Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
nam thuc » nam thuoc, am thuc, nam thu
hieu ve » hieu va, hieu van
sach ly » sach y, sach lo, sach ty
cao hoi » cau hoi, cao hoc, tao hoi
ly nang » ky nang, ly hang, ly vang
hai cau » hai chau, hai hau, hoi cau
hai chu » hai chau, hoi chu, hai chi
su sach » so sach, vu sach
co hoi » co hoc, co loi
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: su sach ly nang ((cao hoi) or (co hoi)). hieu ve nam thuc van hanh ((hai cau) or (hai chu)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ((cao hoi) OR (co hoi)). hieu ve nam thuc van hanh ((hai cau) OR (hai chu)) treo.
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((cao hoi) or (co hoi)). hieu ve nam thuc van hanh ((hai cau) or (hai chu)) treo*.