Perhaps you should try some spelling variations:
hieu hieu » hien hieu, hieu hien, thien hieu
van thanh » ban thanh, van tuan
hieu cac » hieu luc, hieu va, hieu van
thai cua » than cua, tai cuc, tri cua
tai cua » tai cuc, tri cua, dai cua
sach ty » sach y, sach tu, sach thu
su sach » so sach, vu sach
nang xa » lang xa, nang ma, mang xa
cac so » cac co, cac bo, cac ho
so van » su van, vo van

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((nang xa) or (nang x)) hoi. hieu hieu cac so van thanh ((tai cua) OR (thai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (nang x)) hoi. hieu hieu cac so van thanh ((tai cua) OR (thai cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang xa) or (nang x)) hoi. hieu hieu cac so van thanh ((tai cua) OR (thai cua)) te".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang xa) or (nang x)) hoi. hieu hieu cac so van thanh ((tai cua) OR (thai cua)) te*.