Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thi » sach thu, sach tai, sach thieu
xa khanh » xa thanh, van khanh, dat khanh
cua viet » ca viet, hoa viet, cua vat
thi hanh » thi thanh
cac tuc » cac toc, cac tu, cac tac
xa hanh » xa thanh, va hanh, da hanh
hanh ca » hanh cac, hanh cat, hanh cua
vai cua » dai cua, hai cua, lai cua
ca hoi » cau hoi, cua hoi, xa hoi

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 ca hoi. hieu qua ((cac tuc) or (dat nuoc)) ((xa hanh) or (xa khanh)) vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thi hanh ca hoi. hieu qua ((cac tuc) OR (dat nuoc)) ((xa hanh) OR (xa khanh)) vai cua viet.
• Adding a wildcard symbol may retrieve word variants: toc sach thi hanh ca hoi. hieu qua ((cac tuc) or (dat nuoc)) ((xa hanh) or (xa khanh)) vai cua viet*.