Perhaps you should try some spelling variations:
thieu nien » thien nhien
su triet » su viet, su tien, ve triet
nien cac » vien cac, dien cac, bien cac
tu nong » tu dong, tu cong, tu tong
tu nano » truc nano
cac toc » cac toi, cac nuoc, cac thoi
toc van » hoc van, toc san, tac van
su sach » so sach, vu sach
anh vi » hanh vi, anh va, anh vu
anh ve » hanh ve, anh va, anh viet

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 ((tu nano) or (tu nong)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((tu nano) OR (tu nong)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tu nano) or (tu nong)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su triet".
• Adding a wildcard symbol may retrieve word variants: su sach ((tu nano) or (tu nong)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su triet*.