Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
su triet » su viet, su tien, ve triet
hieu va » lieu va, hieu qua
duc ban » duc tan, duc van, duc man
dua ban » dia ban, cua ban, qua ban
da nang » cam nang, kha nang, cao nang
hanh ki » hanh vi, hanh ky, hanh kien
va cam » va cham, va cac, va cao
x hoi » xa hoi, o hoi, x ho
ki su » ky su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((da nang) or (van ban)) x hoi. hieu va cam ((duc ban) OR (dua ban)) hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((da nang) OR (van ban)) x hoi. hieu va cam ((duc ban) OR (dua ban)) hanh ki su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((da nang) or (van ban)) x hoi. hieu va cam ((duc ban) OR (dua ban)) hanh ki su triet*".