Perhaps you should try some spelling variations:
ve triet » va trien, su triet
cau thuc » cuu thuc, can thuc, cau phuc
hanh vai » hanh vi, hanh va, hanh tai
hieu van » thien van, lieu va, hieu ve
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
sang ma » tang ma, nang ma, sang tao
sach v » sach va, sach y, sach 2
ma hoi » mai hoi, xa hoi, ma hoa
v sang » va sang, ve sang, _ sang
vai ve » va ve, dai ve, vai va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v sang ma hoi. ((hieu van) OR (hieu va)) ((cau thuc) OR (cau truc)) va hanh vai ve triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v sang ma hoi. ((hieu van) or (hieu va)) ((cau thuc) OR (cau truc)) va hanh vai ve triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach v sang ma hoi. ((hieu van) or (hieu va)) ((cau thuc) OR (cau truc)) va hanh vai ve triet*.