Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
dan vat » dang vat, van vat, dan va
dan vai » dan va, dan tai, den vai
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
hieu ve » hieu van
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
toc va » hoc va, toc ta, tuc va
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 ky sang ma hoa. ((hieu ve) or (hieu va)) cac toc va ((dan vai) OR (dan vat)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ma hoa. ((hieu ve) OR (hieu va)) cac toc va ((dan vai) OR (dan vat)) cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang ma hoa. ((hieu ve) or (hieu va)) cac toc va ((dan vai) OR (dan vat)) cua te*".