Perhaps you should try some spelling variations:
chat duc » chat xuc, chat doc, chet duoc
va thieu » va thiet, va hieu, va tieu
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
han tri » han tai, thanh tri, chan troi
van tri » van tai, van thi, van toi

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 nang xa hoi. ((hieu ve) OR (hieu va)) chat duc va ((han tri) or (van tri)) va thieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. ((hieu ve) OR (hieu va)) chat duc va ((han tri) OR (van tri)) va thieu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. ((hieu ve) OR (hieu va)) chat duc va ((han tri) or (van tri)) va thieu".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. ((hieu ve) OR (hieu va)) chat duc va ((han tri) or (van tri)) va thieu*.