Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
vu nang » vuc nang, va nang, vu dang
mai hoi » mai khoi, dai hoi, lai hoi
va cham » va chat, va tham
su sach » so sach, vu sach
vuc van » duc van, luc van, thuc van
hanh ki » hanh vi, hanh ky, hanh kien
va cam » va cac, va cao, va cai
ki su » ky su

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) or (su sach)) vu nang mai hoi. hieu ((va cam) OR (va cham)) vuc van hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (su sach)) vu nang mai hoi. hieu ((va cam) OR (va cham)) vuc van hanh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (su sach)) vu nang mai hoi. hieu ((va cam) OR (va cham)) vuc van hanh ki su triet".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (su sach)) vu nang mai hoi. hieu ((va cam) OR (va cham)) vuc van hanh ki su triet*.