Perhaps you should try some spelling variations:
than cua » nhan cua, ban cua, gian cua
thai cua » tai cuc, tri cua, dai cua
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
hac duc » hoc duc, ha duc, thach duc
duc van » duc va, duc tan, duc manh
van hac » van hoc, van ha, van hai
sach ty » sach tu, sach thu, xach tay
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) or (sach y)) nang o hoi. hieu van hac duc van hanh ((thai cua) OR (than cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach y)) nang o hoi. hieu van hac duc van hanh ((thai cua) OR (than cua)) tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach y)) nang o hoi. hieu van hac duc van hanh ((thai cua) OR (than cua)) tu*".