Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, qua ban
tang ma » tang van
vai cua » dai cua, hai cua, lai cua
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
cam dua » ca dua, cay dua, chay dua
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 ty ((tang ma) or (mang may)) hoa. ((hieu van) OR (hieu va)) cam dua ban thanh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((tang ma) OR (mang may)) hoa. ((hieu van) OR (hieu va)) cam dua ban thanh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((tang ma) or (mang may)) hoa. ((hieu van) OR (hieu va)) cam dua ban thanh vai cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((tang ma) or (mang may)) hoa. ((hieu van) OR (hieu va)) cam dua ban thanh vai cua te*.