Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
vat hanh » vat thanh, van hanh, va hanh
cam thuc » am thuc, nam thuc, cam thu
hanh va » hang va, hanh vi
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
nang co » nang doc, nang noi, nang hoc
te sach » toc sach
va cam » va cham, va cac, va cao
va va » va van, va vua, va vai

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) or (te sach)) ky ((nang co) OR (nang cao)) hoi. hieu va cam thuc vat hanh va va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (te sach)) ky ((nang co) OR (nang cao)) hoi. hieu va cam thuc vat hanh va va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (te sach)) ky ((nang co) OR (nang cao)) hoi. hieu va cam thuc vat hanh va va triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (te sach)) ky ((nang co) OR (nang cao)) hoi. hieu va cam thuc vat hanh va va triet*.