Perhaps you should try some spelling variations:
phan dau » phan tu, hang dau
hieu van » hieu va, thien van, lieu va
phan duc » pham duc, phan tu, tran duc
van hanh » van thanh, ban hanh, van anh
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang xa hoi. hieu van ((phan duc) OR (phan dau)) van hanh ((vai cua) or (di cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu van ((phan duc) OR (phan dau)) van hanh ((vai cua) OR (di cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu van ((phan duc) OR (phan dau)) van hanh ((vai cua) or (di cua)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu van ((phan duc) OR (phan dau)) van hanh ((vai cua) or (di cua)) triet*.