Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
va triet » va thiet, va trien, ve triet
sach dao » lanh dao
hanh xa » hanh ma, hanh xu, canh xa
hieu va » lieu va, hieu qua
cac toc » cac toi, cac nuoc, cac thoi
xa hanh » xa thanh, xa khanh, va hanh
hanh va » hang va, hanh vi
cac tac » cac bac, cac dac, cac tai
va va » va van, va vua, va vai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((sach thi) or (sach dao)) hanh xa hoi. hieu va ((cac tac) or (cac toc)) xa hanh va va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((sach thi) OR (sach dao)) hanh xa hoi. hieu va ((cac tac) OR (cac toc)) xa hanh va va triet.
• Adding a wildcard symbol may retrieve word variants: hoc ((sach thi) or (sach dao)) hanh xa hoi. hieu va ((cac tac) or (cac toc)) xa hanh va va triet*.