Perhaps you should try some spelling variations:
nganh nong » nganh cong
van thanh » ban thanh, van tuan
thanh van » thanh san, thanh toan, thanh phan
mach hoc » cach hoc, dich hoc, anh hoc
nong hoc » dong hoc, nang hoc, nong thon
tu mach » tu cach, tu manh, tu hach
tin hoc » sinh hoc
hoc mai » hoc ma, hoc dai, hoc bai
mai hoa » mai khoa, ma hoa, dai hoa
hoa van » hoa dan, hoang van, hoa phan

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 ((tin hoc) or (hoa hoc)) nganh nong hoc mai hoa van thanh van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu mach hoc tap, nghien cuu ((tin hoc) OR (hoa hoc)) nganh nong hoc mai hoa van thanh van.
• Adding a wildcard symbol may retrieve word variants: tu mach hoc tap, nghien cuu ((tin hoc) or (hoa hoc)) nganh nong hoc mai hoa van thanh van*.