variation of ecological benefit

delay variation delay and delay variation bounded

interdecadal variation and interannual variation

noncyclic variation (=non-periodic variation)

Seasonal variation of diurnal variation

wide-agriculture with ecological type

a view of ecological development

accessibility surface of ecological restoration model

accounting ecological civilization

Adaptability to the ecological environment

Advance in ecological economics research

agric-ecological environment

agricultural and ecological water-saving

agricultural development-ecological reaction

agricultural ecological condition

agricultural ecological environment

Agricultural ecological safety

agricultural ecological sections

agricultural ecological security