Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
hieu vien » thieu nien, hieu tieng, nhieu viec
hieu hien » bieu hien, dieu hien, chieu chien
tu sach » thu sach, su sach, te sach
cac bac » cac bai, cac ban, cac cach
cu tren » tu tren, dua tren
sach ky » sac ky, sach y, sach ty
bac ca » bac can, bac cao, bac cau
ca dan » cac dan, ca dao
dan vi » doan vi, don vi, dan va
x hoi » xa hoi, o hoi, x ho
vi cu » vi su, vi xu, vi du

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang x hoi. ((((hieu vien) OR (hieu viec))) or (hieu hien)) cac bac ca dan vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((((hieu vien) OR (hieu viec))) OR (hieu hien)) cac bac ca dan vi cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. ((((hieu vien) OR (hieu viec))) or (hieu hien)) cac bac ca dan vi cu tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((((hieu vien) OR (hieu viec))) or (hieu hien)) cac bac ca dan vi cu tren*.