Perhaps you should try some spelling variations:
hoc thieu » toc thieu, hoc hien
hanh manh » hanh mang, lanh manh, hoang manh
phan cong » thanh cong
theo chu » theo chieu, cho chu, chao chu
manh cua » doanh cua, ban cua
ban cong » bang cong, van cong, ban huong
tap toan » tap doan, tap quan, bai toan
toan ban » van ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (theo chu)) xanh - hanh manh cua ((ban cong) OR (phan cong)) tap toan ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thieu) or (theo chu)) xanh - hanh manh cua ((ban cong) OR (phan cong)) tap toan ban~".
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) or (theo chu)) xanh - hanh manh cua ((ban cong) OR (phan cong)) tap toan ban*.