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291.
Junming Guo Shichang Kang Jie Huang Mika Sillanpää Hewen Niu Xuejun Sun Yuanqing He Shijing Wang Lekhendra Tripathee 《环境科学学报(英文版)》2017,29(2):18-28
In order to investigate the compositions and wet deposition fluxes of trace elements and rare earth elements (REEs) in the precipitation of the southeastern edge of the Tibetan Plateau, 38 precipitation samples were collected from March to August in 2012 in an urban site of Lijiang city in the Mt. Yulong region. The concentrations of most trace elements and REEs were higher during the non-monsoon season than during the monsoon season, indicating that the lower concentrations of trace elements and REEs observed during monsoon had been influenced by the dilution effect of increased precipitation. The concentrations of trace elements in the precipitation of Lijiang city were slightly higher than those observed in remote sites of the Tibetan Plateau but much lower than those observed in the metropolises of China, indicating that the atmospheric environment of Lijiang city was less influenced by anthropogenic emissions, and, as a consequence, the air quality was still relatively good. However, the results of enrichment factor and principal component analysis revealed that some anthropogenic activities (e.g., the increasing traffic emissions from the rapid development of tourism) were most likely important contributors to trace elements, while the regional/local crustal sources rather than anthropogenic activities were the predominant contributors to the REEs in the wet deposition of Lijiang city. Our study was relevant not only for assessing the current status of the atmospheric environment in the Mt. Yulong region, but also for specific management actions to be implemented for the control of atmospheric inputs and the health of the environment for the future. 相似文献
292.
含氮杂环化合物吡啶缺氧降解过程中硝酸还原酶活性研究 总被引:4,自引:0,他引:4
在实验室中,采用摇床试验,在保证缺氧的条件下。研究了含氮杂环化合物吡啶缺氧反硝化降解过程中,硝酸还原酶的适宜作用条件、吡啶降解过程中硝酸还原酶活性变化情况及吡啶和硝态氮等的降解情况。结果表明,C/N对吡啶缺氧反硝化降解具有重要意义,pH和温度均对硝黧还原酶活性具有一定影响。硝酸还原酶的适宜作用条件为:温度25—30℃,pH7.5。吡啶降解过程中,硝酸还原酶活性由低到高逐渐提高,最后达到一个相对稳定的数值。在适宜的碳氮比条件下,吡啶起始浓度越高,硝酸还原酶最后稳定活性越高。 相似文献
294.
Bin Han Yating Liu Yan You Jia Xu Jian Zhou Jiefeng Zhang Can Niu Nan Zhang Fei He Xiao Ding Zhipeng Bai 《Environmental science and pollution research international》2016,23(20):20194-20204
Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAHs) is limited by the lack of environmental exposure data among different subpopulations. To assess the exposure cancer risk of particulate carcinogenic polycyclic aromatic hydrocarbon pollution for the elderly, this study conducted a personal exposure measurement campaign for particulate PAHs in a community of Tianjin, a city in northern China. Personal exposure samples were collected from the elderly in non-heating (August–September, 2009) and heating periods (November–December, 2009), and 12 PAHs individuals were analyzed for risk estimation. Questionnaire and time-activity log were also recorded for each person. The probabilistic risk assessment model was integrated with Toxic Equivalent Factors (TEFs). Considering that the estimation of the applied dose for a given air pollutant is dependent on the inhalation rate, the inhalation rate from both EPA exposure factor book was applied to calculate the carcinogenic risk in this study. Monte Carlo simulation was used as a probabilistic risk assessment model, and risk simulation results indicated that the inhalation-ILCR values for both male and female subjects followed a lognormal distribution with a mean of 4.81?×?10?6 and 4.57?×?10?6, respectively. Furthermore, the 95 % probability lung cancer risks were greater than the USEPA acceptable level of 10?6 for both men and women through the inhalation route, revealing that exposure to PAHs posed an unacceptable potential cancer risk for the elderly in this study. As a result, some measures should be taken to reduce PAHs pollution and the exposure level to decrease the cancer risk for the general population, especially for the elderly. 相似文献
295.
Zhi-Guang Niu Shi-Ying Xu Qing-Chao Gong 《Environmental science and pollution research international》2014,21(17):10349-10360
In order to evaluate the potential adverse health effects of odor emissions from wastewater pump stations (WWPSs) to human, a health risk assessment was performed to study the odors emitted from an urban WWPS in a residential area, Tianjin (in North China). First, 15 types of volatile organic compounds in the WWPS were collected and analyzed using gas chromatography-mass spectrometry. Next, Monte Carlo probabilistic modeling was applied to evaluate the potential health effects of four odors (chlorobenzene, dichloromethane, hydrogen sulfide, and carbon disulfide), which had higher concentrations. The results revealed that the 95th percentile of the total non-carcinogenic risk was approximately 1.73, which poses a threat to human health. In addition, hydrogen sulfide had the highest non-carcinogenic risk value of the four; the hazard quotient of hydrogen sulfide was estimated to be 1.60 at the 95th percentile, higher than the upper confidence limit (1.0). The 95th percentile of the carcinogenic risk was approximately 5.47E-08, much lower than the maximum acceptable level (1.0E-06). Finally, the influence of the input variables on the output was evaluated using sensitivity analysis, and contaminant concentration, reference concentration, and inhalation unit risk were the most influential variables. 相似文献
296.
关于灾害系统的若干问题 总被引:2,自引:0,他引:2
本文简述了灾害系统的某些基本概念,提出了灾害学系统划分的基本原则,讨论了灾害系统的一些重要特征。指出灾害系统是一个非常复杂的大系统,它不仅是一个随着时间演化的开放系统,而且具有非线性、不确知性、不确定性和社会性。灾害系统的分析、综合和广义模型化是当前的重要课题。 相似文献
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300.
Niu Wenyuan 《环境科学学报(英文版)》1990,2(3):79-85
In order to give out the correct conclusion for evaluating Chinese eco-environmental situation, in this paper, a special assessmental procedure has been used to analyse following 7 basic environmental problems: (1) Natural hazards; (2) Soil erosion; (3) Forest shrinkage and grassland degradation; (4) Water resources shortage; (5) Desertification; (6) Environmental pollution; (7) Farmland decrease. The basic strategies for improving Chinese environmental situation have been suggested. 相似文献