Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu viec » nhieu viec, hieu ve, sieu viet
viec day » viec dat, viec xay, viec hay
cua tre » cua te, cuu tre, dua tren
hanh di » hanh vi, hanh de, hang di
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
thuc va » thuc dan, thuc day

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

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