Perhaps you should try some spelling variations:
phan duc » phan tu, phan dau, tran duc
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu ke » hieu kem, chieu ke, hieu ky
va hanh » va thanh, va danh, ban hanh
kem » kiem

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