Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
hieu va » lieu va, hieu qua
va hanh » van hanh, va danh, ban hanh
cac suc » cao suc, cac nuoc, cac cuoc
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac suc ((va hanh) or (va thanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac suc ((va hanh) OR (va thanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac suc ((va hanh) or (va thanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac suc ((va hanh) or (va thanh)) di cua tre*.