Perhaps you should try some spelling variations:
thanh dieu » thanh lieu, than dieu, hanh dieu
dan thanh » dang thanh, danh thanh, ban thanh
thuoc dan » thuoc dang, thuc dan, thuoc ban
nam thuoc » nam thuc, nam thu, nha thuoc
dieu tra » dieu tri, kiem tra, dieu cua
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
tra tre » tran tren, tran tri, tran tro
tang ho » tang cho, tung ho, tang ha
ky tang » ky nang, ky dang, kho tang
vu sach » vu bach, vu khach
su sach » so sach
ho hoi » hoc hoi, hoa hoi, hoi hoi

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) or (vu sach)))) ky tang ho hoi. hieu van nam thuoc dan thanh dieu tra tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (((su sach) OR (vu sach)))) ky tang ho hoi. hieu van nam thuoc dan thanh dieu tra tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (((su sach) or (vu sach)))) ky tang ho hoi. hieu van nam thuoc dan thanh dieu tra tre*.