Perhaps you should try some spelling variations:
phap thuc » phap thu, phap hoc, phap tu
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
xay hoi » xa hoi, tay hoi, cay phoi
hieu ve » hieu van
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
hieu va » lieu va, hieu qua
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 dang xay 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 dang xay 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 dang xay hoi. ((hieu ve) or (hieu va)) phap thuc va danh ((va va) or (va vua)) trien*.