Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu viec » nhieu viec, hieu ve, sieu viet
dang xay » dang van, van xay
sach ky » sac ky, sach y, sach ty
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
tu sach » thu sach, su sach, te sach
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
ca cua » co cua

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 dang xay hoi. ((hieu hien) or (hieu viec)) ((cac duc) OR (cac dac)) va dan ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang xay hoi. ((hieu hien) OR (hieu viec)) ((cac duc) OR (cac dac)) va dan ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang xay hoi. ((hieu hien) or (hieu viec)) ((cac duc) OR (cac dac)) va dan ca cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang xay hoi. ((hieu hien) or (hieu viec)) ((cac duc) OR (cac dac)) va dan ca cua tre*.