Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
va triet » va thiet, va trien, ve triet
cham tuc » nham thuc, tham thuc, cham soc
tu sach » thu sach, te sach, tu cach
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ma hoi » mai hoi, xa hoi, ma hoa
dao va » dao van, tao va, do va

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) or (su sach)) ky tang ma hoi. hieu ve ((cham tuc) OR (pham thuc)) va van dao va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky tang ma hoi. hieu ve ((cham tuc) OR (pham thuc)) va van dao va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky tang ma hoi. hieu ve ((cham tuc) OR (pham thuc)) va van dao va triet*".