Perhaps you should try some spelling variations:
phap thuc » phap thu, phap hoc, phap tu
toc sach » hoc sach, doc sach, thuoc sach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
va va » va van, va vai, va vat

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 ky lang xa hoi. ((hieu ve) or (hieu va)) phap thuc va danh ((va va) OR (va vua)) trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. ((hieu ve) OR (hieu va)) phap thuc va danh ((va va) OR (va vua)) trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang xa hoi. ((hieu ve) or (hieu va)) phap thuc va danh ((va va) OR (va vua)) trien".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. ((hieu ve) or (hieu va)) phap thuc va danh ((va va) OR (va vua)) trien*.