Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cau tren » cu tren, dau tren, ca tren
hanh vai » hanh vi, hanh va, hanh tai
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
nam da » nam dan, nam a, nam va
da ban » dia ban, dua ban, day ban
ma hoi » mai hoi, xa hoi, me hoi

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 ty nang ((ma hoi) or (ma hoa)). hieu van nam da ban hanh vai ((cau tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ty nang ((ma hoi) OR (ma hoa)). hieu van nam da ban hanh vai ((cau tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: thuoc sach ty nang ((ma hoi) or (ma hoa)). hieu van nam da ban hanh vai ((cau tren) or (cua tre))*.