Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cau tren » cu tren, dau tren, ca tren
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
va hang » van hang, va nang, va lang
nam tu » nam thuc
va cau » van cau, va cac, va dau
x hoi » o hoi, x ho, 5 hoi

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) or (xa hoi)). hieu van ((nam tu) or (nam thu)) va hang va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang ((x hoi) OR (xa hoi)). hieu van ((nam tu) OR (nam thu)) va hang va cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang ((x hoi) or (xa hoi)). hieu van ((nam tu) or (nam thu)) va hang va cau tren*.