Perhaps you should try some spelling variations:
hoc thieu » hoc hien
hanh sinh » hanh tinh, hanh dinh, hinh sinh
tong cong » trong cong, cong cong, dung cong
cong ban » cong bang, cong san, cong tan
ban khan » ban than, ban nhan, ban chan
khan cap » khan ap, than cap, khoan cam
sinh va » sinh vat, tinh va, dinh van
va tong » va thong, va tuong, va trong

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc thieu) or (toc thieu)) tinh - hanh sinh va tong cong ban khan cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (toc thieu)) tinh - hanh sinh va tong cong ban khan cap*.