Perhaps you should try some spelling variations:
hoc thieu » hoc hien
hanh sinh » hanh tinh, hanh dinh, hinh sinh
cong cong » cong dong, trong cong, dung cong
cong sang » cong san, cong lang, cong vang
sang khan » sang than, dang khanh, sang a.han
khan cap » khan ap, than cap, khoan cam
sinh va » sinh vat, tinh va, dinh van
va cong » tai cong, cua cong

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 cong cong sang khan cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (toc thieu)) tinh - hanh sinh va cong cong sang khan cap*.