Perhaps you should try some spelling variations:
sach duoc » sach nuoc, sach dao, sach dung
thanh ha » thanh hoa, thanh hai, nhanh ha
duoc gia » duoc giao, quoc gia, duc gia
tu sach » thu sach, su sach, te sach
cua tre » cuu tre, cua triet, dua tren
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
hieu vu » hieu va, hieu ve, hieu su
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang
ma hoi » xa hoi, ma hoa, me hoi
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 nang ((ma hoi) or (mai hoi)). hieu vu sach duoc gia thanh ha ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((ma hoi) OR (mai hoi)). hieu vu sach duoc gia thanh ha ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((ma hoi) or (mai hoi)). hieu vu sach duoc gia thanh ha ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((ma hoi) or (mai hoi)). hieu vu sach duoc gia thanh ha ((cua tre) OR (cua te))*.