全文获取类型
收费全文 | 847篇 |
免费 | 84篇 |
国内免费 | 217篇 |
专业分类
安全科学 | 143篇 |
废物处理 | 56篇 |
环保管理 | 109篇 |
综合类 | 506篇 |
基础理论 | 125篇 |
污染及防治 | 116篇 |
评价与监测 | 73篇 |
社会与环境 | 14篇 |
灾害及防治 | 6篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 21篇 |
2021年 | 31篇 |
2020年 | 22篇 |
2019年 | 14篇 |
2018年 | 18篇 |
2017年 | 21篇 |
2016年 | 33篇 |
2015年 | 36篇 |
2014年 | 40篇 |
2013年 | 53篇 |
2012年 | 56篇 |
2011年 | 70篇 |
2010年 | 44篇 |
2009年 | 49篇 |
2008年 | 39篇 |
2007年 | 71篇 |
2006年 | 57篇 |
2005年 | 51篇 |
2004年 | 50篇 |
2003年 | 49篇 |
2002年 | 50篇 |
2001年 | 35篇 |
2000年 | 49篇 |
1999年 | 32篇 |
1998年 | 32篇 |
1997年 | 24篇 |
1996年 | 14篇 |
1995年 | 13篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1148条查询结果,搜索用时 93 毫秒
981.
Indoor environments are dynamic reactors where consumer products (such as cleaning agents, deodorants, and air fresheners) emit volatile organic compounds (VOCs) that can subsequently interact with indoor oxidants such as ozone (O3), hydroxyl radicals, and nitrate radicals. Typically, consumer products consist of mixtures of VOCs and semi-VOCs which can react in the gas-phase or on surfaces with these oxidants to generate a variety of oxygenated products. In this study, the reaction of a pine-oil cleaner (POC) with O3 (100 ppb) on a urethane-coated vinyl flooring tile was investigated at 5% and 50% relative humidity. These results were compared to previous α-terpineol + O3 reactions on glass and vinyl surfaces. Additionally, other terpene and terpene alcohol mixtures were formulated to understand the emission profiles as seen in the POC data. Results showed that the α-terpineol + O3 reaction products were the prominent species that were also observed in the POC/O3 surface experiments. Furthermore, α-terpineol + O3 reactions generate the largest fraction of oxygenated products even in equal mixtures of other terpene alcohols. This finding suggests that the judicial choice of terpene alcohols for inclusion in product formulations may be useful in reducing oxidation product emissions. 相似文献
982.
983.
对亚硝酸盐氮测定的清洁水样及1.00mg/L亚硝酸盐氮标准使用溶液分别进行了稳定性试验,试验表明,清洁水样置冰箱内至少可保存30d;1.00mg/L亚硝酸盐氮标准溶液可保存180d,大大延长了国标方法中规定的24h的保存期,既提高了工作效率,又节约了试剂,在实际工作中具有一定的可行性及推广性。 相似文献
984.
介绍了一种革取技术,可在生产过程中处理印制线路板生产的碱性蚀刻废液,使之脱铜后再生,实现碱性蚀刻废液的循环使用;运用反革取技术使苹取剂复活循环使用;反革取提取到的硫酸铜经电解为电解铜,电解液可循环使用。 相似文献
985.
随着科技进步和经济发展,地下卤水和岩盐矿床逐步得到开发利用,该类矿床开采引起的环境影响日益受到关注。本文在分析水溶开采岩盐矿钻探工艺和采输工程基础上,重点分析了岩盐矿水溶开采项目环境影响评价中的污染源及源强,着重阐述了重点污染源的环境影响。并针对特征环境影响因素提出了指导性的环境防护措施。 相似文献
986.
Mehdi Zeidouni Mehran Pooladi-Darvish David Keith 《International Journal of Greenhouse Gas Control》2009,3(5):600-611
Carbon dioxide sequestration in deep saline aquifers is a means of reducing anthropogenic atmospheric emissions of CO2. Among various mechanisms, CO2 can be trapped in saline aquifers by dissolution in the formation water. Vaporization of water occurs along with the dissolution of CO2. Vaporization can cause salt precipitation, which reduces porosity and impairs permeability of the reservoir in the vicinity of the wellbore, and can lead to reduction in injectivity. The amount of salt precipitation and the region in which it occurs may be important in CO2 storage operations if salt precipitation significantly reduces injectivity. Here we develop an analytical model, as a simple and efficient tool to predict the amount of salt precipitation over time and space. This model is particularly useful at high injection velocities, when viscous forces dominate.First, we develop a model which treats the vaporization of water and dissolution of CO2 in radial geometry. Next, the model is used to predict salt precipitation. The combined model is then extended to evaluate the effect of salt precipitation on permeability in terms of a time-dependent skin factor. Finally, the analytical model is corroborated by application to a specific problem with an available numerical solution, where a close agreement between the solutions is observed. We use the results to examine the effect of assumptions and approximations made in the development of the analytical solution. For cases studied, salt saturation was a few percent. The loss in injectivity depends on the degree of reduction of formation permeability with increased salt saturation. For permeability-reduction models considered in this work, the loss in injectivity was not severe. However, one limitation of the model is that it neglects capillary and gravity forces, and these forces might increase salt precipitation at the bottom of formation particularly when injection rate is low. 相似文献
987.
