Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thuc day » thuc dan
dinh dai » dinh dat, sinh dai, dinh dao
nang co » nang cao, nang doc, nang noi
su tien » su kien, su hien, tu tieng
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
co hoi » co hoc, co loi
dai su » dai sua, dai so, dan su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang co hoi. hieu van nam ((thuc day) or (thuc vat)) dinh dai su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang co hoi. hieu van nam ((thuc day) OR (thuc vat)) dinh dai su tien.
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang co hoi. hieu van nam ((thuc day) or (thuc vat)) dinh dai su tien*.