Perhaps you should try some spelling variations:
hoc khanh » hoc nhanh, hoc thanh, hoc hanh
khanh hoa » thanh hoa, hang hoa
sach hoc » cach hoc, sach hoi, sach duoc
mach hoc » cach hoc, dich hoc, anh hoc
mai khoi » mai khoa, tai khoa, cac khoi
nhan tai » hang tai, van tai, toan tai
hoc mai » hoc ma, hoc dai, hoc bai
khoi va » hoi va, khi va, choi va
va nhan » van nhan, ca nhan, va phan
mo hoc » mon hoc, co hoc

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 mo hoc khanh hoa hoc mai khoi va nhan tai~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach hoc) OR (mach hoc)) tap, nghien cuu mo hoc khanh hoa hoc mai khoi va nhan tai".
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoc) OR (mach hoc)) tap, nghien cuu mo hoc khanh hoa hoc mai khoi va nhan tai*.