Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu va, hieu van
nang o » nang co, nang ho, nang ro
ve bac » ve bao, ve cac, ve ban
bo van » vo van, so van, do van
o hoi » co hoi, o hoc, o hai

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 o hoi. hieu ve bac bo van hanh ((ve su) or (va su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang o hoi. hieu ve bac bo van hanh ((ve su) OR (va su)) triet.
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang o hoi. hieu ve bac bo van hanh ((ve su) or (va su)) triet*.