全文获取类型
收费全文 | 456篇 |
免费 | 13篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 19篇 |
环保管理 | 78篇 |
综合类 | 114篇 |
基础理论 | 88篇 |
污染及防治 | 83篇 |
评价与监测 | 46篇 |
社会与环境 | 23篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 6篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 10篇 |
2013年 | 30篇 |
2012年 | 12篇 |
2011年 | 23篇 |
2010年 | 23篇 |
2009年 | 27篇 |
2008年 | 21篇 |
2007年 | 24篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 28篇 |
2003年 | 23篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1995年 | 5篇 |
1991年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1968年 | 2篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1964年 | 6篇 |
1963年 | 2篇 |
1961年 | 2篇 |
1960年 | 5篇 |
1958年 | 4篇 |
1957年 | 2篇 |
1956年 | 3篇 |
1953年 | 4篇 |
排序方式: 共有478条查询结果,搜索用时 0 毫秒
471.
Mike Kolich Salem M. Taboun Ali I. Mohamed 《International journal of occupational safety and ergonomics》2013,19(1):113-128
This investigation was conducted to determine the effects of a massaging lumbar support system on low back muscle activity. The apparatus included a luxury-level automobile seat, six 10-mm diameter bipolar surface electrodes, an amplifier, an analog-to-digital conversion board, data acquisition software, and a personal computer. Six experimental conditions, each involving a variation of massage time, were considered. The dependent variable was the change in the root mean square variation of the EMG signal. One minute of lumbar massage every 5 min was found to have a beneficial effect on low back muscle activity (as compared to no massage). This may prove to be an extremely important result in the quest to combat low back pain attributable to automobile seating. 相似文献
472.
Sharpe M 《Journal of environmental monitoring : JEM》2003,5(1):4N-9N
As the EU launches its latest 17 billion research programme, which includes significant funding for environmental research, JEM takes a look at the trends in and dynamics of innovation in environmental analysis. 相似文献
473.
Liisa Ukonmaanaho Mike Starr Antti-Jussi Lindroos Tiina M. Nieminen 《Environmental monitoring and assessment》2014,186(11):7733-7752
The main objective of this study was to examine if any detectable trends in dissolved organic carbon (DOC), sulphate (SO4-S) concentrations and acid neutralizing capacity (ANC) in throughfall (TF) and soil water (SW) could be found during 1990–2010 and to relate them to recent changes in decreased acid deposition. The study was conducted in seven boreal coniferous forest sites: four of which are managed and three unmanaged forests sites. Generally, temporal trend showed a significant decrease in SO4-S concentrations in bulk precipitation (BP), TF and SW. At some of the sites, there was an increasing tendency in BP and TF in the DOC concentrations. This feature coincides with decreasing SO4-S concentration, indicating that SO4-S may be an important driver of DOC release from the canopy. However, a slightly increased temperature, larger senescing needle mass and consequently increased decaying activity in the canopy may partly explain the increasing trend in DOC. In SW, no consistent DOC trend was seen. At some sites, the decreased base cation concentrations mostly account for the decrease in the ANC values in SW and TF. 相似文献
474.
Deming ZHAO Jie CHENG Michael R. HOFFMANN 《Frontiers of Environmental Science & Engineering》2011,5(1):57-64
Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H2O2 is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H2O2. A detailed parametric study showed that the degradation rate of phenol increased with increasing [H2O2] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H2O2 oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H2O2 system, mainly because microwave could accelerate H2O2 to generate hydroxyl radical (·OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H2O2 process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly. 相似文献
475.
Shi T Schins RP Knaapen AM Kuhlbusch T Pitz M Heinrich J Borm PJ 《Journal of environmental monitoring : JEM》2003,5(4):550-556
Epidemiological studies have demonstrated the relationship between exposure to ambient particulate matter (PM) and health effects in those with cardiopulmonary diseases. The free radical generating activity of particles has been suggested as a unifying factor in the biological activity of PM in toxicological studies but so far has not been applied as a method for environmental monitoring of PM. The purpose of this study was to characterize hydroxyl radical (OH*) production by different size fractions of PM, to use as an alternative method for monitoring of PM composition and activity. We have developed a method, using electron paramagnetic resonance (EPR), to measure OH* radical formation in suspensions of particles in the presence of hydrogen peroxide and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a specific spin-trap. Samples of ambient particulate matter (PM) of different size fractions were collected from various sites on various filters. PM deposited on filters as well as suspensions in water retain its ability to generate OH* and this generation is determined by concentration of hydrogen peroxide and soluble metals. However, large variations in OH* radical formation and kinetics were found with different soluble metals and within metals (Fe, V) with different valencies. The method was applied to environmental monitoring in Hettstedt-Zerbst, situated in South-Eastern Germany, where it showed a relation to Cu-content of PM. The method was also applied in Duisburg, where the PMI fraction showed the highest DMPO-OH* generation but was not linked to particle counts. The method integrates metal bioavailability and reactivity and can provide a better understanding of the effect of small variations in mass concentrations on health. 相似文献
476.
The long-term performance of laboratories is examined using results from three proficiency testing programmes in the water and environmental monitoring sector. A medium term proficiency test pass rate of greater than approximately 75% is suggested as a minimum target for routine analysis to demonstrate fitness for purpose. This pass rate is proposed as a practical yardstick to be used by QA managers and accreditation bodies. This recommendation is contingent on a laboratory's continued and largely uninterrupted participation in a PT programme. 相似文献
477.
478.
A comparison of five rapid direct toxicity assessment methods to determine toxicity of pollutants to activated sludge 总被引:4,自引:0,他引:4
Dalzell DJ Alte S Aspichueta E de la Sota A Etxebarria J Gutierrez M Hoffmann CC Sales D Obst U Christofi N 《Chemosphere》2002,47(5):535-545
Five rapid direct toxicity assessment methods were used in three European partner countries to determine the toxicity of single toxicants, mixed toxicants and real industrial wastes. The final aim was to protect microbial degradation of organic wastes in biological treatment processes and hence enhance the quality of treated effluents to be discharged to the environment. Nitrification inhibition, Respirometry, Adenosine triphosphate luminescence and Enzyme inhibition were tested utilising activated sludge as the testing matrix. The Vibrio fischeri toxicity test was used as a surrogate to compare the various microbial bioassays. The IC50 (toxicant concentration eliciting a 50% inhibitory effect) was determined for a number of pollutants including single toxicants Cd, Cr, Cu, Zn, 3,5-dichlorophenol, toluene and linear alkylbenzenesulphonate (LAS); a standard mixture of metals and LAS; a standard mixture of organics and LAS, and 16 industrial effluents. The V. fischeri bioassay was also chosen in order to assess quality control of toxicant preparation during testing in the different laboratories of the partner countries. Comparisons of sensitivity, cost of implementation, cost per test, relevance, and ease of use were made. The most sensitive bioassays were V. fischeri and Nitrification inhibition, however, this depended in the main on the pollutant and mixtures tested. It is recommended that during assessment of wastewater toxicity a suite of tests be used rather than reliance on one particular test. 相似文献