Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
dau thuc » dan thuc, dai thuc, dam thuc
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
vu lang » va lang, vu dang, cu lang
va dau » va 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: ((toc sach) or (hoc sach)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) OR (di cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) OR (di cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) OR (di cua)) te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) vu lang xa hoi. hieu va dau thuc va hanh ((vi cua) OR (di cua)) te*.