Perhaps you should try some spelling variations:
toan khoan » toan khoa, toan phan, toan hoat
khoan dinh » khoan danh, phan dinh, hoang dinh
thanh phan » thanh pho, thanh san, thanh toan
ban thanh » ban hanh, ban hang
sach hoc » cach hoc, sach hoi, sach duoc
mach hoc » cach hoc, dich hoc, anh hoc
cuu toan » cuu hoan, cua toan, huu toan
dinh hoa » dinh khoa, minh hoa, tinh hoa
hoc bai » hoc dai, hoc giai
bai co » bai con, mai co, bai ca

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 hoc) or (mach hoc)) tap, nghien cuu toan khoan dinh hoa hoc bai co ban thanh phan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach hoc) OR (mach hoc)) tap, nghien cuu toan khoan dinh hoa hoc bai co ban thanh phan.
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoc) or (mach hoc)) tap, nghien cuu toan khoan dinh hoa hoc bai co ban thanh phan*.