Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » thieu nien, hieu tieng, nhieu viec
hieu viec » nhieu viec, hieu ve, sieu viet
tu sach » thu sach, su sach, te sach
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
cac bac » cac bai, cac ban, cac cach
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
bac va » ban va, bac ha, bao va
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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 va danh vi cua tre~.
• 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 va danh vi cua tre.
• 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 va danh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((((hieu vien) OR (hieu viec))) or (hieu hien)) cac bac va danh vi cua tre*.