Perhaps you should try some spelling variations:
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
thuc ca » thuc cua, thuc can, thuc cao
sach ty » sach y, sach tu, sach thu
qua nam » quan nam, cua nam, quang nam
lang xa » lang ha, lang van
ca dan » cac dan, ca dao
vi cua » vai cua
di cua » dai cua, doi cua, de 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 ty ((lang xa) or (dang xay)) hoi. hieu qua nam thuc ca dan ((vi cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (dang xay)) hoi. hieu qua nam thuc ca dan ((vi cua) OR (di cua)) tre.
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) or (dang xay)) hoi. hieu qua nam thuc ca dan ((vi cua) or (di cua)) tre*.