Perhaps you should try some spelling variations:
dong hoa » dong hoc, dong co
hanh va » hang va, hanh vi
sach sy » sach ty, sach hay, sach nay
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
hoa hoi » khoa hoi, hoa hoc, hoa doi
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
va cua » va chua, via cua, ca cua
va nam » van nam, ha nam, va nay

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 sy) or (sach y)) dong hoa hoi. hieu va nam ((xuc va) or (luc va)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach sy) OR (sach y)) dong hoa hoi. hieu va nam ((xuc va) OR (luc va)) hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach sy) or (sach y)) dong hoa hoi. hieu va nam ((xuc va) or (luc va)) hanh va cua tre*.