Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
va trien » va truyen, va thiet, va tuyen
lang van » dang van, tang van, hoang van
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
nang xa » nang x, lang xa, nang ma
vai va » mai va, dai va, hai va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((nang xa) or (lang van)) hoi. ((hieu ve) or (hieu van)) cac luc van hanh vai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang xa) OR (lang van)) hoi. ((hieu ve) OR (hieu van)) cac luc van hanh vai va trien.
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((nang xa) or (lang van)) hoi. ((hieu ve) or (hieu van)) cac luc van hanh vai va trien*.