Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
doc sach » hoc sach, toc sach, nuoc sach
dang van » hoang van
cam thuc » am thuc, nam thuc, cam thu
thuc van » thuc vat, thuc dan, thuc va
sach lo » sach dao, sach doi, sach hoi
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
vi cua » vai cua, di cua

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 lo ((dang van) or (hang va)) hoi. hieu ve cam thuc van thanh ((vi cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach lo ((dang van) OR (hang va)) hoi. hieu ve cam thuc van thanh ((vi cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: doc sach lo ((dang van) or (hang va)) hoi. hieu ve cam thuc van thanh ((vi cua) or (dai cua)) tre*.