Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
tac van » tac vang, tac va, tac can
cac van » cac dan
hang di » hang doi, hang vi, hang dien
di cua » dai cua, doi cua, de cua
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: thu sach ky nang x ho. ((hieu vien) or (dieu khien)) cac ((tac van) OR (cac van)) hang di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang x ho. ((hieu vien) OR (dieu khien)) cac ((tac van) OR (cac van)) hang di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang x ho. ((hieu vien) or (dieu khien)) cac ((tac van) OR (cac van)) hang di cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x ho. ((hieu vien) or (dieu khien)) cac ((tac van) OR (cac van)) hang di cua te*.