Perhaps you should try some spelling variations:
hang down » hang doanh, hang dien, hang doi
su triet » su viet, su tien, ve triet
hang ton » hang nong, hang cong, hang tai
truc van » truc va, thuc van, truc ban
cac truc » cau truc, cac tru, cac trung
su sach » so sach, vu sach
vu nang » vuc nang, va nang, vu dang
hieu va » lieu va, hieu qua
v nang » va nang, van nang, voi nang

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 ((v nang) or (vu nang)) xa hoi. hieu va cac truc van ((hang down) OR (hang ton)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (vu nang)) xa hoi. hieu va cac truc van ((hang down) OR (hang ton)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (vu nang)) xa hoi. hieu va cac truc van ((hang down) OR (hang ton)) su triet".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) or (vu nang)) xa hoi. hieu va cac truc van ((hang down) OR (hang ton)) su triet*.