Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hang hai » hoang hai, hang tai, thanh hai
ban hang » ngan hang
hieu van » hieu va, thien van, lieu va
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
da ban » dia ban, dua ban, day ban
ma hoi » mai hoi, xa hoi, me hoi
nam da » nam dan, nam a, nam va

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 ky nang ((ma hoi) or (ma hoa)). hieu van nam da ban hang hai ((cuu tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((ma hoi) OR (ma hoa)). hieu van nam da ban hang hai ((cuu tre) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((ma hoi) or (ma hoa)). hieu van nam da ban hang hai ((cuu tre) or (su triet))*.