Perhaps you should try some spelling variations:
thien van » thi van
hanh dai » hanh tai, hanh dao, vanh dai
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
van dau » van dao, phan dau
su viet » so viet
nang o » nang co, nang ho, nang ro
v nang » va nang, vu nang, van nang
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
dai su » dai sua, dai so, dan su
o hoi » co hoi, o hoc, o hai

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) OR (thu sach)) v nang o hoi. thien van dau ((luc va) or (tuc va)) hanh dai su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) v nang o hoi. thien van dau ((luc va) OR (tuc va)) hanh dai su viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) v nang o hoi. thien van dau ((luc va) or (tuc va)) hanh dai su viet*".