全文获取类型
收费全文 | 1612篇 |
免费 | 218篇 |
国内免费 | 828篇 |
专业分类
安全科学 | 261篇 |
废物处理 | 51篇 |
环保管理 | 147篇 |
综合类 | 1463篇 |
基础理论 | 258篇 |
污染及防治 | 252篇 |
评价与监测 | 168篇 |
社会与环境 | 45篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 6篇 |
2023年 | 31篇 |
2022年 | 64篇 |
2021年 | 102篇 |
2020年 | 103篇 |
2019年 | 87篇 |
2018年 | 85篇 |
2017年 | 105篇 |
2016年 | 103篇 |
2015年 | 117篇 |
2014年 | 139篇 |
2013年 | 194篇 |
2012年 | 177篇 |
2011年 | 187篇 |
2010年 | 131篇 |
2009年 | 114篇 |
2008年 | 99篇 |
2007年 | 148篇 |
2006年 | 127篇 |
2005年 | 69篇 |
2004年 | 68篇 |
2003年 | 65篇 |
2002年 | 61篇 |
2001年 | 39篇 |
2000年 | 39篇 |
1999年 | 47篇 |
1998年 | 37篇 |
1997年 | 26篇 |
1996年 | 19篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有2658条查询结果,搜索用时 15 毫秒
91.
Park JS Oh S Shin MY Kim MK Yi SM Zoh KD 《Environmental pollution (Barking, Essex : 1987)》2008,154(1):12-20
Dissolved gaseous mercury (DGM) and total mercury (TM) concentrations were measured in Juam Reservoir, Korea. DGM concentrations were higher in spring (64+/-13pgL(-1)) and summer (109+/-15pgL(-1)), and lower in fall (20+/-2pgL(-1)) and winter (23+/-6pgL(-1)). In contrast, TM concentrations were higher in fall (3.2+/-0.1ngL(-1)) and winter (3.3+/-0.1ngL(-1)) than in spring (2.3+/-0.1ngL(-1)) and summer (2.2+/-0.4ngL(-1)). DGM concentrations were correlated with water temperature (p<0.0001), ORP (p<0.0001), UV intensity (UV-A: p=0.008; UV-B: p=0.003), and DOC concentration (p=0.0107). DGM concentrations varied diurnally with UV intensity. The average summer DGM (109+/-15pgL(-1)) and TM (2.2+/-0.4ngL(-1)) concentrations in Juam Reservoir were higher than the averages for North American lakes (DGM=38+/-16pgL(-1); TM=1.0+/-1.2ngL(-1)), but lower than levels reported for Baihua Reservoir in China. 相似文献
92.
In the last years many efforts were made to transform standardized algal test protocols into low-cost microplate assays. While advantages were pointed out frequently, limitations are not systematically addressed, thus hindering a widespread utilisation. In this study a group of organic substances with a wide distribution of volatility (log KAW from −6.53 to −2.13) and lipophilicity (log KOW from 1.26 to 4.92) was investigated with respect to the influence of these physicochemical properties on their algal toxicity in different assays. Therefore the EC50 values were determined with a microplate assay based on ISO 8692 protocol and the results were compared with those of an established algal growth inhibition test conducted in air tight glass vessels. Using the ratio of the EC50 values, a clear connection between biological response and volatility as well as lipophilicity of test substances could be detected. Chemicals with a log KOW higher than 3 or a Henry coefficient log KAW higher than −4 were identified as less effective in the microplate assay than in the comparative assay. The loss in nominal concentration due to physicochemical properties could be shown to contribute to this using HPLC analysis. Consequently, when using microplate assay’s one should be aware that lipophilic and volatile chemicals might be underestimated in their toxicity, which could be indicated from evaluating related physicochemical properties modelled from structural information prior to an experimental investigation. 相似文献
93.
畜禽粪便除臭及生物干燥技术研究进展 总被引:5,自引:0,他引:5
综述了近几年来国内外畜禽粪便除臭及脱水技术的研究进展,其中对生物干燥技术的发展进行了比较详细的介绍,以期推动我国畜禽粪便处理技术水平的提高。 相似文献
94.
