Perhaps you should try some spelling variations:
nang dinh » dang dinh, nang kinh, nang sinh
khac tuc » khac phuc, khac tung, khac cuoc
va khac » va khao, va kha, vu khac
va nang » van nang, da nang, cam nang
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
tuc va » thuc va, truc va, tuc xa
cu tre » cu tren, cua tre, cu tri
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((x hoi) or (o hoi)). hieu va khac tuc va nang dinh ((cu tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (o hoi)). hieu va khac tuc va nang dinh ((cu tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) or (o hoi)). hieu va khac tuc va nang dinh ((cu tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (o hoi)). hieu va khac tuc va nang dinh ((cu tre) OR (cuu tre))*.