Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
lang ha » long ha
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, dua tren

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 thu ((nang xa) or (lang ha)) hoi. hieu van cac luc van hanh di ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu ((nang xa) OR (lang ha)) hoi. hieu van cac luc van hanh di ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach thu ((nang xa) or (lang ha)) hoi. hieu van cac luc van hanh di ((cua tre) or (cua triet))*.