全文获取类型
收费全文 | 1935篇 |
免费 | 16篇 |
国内免费 | 77篇 |
专业分类
安全科学 | 81篇 |
废物处理 | 203篇 |
环保管理 | 201篇 |
综合类 | 181篇 |
基础理论 | 320篇 |
环境理论 | 3篇 |
污染及防治 | 777篇 |
评价与监测 | 175篇 |
社会与环境 | 68篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 23篇 |
2022年 | 43篇 |
2021年 | 41篇 |
2020年 | 19篇 |
2019年 | 32篇 |
2018年 | 49篇 |
2017年 | 70篇 |
2016年 | 85篇 |
2015年 | 46篇 |
2014年 | 76篇 |
2013年 | 180篇 |
2012年 | 117篇 |
2011年 | 137篇 |
2010年 | 106篇 |
2009年 | 115篇 |
2008年 | 131篇 |
2007年 | 126篇 |
2006年 | 121篇 |
2005年 | 97篇 |
2004年 | 96篇 |
2003年 | 66篇 |
2002年 | 69篇 |
2001年 | 51篇 |
2000年 | 25篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有2028条查询结果,搜索用时 343 毫秒
831.
This paper addresses a measurement of corporate environmental performance, and its application to the analysis of efficiency in the petroleum firms. In order to measure firms' environmental performance, we suggest a framework called “Gscore” that consists of five categories, namely general environmental management (GEM), input, process, output, and outcome. Gscore is a proxy measure of corporate environmental performance based on voluntary environment, health, and safety (EHS) report and is calculated by aggregating the points of the above five-categories. We apply our measurement framework to the data of 39 firms' voluntary EHS reports which are available on the internet. Ten of them, on which efficiency analysis was conducted with Gscore, assets, employee, and profits, are in petroleum and refining industry. According to our results: (1) a gap is found between rhetoric and practical environmental management stemming from calculating the relation between GEM and data part in 39 EHS reports. (2) On the whole, EHS reports of petroleum firms have something in common, but there are significant differences in the type and amounts of disclosed data among the EHS reports. (3) From the results of efficiency analysis, it is found that the number of employee exerts a considerable influence on determining the relative efficiency of petroleum firms, then Gscore, profits, and assets in sequence. Furthermore, Exxon, Ashland, Phillips Petroleum, and ARCO are shown to be efficient among 10 petroleum firms. 相似文献
832.
石化生产噪声与防治 总被引:1,自引:0,他引:1
黄顺才 《石油化工环境保护》1997,(3):45-48
噪声污染已被列为当今世界三大污染之一,对人们的身体健康产生多种危害.结合石化生产噪声的特点与控制,进行噪声治理. 相似文献
833.
Pseudomosaicism is of particular concern in prenatal diagnosis when it involves mosaicism for a cytogenetic abnormality associated with a clinical syndrome which is compatible with postnatal life, such as trisomies for chromosomes 13, 18, and 21. The lack of data regarding the outcome of pregnancies involving these specific kinds of pseudomosaicism makes genetic counselling difficult. Three cases of prenatal diagnosis of pseudomosaicism for trisomy 13, each of which had a normal outcome, will be presented (Tables 1 and 2). The three main areas for consideration are: (1) the genetic counselling issues, (2) the additional prenatal diagnostic options available to evaluate the status of the fetus in an attempt to identify some of the clinical features of trisomy 13, and (3) the outcome of the pregnancies. 相似文献
834.
Stephen J. Vermette Kim N. Irvine John J. Drake 《Environmental monitoring and assessment》1991,18(1):69-77
Urban Street dust is recognized as a source of urban air and runoff degradation. This paper takes a preliminary step toward a better understanding of temporal variability in street dust chemistry and of the controlling mechanisms. Street dust samples, collected over four seasons in the city of Hamilton, Canada, show a variability dependent on element and source-anthropogenic sources exhibiting the greatest temporal variability. In addition, elements attributed to common sources exhibit similar temporal patterns. The use of generic or even one-time samples may seriously misrepresent the elemental make-up of urban street dust. Based on the samples collected in this study, a number of questions/insights are posed to further the study of street dust temporal variability. 相似文献
835.
Summary The purpose of this paper is to examine subjects to show the nature and limit of interdisciplinary communication in existing environmental programmes in US graduate schools. Ultimately, this analysis may provide more effective communication with the general public. Following comparative historical reviews of both the sciences and the human activity for environmental protection, and a content analysis of empirical documents used by the public, a mushroom computer model has been produced. This model is based on organizational behaviour theory and contains the following 15 subjects which were originally introduced before the lack of communication resulting from curriculum failure in the 19th century: philosophy, politics, economics, architecture, sociology, biology, medicine, agriculture, ecology, public health, mathematics, physics, chemistry, geology, statistics. The subjects should foster effective communication with the general public, leading to more effective environmental protection.Dr Hong S. Kim is at the Environmental Studies Program, California State University, Fullerton, USA. He received a PhD from the Administration and Management Program at Walden University, Minneapolis, Minnesota, USA. His numerous papers are focused on environmental pollution analysis, environmental impact assessment, environmental management, and environmental law. He has written a book entitledEnvironmentology which is forthcoming.Dr James P. Dixon is the Chairperson of Health Services at Walden University, Minneapolis, Minnesota 55401, USA. He was recently Professor of the Department of Policy and Administration at the University of North Carolina at Chapel Hill, USA. He was also past President of Antioch College (1959–1975). His many publications are concentrated in the areas of organizational development, public health and preventive medicine, and administration of human service organizations. 相似文献
836.
