Perhaps you should try some spelling variations:
thieu nien » thien nhien
nien cac » vien cac, dien cac, bien cac
toc van » hoc van, toc san, tac van
cac toc » cac toi, cac nuoc, cac thoi
so sach » so sanh, bo sach, co sach
tu nano » truc nano
tu nang » tru nang, tu nong, tu lang
su tien » su kien, su hien, tu tieng
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: so sach ((tu nang) or (tu nano)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((tu nang) OR (tu nano)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((tu nang) or (tu nano)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su tien".
• Adding a wildcard symbol may retrieve word variants: so sach ((tu nang) or (tu nano)) xa hoi. thieu nien cac toc van ((anh vi) OR (anh ve)) su tien*.