Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
van can » van canh, van ban, ban can
can tac » canh tac, cac tac, cong tac
so hoc » co hoc, mo hoc, so hoa
cua tu » cua tuc, cua su, cua cu
o hoc » co hoc, mo hoc, y hoc
gia » giao

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky nang ((o hoc) or (so hoc)). hieu van can tac gia ((thanh hai) or (thanh san)) cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang ((o hoc) OR (so hoc)). hieu van can tac gia ((thanh hai) OR (thanh san)) cua tu.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ((o hoc) or (so hoc)). hieu van can tac gia ((thanh hai) or (thanh san)) cua tu*.