Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » thien van, lieu va, hieu ve
va thanh » gia thanh, ban thanh, va tinh
chat luc » chat xuc, chat lua, nhan luc
hieu va » lieu va, hieu qua
sach ty » sach y, sach thu, xach tay
nang xa » nang x, lang xa, nang ma
sach tu » sach thu, cach tu, sach uu
luc va » duc va, tuc va, loc va
tai va » thai va, mai va, tri va
thiet » thieu

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