Perhaps you should try some spelling variations:
dong hoa » dong hoc, dong co
vu sach » vu bach, vu khach
va hanh » van hanh, va thanh, va danh
cac tac » cac toc, cac bac, cac dac
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu va » lieu va, hieu qua
ky dong » ly dong, ky dang, ky cong
su sach » so sach
cua tre » cua te, cuu tre, cua triet
cac tu » cac thu, cach tu, cac du
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) or (su sach)) ky dong hoa hoi. hieu va ((cac tu) or (cac tac)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (su sach)) ky dong hoa hoi. hieu va ((cac tu) OR (cac tac)) va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (su sach)) ky dong hoa hoi. hieu va ((cac tu) or (cac tac)) va hanh vi cua tre*.