Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
vai cua » hai cua, lai cua, bai cua
v nang » va nang, vu nang, van nang

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 ((2 nang) or (v nang)) xa hoi. hieu va cac luc van hanh ((vai cua) OR (dai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((2 nang) OR (v nang)) xa hoi. hieu va cac luc van hanh ((vai cua) OR (dai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((2 nang) or (v nang)) xa hoi. hieu va cac luc van hanh ((vai cua) OR (dai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((2 nang) or (v nang)) xa hoi. hieu va cac luc van hanh ((vai cua) OR (dai cua)) triet*.