Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
van bac » van ban, van bao, van hac
bac day » bac dai, bac dan, bac thay
va tinh » may tinh

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 ty nang ((ma hoa) or (mai hoi)). hieu van bac day ((va tinh) or (ban thanh)) nam cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((ma hoa) OR (mai hoi)). hieu van bac day ((va tinh) OR (ban thanh)) nam cua triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((ma hoa) or (mai hoi)). hieu van bac day ((va tinh) or (ban thanh)) nam cua triet*.