Perhaps you should try some spelling variations:
nam trung » nam trong, tai trung, ba trung
hieu van » thien van, lieu va, hieu ve
nam truc » nam truoc, nam thuc, nam thuoc
van hanh » van thanh, ban hanh, van anh
cau treo » cau theo, cau tren, cau triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
vi cau » va cau, ve cau, di cau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. ((hieu van) OR (hieu va)) ((nam truc) OR (nam trung)) van hanh vi cau treo~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. ((hieu van) OR (hieu va)) ((nam truc) or (nam trung)) van hanh vi cau treo~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu van) OR (hieu va)) ((nam truc) or (nam trung)) van hanh vi cau treo*.