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851.
A joint monitoring of dust-storms that occurred in East Asia from March until May 2003 has been carried. Our discussions include dust-storm observations in the source areas of China and Mongolia, and measurements with satellites and ground monitors in central Korea. Differences were found in the definition and measurement of dust-storms. Over the source area of Mongolia there were 6 dusty days in March, 18 days in April, and 10 dusty days in May. In Inner Mongolia of northern China there were 4 dust-storms with 14 dusty days observed over the three months. In central Korea, a sink area, there were 4 cases of weak dust-storm and 17 dusty days in the spring of 2003. The highest PM10 value was 607 μgm−3 and PM 2.3 was 149 μgm−3, respectively. These observations identify the growing need for further universal observation practices and dust-storm reporting in future. Observations indicated that snow covered the central part of the Gobi Desert, near the boundary of China and Mongolia, from December until mid-March. This is in contrast to other years when the Gobi was relatively wet, producing unfavourable conditions for the formation of intense dust-storms. In addition, the very strong winds associated with intense cyclones and anticyclones were not apparent and the systems shifted northward during the spring. As a result, the frequency and intensity of observed dust-storms in 2003 in this region were very low. This confirms that there is variability in the frequency of dust-storm formation due to the current process of desertification and climate change.  相似文献   
852.
To investigate the large-scale environmental conditions of duststorms occurring in Northern China, a synoptic situation of tendust events in Northern China during 2000–2001 was composed andits dynamic features were identified. The composite synoptic situation showed that the occurrence of the ten dust events was associated with the eastward movement of a strong cold high fromMongolia, and the development of a cyclone in Northeast China, which caused the pressure gradient to intensify considerably in Northern China. The upper level circulation revealed that a 500 hPa trough developed rapidly above Northern China, and diagnosis showed that composite ascending motion was pronouncedabove the Siberian district. The change of vertical motion in themiddle and low troposphere above Mongolia was also related to theoccurrence of the ten dust events. When the descendingcurrent, 12 hr before the occurrence, was completely replacedby the ascending current, the instable atmospheric stratificationof the lower troposphere enabled dry dust to be transported from the surface to high altitudes toward Northern China.  相似文献   
853.
Heavy metal accumulation (Cu, Zn, Ni, and Pb) in common marine macroalga, Acrosorium uncinatum under nutrient (phosphate and nitrate) enriched (experiment 1) and starved (experiment 2) conditions over a short exposure period (12 h) were examined in this study. Control was maintained in seawater contained nutrient solution without addition of metals and in seawater alone for experiment 1 and 2, respectively. Among the four metals studied, the accumulation of Zn, Ni, and Pb was considerably lower than Cu. The accumulation factor for all metals varies greatly in different nutrient concentrations, but it increases as the exposure of metal concentration decreases in both the experiments. The results of the present findings established that this macroalga is an accumulator of metals Cu, Zn, Ni, and Pb and have the potential to accumulate these metals even in a short time exposure period (12 h). Even though metal accumulation by A. uncinatum largely depends on the available concentration in the medium, nutrients like phosphate and nitrate can affect the accumulation significantly.  相似文献   
854.
The stabilization potential of negatively charged sodium carboxymethyl cellulose (CMC) solution was assessed through investigation of its retention on clays under environmental conditions that promote soil desiccation. Sodium montmorillonite and kaolinite, commonly used in clayey soils, were mixed with aqueous CMC solutions in concentrations ranging from 0 to 10 g/L. These samples were dried in a specially-designed desiccation chamber which was operated at a temperature of 25°C and relative humidity of 30%. The results show an inverse proportionality between liquid loss and CMC concentration. Liquid loss from clayey soil follows the first-order reaction with a rate constant in the range of 4.6–6.7 mg/h. CMC half-lives on sodium montmorillonite during desiccation ranged from 103 to 181 h for an aqueous concentration range of 0.5–10 g/L compared to 108 h for distilled water. For kaolinite, more liquid was retained at 10 g/L CMC concentration than at other concentrations, but liquid retention was generally insignificant. These conclusions are valid for a desiccation duration of 890 h, a time that is reasonably simulative of the duration of exposures of bare ground surfaces to weather elements. The experimental results are explained in terms of the role of CMC molecular interactions with clay minerals in controlling fluid flow to desiccating clay surfaces.  相似文献   
855.
This paper investigates the challenges and opportunities of how firms and organizations can and will be able to strike a better balance between economic growth and environmental stewardship in the context of China’s emerging ‘circular economy’ policy paradigm and based on ecological modernization theoretic approaches.Based on three company case studies in the information technology and electronic industries in China, we identify and demonstrate how a blended business and environmental value can be created from adopting a sustainable supply chain management approach. The adoption of a sustainable supply chain management approach is rapidly becoming a key business challenge and opportunity in China and other large emerging economies around the world, where our greatest environmental management challenges currently reside and will continue to exist for many years to come. The value creation framework proposed in research focuses on evaluating three case study companies who appear in various stages of an electronic industry supply chain. Value creation within a supply chain can provide the impetus for organizations to adopt circular economy, sustainable supply chain practices, for competitive reasons.In addition, we describe how a value proposition can be evaluated at two levels of analysis, a more specific micro-level and a more general meso-level of analysis. The four major business value dimensions include cost reduction, revenue generation, resiliency, and legitimacy and image.The initial findings are that a variety of opportunities exist for electronic firms in emerging and developing countries, while results from this study provide an important scholarly foundation to develop and refine sustainable supply chain management practices in emerging and developing economies.  相似文献   
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The purpose of this study was to ascertain, through the use of an input-output model, the impact of air pollution control costs on income groups in the Philadelphia Region. The range of increases in consumption expenditure was found to be fairly narrow, with the middle-income group bearing the largest increase (2.9%) and the highest and lowest groups slightly lower increases (about 2%). This finding lends support to the proposition that all income groups would probably share the costs of control equally, which leads to a slightly regressive effect on income distribution. The sharing of the region's air quality costs by other areas was also analyzed.  相似文献   
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