Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
cac duc » cao duc, cac dac, cac nuoc
sach ty » sach y, sach tu, xach tay
nang xa » nang x, lang xa, nang ma
vi cua » vai cua, di cua
cua cu » cua chu, cua cau, cua 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 thu)) nang xa hoi. hieu van ((cac duc) or (cac du)) van hanh vi cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach thu)) nang xa hoi. hieu van ((cac duc) OR (cac du)) van hanh vi cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach thu)) nang xa hoi. hieu van ((cac duc) or (cac du)) van hanh vi cua cu".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach thu)) nang xa hoi. hieu van ((cac duc) or (cac du)) van hanh vi cua cu*.