Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cua triet, dua tren
hanh di » hanh vi, hanh de, hang di
luc van » luoc van, luu van, duc van
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
tu sach » thu sach, su sach, te sach
cuu tre » cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (tu sach)) ky tang xa hoi. hieu van cau luc van hanh di ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (tu sach)) ky tang xa hoi. hieu van cau luc van hanh di ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu hoach) or (tu sach)) ky tang xa hoi. hieu van cau luc van hanh di ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (tu sach)) ky tang xa hoi. hieu van cau luc van hanh di ((cua tre) OR (cuu tre))*.