Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach tai » sach bai, sach tham, sach dao
hanh tai » thanh tai, hang tai, han tai
hanh dao » lanh dao, thanh dat, thanh dam
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cua viet » ca viet, hoa viet, cua vat
hanh cua » manh cua, hang cua, hanh sua
tai hanh » tai thanh, tai nhanh, thi hanh
cac tuc » cac toc, cac tu, cac tac
cua hoi » cua moi

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 tai hanh cua hoi. lieu va ((cac tuc) or (cac nuoc)) va ((hanh dao) or (hanh tai)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tai hanh cua hoi. lieu va ((cac tuc) OR (cac nuoc)) va ((hanh dao) OR (hanh tai)) cua viet.
• Adding a wildcard symbol may retrieve word variants: toc sach tai hanh cua hoi. lieu va ((cac tuc) or (cac nuoc)) va ((hanh dao) or (hanh tai)) cua viet*.