Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hanh hai » thanh hai, nhanh hai, hang hai
nam thue » nam thu, nam thuc, lam thue
hiem he » hiem xe, thien he, hiem cho
hai cua » thai cua, dai cua, hoi cua
va hanh » van hanh, va thanh, va danh
thue va » thuc va, thuyet va, thuc vat
cua tre » cua te, cuu tre, cua triet
hieu he » hieu ve, hieu le, hieu hien
nang ma » tang ma, sang ma, nang cao
tu sach » su sach, te sach, tu cach
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: ((thu sach) or (tu sach)) y nang ma hoa. ((hieu he) or (hiem he)) nam thue va hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) y nang ma hoa. ((hieu he) OR (hiem he)) nam thue va hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) y nang ma hoa. ((hieu he) or (hiem he)) nam thue va hanh hai cua tre*.