Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
nganh khoa » nganh hoa, nganh khong, doanh khoa
hoc nganh » hoc nhanh
sach hoc » cach hoc, sach hoi, mach hoc
cac cong » cua cong
cong hoc » dong hoc, cong hoa, cong coc
khoa hoc » hoa hoc
va thanh » ban thanh, va tinh, le thanh
su sach » so sach, vu sach
hoc mai » hoc ma, hoc dai, hoc bai
mai hoi » mai khoi, dai hoi, lai hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach hoc tap, nghien cac cong hoc nganh khoa hoc mai hoi ((va thanh) or (gia thanh)) toan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach hoc tap, nghien cac cong hoc nganh khoa hoc mai hoi ((va thanh) OR (gia thanh)) toan.
• Adding a wildcard symbol may retrieve word variants: su sach hoc tap, nghien cac cong hoc nganh khoa hoc mai hoi ((va thanh) or (gia thanh)) toan*.