Perhaps you should try some spelling variations:
nang duoc » ngang duoc, nang doc, nganh duoc
duoc hoi » quoc hoi, duoc hoc, duoc si
hieu van » thien van, lieu va, hieu ve
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lam tuc » lam thuoc, lam truoc, luat tuc
xa hanh » xa thanh, xa khanh, va hanh
vai va » mai va, dai va, hai va
vi va » vi van, vu va, bi va

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