Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
tu cach » tu cac
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, dua tren

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

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