Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
thuc van » thuc vat, thuc dan, thuc va
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
hieu ha » hieu hoa, hieu va, hieu ca
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky lang » ky dang, ky tang, tay lang
tu sach » thu sach, su sach, te sach

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 ((ky lang) OR (ky nang)) hoa hoi. hieu ha nam thuc van hanh vai ((cua triet) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky nang)) hoa hoi. hieu ha nam thuc van hanh vai ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) OR (ky nang)) hoa hoi. hieu ha nam thuc van hanh vai ((cua triet) or (va triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) OR (ky nang)) hoa hoi. hieu ha nam thuc van hanh vai ((cua triet) or (va triet))*.