Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hanh may » hanh ma, hanh mau, hanh ngay
te sach » toc sach
may cua » day cua, may bua, may sua
va hanh » van hanh, va thanh, va danh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
v nang » va nang, vu nang, van nang
y nang » ky nang, ly nang, may nang

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 (doc sach)) ((y nang) OR (v nang)) ma hoi. hieu va cac duc va hanh may cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (doc sach)) ((y nang) OR (v nang)) ma hoi. hieu va cac duc va hanh may cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (doc sach)) ((y nang) OR (v nang)) ma hoi. hieu va cac duc va hanh may cua tre*".