Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, thanh san
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
sach ty » sach tu, sach thu, xach tay
cam lo » nam lo, cam ly, cam o
lo van » le van, vo van, so van
va cam » va cham, va cac, va cao

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 y) or (sach ty)) nang ma hoa. hieu va cam lo van ((thanh tai) OR (doanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach y) OR (sach ty)) nang ma hoa. hieu va cam lo van ((thanh tai) OR (doanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach y) or (sach ty)) nang ma hoa. hieu va cam lo van ((thanh tai) OR (doanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach y) or (sach ty)) nang ma hoa. hieu va cam lo van ((thanh tai) OR (doanh tai)) cua tre*.