THANH HUE, Ha; THI LOAN, Bui. DIFFICULTIES IN EDUCATIONAL ACTIVITIES OF SECONDARY SCHOOL TEACHERS IN THE NORTHERN MIDLANDS AND MOUNTAINOUS PROVINCES. Journal of Science Educational Science, [S. l.], v. 70, n. 1, p. 101–112, 2025. DOI: 10.18173/2354-1075.2025-0010. Disponível em: https://hnuejs.edu.vn/es/article/view/409. Acesso em: 12 sep. 2025.