Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, su sach, te sach
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
cua tre » cuu tre, cua triet, dua tren
truc va » thuc va, thuc vat, trung va
cua te » cua tu

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 mai hoi. hieu van cam ((duc va) or (truc va)) hanh tai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang mai hoi. hieu van cam ((duc va) OR (truc va)) hanh tai ((cua tre) OR (cua te))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang mai hoi. hieu van cam ((duc va) or (truc va)) hanh tai ((cua tre) OR (cua te))*".