Perhaps you should try some spelling variations:
cham tuc » nham thuc, pham thuc, tham thuc
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
va cham » va chat, va tham
va hanh » va thanh, va danh, ban hanh
vai va » mai va, dai va, hai va
thiet » thieu

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 y)) nang cao hoi. lieu va cham tuc ((va hanh) OR (van hanh)) vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang cao hoi. lieu va cham tuc ((va hanh) OR (van hanh)) vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang cao hoi. lieu va cham tuc ((va hanh) OR (van hanh)) vai va thiet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang cao hoi. lieu va cham tuc ((va hanh) OR (van hanh)) vai va thiet*.