Perhaps you should try some spelling variations:
hieu vien » hieu hien, thieu nien, hieu tieng
van doanh » toan doanh, van dong, van thanh
hieu viec » nhieu viec, hieu ve, sieu viet
doanh va » doan va, doanh tai, doanh cua
cua tre » cua te, cuu tre, cua triet
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
sac ky » cac ky, sai ky
cac le » cach le, cac he, mac le
va cua » va chua, via cua, ca 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) or (sac ky)) nang xa hoi. ((hieu vien) OR (hieu viec)) cac le van doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang xa hoi. ((hieu vien) OR (hieu viec)) cac le van doanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) nang xa hoi. ((hieu vien) OR (hieu viec)) cac le van doanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang xa hoi. ((hieu vien) OR (hieu viec)) cac le van doanh va cua tre*.