Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
bo sach » co sach
tinh va » tich va, trinh van, tinh gia
van cam » van nam, van lam, van cau
chu tre » cho tre, chu tri, cuu tre
xuc va » duc va, tuc va, luc va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((bo sach) or (hoc sach)) ky nang x hoi. hieu van cam xuc va ((tinh va) OR (trinh vat)) chu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((bo sach) OR (hoc sach)) ky nang x hoi. hieu van cam xuc va ((tinh va) OR (trinh vat)) chu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((bo sach) or (hoc sach)) ky nang x hoi. hieu van cam xuc va ((tinh va) OR (trinh vat)) chu tre".
• Adding a wildcard symbol may retrieve word variants: ((bo sach) or (hoc sach)) ky nang x hoi. hieu van cam xuc va ((tinh va) OR (trinh vat)) chu tre*.