Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hieu ve » hieu va
tu sach » thu sach, su sach, te sach
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di cua
tu sac » tu cac, tu san, tu bac
cua te » cua tu

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

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