Perhaps you should try some spelling variations:
nang cai » nang cao, nang tai, nang cap
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hanh va » hang va, hanh vi
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
hieu vu » hieu va, hieu su, dieu vu
cai hoi » cau hoi, dai hoi, cai hoa
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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