Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
sai cua » dai cua, hai cua, lai cua
dan sai » danh sai, doan sai, dan tai
thuc va » thuc vat, thuc dan, thuc day
lang xa » lang ha, dang xay, lang van
bang xa » bang va, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet
van am » van nam, van lam, van dam
va dan » ca dan, va dao, va dau

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 (thuat sach)) thu ((bang xa) or (lang xa)) hoi. hieu van am thuc va dan sai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) thu ((bang xa) OR (lang xa)) hoi. hieu van am thuc va dan sai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuat sach)) thu ((bang xa) or (lang xa)) hoi. hieu van am thuc va dan sai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuat sach)) thu ((bang xa) or (lang xa)) hoi. hieu van am thuc va dan sai cua tre*.