Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hanh dai » hanh tai, hanh dao, vanh dai
hieu ve » hieu va, hieu van
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam
sach 2 » sach y
2 nang » v nang
dai su » dai sua, dai so, dan su
x hoi » xa hoi, o hoi, 5 hoi

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 2 nang ((x hoi) OR (x ho)). hieu ve cam ((truc va) or (thuc va)) hanh dai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach 2 nang ((x hoi) OR (x ho)). hieu ve cam ((truc va) OR (thuc va)) hanh dai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach 2 nang ((x hoi) OR (x ho)). hieu ve cam ((truc va) or (thuc va)) hanh dai su triet".
• Adding a wildcard symbol may retrieve word variants: su sach 2 nang ((x hoi) OR (x ho)). hieu ve cam ((truc va) or (thuc va)) hanh dai su triet*.