Perhaps you should try some spelling variations:
hieu cua » hieu qua, dieu cua, bieu cua
va nhanh » va thanh, va hanh, va nganh
tu sach » thu sach, su sach, te sach
cay cuu » cap cuu, cay chu, cham cuu
va nhan » van nhan, ca nhan, va phan
cac tuc » cac toc, cac tu, cac tac
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
cuu tre » cua tre, cau tren, cau treo

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

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