Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
van thanh » ban thanh, van tuan
sach doi » sach hoi, sach moi, sach dao
cong hoc » dong hoc, cong hoa, cong coc
hoc danh » hoc dan, hoc anh, hoc hanh
hoan hoc » toan hoc, hoang hoa, khoan hoi
so sach » so sanh, bo sach, co sach
doi tai » hoi tai, dai tai, doi tac
hai van » thai van, ha van, hai tan
ma hai » ta hai, va hai, xa hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach doi tai, nghien cua cong hoc danh ((hoan hoc) or (hoa hoc)) ma hai van thanh san~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach doi tai, nghien cua cong hoc danh ((hoan hoc) OR (hoa hoc)) ma hai van thanh san.
• Adding a wildcard symbol may retrieve word variants: so sach doi tai, nghien cua cong hoc danh ((hoan hoc) or (hoa hoc)) ma hai van thanh san*.