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

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