Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
thanh tai » thanh hai, thanh toan, doanh tai
dang mam » dang nam, dang mau, dang mat
cua tre » cua te, cuu tre, cua triet
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
dang ma » dang mau, dang mat, tang ma
ve cac » va cac, vien cac
dao ky » cao ky, dan ky, do ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc dao ky ((dang ma) or (dang mam)) hoi. hieu ve cac duc va ((thanh van) or (thanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc dao ky ((dang ma) OR (dang mam)) hoi. hieu ve cac duc va ((thanh van) OR (thanh tai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc dao ky ((dang ma) or (dang mam)) hoi. hieu ve cac duc va ((thanh van) or (thanh tai)) cua tre*.