Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
mai hoi » mai khoi, dai hoi, lai hoi
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
san ky » sang ky, dan ky, ban ky
dao tu » dao tuc, dao tru, tao 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 ((san ky) OR (van ky)) nang mai hoi. hieu van dao tu va hanh vi ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((san ky) OR (van ky)) nang mai hoi. hieu van dao tu va hanh vi ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((san ky) OR (van ky)) nang mai hoi. hieu van dao tu va hanh vi ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu ((san ky) OR (van ky)) nang mai hoi. hieu van dao tu va hanh vi ((cua tre) or (cua triet))*.