Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
tinh vi » trinh vi, tinh voi, tinh va
cac ban » cac dan, cac van, can ban
cuc ban » cua ban, cuu ban, duc ban
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
vi cua » vai cua, di cua
va cam » va cham, va cac, va cao

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 ((2 danh) OR (1 danh)) xa hoi. hieu va cam ((cuc ban) or (cac ban)) tinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((2 danh) OR (1 danh)) xa hoi. hieu va cam ((cuc ban) OR (cac ban)) tinh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((2 danh) OR (1 danh)) xa hoi. hieu va cam ((cuc ban) or (cac ban)) tinh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((2 danh) OR (1 danh)) xa hoi. hieu va cam ((cuc ban) or (cac ban)) tinh vi cua tre*.