Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hoc quoc » hoc nuoc, hoc duoc, hoc thuoc
tu xang » tu lang, tu quang, tct xang
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
vu sach » vu bach, su sach, vu khach
va hoc » van hoc
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: vu sach ((tu xang) OR (ty xang)) xa hoi. hieu va hoc quoc ((va hanh) or (va danh)) di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((tu xang) OR (ty xang)) xa hoi. hieu va hoc quoc ((va hanh) OR (va danh)) di su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((tu xang) OR (ty xang)) xa hoi. hieu va hoc quoc ((va hanh) or (va danh)) di su triet".
• Adding a wildcard symbol may retrieve word variants: vu sach ((tu xang) OR (ty xang)) xa hoi. hieu va hoc quoc ((va hanh) or (va danh)) di su triet*.