Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van pham » san pham, van phan, van phat
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
va pham » va phat, va phap, va phan
duc van » duc va, duc tan, duc manh
hanh di » hanh vi, hanh de, hang di
ro hoi » co hoi, mo hoi, ro doi
o hoi » co hoi, o hoc, o hai
di su » doi su, ki su, da su

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

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