Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
tham hoc » thai hoc, tham hoa, than hoc
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
luu tre » cuu tre, luy tre
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
tru » truc

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky lang xa hoi. ((hieu van) or (hieu va)) tham hoc va hanh vi ((luu tre) OR (luu tru))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky lang xa hoi. ((hieu van) OR (hieu va)) tham hoc va hanh vi ((luu tre) OR (luu tru)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky lang xa hoi. ((hieu van) or (hieu va)) tham hoc va hanh vi ((luu tre) OR (luu tru))".
• Adding a wildcard symbol may retrieve word variants: te sac ky lang xa hoi. ((hieu van) or (hieu va)) tham hoc va hanh vi ((luu tre) OR (luu tru))*.