Perhaps you should try some spelling variations:
dieu hien » dieu khien, dieu kien, bieu hien
hieu vien » hieu hien, hieu viec, thieu nien
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
cac tac » cac toc, cac bac, cac dac
va hang » van hang, va nang, va lang
hang di » hang doi, hang vi, hang dien
tac va » tac da, tac xa, tuc va
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 hien)) cac tac va 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 hien)) cac tac va hang di cua te.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x ho. ((hieu vien) or (dieu hien)) cac tac va hang di cua te*.