Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
van hanh » van thanh, ban hanh, van anh
va hanh » va thanh, va danh, ban hanh
cam tuc » cam xuc, cam tu, nam thuc
hieu ve » hieu va, hieu van
su sach » so sach, vu sach
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
vai va » mai va, dai va, hai va
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam tuc ((va hanh) or (van hanh)) vai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam tuc ((va hanh) OR (van hanh)) vai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam tuc ((va hanh) or (van hanh)) vai va triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang ma) OR (tang ma)) hoi. hieu ve cam tuc ((va hanh) or (van hanh)) vai va triet*.