Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, hieu ve
va thanh » gia thanh, ban thanh, va tinh
thanh de » hanh de, thanh ve, thanh do
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
cam tuc » cam xuc, cam tu, nam thuc
ma hoi » mai hoi, xa hoi, ma hoa
tuc va » thuc va, truc va, tuc xa
de cua » le cua, te cua, dieu cua

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) or (thu hoach)) ky nang ma hoi. ((hieu van) OR (lieu va)) cam tuc va thanh de cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky nang ma hoi. ((hieu van) OR (lieu va)) cam tuc va thanh de cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky nang ma hoi. ((hieu van) OR (lieu va)) cam tuc va thanh de cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky nang ma hoi. ((hieu van) OR (lieu va)) cam tuc va thanh de cua viet*.