Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
thu sach » thuat sach, thuoc sach, thu hoach
va thanh » gia thanh, ban thanh, va tinh
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
tu sach » su sach, te sach, tu cach
ma hoi » mai hoi, xa hoi, ma hoa
cam lo » nam lo, cam ly, cam o
cam ky » cao ky, cac ky
y tang » ky tang, 6 tang, 7 tang

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 tang ma hoi. hieu va ((cam lo) or (cam ky)) va thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) y tang ma hoi. hieu va ((cam lo) OR (cam ky)) va thanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) y tang ma hoi. hieu va ((cam lo) or (cam ky)) va thanh vai cua tre*.