Perhaps you should try some spelling variations:
su triet » su tien, ve triet
van hanh » van thanh, ban hanh, van anh
vien cac » vien dai, vien da, gian cac
nuoc van » nuoc va, nuoc san, luoc van
su sach » so sach, vu sach
su viet » so viet
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
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 tang ma hoi. hieu ((vien cac) OR (vien bach)) nuoc van hanh vi ((su triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ma hoi. hieu ((vien cac) OR (vien bach)) nuoc van hanh vi ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang ma hoi. hieu ((vien cac) OR (vien bach)) nuoc van hanh vi ((su triet) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ma hoi. hieu ((vien cac) OR (vien bach)) nuoc van hanh vi ((su triet) or (su viet))*.