Perhaps you should try some spelling variations:
mach hoc » cach hoc, dich hoc, anh hoc
cuu dong » cuu cong, cuu tong, cuu long
dong hoc » dong co, dong luc
hoc hang » hoc hanh, hoc bang, hoc tang
hoc benh » soc benh, hoc kinh, so benh
nhan tao » nhan tai, nhan dan
tu mach » tu cach, tu manh, tu hach
xa hoc » xa hoi, va hoc, xa hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu mach hoc tap, nghien cuu dong hoc hang ((khoa hoc) or (hoa hoc)) xa hoc benh nhan tao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu mach hoc tap, nghien cuu dong hoc hang ((khoa hoc) OR (hoa hoc)) xa hoc benh nhan tao.
• Adding a wildcard symbol may retrieve word variants: tu mach hoc tap, nghien cuu dong hoc hang ((khoa hoc) or (hoa hoc)) xa hoc benh nhan tao*.