Perhaps you should try some spelling variations:
vuc nang » cuc nang, chuc nang, van nang
van hanh » van thanh, ban hanh, van anh
cam luc » cam xuc, cau luc
tien su » thien su, tieu su, nien su
kien su » nien su, vien sau, bien sua
luc van » luoc van, luu van, duc van
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
vu nang » va nang, vu dang, v nang
va cam » va cham, va cac, va cao

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

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