Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
hanh voi » hanh vi, hanh noi, hanh moi
van hanh » van thanh, ban hanh, van anh
tang dai » tang tai, tang dan, lang dai
cham tuc » nham thuc, pham thuc, cham soc
voi hoa » voi hoat, voi khoa, boi hoa
hieu va » lieu va, hieu qua
dai hoi » dai hoc, dai hai, dai moi
ky tang » ky nang, ky dang, kho tang
su sach » so sach, vu sach
su sac » su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sac) or (su sach)) ky tang dai hoi. hieu va ((cham tuc) OR (tham thuc)) van hanh voi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sac) OR (su sach)) ky tang dai hoi. hieu va ((cham tuc) OR (tham thuc)) van hanh voi hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sac) or (su sach)) ky tang dai hoi. hieu va ((cham tuc) OR (tham thuc)) van hanh voi hoa viet".
• Adding a wildcard symbol may retrieve word variants: ((su sac) or (su sach)) ky tang dai hoi. hieu va ((cham tuc) OR (tham thuc)) van hanh voi hoa viet*.