Perhaps you should try some spelling variations:
ngoc khanh » ngoc anh
hoc nhanh » hoc nganh, hoc phan
chong hoc » chung hoc, chong doc, thong hoc
sach hoc » cach hoc, sach hoi, mach hoc
cac nhan » ca nhan, cac nha, cam nhan
nhan tai » hang tai, van tai, toan tai
tu sach » thu sach, su sach, te sach
hoi cac » hoc cac, voi cac, hoa cac
ma hoi » mai hoi, xa hoi, ma 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 sach hoc tap, nghien cuu mo ((hoc nhanh) or (ngoc khanh)) chong hoc ma hoi cac nhan tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien cuu mo ((hoc nhanh) OR (ngoc khanh)) chong hoc ma hoi cac nhan tai.
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cuu mo ((hoc nhanh) or (ngoc khanh)) chong hoc ma hoi cac nhan tai*.