Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh gia » danh gia, thanh gian, hinh giao
van hanh » van thanh, ban hanh, van anh
phan duc » pham duc, phan tu, phan dau
tang van » dang van, hoang van, trong van
gia cua » gian cua, giau cua, gia cuc
duc van » duc va, duc tan, duc manh
ve phan » va phan, ke phan, ve phat
hieu ve » hieu va, hieu van
tang ma » mang may
cua tre » cua te, cuu tre, cua triet

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) or (toc sach)) ky ((tang ma) OR (tang van)) hoi. hieu ve phan duc van hanh gia cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky ((tang ma) OR (tang van)) hoi. hieu ve phan duc van hanh gia cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky ((tang ma) OR (tang van)) hoi. hieu ve phan duc van hanh gia cua tre*".