Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
thanh tri » thanh tra, chinh tri, thanh hai
thu sach » tu sach, thuat sach, thuoc sach
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
tang ma » mang may, tang van
cuu tre » cua tre, cau tren, cau treo

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 ty ((tang ma) or (lang xa)) hoi. hieu va cac duc va ((thanh tri) OR (thanh tai)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((tang ma) OR (lang xa)) hoi. hieu va cac duc va ((thanh tri) OR (thanh tai)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty ((tang ma) or (lang xa)) hoi. hieu va cac duc va ((thanh tri) OR (thanh tai)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((tang ma) or (lang xa)) hoi. hieu va cac duc va ((thanh tri) OR (thanh tai)) cuu tre*.