Perhaps you should try some spelling variations:
sach hoi » sach doi, cach thoi, hoach hoi
sach moi » sach doi, bach mai, sach bai
tinh van » trinh van, dinh van, tinh va
cuu mon » cuu mo, cuu mot, cuu cong
mon hoc » toan hoc, dong hoc
tap hoa » tap hop, tap doan, tap toan
va tinh » may tinh
hoc xa » hoc ma

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 hoi) or (sach moi)) tap, nghien cuu mon hoc tap hoa hoc xa hoi va tinh van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach hoi) OR (sach moi)) tap, nghien cuu mon hoc tap hoa hoc xa hoi va tinh van.
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoi) or (sach moi)) tap, nghien cuu mon hoc tap hoa hoc xa hoi va tinh van*.