Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
coc doanh » hoa doanh, cho doanh, voi doanh
cac doanh » cac dan, cac dang, van doanh
sach doi » sach hoi, sach moi, sach dao
phan van » pham van, thanh van, luan van
tu sach » thu sach, su sach, te sach
doi dap » hoi dap, doi dau, do dap
va phan » van phan, va phat, va phap
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach doi dap, nghien cua cong ((coc doanh) or (cac doanh)) hoa hoc xa hoi va phan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi dap, nghien cua cong ((coc doanh) OR (cac doanh)) hoa hoc xa hoi va phan van.
• Adding a wildcard symbol may retrieve word variants: tu sach doi dap, nghien cua cong ((coc doanh) or (cac doanh)) hoa hoc xa hoi va phan van*.