Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
va triet » va thiet, ve triet, cua triet
hanh dai » hanh tai, hanh dao, vanh dai
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
tuc va » truc va, tuc xa, duc va
ve cam » ve cham, ve cac, va cam
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky sang ma hoi. hieu ve cam ((tuc va) or (thuc va)) hanh dai ((va triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ma hoi. hieu ve cam ((tuc va) OR (thuc va)) hanh dai ((va triet) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ma hoi. hieu ve cam ((tuc va) or (thuc va)) hanh dai ((va triet) OR (va trien))".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ma hoi. hieu ve cam ((tuc va) or (thuc va)) hanh dai ((va triet) OR (va trien))*.