Perhaps you should try some spelling variations:
va khac » va khao, va kha, vu khac
thuc va » thuc vat, thuc dan, thuc day
cuu tre » cua tre, cau tren, cau treo
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
va hac » van hac, va cac, va hoc
dau vi » dau ve, dat vi, dau viet
dau va » dau ve, lau va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang x ho. hieu ((va hac) or (va khac)) thuc va ((dau vi) OR (dau va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang x ho. hieu ((va hac) OR (va khac)) thuc va ((dau vi) OR (dau va)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang x ho. hieu ((va hac) or (va khac)) thuc va ((dau vi) OR (dau va)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang x ho. hieu ((va hac) or (va khac)) thuc va ((dau vi) OR (dau va)) cuu tre*.