Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
va thanh » gia thanh, ban thanh, va tinh
ly quang » le quang, vu quang
hieu van » hieu va, thien van, lieu va
co sach » bo sach, cuon sach, hoc sach
cac toc » cac toi, cac nuoc, cac thoi
tai duc » tai cuc, mai duc, tai du
cac tuc » cac tu, cac tac, cac nuoc
duc tre » duoc tren, duc tien

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ((ly hang) or (ly quang)) xa hoi. hieu van ((cac tuc) OR (cac toc)) va thanh tai duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ((ly hang) OR (ly quang)) xa hoi. hieu van ((cac tuc) OR (cac toc)) va thanh tai duc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ((ly hang) or (ly quang)) xa hoi. hieu van ((cac tuc) OR (cac toc)) va thanh tai duc tre".
• Adding a wildcard symbol may retrieve word variants: co sach ((ly hang) or (ly quang)) xa hoi. hieu van ((cac tuc) OR (cac toc)) va thanh tai duc tre*.