Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
doanh khoa » toan khoa
hoc doanh » hoa doanh, hoc danh, hoc dan
sach hoc » cach hoc, mach hoc, sach duoc
sach hoi » sach doi, sach moi, cach thoi
cong hoc » dong hoc, cong hoa, cong coc
khoa hoc » hoa hoc
hop benh » hoc benh, hap benh, hoa benh
nhan tao » nhan tai, nhan dan
ma hop » mau hop, ma hoa, va hop

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 hoc) or (sach hoi)) tap, nghien thu cong hoc doanh khoa hoc ma hop benh nhan tao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach hoc) OR (sach hoi)) tap, nghien thu cong hoc doanh khoa hoc ma hop benh nhan tao.
• Adding a wildcard symbol may retrieve word variants: so ((sach hoc) or (sach hoi)) tap, nghien thu cong hoc doanh khoa hoc ma hop benh nhan tao*.