Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
van thanh » ban thanh, van tuan
sach hoc » cach hoc, mach hoc, sach duoc
sach hoi » sach doi, sach moi, cach thoi
khoa hoc » hoa hoc
cong so » cong san, cong hoa
so toan » so tan, so than, bao toan
hai van » thai van, ha van, hai tan
hoc xa » hoc ma
xa hai » xa thai, xua hai, xa hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc ((sach hoc) or (sach hoi)) tap, nghien thu cong so toan khoa hoc xa hai van thanh san~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sach hoc) OR (sach hoi)) tap, nghien thu cong so toan khoa hoc xa hai van thanh san.
• Adding a wildcard symbol may retrieve word variants: thuoc ((sach hoc) or (sach hoi)) tap, nghien thu cong so toan khoa hoc xa hai van thanh san*.