随着遥感数据源的不断丰富,遥感技术不断提高,可以解决越来越多的水环境问题。指出了当前水生态环境管理方面的主要需求,结合目前遥感技术的发展,对国内外的水环境遥感研究进展进行综述。以湖泊富营养化监测与评估、核电站温排水遥感监测及城市黑臭水体遥感监测为案例,具体阐述遥感在水环境管理中的应用方法及成效。未来水生态环境管理发展趋势将以水污染防治为主向水污染防治和水生态修复与保护并重发展。基于此趋势,提出遥感在水生态修复的应用潜力,利于更多地方部门积极有效应用遥感技术,解决水生态环境问题。 相似文献
95.
96.
石油炼制是产生恶臭污染的重点行业之一,恶臭强度是评估恶臭污染程度的重要参数。以炼油厂厂界大气特征污染物为研究对象,综合考虑检出率、嗅阈值和物质浓度3项指标,采用指标评分法筛选出厂界主要恶臭污染物硫化氢、氨、甲苯和二甲苯。基于韦伯-费希纳定律构建了恶臭强度分级评估方法,以某炼油厂为例进行了厂界恶臭强度评估,结果表明,厂界恶臭强度值为0.63,属于Ⅱ级(轻污染),硫化氢是恶臭强度的主要贡献源。应用感官测定法验证了该评估方法的可靠性。从恶臭管理的角度看,炼油厂在厂界达标排放的基础上应进一步实施恶臭污染综合治理措施,以改善周边的环境质量。 相似文献
97.
A method to estimate the impact of clear-cutting on nutrient concentrations in boreal headwater streams 总被引:1,自引:0,他引:1
Large-scale forestry operations, like clear-cutting, may impair surface water quality if not done with environmental considerations in mind. Catchment and country level estimates of nutrient loads from forestry are generally based on specific export values, i.e., changes in annual exports due to the implemented forestry operations expressed in kg ha−1. We introduce here a specific concentration approach as a method to estimate the impact of clear-cutting on nutrient concentrations and export in headwater streams. This new method is potentially a more dynamic and flexible tool to estimate nutrient loads caused by forestry, because variation in annual runoff can be taken into account in load assessments. We combined water quality data from eight boreal headwater catchment pairs located in Finland and Sweden, where the effect of clear-cutting on stream water quality has been studied experimentally. Statistically significant specific concentration values could be produced for total nitrogen, nitrate, ammonium, and phosphate. The significant increases in the concentrations of these nutrients occurred between 2 and 6 years after clear-cutting. Significant specific concentration values could not be produced for total phosphorus and total organic carbon with the whole dataset, although in some single studies significant increases in their concentrations after clear-cutting were observed. The presented method enables taking into account variation in runoff, temporal dynamics of effects, and the proportional size of the treated area in load calculations. The number of existing studies considering large site-specific variation in responses to clear-cutting is small, and therefore further empirical studies are needed to improve predictive capabilities of the specific concentration values. 相似文献
98.
99.
100.
屋顶形状对街道峡谷内污染物扩散的影响 总被引:4,自引:3,他引:1
采用Spalart-Allmaras湍流模型,通过求解二维连续性方程,Navier-Stokes方程及污染物输运方程,模拟了具有不同屋顶形状的街道峡谷的流场及交通污染物浓度场.计算结果与风洞试验结果总体趋势一致.由于屋顶形状的不同,峡谷内的流场会形成顺时针或逆时针方向的旋涡,从而影响建筑物迎风面与背风面污染物浓度分布.在各种屋顶形状的街道峡谷中,壁面污染物浓度的相对大小与其附近的速度分布有直接关系.通过对街道峡谷建筑屋顶高度处垂直方向污染物通量的计算和比较,说明了不同屋顶形状的街道峡谷平均流扩散和湍流扩散的强弱,污染物湍流扩散通量值有可能为正或为负;同时,峡谷内剩余污染物浓度的大小表明了屋顶形状对污染物扩散出街道峡谷难易的影响. 相似文献