Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
dieu tra » dieu tri, dieu cua
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, te sach, tu cach
hieu he » hieu ve, hiem he, hieu le
dang ha » dong ha, dung ha, lang ha
ky dang » ky nang, ky danh
su sach » so sach, vu sach
ha hoi » hoa hoi, ha noi, xa hoi
he nam » ha nam, nghe 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 dang ha hoi. hieu he nam thuc day thanh ((dieu tra) or (kiem tra)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky dang ha hoi. hieu he nam thuc day thanh ((dieu tra) OR (kiem tra)) tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky dang ha hoi. hieu he nam thuc day thanh ((dieu tra) or (kiem tra)) tre*.