Perhaps you should try some spelling variations:
va gianh » van giang, va giai, va thanh
te sach » toc sach
hieu ve » hieu va, hieu van
lai cua » dai cua, hai cua, lai chau
va gian » van gian, va giai, va gia
ve pham » vi pham, v pham, ve phan
sach ky » sac ky, sach y, sach ty
tay hoi » tao hoi, tay thai
ky bang » ky nang, ky dang, ke bang
tay ho » tay co, tay o, tay khao
cua te » cua tu

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 ky bang ((tay hoi) or (tay ho)). hieu ve pham duc ((va gianh) OR (va gian)) lai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky bang ((tay hoi) OR (tay ho)). hieu ve pham duc ((va gianh) OR (va gian)) lai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky bang ((tay hoi) or (tay ho)). hieu ve pham duc ((va gianh) OR (va gian)) lai cua te".
• Adding a wildcard symbol may retrieve word variants: te sach ky bang ((tay hoi) or (tay ho)). hieu ve pham duc ((va gianh) OR (va gian)) lai cua te*.