Perhaps you should try some spelling variations:
hanh dieu » han dieu, hinh dieu, hoang dieu
khoc doi » khoa doi, khoe doi, cuoc doi
dieu tra » dieu tri, kiem tra, dieu cua
dao hanh » dao thanh, dang hanh, ban hanh
thuc dao » thuc dan, thuc day, chuc dao
nam thuc » nam thuoc, am thuc, nam thu
hieu ve » hieu va, hieu van
tu sach » thu sach, te sach, tu cach
hoc doi » hoc dai, hoc noi, hoc moi
ky tang » ky nang, ky dang, kho tang
su sach » so sach, vu sach
tra tre » tran tren, tran tri, tran tro
ve nam » he nam, va nam, le nam

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) or (su sach)) ky tang ((hoc doi) or (khoc doi)). hieu ve nam thuc dao hanh dieu tra tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky tang ((hoc doi) OR (khoc doi)). hieu ve nam thuc dao hanh dieu tra tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky tang ((hoc doi) or (khoc doi)). hieu ve nam thuc dao hanh dieu tra tre*.