Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
nang mai » nang ma, nang tai, lang mai
mai hoi » mai khoi, dai hoi, lai hoi
va pham » van pham, va phat, va phap
va hang » van hang, va lang, va hanh
va nang » van nang, da nang, cam nang
hai cua » thai cua, dai cua, hoi cua
y nang » ky nang, ly nang, v nang

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) or (doc sach)) y nang mai hoi. lieu va pham duc ((va hang) OR (va nang)) hai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) y nang mai hoi. lieu va pham duc ((va hang) OR (va nang)) hai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) y nang mai hoi. lieu va pham duc ((va hang) OR (va nang)) hai cua triet".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) y nang mai hoi. lieu va pham duc ((va hang) OR (va nang)) hai cua triet*.