Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thi » sach thu, sach tai, sach thieu
thi hanh » thi thanh
cua viet » ca viet, hoa viet, cua vat
hanh vai » hanh vi, hanh va, hanh tai
xa hanh » xa thanh, xa khanh, va hanh
cac toc » cac toi, cac nuoc, cac thoi
cac tuc » cac tu, cac tac, cac nuoc
hieu va » lieu va, hieu qua
hanh xa » hanh va, hanh ma, hanh xu
va viet » hoa viet, san viet, mai viet

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

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