Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh vi » hanh vi, thanh va, thanh ve
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
tang ma » tang van
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
vi cua » vai cua, di cua
cua te » cua tu
cac o » cac co, cac bo, cac ho
o van » vo van, so van, do van

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 ((mang may) or (tang ma)) hoi. hieu ve cac o van thanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((mang may) OR (tang ma)) hoi. hieu ve cac o van thanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((mang may) or (tang ma)) hoi. hieu ve cac o van thanh vi cua te*.