Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
thanh di » thanh doi, thanh de, thanh do
va thanh » gia thanh, ban thanh, va tinh
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
cau luc » cau truc, cau phuc
di cua » dai cua, doi cua, de cua
luc va » duc va, tuc va, loc va
cua te » cua tu
ma hoi » mai hoi, xa hoi, ma hoa
y nang » ky nang, ly nang, v nang

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