Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
khoa hoi » khoan hoi, khoa hoc, khoa doi
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
thai do » thay doi, thai den
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
do va » do van, so 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 cac ((ky lang) OR (ky dang)) khoa hoi. ((hieu quan) or (hieu qua)) thai do va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ((ky lang) OR (ky dang)) khoa hoi. ((hieu quan) OR (hieu qua)) thai do va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ((ky lang) OR (ky dang)) khoa hoi. ((hieu quan) or (hieu qua)) thai do va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu cac ((ky lang) OR (ky dang)) khoa hoi. ((hieu quan) or (hieu qua)) thai do va hanh vi cuu tre*.