Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
doc sach » hoc sach, toc sach, nuoc sach
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
va nam » van nam, ha nam, va nay
va dao » ca dao
va dan » ca dan, va dau, va dap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty lang xa hoi. hieu va nam thuoc ((va dan) OR (va dao)) vai ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty lang xa hoi. hieu va nam thuoc ((va dan) OR (va dao)) vai ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty lang xa hoi. hieu va nam thuoc ((va dan) OR (va dao)) vai ((cau tren) or (dau tren))".
• Adding a wildcard symbol may retrieve word variants: doc sach ty lang xa hoi. hieu va nam thuoc ((va dan) OR (va dao)) vai ((cau tren) or (dau tren))*.