Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
he trung » le trung, he thong, do trung
trung va » truong va, trang va, trung ha
tinh dai » trinh dai, tinh da, tinh hai
mai hoi » mai khoi, dai hoi, lai hoi
va tinh » may tinh
y nang » ky nang, ly nang, v nang
me hoi » le hoi
qua he » quan he, cua he, mua he
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: toc sach y nang ((me hoi) or (mai hoi)). hieu qua he trung va tinh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((me hoi) OR (mai hoi)). hieu qua he trung va tinh dai cua te.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((me hoi) or (mai hoi)). hieu qua he trung va tinh dai cua te*.