全文获取类型
收费全文 | 1063篇 |
免费 | 45篇 |
国内免费 | 350篇 |
专业分类
安全科学 | 61篇 |
废物处理 | 63篇 |
环保管理 | 88篇 |
综合类 | 538篇 |
基础理论 | 190篇 |
污染及防治 | 376篇 |
评价与监测 | 48篇 |
社会与环境 | 32篇 |
灾害及防治 | 62篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 59篇 |
2021年 | 44篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 41篇 |
2017年 | 42篇 |
2016年 | 47篇 |
2015年 | 67篇 |
2014年 | 80篇 |
2013年 | 102篇 |
2012年 | 96篇 |
2011年 | 93篇 |
2010年 | 77篇 |
2009年 | 65篇 |
2008年 | 79篇 |
2007年 | 69篇 |
2006年 | 74篇 |
2005年 | 47篇 |
2004年 | 31篇 |
2003年 | 32篇 |
2002年 | 32篇 |
2001年 | 29篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 22篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有1458条查询结果,搜索用时 13 毫秒
491.
492.
An accurate quantitative evaluation of anthropogenic effects on regional groundwater dynamics is critical to the rational planning, management, and use of such resources and in maintaining the sustainability of groundwater-dependent ecosystems. Based on groundwater dynamics, a series of groundwater depth evaluation indexes were created to quantitatively evaluate the effects of anthropogenic activities on the groundwater system. These indexes were based on mathematical relationships relating groundwater depth to surface runoff (gammat), precipitation (rhot), and extraction (deltat). The anthropogenic effects on these relationships were evaluated statistically, with respect to both temporal and spatial variation. The anthropogenic effects on groundwater dynamics within the arid Zhangye Basin, located in the middle reaches of northwest China's Heihe River, were investigated. River valley plains in the western portion of the basin excepted, anthropogenic activities have, since 1995, dramatically altered the basin's groundwater dynamics; in particular, in the mid-upper and lower portions of alluvial-diluvial fans and in localized northerly fine-soil plains regions, the relationship of groundwater to surface runoff and atmospheric precipitation has shifted. This and other changes indicate that anthropogenic effects on groundwater systems in this region show clear spatiotemporal variation. 相似文献
493.
Wu CF Chen CH Chang SY Chang PE Shie RH Sung LY Yang JC Su JW 《Journal of the Air & Waste Management Association (1995)》2008,58(10):1360-1369
This paper presents the simulation and field evaluation results of two approaches to localize pollutant emission sources with open-path Fourier transform infrared (OP-FTIR) spectroscopy. The first approach combined the plume's peak location information reconstructed from the Smooth Basis Function Minimization (SBFM) algorithm and the wind direction data to calculate source projection lines. In the second approach, the plume's peak location was determined with the Monte Carlo methodology by randomly sampling within the beam segment having the largest path-integrated concentration. We first conducted a series of simulation studies to investigate the sensitivity of using different basis functions in the SBFM algorithm. It was found that fitting with the beta and Weibull basis functions generally gave better estimates of the peak locations than with the normal basis function when the plumes were mainly within the OP-FTIR's monitoring line. However, for plumes that were symmetric to the peak position or spread over the OP-FTIR, fitting with the normal basis function gave better performance. In the field experiment, two tracer gases were released simultaneously from two locations and the OP-FTIR collected data downwind from the sources with a maximum beam path length of 97 m. For the first approach, the release locations were within the 0.25- to 0.5-probability area only after the uncertainty of the peak locations was included in the calculation process. The second approach was easy to implement and still performed as satisfactorily as the first approach. The distances from the sources to the best-fit lines (i.e., the regression lines) of the estimated locations were smaller than 10 m. 相似文献
494.
With the development of science and technology, solid waste management has become a serious environmental problem for most communities all over the world. This paper presents a multi-objective optimization model for the management of municipal solid waste (MSW) via an uncertainty approach. In this model, the system cost of solid waste management and the environmental impact are considered as the main objectives, and some necessary constraints based on the characteristics of China are included; additionally, Pollution loss theory is applied to evaluate the environmental impact.This model is applied to the City of Fo Shan, China. Compared with the primary project of Fo Shan, which is provided by the government, the results of the optimization procedure show that the overall system cost could be reduced by $1–2.4/ton, i.e., $3.7 million/yr. The model presented in this paper was proven to be an effective response to the multi-objective solid waste management problem, and provides a new technique to optimize MSW management and operation. Why is the optimization result better? By analyzing the modelling with respect to function, constraints, and results, we conclude that the profit would be augmented due to the amount of the waste that would be treated by recycling technology, which would increase rapidly during the planning time; thus, the total system cost could be reduced accordingly. 相似文献
495.
496.
497.
基于GIS的唐山市综合防灾与生态规划 总被引:4,自引:0,他引:4
中国北方东部城市正处于高速发展时期,大部分城市由于处于环太平洋地震带和北纬中度灾害带的交叉部位,灾害问题严重,造成的经济损失巨大。因此,为了城市的可持续发展,必须把城市的生态建设和综合防灾工作结合起来,进行整体规划。通过自然灾害数据库的建立,灾害源、工程地质、建筑和城市生命线等数据的ACCESS数据库分别建立起来了。基于数理统计分析模型的GIS技术,以MAPINFO为平台,采用MAPBASIC开发工具,创建了唐山市综合防灾和生态规划信息管理系统,为唐山市的综合防灾的可持续发展规划提供了建议和依据。 相似文献
498.
苯酚、苯在水/阴离子有机膨润土界面的环境行为研究 总被引:8,自引:0,他引:8
研究了苯酚在水/阴离子有机膨润土界面的吸附行为,初步探讨了阴离子有机膨润土对苯酚、苯的吸附性能、机理及影响因素。结果表明,阴离子表面活性剂改性后,膨润土中有机碳含量增加了10~38倍,对苯酚、苯的吸附能力大大提高。水中苯酚、苯在水/阴离子有机膨润土界面的吸附行为主要分配作用所致,其吸附等温线呈线性。 相似文献
499.
500.
山梨醇型凝油剂的制备与性能 总被引:4,自引:0,他引:4
介绍了山梨醇型凝油剂的制备方法,以及其胶凝轻质渍及类油物质的性质。结果表明,此类凝油剂对汽油,柴油,机油以及基苯及苯系有机溶剂等的去除率达90%以上。经生物毒性试验表明,不会对水中鱼类产生毒性效应,凝油后油凝体硬度可达3.9×10^4-9.8×10^4Pa。可用于各种轻质油及类油物质泄漏等突发性事故的应急处理。 相似文献