Perhaps you should try some spelling variations:
thien van » thi van
lam truoc » lam thuoc, nam truoc, lam truong
duoc hoi » quoc hoi, duoc hoc, duoc si
truoc va » truc va, thuoc va, truong va
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
doc hoi » hoc hoi, doc hai, doi hoi
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
vi va » vi van, vai va, vu va

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