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

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ky nang ((ma hoi) or (ma hoa)). hieu van nam da ban hang hai ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky nang ((ma hoi) OR (ma hoa)). hieu van nam da ban hang hai ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky nang ((ma hoi) or (ma hoa)). hieu van nam da ban hang hai ((cua tre) or (cua triet))*.