Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
thu sach » tu sach, thuat sach, thuoc sach
nang doc » nang luc
nang du » nang tu, nang luc
thuc va » thuc vat, thuc dan, thuc day
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
ky hang » ky nang, ly hang, ky dang
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
va hoi » xa hoi, va hoc, va hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (su sach)) ky hang va hoi. hieu ve cham thuc va ((nang du) OR (nang doc)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (su sach)) ky hang va hoi. hieu ve cham thuc va ((nang du) OR (nang doc)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (su sach)) ky hang va hoi. hieu ve cham thuc va ((nang du) OR (nang doc)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (su sach)) ky hang va hoi. hieu ve cham thuc va ((nang du) OR (nang doc)) cua tre*.