Perhaps you should try some spelling variations:
quoc ban » quoc bao, quoc lan, quoc quan
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
cua tre » cua te, cua triet, dua tren
duc ban » duc tan, duc van, dua ban
hieu va » lieu va, hieu qua
tong xa » thong xa, trong xa, song xa
tu tong » tu tuong, tu trong, tu dong
cuu tre » cau tren, cau treo
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 tu tong xa hoi. hieu va cam ((duc ban) or (quoc ban)) hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu tong xa hoi. hieu va cam ((duc ban) OR (quoc ban)) hanh vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach tu tong xa hoi. hieu va cam ((duc ban) or (quoc ban)) hanh vi ((cua tre) or (cuu tre))*.