Perhaps you should try some spelling variations:
thien van » thi van
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
tuc van » thuc van, truc van, tuc va
cac tuc » cac toc, cac tu, cac tac
van cac » van hac, van cau, van bac
cuu tre » cua tre, cau tren, cau treo
ly vang » ly hang, ly quang
ly van » le van, ly va, ly von

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ly vang) or (ly van)) xa hoi. thien van cac tuc van hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ly vang) OR (ly van)) xa hoi. thien van cac tuc van hanh vi ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: su sach ((ly vang) or (ly van)) xa hoi. thien van cac tuc van hanh vi ((dua tren) or (cuu tre))*.