Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
cach hoc » cach thuc, dich hoc, cac hop
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
anh tay » canh tay, anh ta, anh hay
tay hoi » tay ho, tao hoi, tay thai
va dinh » van dinh, va kinh, va tinh
vi cua » vai cua, di cua
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
ky anh » ky danh, ly anh, ty anh

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky anh tay hoi. lieu va ((cach hoc) OR (cach thoi)) ((va hanh) or (va dinh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky anh tay hoi. lieu va ((cach hoc) OR (cach thoi)) ((va hanh) OR (va dinh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky anh tay hoi. lieu va ((cach hoc) OR (cach thoi)) ((va hanh) or (va dinh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky anh tay hoi. lieu va ((cach hoc) OR (cach thoi)) ((va hanh) or (va dinh)) vi cua tre*.