Perhaps you should try some spelling variations:
doanh luan » doanh nhan
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac xuc » cam xuc, cac nuoc, chat xuc
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » duc va, tuc va, luc va
cua te » cua tu

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