Perhaps you should try some spelling variations:
cach hoc » cach thuc, cach thoi, dich hoc
tay thai » lay thai, toc thai, y thai
ky dang » ky nang, ky danh
va hanh » van hanh, va thanh, va danh
va cach » va cac
hieu va » lieu va, hieu qua
tay hoi » tay ho, tao hoi
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
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: tu cac ky dang ((tay hoi) or (tay thai)). hieu va cach hoc ((va hanh) or (va dan)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky dang ((tay hoi) OR (tay thai)). hieu va cach hoc ((va hanh) OR (va dan)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu cac ky dang ((tay hoi) or (tay thai)). hieu va cach hoc ((va hanh) or (va dan)) vi cua tre*.