Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
va thanh » gia thanh, ban thanh, va tinh
va hanh » van hanh, va danh, ban hanh
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
so sanh » do sanh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
v nang » va nang, vu nang, van nang
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: ((su sach) or (so sanh)) v nang ma hoi. lieu va cac thuc ((va hanh) OR (va thanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sanh)) v nang ma hoi. lieu va cac thuc ((va hanh) OR (va thanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sanh)) v nang ma hoi. lieu va cac thuc ((va hanh) OR (va thanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) v nang ma hoi. lieu va cac thuc ((va hanh) OR (va thanh)) vi cua tre*.