Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
dan tai » van tai, dan thi, han tai
dan vai » dan va, dan vat, den vai
cac tuc » cac toc, cac tu, cac tac
hieu va » lieu va, hieu qua
dang ma » dang mau, dang mam, dang mat
hieu ve » hieu van
ky dang » ky nang, ky danh
tuc va » thuc va, truc va, tuc xa
ma hoi » mai hoi, xa hoi, ma hoa
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 dang ma hoi. ((hieu ve) or (hieu va)) cac tuc va ((dan vai) OR (dan tai)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ma hoi. ((hieu ve) OR (hieu va)) cac tuc va ((dan vai) OR (dan tai)) cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ma hoi. ((hieu ve) or (hieu va)) cac tuc va ((dan vai) OR (dan tai)) cua te*".