Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh tai, hanh van
hanh va » hang va, hanh vi
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
ky sang » ky nang, ky tang, duy sang
van cam » van nam, van lam, van cau
xuc va » duc va, tuc va, luc va

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 ((ky sang) OR (ky dang)) mai hoi. hieu van cam xuc va ((hanh vai) or (hanh va)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky dang)) mai hoi. hieu van cam xuc va ((hanh vai) OR (hanh va)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky sang) OR (ky dang)) mai hoi. hieu van cam xuc va ((hanh vai) or (hanh va)) cau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky sang) OR (ky dang)) mai hoi. hieu van cam xuc va ((hanh vai) or (hanh va)) cau tren*.