Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
sach ty » sach tu, sach thu, xach tay
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cua co » cua bo, cua cong
cua su » qua su

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 xa hoi. hieu van cac duc van hanh vi ((cua co) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach y)) nang xa hoi. hieu van cac duc van hanh vi ((cua co) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach y)) nang xa hoi. hieu van cac duc van hanh vi ((cua co) or (cua su))".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach y)) nang xa hoi. hieu van cac duc van hanh vi ((cua co) or (cua su))*.