Perhaps you should try some spelling variations:
hanh dan » thanh dan, hanh san, canh dan
va hanh » van hanh, va thanh, va danh
cac toc » cac toi, cac nuoc, cac thoi
sach ky » sac ky, sach y, sach kem
cac tuc » cac tu, cac tac, cac nuoc
may hoi » may thoi, tay hoi, mai hoi
sach ty » sach y, sach tu, sach thu
su viet » so viet
dan su » dang su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sach ty)) mang may hoi. hieu qua ((cac tuc) OR (cac toc)) va hanh dan su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) mang may hoi. hieu qua ((cac tuc) OR (cac toc)) va hanh dan su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach ty)) mang may hoi. hieu qua ((cac tuc) OR (cac toc)) va hanh dan su viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach ty)) mang may hoi. hieu qua ((cac tuc) OR (cac toc)) va hanh dan su viet*.