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 cuu » may ruou
va hanh » van hanh, va thanh, va danh
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
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: ((te sach) or (doc sach)) y nang ma hoi. hieu va ((cac duc) OR (cac dac)) va hanh may cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (doc sach)) y nang ma hoi. hieu va ((cac duc) OR (cac dac)) va hanh may cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (doc sach)) y nang ma hoi. hieu va ((cac duc) OR (cac dac)) va hanh may cuu tre*".