Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc dao » thuc dan, thuc day, chuc dao
cau tren » cu tren, dau tren, ca tren
lang ha » long ha
sach ty » sach y, sach tu, sach thu
lang xa » dang xay, lang van
dao dan » dao van, cao dang, dao dong
dan vat » dang vat, van vat, dan va
vat cau » dat cau, va cau, van cau
va nam » ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty ((lang xa) or (lang ha)) hoi. hieu ((va nam) or (van nam)) thuc dao dan vat cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((lang xa) OR (lang ha)) hoi. hieu ((va nam) OR (van nam)) thuc dao dan vat cau tren.
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((lang xa) or (lang ha)) hoi. hieu ((va nam) or (van nam)) thuc dao dan vat cau tren*.