Perhaps you should try some spelling variations:
mach hoc » cach hoc, dich hoc, anh hoc
cuu cong » cua cong, thu cong, cac cong
cong hoa » dong hoa, dong hoc, hang hoa
hoa toan » hoa tan, hop toan, hoa than
toan hoa » toan khoa, toan hoat, toan hoc
nhan tao » nhan tai, nhan dan
hoc dai » hoc dan
hoi dan » hoa dan, hoc dan, thoi dai
tim » time

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

• Performing a fuzzy search may retrieve terms with similar spellings: tim mach hoc tap, nghien cuu cong hoa toan hoa hoc dai ((hoi dan) or (hoi dap)) nhan tao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tim mach hoc tap, nghien cuu cong hoa toan hoa hoc dai ((hoi dan) OR (hoi dap)) nhan tao.
• Adding a wildcard symbol may retrieve word variants: tim mach hoc tap, nghien cuu cong hoa toan hoa hoc dai ((hoi dan) or (hoi dap)) nhan tao*.