Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu va, hieu van
va doan » va doanh, van doan, va dan
vi cua » vai cua
di cua » dai cua, doi cua, de 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: thu sach ty nang x hoi. hieu ve ((tac tu) or (cac du)) va doan ((vi cua) OR (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang x hoi. hieu ve ((tac tu) OR (cac du)) va doan ((vi cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang x hoi. hieu ve ((tac tu) or (cac du)) va doan ((vi cua) OR (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang x hoi. hieu ve ((tac tu) or (cac du)) va doan ((vi cua) OR (di cua)) tre*.