Perhaps you should try some spelling variations:
sach hoi » sach doi, sach moi, cach thoi
tap khoa » tap hoa, lap khoa, phap khoa
khoa hoc » hoa hoc
tinh van » trinh van, dinh van, tinh va
cuu mon » cuu mo, cuu mot, cuu cong
mon hoc » toan hoc, dong hoc
va tinh » may tinh
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 hoi) or (bach mai)) tap, nghien cuu mon hoc tap khoa hoc ma hoi va tinh van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach hoi) OR (bach mai)) tap, nghien cuu mon hoc tap khoa hoc ma hoi va tinh van.
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoi) or (bach mai)) tap, nghien cuu mon hoc tap khoa hoc ma hoi va tinh van*.