Acute toxicity of phoxim, acephate, isofenphos-methyl and isocarbophos on male SD rats of clean grade was carried out by gastric lavage method at room temperature of 18℃. These rats are 4 to 5 months old with body weight of 180 to 220 kg. The results indicate that the orders of the...

In this paper, we analyzed a fresh conception of the urban comprehensive carrying capacity in the context of ecosystem, economy and social dimensions. Based on the AHP methodology, the author constructs the urban comprehensive carrying capacity hierarchical structure model for the chosen ten...

The purpose of this paper is to use a center of gravity theory to study the spatial distribution and centers of gravity for the global energy supply and consumption and to determine how they have changed over time. In 2011, Middle East was the biggest oil producer and Asia Pacific was the...