Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
sach thi » sach thu, sach tai, sach thieu
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
sach bai » sach dao, cac bai, sach xa
va trien » va truyen, va thiet, va tuyen
hanh ca » hanh cac, hanh cat, hanh cua
cac toc » cac toi, cac thoi
xa vanh » xa vinh, xa van, xa thanh
ca hoi » cau hoi, cua hoi, xa hoi
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach thi) or (sach bai)) hanh ca hoi. hieu qua ((cac nuoc) or (cac toc)) xa vanh dai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach thi) OR (sach bai)) hanh ca hoi. hieu qua ((cac nuoc) OR (cac toc)) xa vanh dai va trien.
• Adding a wildcard symbol may retrieve word variants: toc ((sach thi) or (sach bai)) hanh ca hoi. hieu qua ((cac nuoc) or (cac toc)) xa vanh dai va trien*.