Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
tu sach » thu sach, te sach, tu cach
tai cua » thai cua, tai cuc, tri cua
hieu vu » hieu va, hieu ve, hieu su
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
ma hoi » mai hoi, xa hoi, ma hoa
lao va » tao va, cao va, bao va
y nang » ky nang, ly nang, v nang
vu nam » su nam, tu nam, va nam
lo va » lo van, ly va, le va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (su sach)) y nang ma hoi. hieu vu nam ((lo va) OR (lao va)) thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang ma hoi. hieu vu nam ((lo va) OR (lao va)) thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) y nang ma hoi. hieu vu nam ((lo va) OR (lao va)) thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) y nang ma hoi. hieu vu nam ((lo va) OR (lao va)) thanh tai cua tre*.