Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
phan huy » phan tu, phan xay, van huy
danh vai » danh sai, danh va, doanh van
sach thu » sach thieu, sach tham, cach thuc
vai cua » dai cua, hai cua, lai cua
nang ma » tang ma, sang ma, nang cao
va danh » va dinh, va dan, va hanh
hieu vi » hieu voi, hieu ve, hien vi
hieu va » lieu va, hieu qua
huy va » hay va, tuy va, thuy van
cua te » cua tu
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach thu) or (sach thue)) nang ma hoi. ((hieu vi) OR (hieu va)) phan huy va danh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach thu) OR (sach thue)) nang ma hoi. ((hieu vi) OR (hieu va)) phan huy va danh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach thu) or (sach thue)) nang ma hoi. ((hieu vi) OR (hieu va)) phan huy va danh vai cua te".
• Adding a wildcard symbol may retrieve word variants: so ((sach thu) or (sach thue)) nang ma hoi. ((hieu vi) OR (hieu va)) phan huy va danh vai cua te*.