Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
mat cua » ma cua, manh cua, mang cua
day cua » dai cua
hieu va » lieu va, hieu qua
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
tac va » tac da, tuc va, tac ha
tac xa » tuc xa, tac da

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 tang xa hoi. hieu va cac ((tac va) OR (tac xa)) van ((day cua) or (mat cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang xa hoi. hieu va cac ((tac va) OR (tac xa)) van ((day cua) OR (mat cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang xa hoi. hieu va cac ((tac va) OR (tac xa)) van ((day cua) or (mat cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang xa hoi. hieu va cac ((tac va) OR (tac xa)) van ((day cua) or (mat cua)) tre*.