Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
hanh dai » hanh tai, hanh dao, vanh dai
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
co hoi » co hoc, co loi
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
tuc va » thuc va, truc va, duc va
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((y nang) OR (v nang)) co hoi. hieu va cac ((tuc va) or (tuc xa)) hanh dai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y nang) OR (v nang)) co hoi. hieu va cac ((tuc va) OR (tuc xa)) hanh dai va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y nang) OR (v nang)) co hoi. hieu va cac ((tuc va) or (tuc xa)) hanh dai va trien".
• Adding a wildcard symbol may retrieve word variants: su sach ((y nang) OR (v nang)) co hoi. hieu va cac ((tuc va) or (tuc xa)) hanh dai va trien*.