Perhaps you should try some spelling variations:
can thiet » dan thiet, cac thiet, cad thiet
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
tu sach » su sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
va hanh » va thanh, va danh, ban hanh
ma hoi » mai hoi, xa hoi, ma hoa
vi can » voi can, vi van, i can

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (tu sach)) ky nang ma hoi. hieu ve cham soc ((va hanh) or (van hanh)) vi can thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ky nang ma hoi. hieu ve cham soc ((va hanh) OR (van hanh)) vi can thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) ky nang ma hoi. hieu ve cham soc ((va hanh) or (van hanh)) vi can thiet".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) ky nang ma hoi. hieu ve cham soc ((va hanh) or (van hanh)) vi can thiet*.