全文获取类型
收费全文 | 21161篇 |
免费 | 1718篇 |
国内免费 | 5010篇 |
专业分类
安全科学 | 1161篇 |
废物处理 | 399篇 |
环保管理 | 5235篇 |
综合类 | 13576篇 |
基础理论 | 2328篇 |
环境理论 | 7篇 |
污染及防治 | 1710篇 |
评价与监测 | 2129篇 |
社会与环境 | 1112篇 |
灾害及防治 | 232篇 |
出版年
2024年 | 65篇 |
2023年 | 363篇 |
2022年 | 556篇 |
2021年 | 651篇 |
2020年 | 727篇 |
2019年 | 614篇 |
2018年 | 535篇 |
2017年 | 769篇 |
2016年 | 887篇 |
2015年 | 1051篇 |
2014年 | 1073篇 |
2013年 | 1503篇 |
2012年 | 1488篇 |
2011年 | 1652篇 |
2010年 | 1233篇 |
2009年 | 1239篇 |
2008年 | 981篇 |
2007年 | 1465篇 |
2006年 | 1452篇 |
2005年 | 1108篇 |
2004年 | 982篇 |
2003年 | 1036篇 |
2002年 | 905篇 |
2001年 | 768篇 |
2000年 | 738篇 |
1999年 | 591篇 |
1998年 | 423篇 |
1997年 | 382篇 |
1996年 | 349篇 |
1995年 | 291篇 |
1994年 | 256篇 |
1993年 | 220篇 |
1992年 | 176篇 |
1991年 | 139篇 |
1990年 | 106篇 |
1989年 | 94篇 |
1988年 | 82篇 |
1987年 | 88篇 |
1986年 | 54篇 |
1984年 | 51篇 |
1983年 | 56篇 |
1982年 | 62篇 |
1981年 | 76篇 |
1980年 | 84篇 |
1979年 | 76篇 |
1978年 | 55篇 |
1977年 | 49篇 |
1973年 | 46篇 |
1972年 | 39篇 |
1971年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
991.
水入渗条件下边坡破坏离心模型试验研究 总被引:3,自引:0,他引:3
水的人渗能对土体强度产生较大的影响,它是造成边坡破坏的一个主要因素.不同含水量土质边坡的离心模型试验表明:边坡的破坏类型与其含水量大小有关,且主要存在两种破坏类型:一种是含水量较小时形成的拉裂缝破坏,另一种是含水量较大时形成的整体滑塌破坏;同时,含水量与边坡的最大稳定高度呈非线性关系.进一步的损伤力学分析表明,随着土体含水量的增加,损伤变量增大,并存在一个突变点;通过同离心模型试验结果比较,发现该突变点对应的含水量可作为两种破坏类型的判据. 相似文献
992.
利用多年的环境监测数据,分析南昌市环境空气中主要污染物尘类、二氧化硫和氮氧化物产生的原因,并提出有效控制上述污染物的具体措施。 相似文献
993.
济南市是资源型缺水城市,地表水遭到严重污染,已成为水质型缺水城市,导致地下水超采、地面沉降、泉水停涌等一系列环境、生态、经济问题,水资源已成为制约济南市发展的瓶颈因素.在对济南市水资源现状及相关问题进行详细分析的基础上,提出加强客水资源调用与管理、水资源循环利用、合理制定水价等水资源可持续利用的措施和对策. 相似文献
994.
入世给我国带来了一定的环境压力,主要表现在资源消耗、污染进口和产业冲击三方面.外商投资增长及外国人入境消费可能引起资源过度消耗,环境风险较大的项目和危险废弃物也可能乘机而入.受国外环保产业和环保服务业的冲击,我国相关产业面临严峻挑战.现阶段,我国的法规标准和公众意识是影响入世所带来的环境压力的两个重要因素.缓解环境压力的举措需要遵循两个原则:制度改革和管理改革结合的原则;短期措施和长期战略结合的原则. 相似文献
995.
刘铁英 《中国环境管理干部学院学报》2004,14(2):15-20
污水深度处理后回用不仅节约水资源,也减少了大量污染物的排放,是一项一举多得的益事。秦皇岛港污水深度处理回用工程利用城市二级处理的污水,经深度生物处理后用于煤炭除尘,解决了除尘水源紧张的局面。本文就如何确定回用工程的出水水质指标及其标准进行了讨论,阐述了制定出水水质标准的基本原则。 相似文献
996.
城市光污染侵害案件法律适用问题的探讨 总被引:1,自引:0,他引:1
在城市光污染侵害案件日益增多的同时,我国光污染侵害的法律救济手段和救济结果却不尽人意。虽然我国在宪法、环境保护法等法律、法规及民法中都有处理光污染侵害案件的法律依据,但由于缺少直接的规定,使环境保护法律体系存在太大的缺陷。因此,亟待制定有关的标准和修改相关的法律,从而更好地防治光污染,维护受害人的合法权益。 相似文献
997.
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
998.
Best management practices compliance monitoring approaches for forestry in the eastern United States
Many of the eastern states that have published best management practices (BMPs) or forest management guidelines have also developed compliance monitoring programs to assess the application of these BMPs or guidelines on public and private forest land. The approaches among these states to collecting on-site monitoring data (measuring compliance) and evaluating sites are variable. A survey of eastern states found that almost all southern states monitor application of BMPs, but proportionally fewer of the northern states have established compliance monitoring programs. The state forestry agencies provide the leadership for these programs in most of the eastern states. States that monitor tend to evaluate all public and private forest landowner categories located within their states. In general, northern states monitor a broader array of site resources (e.g., cultural resources, visual quality) as compared to southern states which focus on water quality and wetlands protection. However, northern states focus their monitoring on timber harvesting, forest road construction and maintenance as compared to southern states which tend to monitor a broader array of forest management activities (e.g., site preparation, reforestation). When selecting sites for monitoring, the most common approach is to select some sites from all landowner categories within the state. Many states do not specify any criteria to identify sites for monitoring so that all sites have an equal chance for selection. Some states do use specific criteria to filter sites for monitoring, most commonly size of forest management activity and proximity to water. 相似文献
999.
Andrew J. Londo 《Water, Air, & Soil Pollution: Focus》2004,4(1):235-243
This study examined the knowledge levels of Mississippi Non Industrial Private Forest (NIPF) landowners. Data were collected by passing out surveys to participants in Best Management Practices (BMP) educational programs held in conjunction with County Forestry Association (CFA) meetings across Mississippi. Ten CFA's participated in this study. Educational program participants were asked to fill out a survey with several demographic and BMP questions prior to the educational program. Results show that BMP program participants owned an average of 113 hectares, whereas the average Mississippi NIPF landowner owns 20 hectares. Responses to BMP related questions show that Mississippi NIPF landowners have a low level of knowledge concerning BMP's. This situation is likely similar to other states in the Southeastern United States. It can be assumed that county forestry association members are more active and informed about managing their forest land. Therefore, these results may overestimate the BMP knowledge level all landowners in Mississippi.Improved educational programs for NIPF landowners, along with better communication between foresters, loggers, and NIPF landowners are needed if BMP's are to be implemented effectively in Mississippi and across the southern region. 相似文献
1000.