to reduce emissions of one nitrogen pollutant can often lead to an increase in another. This project represents a step towards greater understanding of these issues by linking together new and existing nitrogen flux models into a larger framework. The modelling framework has been constructed and some of the nitrogen flows between fields, farms and the atmosphere have been modelled for a UK study area for typical farm management scenarios. 相似文献
62.
James F. Saunders Marylee Murphy Martyn Clark William M. Lewis 《Journal of the American Water Resources Association》2004,40(5):1339-1349
ABSTRACT: Historical flow records are used to estimate the regulatory low flows that serve a key function in setting discharge permit limits through the National Pollutant Discharge Elimination System, which provides a nationwide mechanism for protecting water quality. Use of historical records creates an implicit connection between water quality protection and climate variability. The longer the record, the more likely the low flow estimate will be based on a broad set of climate conditions, and thus provides adequate water quality protection in the future. Unfortunately, a long record often is not available at a specific location. This analysis examines the connection between climate variability and the variability of biologically based and hydrologically based low flow estimates at 176 sites from the Hydro‐Climatic Data Network, a collection of stream gages identified by the USGS as relatively free of anthropogenic influences. Results show that a record of 10 to 20 years is necessary for satisfactory estimates of regulatory low flows. Although it is possible to estimate a biologically based low flow from a record of less than 10 years, these estimates are highly uncertain and incorporate a bias that undermines water quality protection. 相似文献
63.
64.
65.
66.
四川汶川茶园沟泥石流灾害特征及危险度评价 总被引:15,自引:1,他引:15
2003年8月9日四川汶川县茶园沟泥石流造成了1人死亡,10人失踪和严重的财产损失.泥石流是由于短历时高强度的大雨激发而形成的.泥石流最大流速为10.8m/s,泥石流洪峰流量为999m3/s,冲出物方量约为5万m3.茶园沟流域内松散固体物质的密度为2.18 g/cm3,含水量为10.7%,空隙率为28%,塑性界限和流性界限分别为18.8%和32.5%,一遇大雨或较长时间的降雨就极易形成泥石流.茶园沟属中度危险的泥石流沟,中度危险的泥石流也造成了严重的人民生命财产的损失,这主要是由于受灾对象,即易损性的特性所决定的.茶园沟泥石流的防灾减灾措施,一是要实行封山育林,停止开矿弃渣;二是要提高公路桥梁的防洪标准,合理布局水利水电设施. 相似文献
67.
灾难模型化及其国外主要开发商 总被引:3,自引:0,他引:3
简略分析了灾难模型化和它在保险业中的应用;介绍了当前国外从事灾难模型化的主要研发单位,包括独立的模型化公司、大学研究所、再保险公司、再保险中介经纪公司和政府机构。同时收集了一些最近灾难模型化些文献,希望这些信息能有助于同行在我国减灾保险方面的研究。 相似文献
68.
可变情报板对交通安全的影响分析 总被引:1,自引:0,他引:1
目前,可变情报板作为最基础、最常用的诱导信息发布平台被大量安装在道路两侧。一方面,它在一定程度上分散了车辆的聚集,减少了车辆的巡游;而另一方面,由于对可变情报板的设置、显示等方面的研究不足,它对交通安全带来了一定的影响,或者诱导效果并不理想。笔者主要围绕北京市西直门桥周边的可变情报板进行调研,从多个方面分析了可变情报板对交通安全的影响,列出了主要的影响因素,如刷新频率、视认性等,并给出了一定的量化指标。 相似文献
69.
70.
Atsumi Miyake Nobuyoshi Yamada Terushige Ogawa 《Journal of Loss Prevention in the Process Industries》2005,18(4-6):380-383
Organic peroxides (POs) have been widely used in chemical industries as initiators of polymerization, hardening or bridge formation agents, and they are known for its self-reactive and also mixing hazard characteristics when mixed with other chemicals such as acids and alkalis. It is the purpose of this investigation to propose a simple but useful evaluation flow of mixing hazards of POs with other chemicals using conventional experimental techniques such as a glass test tube test, Dewar vessel test and DSC is proposed. 7 kinds of POs (DEPD, THP, TBEH, TBTC, MEKPO, DTBP, THHP) were mixed with sulfuric acids with various concentration, sodium hydroxide solutions, -iron(III) oxide and acrylonitrile (AN).
Based on the proposed evaluation flow the testing results were classified into 4 ranks due to the hazard criteria. Futhermore DEPD/acrylonitrile mixtures were investigated in more detail and the influences of the mixing ratio and the stirring speed were discussed. 相似文献