Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dau thuc » dan thuc, dai thuc, dam thuc
vu lang » va lang, vu dang, cu lang
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
va dau » va dao
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: ((toc sach) or (hoc sinh)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) or (dai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sinh)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) OR (dai cua)) te.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sinh)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) or (dai cua)) te*.