Disruptive selection for responsiveness to queen mandibular gland pheromone (QMP) in the retinue bioassay resulted in the
production of high and low QMP responding strains of honeybees (Apis mellifera L.). Strains differed significantly in their retinue response to QMP after one generation of selection. By the third generation
the high strain was on average at least nine times more responsive than the low strain. The strains showed seasonal phenotypic
plasticity such that both strains were more responsive to the pheromone in the spring than in the fall. Directional selection
for low seasonal variation indicated that phenotypic plasticity was an additional genetic component to retinue response to
QMP. Selection for high and low retinue responsiveness to QMP was not an artifact of the synthetic blend because both strains
were equally responsive or non-responsive to whole mandibular gland extracts compared with QMP. The use of these strains clearly
pointed to an extra-mandibular source of retinue pheromones (Pankiw et al. 1995; Slessor et al. 1998; Keeling et al. 1999).
Received: 2 March 2000 / Accepted in revised form: 4 September 2000 相似文献
837.
Fetal ultrasound evaluations at 18 weeks gestation on two consecutive pregnancies of a woman who previously gave birth to a stillborn female affected with dyssegmental dwarfism, resulted in accurate diagnoses of unaffected and affected fetuses. Marked disorganization of vertebral bodies and associated encephalocele found in two affected cases in this family are consistent with the original observation of this new syndrome as two major aspects which differentiate it from other forms of lethal dwarfism. 相似文献
838.
Tsai CJ Cheng KC Aggarwal SG Shih TS Hung IF 《Journal of the Air & Waste Management Association (1995)》2003,53(10):1265-1272
A new triple filter system sampler/model is proposed for the precise and accurate simultaneous sampling and determination of gas- and aerosol-phase 2,4-toluene diisocyanate (TDI). The system consists of two front Teflon filters for sampling aerosol-phase TDI and a final coated glass fiber filter to collect gas-phase TDI. The aerosol-phase TDI is collected on the first Teflon filter, while the second Teflon filter is used to estimate gaseous TDI adsorbed by the first. According to the gas adsorption test of two Teflon filters in series, the TDI gas adsorption fraction of the two filters is almost the same. Results of the evaporation test using pure TDI aerosols collected on the Teflon filter show that significant evaporation of the compound does not occur during sampling. These two findings allow the use of a model to estimate accurate gas- and aerosol-phase TDI concentrations. The comparison test with an annular denuder shows that the triple filter system can minimize the TDI sampling bias between the dual filter and the annular denuder systems. 相似文献
839.
Trickle-bed air biofilters (TBABs) are suitable for treating volatile organic compounds (VOCs) at a significantly high practical loading because of their controlled environmental conditions. The application of TBAB for treating styrene-contaminated air under periodic backwashing and cyclical nonuse periods at a styrene loading of 0.64-3.17 kg chemical oxygen demand (COD)/m3 x day was the main focus of this study. Consistent long-term efficient performance of TBAB strongly depended on biomass control. A periodic in situ upflow with nutrient solution under media fluidization, that is, backwashing, was approached in this study. Two different nonuse periods were employed to simulate a shutdown for equipment repair or during weekends and holidays. The first is a starvation period without styrene loading, and the second is a stagnant period, which reflects no flow passing through the biofilter. For styrene loadings up to 1.9 kg COD/m3 x day, removal efficiencies consistently above 99% were achieved by conducting a coordinated biomass control strategy, that is, backwashing for 1 hr once per week. Under cyclical nonuse periods for styrene loadings up to 1.27 kg COD/m3 x day, stable long-term performance of the biofilter was maintained at more than 99% removal without employing backwashing. No substantial impact of nonuse periods on the biofilter performance was revealed. However, a coordinated biomass control by backwashing subsequently was unavoidable for attaining consistently high removal efficiency at a styrene loading of 3.17 kg COD/m3 x day. As styrene loading was increased, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing or the nonuse periods was delayed. After the non-use periods, the response of the biofilter was a strong function of the biomass in the bed. No significant difference between the effects of the two different nonuse periods on TBAB performance was observed during the study period. 相似文献
840.
Jones K Martinez A Rizwan M Boswell J 《Journal of the Air & Waste Management Association (1995)》2005,55(4):415-420
Two types of media, a natural medium (wood chips) and a commercially engineered medium, were evaluated for sulfur inhibition and capacity for removal of hydrogen sulfide (H2S). Sulfate was added artificially (40, 65, and 100 mg of S/g of medium) to test its effect on removal efficiency and the media. A humidified gas stream of 50 ppm by volume H2S was passed through the media-packed columns, and effluent readings for H2S at the outlet were measured continuously. The overall H2S baseline removal efficiencies of the column packed with natural medium remained >95% over a 2-day period even with the accumulated sulfur species. Added sulfate at a concentration high enough to saturate the biofilter moisture phase did not appear to affect the H2S removal process efficiency. The results of additional experiments with a commercial granular medium also demonstrated that the accumulation of amounts of sulfate sufficient enough to saturate the moisture phase of the medium did not have a significant effect on H2S removal. When the pH of the biofilter medium was lowered to 4, H2S removal efficiency did drop to 36%. This work suggests that sulfate mass transfer through the moisture phase to the biofilm phase does not appear to inhibit H2S removal rates in biofilters. Thus, performance degradation for odor-removing biofilters or H2S breakthrough in field applications is probably caused by other consequences of high H2S loading, such as sulfur precipitation. 相似文献