Perhaps you should try some spelling variations:
sach hoc » cach hoc, sach hoi, mach hoc
nha dong » nhan dong, nha dung, nhanh dong
tu sach » thu sach, su sach, te sach
cuu mon » cuu mo, cuu mot, cuu cong
mon hoc » toan hoc, dong hoc
ha dong » hoat dong, van dong
vo pham » vi pham, v pham, toi pham
luc ma » luc va, luc ha, suc ma
hoa vo » hoa co

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien cuu mon hoc ((nha dong) OR (ha dong)) luc ma hoa vo pham van~.
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cuu mon hoc ((nha dong) or (ha dong)) luc ma hoa vo pham van*.