Perhaps you should try some spelling variations:
kho tang » cao tang
tu sach » thu sach, su sach, te sach
ky tang » ky nang, ky dang, ky trong
hieu va » lieu va, hieu qua
cac tac » cac toc, cac bac, cac dac
day cua » dai cua
mat cua » ma cua, manh cua, mang cua
tac va » tac da, tac xa, tuc va

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