Perhaps you should try some spelling variations:
nang khoa » hang khoa, dang khoa, nang hoa
cua viet » ca viet, hoa viet, cua vat
thuc day » thuc dan, thuc vat
hang hai » hoang hai, hang tai, thanh hai
khoa hoi » khoan hoi, khoa hoc, khoa doi
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan
hai cua » thai cua, dai cua, hoi cua
ve nam » he nam, va nam, le nam
sac ky » sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sac ky) or (cac ky)) nang khoa hoi. hieu ve nam ((thuc va) or (thuc day)) hang hai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sac ky) OR (cac ky)) nang khoa hoi. hieu ve nam ((thuc va) OR (thuc day)) hang hai cua viet.
• Adding a wildcard symbol may retrieve word variants: te ((sac ky) or (cac ky)) nang khoa hoi. hieu ve nam ((thuc va) or (thuc day)) hang hai cua viet*.