Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cham duc » pham duc, cham soc, pham duy
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
duc van » duc va, duc tan, duc manh
nang ma » sang ma, nang cao, mang may
tu sach » thu sach, su sach, te sach
tai su » tai so, tai tu, lai 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 y ((((nang ma) OR (tang ma))) or (nang x)) hoi. hieu ve cham duc van hanh tai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((((nang ma) OR (tang ma))) OR (nang x)) hoi. hieu ve cham duc van hanh tai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((((nang ma) OR (tang ma))) or (nang x)) hoi. hieu ve cham duc van hanh tai su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((((nang ma) OR (tang ma))) or (nang x)) hoi. hieu ve cham duc van hanh tai su triet*.