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281.
BACKGROUND: Taiwan's geography and limited stock of sandstone have caused sandstone resources to gradually decline to the point of exhaustion after long-term excavation. Moreover, the Taiwanese government has continuously increased the amount of land area near rivers that cannot be excavated to facilitate riverbed remediation and promote conservation of water resources. Accordingly, predicting and managing the annual production of construction aggregates in future construction projects, and dealing appropriately with some thorny problems, for instance, demand that excess supply, excessive excavation, unregulated excavation, and the consequent environmental damage, will significantly affect the efficient use of natural resources in a manner that accords with the national policy of Sustainable Development (SD). METHODS:. This study establishes an empirical model for forecasting the annual production of future construction aggregates using Artificial Neural Networks (ANN), based on 15 relevant socio-economic indicators, such as indicator of annual consumption of cement. A sensitivity analysis is then performed on these indicators. RESULTS AND DISCUSSION: This work applies ANN to estimate the annual production of construction aggregates; the estimates, the verification of the model and the sensitivity analysis are all acceptable. Furthermore, sensitivity analysis results indicate that the annual consumption of cement is the indicator that most strongly influences the production of construction aggregates, as well as whether construction waste can be recycled and steel structures can be used in buildings, helping to reduce the future production of construction aggregates in Taiwan. CONCLUSIONS: The elaborate prediction methodology presented in this study avoids some of the weaknesses or limitations of conventional linear statistics, linear programming or system dynamics. Additionally, the results not only provide a short-term prediction of the production of construction aggregates in Taiwan, but also provide a viable and flexible means of verifying quality certification of the production data of construction aggregates in the future by incorporating those relevant socio-economic indicators. RECOMMENDATIONS AND OUTLOOK: The continuity and quality of the database of relevant indicators used in this study should be closely scrutinized in order to ensure the SD means of exploiting resources. 相似文献
282.
山西省稷山和永济两地矮牡丹体内无机元素含量的比较 总被引:3,自引:0,他引:3
采用原子吸收分光光度法和比色法测定了山西省稷山和永济两地区矮牡丹体内和生境土壤中的10种元素(K、Mg、Mn、Fe、Ni、Zn、Cu、Cd、Cr、Pb),分析比较了各种元素在不同地区矮牡丹体内和生境土壤中的分布规律及不同地区矮牡丹对无机元素的吸收富集能力.结果表明,两地区矮牡丹体内和生境土壤中无机元素含量无显著性差异;土壤及植株不同器官间元素含量也无显著性差异;两地区矮牡丹对不同元素的富集系数有显著差异,差异主要表现在对Cd(永济0.457,稷山0.213)和Ni(永济0.093,稷山0.167)的富集上,植株不同器官之间的富集系数无显著差异.表4参9 相似文献
283.
Spatial and Seasonal Variations of Water Quality in a Mediterranean Catchment: The Llobregat River (NE Spain) 总被引:2,自引:0,他引:2
Fernández-Turiel JL Gimeno D Rodriguez JJ Carnicero M Valero F 《Environmental geochemistry and health》2003,25(4):453-474
The Llobregat and Ter Rivers, typical Mediterranean catchments in Northeast Spain, supply water to more than 4.5 million inhabitants residing in the metropolitan area of Barcelona. The objective of this work is to study the factors that influence the surface water quality of Llobregat catchment. As such, spatial and temporal variations of more 50 water chemical parameters were monitored in 10 sampling sites for a period that extended from July 1996 to December 2000. The temperature, pH and conductivity were measured at sites, whereas metals were analysed using ICP-OES and ICP-MS instrumental techniques. The head waters of the Llobregat River catchment flow through detrital Mesozoic-Cenozoic sedimentary rocks resulting in calcium bicarbonate-type water with low mineral content. The high water quality of the waterhead is deteriorated in the upper-middle part of the catchment due to: occurrence of evaporite-bearing geological formations, and the mining and industrial activities related to potash exploitation. As a result, an obvious increase in Na, K, Mg, Cl-, Br, Rb, and Sr concentrations is reported leading to a sodium (potassium) chloride water type. This saline hydrochemical fingerprint persists downstream. This important feature renders the low water quality of the Llobregat River to be adequate for drinking supply purposes. In addition, the industrial and residential activities, specially at the lower part of the catchment, increases P, B, Mn, Fe, Pb, Al, Cr, Co, Ni, Cu, Zn, As and Sb water concentrations. 相似文献
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用特征有限无法预测大运河对某市潜水污染的影响 总被引:1,自引:0,他引:1
用特征有限元法预测了在井群开采条件下大运河水对某市潜水污染的影响,计算了直到2020年的污染物相对浓度的分布.该方法数值弥散和数值振荡较小,有相当的实用价值. 相似文献
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利用采样和分析全程质量控制程序(SAX),对于吉林省内7个天然水体底质中Mn元素的采样和分析过程进行了质量控制(QC)实例研究.实验采用了平行采样平行分析的设计方案,并进行了空白实验、重复测定和加标回收率的测定.然后利用稳健方差分析(Robust ANOVA)计算了采样分析全过程中的地理方差、采样方差和分析方差,并对整个质控过程按照适目的性原则进行了评价.通过本文的研究以及其他工作成果,可知评价中采用的比例限值标准在一般意义下的SAX过程中是行之有效的.但是,也应注意到该限值标准不是绝对的,在具体的实验设计中需要考虑多方面因素. 相似文献