Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
hoi cua » hoi chuc
cuc ban » cua ban, cac ban, cuu ban
nam cuc » nam cac, nam cua, nam thuc
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, mang may
di cua » dai cua, doi cua, de cua
va nam » van nam, ha nam, va nay

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 thu ((nang ma) OR (nang cao)) hoa. hieu va nam cuc ban hanh ((di cua) or (hoi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu ((nang ma) OR (nang cao)) hoa. hieu va nam cuc ban hanh ((di cua) OR (hoi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu ((nang ma) OR (nang cao)) hoa. hieu va nam cuc ban hanh ((di cua) or (hoi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach thu ((nang ma) OR (nang cao)) hoa. hieu va nam cuc ban hanh ((di cua) or (hoi cua)) tre*.