It is known that fugitive dust can cause human health and environmental problems, alone or in combination with other air pollutants.
These problems are referred to as ‘external costs’ that have been traditionally ignored. However, there is a growing interest towards quantifying externalities to assist policy
and decision-making. With this in mind, the present study aimed at discussing the environmental regulations that deal with
fugitive dust, the impact of fugitive dust on human health and global climate system, and the available methods for calculating
fugitive dust externalities. The damage cost associated with human health and global environmental problems was predicted
based on the environmental strategy priority model. The damage cost estimated by the model ranged from 40 to 374 EUR/kg of
emitted fugitive dust with a mean value of 120 EUR/kg of emitted fugitive dust. It was also found that PM2.5 and PM10 have contributed to about 60% and 36% of the estimated damage cost, respectively. The remaining 4% was attributed to both
nitrate and sulfate aerosols. 相似文献
988.
Iannuzzi TJ Armstrong TN Long ER Iannuzzi J Ludwig DF 《Environmental monitoring and assessment》2008,139(1-3):257-275
The lower Passaic River in northern New Jersey (USA) has been heavily industrialized since the mid-nineteenth century and
its shoreline and aquatic habitats degraded or destroyed. Similar to other urban systems, Passaic River sediments, both surface
and buried, historically have contained elevated levels of numerous contaminants that may pose risks to ecological receptors
and humans. Sediments from 15 stations in the lower Passaic River and 3 reference stations in the Mullica River in southern
New Jersey were sampled in 1999 and characterized for chemical contamination, toxicity, and impairment of the benthic community.
The objective of this study was to determine the incidence, degree, and nature of degraded surficial sediments in the area
to support subsequent plans for restoration of the system. Results demonstrated that Passaic River sediments had concentrations
of many organic and inorganic contaminants at levels significantly greater than the reference area and effect-based guidelines.
Sediments were toxic to marine amphipods at 11 stations and the benthic assemblages were impaired relative to the reference
area at all stations. The weight-of-evidence of this sediment quality triad (SQT) assessment indicates that impacts from multiple
contaminants are occurring throughout the lower Passaic River and, that these impacts must be evaluated further and addressed
as part of ongoing restoration initiatives for the river. 相似文献
989.
Sullivan TJ Cosby BJ Webb JR Dennis RL Bulger AJ Deviney FA 《Environmental monitoring and assessment》2008,137(1-3):85-99
A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and
to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems
in the park have acid neutralizing capacity (ANC) less than 20 μeq/L, levels at which chronic and/or episodic adverse impacts
on native brook trout are possible. Model hindcasts suggested that none of these streams had ANC less than 50 μeq/L in 1900.
Model projections, based on atmospheric emissions controls representative of laws already enacted as of 2003, suggested that
the ANC of those streams simulated to have experienced the largest historical decreases in ANC will increase in the future.
The levels of S deposition that were simulated to cause streamwater ANC to increase or decrease to three specified critical
levels (0, 20, and 50 μeq/L) ranged from less than zero (ANC level not attainable) to several hundred kg/ha/year, depending
on the selected site and its inherent acid-sensitivity, selected ANC endpoint criterion, and evaluation year for which the
critical load was calculated. Several of the modeled streams situated on siliciclastic geology exhibited critical loads <0 kg/ha/year
to achieve ANC >50 μeq/L in the year 2040, probably due at least in part to base cation losses from watershed soil. The median
modeled siliciclastic stream had a calculated critical load to achieve ANC >50 μeq/L in 2100 that was about 3 kg/ha/year,
or 77% lower than deposition in 1990, representing the time of model calibration. 相似文献
990.
废气中的NO和SO2可通过钴氨吸收液去除,但钴氨吸收液中的Co~(2+)易被氧化成Co~(3+)而失去脱硝能力。为了实现Co~(2+)的再生,采用酒石酸溶液对活性炭进行改性,提高其对Co~(3+)的催化还原能力,考察了活性炭催化剂改性及活化条件对钴氨吸收液Co~(3+)还原率及NO去除率的影响。实验结果表明:在酒石酸溶液浓度为1.5 mol/L、改性时间为18 h、活化温度为400℃、活化时间为4 h的条件下,改性活性炭的催化性能最佳;Co~(3+)还原率为67.5%,比原炭提高了11.9百分点;对应的钴氨吸收液的NO去除率为86.0%,比原炭提高了26.0百分点。pHpzc测定、Boehm滴定和BET表征结果表明,与原炭相比,改性活性炭酸性增强,羧基和内酯基含量增加,微孔数目增加,比表面积增大。这些表面特性的改变使改性活性炭的催化性能得到改善。 相似文献