Perhaps you should try some spelling variations:
hanh may » hanh ma, hanh mau, hanh ngay
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach xu » sach xa, cach xu, mach xu
xuc van » duc van, luc van, vuc van
so viet » hoc viet
cao hoi » cau hoi, co hoi, cao hoc
xu nang » vu nang, xu dang, xu lang
va cam » va cham, va cac, va cai
may so » may son, ma so, cay so
va cao » va cac, va dao, va bao
va co » vo co

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 xu nang cao hoi. hieu ((va cam) or (((va cao) or (va co)))) xuc van hanh may so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach xu nang cao hoi. hieu ((va cam) OR (((va cao) OR (va co)))) xuc van hanh may so viet.
• Adding a wildcard symbol may retrieve word variants: tu sach xu nang cao hoi. hieu ((va cam) or (((va cao) or (va co)))) xuc van hanh may so viet*.