Species diversity and colony characteristics of bumblebees in the Hebei region of North China. Quantitative investigation of the interactive coupling relationship between urbanization and eco-environment Assessment on coordinative ability of sustainable development of Beijing-Tianjin-Hebei Region based on set pair analysis Changes and driving forces of land use/cover and landscape patterns in Beijing-Tianjin-Hebei region STUDY ON FLORA OF VASCULAR PLANTOF HEBEI REGION IN HEILONGJING PROVINCE